Homebrew_PCBs

Just been looking on flea bay and came across these

36W Nail UV Lamp Acrylic Gel Curing Light

has anyone had any experience with these unit for producing pcbs - seem quite cheap might be worth a llok
Dave

Somebody told, some time ago, it was perfect for small pcbs.


El s�bado, 5 de enero de 2013, dave_donlan <dhd01@...> escribi�:

>
>
> Just been looking on flea bay and came across these
>
> 36W Nail UV Lamp Acrylic Gel Curing Light
>
> has anyone had any experience with these unit for producing pcbs - seem

quite cheap might be worth a llok

> Dave
>
>

[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "dave_donlan" wrote:

>
> Just been looking on flea bay and came across these
>
> 36W Nail UV Lamp Acrylic Gel Curing Light
>
> has anyone had any experience with these unit for producing pcbs - seem quite cheap might be worth a llok
> Dave
>

I ordered on a while back to make an expousure box. The one I go has 4 U shaped 8W tubes (36W total). As is, it would do a 4x4 board. I figured I wanted a little larger unit so the plan was to go with more tubes in a DIY box. Also wanted the ability to do both sides of the board at once.

The replacement 8W bulbs are quite inexpensive, so I will just buy more bulbs. No need for bulb sockets, just RTV the bulbs in place and solder directly to the pins. The real issue is where to get low cost ballasts. The nail unit I got had one ckt board that powered 4 bulbs, best I could tell there was one main line chopper and 4 bulb current limiting inductors. If you don't want to roll your own ballast just hack some from old CFL cork screw bulbs -- they work fine. FYI inside the blastic base of the bulb each end of the tube has two filiment wires. One wire from each filiment is connected to the pin on the base of the bulb. The ohter filiment pins are joined together with a series capacitor. Thus the bulbs will appear open to dc and an ohm meter.

Craig

Thanks for the replies guy very helpful

Guess what i am going to get next
Cheers

--- In Homebrew_PCBs@yahoogroups.com, "designer_craig" wrote:
>
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "dave_donlan" wrote:
> >
> > Just been looking on flea bay and came across these
> >
> > 36W Nail UV Lamp Acrylic Gel Curing Light
> >
> > has anyone had any experience with these unit for producing pcbs - seem quite cheap might be worth a llok
> > Dave
> >
> I ordered on a while back to make an expousure box. The one I go has 4 U shaped 8W tubes (36W total). As is, it would do a 4x4 board. I figured I wanted a little larger unit so the plan was to go with more tubes in a DIY box. Also wanted the ability to do both sides of the board at once.
>
> The replacement 8W bulbs are quite inexpensive, so I will just buy more bulbs. No need for bulb sockets, just RTV the bulbs in place and solder directly to the pins. The real issue is where to get low cost ballasts. The nail unit I got had one ckt board that powered 4 bulbs, best I could tell there was one main line chopper and 4 bulb current limiting inductors. If you don't want to roll your own ballast just hack some from old CFL cork screw bulbs -- they work fine. FYI inside the blastic base of the bulb each end of the tube has two filiment wires. One wire from each filiment is connected to the pin on the base of the bulb. The ohter filiment pins are joined together with a series capacitor. Thus the bulbs will appear open to dc and an ohm meter.
>
> Craig
>

Hi Vicent,

Some of the eBay ads which can be found by searching for:

36W Nail UV Lamp Acrylic Gel Curing Light

show that they contain four long U-shaped fluorescent lamps. This ad:

http://www.ebay.com/itm/310556445104

shows one of these types of lamp - and they have "365nm" written on
them, which is most helpful! The Riston General Processing Guide at:


http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.html

indicates peak sensitivity is in the 350-380 nm near-UV range, with some
sensitivity from 300nm (UV) to 450nm (blue).

I am not sure what wavelengths other photoresists are most sensitive to,
such as positive photoresists.

I think it is much better to have a relatively compact source of light
than something broad like these.

In some previous messages to this list, such as message 30440, I
described using a 500 watt linear halogen incandescent lamp with
reflector - a cheap hardware-store "floodlamp". Such lamps put out
enough near-UV to give me a sun-tan when I extensively used an old
process camera which had four of these lamps. Glass would reduce the
tanning/burning shorter wavelength UV rays to some extent but I think
would hardly affect the transmission of the 350-380nm light of interest.

The 500 watt lamp radiates most of its energy in the visible and
infra-red (with some being lost as hot air), and only a fraction of it
is the light we are interested in. I couldn't find a suitable source of
dark-violet-looking "Woods glass" to make a filter which would reject
most of the visible and IR I don't want. This visible and IR energy is
substantial and will warm the board, which might cause differential
expansion of the phototool and board. However, this can be largely
solved by blowing a fan on the board, with its phototool and glass or
other surface which clamps the phototool to the board.

This way, most of the light comes from an area about 10cm wide and 45cm
away from the board. These rays of light are relatively parallel, so
the shadow from the phototool remains relatively sharp even if the
phototool is not completely flat against the photoresist.

With a broader source of light, as would inevitably be the case with
these less intense, larger, fluorescent lamps, the shadow would be much
less sharp.

It is difficult to get the phototool sitting flat against the PCB. The
PCB is reasonably rigid and is not necessarily flat. If the top cover
is glass or acrylic, then any dust or mismatch between the flatness of
the glass and the PCB will cause a gap and loss of sharpness.

It would also be possible to use a vacuum frame with a soft, flexible,
top surface, such as clear PVC sheet (retailed at fabric and other shops
as a table covering), which would press the phototool close to the PCB
even if the PCB was not completely flat. This would also largely avoid
problems caused by dust, since it would tend to stretch the phototool
over the dust particle and so press it close even one or two mm away
from the particle, whereas with the glass or acrylic approach, the dust
particle would lift the phototool and glass off the board for a larger
surrounding area.

Another likely problem with fluorescent lamps of all types is that their
output would vary considerably with how long they have been on for,
which would be affected by their starting temperature and therefore how
long they had been on for in the last 30 minutes or so. This would make
it difficult to run them from a timer. This might be OK if you ran them
all the time and had a way of simply placing them over the PCB with
phototool etc. However, I prefer to place the phototool and my existing
glass sheet arrangement together by a safelight (a bunch of red LEDs)
and place it under the lamp, before turning the lamp on for a fixed
time. The 500W incandescent lamp would have its near-UV output affected
somewhat by mains voltage fluctuations, but I doubt if this is a
significant problem.

- Robin http://www.firstpr.com.au/pcb-diy/

I experimented with a ziplock bag and a vacuum pump. The transparency is
held to the board very very well. Much better than glass can ever do.
However, I found a drawback and that is the plastic forms imperfections and
scratches from fingernails, stretching and pulling to get wrinkles out
during vacuum, and around the transparency and copper clad edges.



I question, as I have not tested, if these imperfections can cause diffusion
of the light as it passes through and decrease results especially if the
imperfections are over a thin trace or spacing between traces. I tried
blanket storage bags, same problem. My conclusion is that very thin glass
like microscope cover slide glass is the ideal material because it is thin
enough to deform over the copper clad. I searched for glass as thin as
cover slide glass but I could not find a place who sells it. Maybe
something better than ziplock bag plastic can be used too that I am not
aware of.



Jeff



_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Robin Whittle
Sent: Sunday, January 06, 2013 9:17 PM
To: Homebrew_PCBs@yahoogroups.com
Cc: Vicent Colomar Prats
Subject: Re: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
phototool-PCB contact closeness, 500W floodlamp





Hi Vicent,

Some of the eBay ads which can be found by searching for:

36W Nail UV Lamp Acrylic Gel Curing Light

show that they contain four long U-shaped fluorescent lamps. This ad:

http://www.ebay.com/itm/310556445104

shows one of these types of lamp - and they have "365nm" written on
them, which is most helpful! The Riston General Processing Guide at:

http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.ht
ml

indicates peak sensitivity is in the 350-380 nm near-UV range, with some
sensitivity from 300nm (UV) to 450nm (blue).

I am not sure what wavelengths other photoresists are most sensitive to,
such as positive photoresists.

I think it is much better to have a relatively compact source of light
than something broad like these.

In some previous messages to this list, such as message 30440, I
described using a 500 watt linear halogen incandescent lamp with
reflector - a cheap hardware-store "floodlamp". Such lamps put out
enough near-UV to give me a sun-tan when I extensively used an old
process camera which had four of these lamps. Glass would reduce the
tanning/burning shorter wavelength UV rays to some extent but I think
would hardly affect the transmission of the 350-380nm light of interest.

The 500 watt lamp radiates most of its energy in the visible and
infra-red (with some being lost as hot air), and only a fraction of it
is the light we are interested in. I couldn't find a suitable source of
dark-violet-looking "Woods glass" to make a filter which would reject
most of the visible and IR I don't want. This visible and IR energy is
substantial and will warm the board, which might cause differential
expansion of the phototool and board. However, this can be largely
solved by blowing a fan on the board, with its phototool and glass or
other surface which clamps the phototool to the board.

This way, most of the light comes from an area about 10cm wide and 45cm
away from the board. These rays of light are relatively parallel, so
the shadow from the phototool remains relatively sharp even if the
phototool is not completely flat against the photoresist.

With a broader source of light, as would inevitably be the case with
these less intense, larger, fluorescent lamps, the shadow would be much
less sharp.

It is difficult to get the phototool sitting flat against the PCB. The
PCB is reasonably rigid and is not necessarily flat. If the top cover
is glass or acrylic, then any dust or mismatch between the flatness of
the glass and the PCB will cause a gap and loss of sharpness.

It would also be possible to use a vacuum frame with a soft, flexible,
top surface, such as clear PVC sheet (retailed at fabric and other shops
as a table covering), which would press the phototool close to the PCB
even if the PCB was not completely flat. This would also largely avoid
problems caused by dust, since it would tend to stretch the phototool
over the dust particle and so press it close even one or two mm away
from the particle, whereas with the glass or acrylic approach, the dust
particle would lift the phototool and glass off the board for a larger
surrounding area.

Another likely problem with fluorescent lamps of all types is that their
output would vary considerably with how long they have been on for,
which would be affected by their starting temperature and therefore how
long they had been on for in the last 30 minutes or so. This would make
it difficult to run them from a timer. This might be OK if you ran them
all the time and had a way of simply placing them over the PCB with
phototool etc. However, I prefer to place the phototool and my existing
glass sheet arrangement together by a safelight (a bunch of red LEDs)
and place it under the lamp, before turning the lamp on for a fixed
time. The 500W incandescent lamp would have its near-UV output affected
somewhat by mains voltage fluctuations, but I doubt if this is a
significant problem.

- Robin http://www.firstpr.com.au/pcb-diy/





[Non-text portions of this message have been removed]

Use thicker glass and let the PCB deform to lay flat against it. The force
of the vacuum (air-pressure) is very large over the big area of the PCB.

Bertho



From: Jeff Heiss Sent: Monday, January 07, 2013 01:46



I experimented with a ziplock bag and a vacuum pump. The transparency is
held to the board very very well. Much better than glass can ever do.
However, I found a drawback and that is the plastic forms imperfections and
scratches from fingernails, stretching and pulling to get wrinkles out
during vacuum, and around the transparency and copper clad edges.

I question, as I have not tested, if these imperfections can cause diffusion
of the light as it passes through and decrease results especially if the
imperfections are over a thin trace or spacing between traces. I tried
blanket storage bags, same problem. My conclusion is that very thin glass
like microscope cover slide glass is the ideal material because it is thin
enough to deform over the copper clad. I searched for glass as thin as
cover slide glass but I could not find a place who sells it. Maybe
something better than ziplock bag plastic can be used too that I am not
aware of.

Jeff





[Non-text portions of this message have been removed]

What are thoughts on exposure time vs. resolution? Pretend a 100w bulb gives a 10 minute exposure and a 200w bulb gives a 5 minute exposure. Is either better, worse, the same?

Jeff


-----Original Message-----
From: Boman33 <boman33@...>
Sent: Monday, January 07, 2013 2:41 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: RE: [Homebrew_PCBs] UV nail lamps - sharpness of shadow, phototool-PCB contact closeness, 500W floodlamp


Use thicker glass and let the PCB deform to lay flat against it. The force
of the vacuum (air-pressure) is very large over the big area of the PCB.

Bertho

From: Jeff Heiss Sent: Monday, January 07, 2013 01:46

I experimented with a ziplock bag and a vacuum pump. The transparency is
held to the board very very well. Much better than glass can ever do.
However, I found a drawback and that is the plastic forms imperfections and
scratches from fingernails, stretching and pulling to get wrinkles out
during vacuum, and around the transparency and copper clad edges.

I question, as I have not tested, if these imperfections can cause diffusion
of the light as it passes through and decrease results especially if the
imperfections are over a thin trace or spacing between traces. I tried
blanket storage bags, same problem. My conclusion is that very thin glass
like microscope cover slide glass is the ideal material because it is thin
enough to deform over the copper clad. I searched for glass as thin as
cover slide glass but I could not find a place who sells it. Maybe
something better than ziplock bag plastic can be used too that I am not
aware of.

Jeff

[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]

I use four cheap fluorescent lamps (9W each, if I do not miss-remember)
attached together with a diffuser cover and the time is between eight and
nine minutes for a simple-sided pcb or seven minutes each side for a
duble-sided pcb. It is absolutely. As Robin appointed, fluorescent lamps
need a pre-heat time to work best.


2013/1/7 Jeff Heiss <jeff.heiss@...>

> **
>
>
> What are thoughts on exposure time vs. resolution? Pretend a 100w bulb
> gives a 10 minute exposure and a 200w bulb gives a 5 minute exposure. Is
> either better, worse, the same?
>
> Jeff
>
>
> -----Original Message-----
> From: Boman33 boman33@...>
> Sent: Monday, January 07, 2013 2:41 AM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: RE: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
> phototool-PCB contact closeness, 500W floodlamp
>
> Use thicker glass and let the PCB deform to lay flat against it. The force
> of the vacuum (air-pressure) is very large over the big area of the PCB.
>
> Bertho
>
> From: Jeff Heiss Sent: Monday, January 07, 2013 01:46
>
> I experimented with a ziplock bag and a vacuum pump. The transparency is
> held to the board very very well. Much better than glass can ever do.
> However, I found a drawback and that is the plastic forms imperfections and
> scratches from fingernails, stretching and pulling to get wrinkles out
> during vacuum, and around the transparency and copper clad edges.
>
> I question, as I have not tested, if these imperfections can cause
> diffusion
> of the light as it passes through and decrease results especially if the
> imperfections are over a thin trace or spacing between traces. I tried
> blanket storage bags, same problem. My conclusion is that very thin glass
> like microscope cover slide glass is the ideal material because it is thin
> enough to deform over the copper clad. I searched for glass as thin as
> cover slide glass but I could not find a place who sells it. Maybe
> something better than ziplock bag plastic can be used too that I am not
> aware of.
>
> Jeff
>
> [Non-text portions of this message have been removed]
>
> [Non-text portions of this message have been removed]
>
>
>

[Non-text portions of this message have been removed]

On Mon, 7 Jan 2013 01:46:29 -0500, you wrote:

>I experimented with a ziplock bag and a vacuum pump. The transparency is
>held to the board very very well. Much better than glass can ever do.
>However, I found a drawback and that is the plastic forms imperfections and
>scratches from fingernails, stretching and pulling to get wrinkles out
>during vacuum, and around the transparency and copper clad edges.
>
>
>
>I question, as I have not tested, if these imperfections can cause diffusion
>of the light as it passes through and decrease results especially if the
>imperfections are over a thin trace or spacing between traces. I tried
>blanket storage bags, same problem. My conclusion is that very thin glass
>like microscope cover slide glass is the ideal material because it is thin
>enough to deform over the copper clad. I searched for glass as thin as
>cover slide glass but I could not find a place who sells it. Maybe
>something better than ziplock bag plastic can be used too that I am not
>aware of.

I used furniture store vinyl, thin gauge, seemed to work just fine,
calibrated exposure with the covering in place.

Did not use saran wrap or the equivalent, since it was too thin and
developed a static charge which tended to lift the positive from the
board and was messy to deal with. You could also use book cover
material, which may be equally nice.

Take something fluorescent, a black light, and see if it glows less
with the material between it and the light.

Harvey

>
>
>
>Jeff
>
>
>
> _____
>
>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>On Behalf Of Robin Whittle
>Sent: Sunday, January 06, 2013 9:17 PM
>To: Homebrew_PCBs@yahoogroups.com
>Cc: Vicent Colomar Prats
>Subject: Re: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
>phototool-PCB contact closeness, 500W floodlamp
>
>
>
>
>
>Hi Vicent,
>
>Some of the eBay ads which can be found by searching for:
>
>36W Nail UV Lamp Acrylic Gel Curing Light
>
>show that they contain four long U-shaped fluorescent lamps. This ad:
>
>http://www.ebay.com/itm/310556445104
>
>shows one of these types of lamp - and they have "365nm" written on
>them, which is most helpful! The Riston General Processing Guide at:
>
>http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.ht
>ml
>
>indicates peak sensitivity is in the 350-380 nm near-UV range, with some
>sensitivity from 300nm (UV) to 450nm (blue).
>
>I am not sure what wavelengths other photoresists are most sensitive to,
>such as positive photoresists.
>
>I think it is much better to have a relatively compact source of light
>than something broad like these.
>
>In some previous messages to this list, such as message 30440, I
>described using a 500 watt linear halogen incandescent lamp with
>reflector - a cheap hardware-store "floodlamp". Such lamps put out
>enough near-UV to give me a sun-tan when I extensively used an old
>process camera which had four of these lamps. Glass would reduce the
>tanning/burning shorter wavelength UV rays to some extent but I think
>would hardly affect the transmission of the 350-380nm light of interest.
>
>The 500 watt lamp radiates most of its energy in the visible and
>infra-red (with some being lost as hot air), and only a fraction of it
>is the light we are interested in. I couldn't find a suitable source of
>dark-violet-looking "Woods glass" to make a filter which would reject
>most of the visible and IR I don't want. This visible and IR energy is
>substantial and will warm the board, which might cause differential
>expansion of the phototool and board. However, this can be largely
>solved by blowing a fan on the board, with its phototool and glass or
>other surface which clamps the phototool to the board.
>
>This way, most of the light comes from an area about 10cm wide and 45cm
>away from the board. These rays of light are relatively parallel, so
>the shadow from the phototool remains relatively sharp even if the
>phototool is not completely flat against the photoresist.
>
>With a broader source of light, as would inevitably be the case with
>these less intense, larger, fluorescent lamps, the shadow would be much
>less sharp.
>
>It is difficult to get the phototool sitting flat against the PCB. The
>PCB is reasonably rigid and is not necessarily flat. If the top cover
>is glass or acrylic, then any dust or mismatch between the flatness of
>the glass and the PCB will cause a gap and loss of sharpness.
>
>It would also be possible to use a vacuum frame with a soft, flexible,
>top surface, such as clear PVC sheet (retailed at fabric and other shops
>as a table covering), which would press the phototool close to the PCB
>even if the PCB was not completely flat. This would also largely avoid
>problems caused by dust, since it would tend to stretch the phototool
>over the dust particle and so press it close even one or two mm away
>from the particle, whereas with the glass or acrylic approach, the dust
>particle would lift the phototool and glass off the board for a larger
>surrounding area.
>
>Another likely problem with fluorescent lamps of all types is that their
>output would vary considerably with how long they have been on for,
>which would be affected by their starting temperature and therefore how
>long they had been on for in the last 30 minutes or so. This would make
>it difficult to run them from a timer. This might be OK if you ran them
>all the time and had a way of simply placing them over the PCB with
>phototool etc. However, I prefer to place the phototool and my existing
>glass sheet arrangement together by a safelight (a bunch of red LEDs)
>and place it under the lamp, before turning the lamp on for a fixed
>time. The 500W incandescent lamp would have its near-UV output affected
>somewhat by mains voltage fluctuations, but I doubt if this is a
>significant problem.
>
>- Robin http://www.firstpr.com.au/pcb-diy/
>
>
>
>
>
>[Non-text portions of this message have been removed]

Is it better to have the light further away increasing sharpness and
increasing the exposure time or closer to the board decreasing exposure time
but reducing sharpness? If exposure affects sharpness, I'm not sure how to
pick the balance point. If exposure does not affect sharpness, I guess the
best method is to position the light as far away as reasonable and wait a
little extra longer for improved results.



A way to check how parallel your light is is to hold a pencil in front of
white paper and observe the shadow. Is the shadow crisp or blurry? How far
can you hold the pencil from the paper before it becomes blurry? Then do it
with a regular light bulb (point source) and compare.



Jeff



_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Harvey White
Sent: Monday, January 07, 2013 2:14 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
phototool-PCB contact closeness, 500W floodlamp

On Mon, 7 Jan 2013 01:46:29 -0500, you wrote:

>I experimented with a ziplock bag and a vacuum pump. The transparency is
>held to the board very very well. Much better than glass can ever do.
>However, I found a drawback and that is the plastic forms imperfections and
>scratches from fingernails, stretching and pulling to get wrinkles out
>during vacuum, and around the transparency and copper clad edges.
>
>
>
>I question, as I have not tested, if these imperfections can cause
diffusion
>of the light as it passes through and decrease results especially if the
>imperfections are over a thin trace or spacing between traces. I tried
>blanket storage bags, same problem. My conclusion is that very thin glass
>like microscope cover slide glass is the ideal material because it is thin
>enough to deform over the copper clad. I searched for glass as thin as
>cover slide glass but I could not find a place who sells it. Maybe
>something better than ziplock bag plastic can be used too that I am not
>aware of.

I used furniture store vinyl, thin gauge, seemed to work just fine,
calibrated exposure with the covering in place.

Did not use saran wrap or the equivalent, since it was too thin and
developed a static charge which tended to lift the positive from the
board and was messy to deal with. You could also use book cover
material, which may be equally nice.

Take something fluorescent, a black light, and see if it glows less
with the material between it and the light.

Harvey

>
>
>
>Jeff
>
>
>
> _____
>
>From: Homebrew_PCBs@yahoogroups.com
<mailto:Homebrew_PCBs%40yahoogroups.com>
[mailto:Homebrew_PCBs@yahoogroups.com
<mailto:Homebrew_PCBs%40yahoogroups.com> ]
>On Behalf Of Robin Whittle
>Sent: Sunday, January 06, 2013 9:17 PM
>To: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com>
>Cc: Vicent Colomar Prats
>Subject: Re: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
>phototool-PCB contact closeness, 500W floodlamp
>
>
>
>
>
>Hi Vicent,
>
>Some of the eBay ads which can be found by searching for:
>
>36W Nail UV Lamp Acrylic Gel Curing Light
>
>show that they contain four long U-shaped fluorescent lamps. This ad:
>
>http://www.ebay.com/itm/310556445104
>
>shows one of these types of lamp - and they have "365nm" written on
>them, which is most helpful! The Riston General Processing Guide at:
>
>http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/index.h
t
>ml
>
>indicates peak sensitivity is in the 350-380 nm near-UV range, with some
>sensitivity from 300nm (UV) to 450nm (blue).
>
>I am not sure what wavelengths other photoresists are most sensitive to,
>such as positive photoresists.
>
>I think it is much better to have a relatively compact source of light
>than something broad like these.
>
>In some previous messages to this list, such as message 30440, I
>described using a 500 watt linear halogen incandescent lamp with
>reflector - a cheap hardware-store "floodlamp". Such lamps put out
>enough near-UV to give me a sun-tan when I extensively used an old
>process camera which had four of these lamps. Glass would reduce the
>tanning/burning shorter wavelength UV rays to some extent but I think
>would hardly affect the transmission of the 350-380nm light of interest.
>
>The 500 watt lamp radiates most of its energy in the visible and
>infra-red (with some being lost as hot air), and only a fraction of it
>is the light we are interested in. I couldn't find a suitable source of
>dark-violet-looking "Woods glass" to make a filter which would reject
>most of the visible and IR I don't want. This visible and IR energy is
>substantial and will warm the board, which might cause differential
>expansion of the phototool and board. However, this can be largely
>solved by blowing a fan on the board, with its phototool and glass or
>other surface which clamps the phototool to the board.
>
>This way, most of the light comes from an area about 10cm wide and 45cm
>away from the board. These rays of light are relatively parallel, so
>the shadow from the phototool remains relatively sharp even if the
>phototool is not completely flat against the photoresist.
>
>With a broader source of light, as would inevitably be the case with
>these less intense, larger, fluorescent lamps, the shadow would be much
>less sharp.
>
>It is difficult to get the phototool sitting flat against the PCB. The
>PCB is reasonably rigid and is not necessarily flat. If the top cover
>is glass or acrylic, then any dust or mismatch between the flatness of
>the glass and the PCB will cause a gap and loss of sharpness.
>
>It would also be possible to use a vacuum frame with a soft, flexible,
>top surface, such as clear PVC sheet (retailed at fabric and other shops
>as a table covering), which would press the phototool close to the PCB
>even if the PCB was not completely flat. This would also largely avoid
>problems caused by dust, since it would tend to stretch the phototool
>over the dust particle and so press it close even one or two mm away
>from the particle, whereas with the glass or acrylic approach, the dust
>particle would lift the phototool and glass off the board for a larger
>surrounding area.
>
>Another likely problem with fluorescent lamps of all types is that their
>output would vary considerably with how long they have been on for,
>which would be affected by their starting temperature and therefore how
>long they had been on for in the last 30 minutes or so. This would make
>it difficult to run them from a timer. This might be OK if you ran them
>all the time and had a way of simply placing them over the PCB with
>phototool etc. However, I prefer to place the phototool and my existing
>glass sheet arrangement together by a safelight (a bunch of red LEDs)
>and place it under the lamp, before turning the lamp on for a fixed
>time. The 500W incandescent lamp would have its near-UV output affected
>somewhat by mains voltage fluctuations, but I doubt if this is a
>significant problem.
>
>- Robin http://www.firstpr.com.au/pcb-diy/
>
>
>
>
>
>[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

Jeff, it's been awhile since I've used the photo-resist method.
(I prefer the iron-on toner because it involves virtually no chemicals.)
If memory serves, the distance between the lamps and board
was ~10 inches. I *think* exposure time was about 20 minutes,
maybe a bit longer.

As far as sharpness, I was very happy with the results. When you
think about it, there's not much spacing between the PCB and trace on the
paper when the trace is laid down flat against the board, so there's no
discernable shadow. One trace pattern will shield most of the light.
It's
best to experiment. "Your mileage may vary." :D)

Instead of using two sheets of the drafting paper, a person can
take a "proven" toner-on-paper pattern to a print shop or T-shirt shop,
and have
a "film positive" made. The black lines on that will be very
opaque. The film positive can be used over and over.

Charlie

On Mon, 7 Jan 2013 23:17:10 -0500 "Jeff Heiss" <jeff.heiss@...>
writes:

Is it better to have the light further away increasing sharpness and
increasing the exposure time or closer to the board decreasing exposure
time
but reducing sharpness? If exposure affects sharpness, I'm not sure how
to
pick the balance point. If exposure does not affect sharpness, I guess
the
best method is to position the light as far away as reasonable and wait a
little extra longer for improved results.

A way to check how parallel your light is is to hold a pencil in front of
white paper and observe the shadow. Is the shadow crisp or blurry? How
far
can you hold the pencil from the paper before it becomes blurry? Then do
it
with a regular light bulb (point source) and compare.

Jeff

_____

From: Homebrew_PCBs@yahoogroups.com
[mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Harvey White
Sent: Monday, January 07, 2013 2:14 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
phototool-PCB contact closeness, 500W floodlamp

On Mon, 7 Jan 2013 01:46:29 -0500, you wrote:

>I experimented with a ziplock bag and a vacuum pump. The transparency is
>held to the board very very well. Much better than glass can ever do.
>However, I found a drawback and that is the plastic forms imperfections
and
>scratches from fingernails, stretching and pulling to get wrinkles out
>during vacuum, and around the transparency and copper clad edges.
>
>
>
>I question, as I have not tested, if these imperfections can cause
diffusion
>of the light as it passes through and decrease results especially if the
>imperfections are over a thin trace or spacing between traces. I tried
>blanket storage bags, same problem. My conclusion is that very thin
glass
>like microscope cover slide glass is the ideal material because it is
thin
>enough to deform over the copper clad. I searched for glass as thin as
>cover slide glass but I could not find a place who sells it. Maybe
>something better than ziplock bag plastic can be used too that I am not
>aware of.

I used furniture store vinyl, thin gauge, seemed to work just fine,
calibrated exposure with the covering in place.

Did not use saran wrap or the equivalent, since it was too thin and
developed a static charge which tended to lift the positive from the
board and was messy to deal with. You could also use book cover
material, which may be equally nice.

Take something fluorescent, a black light, and see if it glows less
with the material between it and the light.

Harvey

>
>
>
>Jeff
>
>
>
> _____
>
>From: Homebrew_PCBs@yahoogroups.com

[mailto:Homebrew_PCBs@yahoogroups.com
]
>On Behalf Of Robin Whittle
>Sent: Sunday, January 06, 2013 9:17 PM
>To: Homebrew_PCBs@yahoogroups.com
>Cc: Vicent Colomar Prats
>Subject: Re: [Homebrew_PCBs] UV nail lamps - sharpness of shadow,
>phototool-PCB contact closeness, 500W floodlamp
>
>
>
>
>
>Hi Vicent,
>
>Some of the eBay ads which can be found by searching for:
>
>36W Nail UV Lamp Acrylic Gel Curing Light
>
>show that they contain four long U-shaped fluorescent lamps. This ad:
>
>http://www.ebay.com/itm/310556445104
>
>shows one of these types of lamp - and they have "365nm" written on
>them, which is most helpful! The Riston General Processing Guide at:
>
>http://www2.dupont.com/Imaging_Materials/en_US/tech_info/datasheets/inde
x.h
t
>ml
>
>indicates peak sensitivity is in the 350-380 nm near-UV range, with some
>sensitivity from 300nm (UV) to 450nm (blue).
>
>I am not sure what wavelengths other photoresists are most sensitive to,
>such as positive photoresists.
>
>I think it is much better to have a relatively compact source of light
>than something broad like these.
>
>In some previous messages to this list, such as message 30440, I
>described using a 500 watt linear halogen incandescent lamp with
>reflector - a cheap hardware-store "floodlamp". Such lamps put out
>enough near-UV to give me a sun-tan when I extensively used an old
>process camera which had four of these lamps. Glass would reduce the
>tanning/burning shorter wavelength UV rays to some extent but I think
>would hardly affect the transmission of the 350-380nm light of interest.
>
>The 500 watt lamp radiates most of its energy in the visible and
>infra-red (with some being lost as hot air), and only a fraction of it
>is the light we are interested in. I couldn't find a suitable source of
>dark-violet-looking "Woods glass" to make a filter which would reject
>most of the visible and IR I don't want. This visible and IR energy is
>substantial and will warm the board, which might cause differential
>expansion of the phototool and board. However, this can be largely
>solved by blowing a fan on the board, with its phototool and glass or
>other surface which clamps the phototool to the board.
>
>This way, most of the light comes from an area about 10cm wide and 45cm
>away from the board. These rays of light are relatively parallel, so
>the shadow from the phototool remains relatively sharp even if the
>phototool is not completely flat against the photoresist.
>
>With a broader source of light, as would inevitably be the case with
>these less intense, larger, fluorescent lamps, the shadow would be much
>less sharp.
>
>It is difficult to get the phototool sitting flat against the PCB. The
>PCB is reasonably rigid and is not necessarily flat. If the top cover
>is glass or acrylic, then any dust or mismatch between the flatness of
>the glass and the PCB will cause a gap and loss of sharpness.
>
>It would also be possible to use a vacuum frame with a soft, flexible,
>top surface, such as clear PVC sheet (retailed at fabric and other shops
>as a table covering), which would press the phototool close to the PCB
>even if the PCB was not completely flat. This would also largely avoid
>problems caused by dust, since it would tend to stretch the phototool
>over the dust particle and so press it close even one or two mm away
>from the particle, whereas with the glass or acrylic approach, the dust
>particle would lift the phototool and glass off the board for a larger
>surrounding area.
>
>Another likely problem with fluorescent lamps of all types is that their
>output would vary considerably with how long they have been on for,
>which would be affected by their starting temperature and therefore how
>long they had been on for in the last 30 minutes or so. This would make
>it difficult to run them from a timer. This might be OK if you ran them
>all the time and had a way of simply placing them over the PCB with
>phototool etc. However, I prefer to place the phototool and my existing
>glass sheet arrangement together by a safelight (a bunch of red LEDs)
>and place it under the lamp, before turning the lamp on for a fixed
>time. The 500W incandescent lamp would have its near-UV output affected
>somewhat by mains voltage fluctuations, but I doubt if this is a
>significant problem.
>
>- Robin http://www.firstpr.com.au/pcb-diy/
>
>
>
>
>
>[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

Some of you have complained that the resist lifts off or gets damaged during handling. laying of the transparent image, static electricity causing the resist to lift off with the image, vacuum bagging causing more surface scratch and so on.

and the use of chemicals.

I just recently ordered a material called puretch from only US distributor. claims that the film is good down to 1 mil resolution provided your image is that good.

links to the US distributor: www.capefearpress.com/puretch.html
youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s

another link: http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html

Developer used is sodium carbonate (do not get it confused with sodium bicarbonate which is baking soda)

capefear press has some good information on how to expose without creating shadows and the lamp recommended. Good solid information. Application at capefearpress is not electronics but rather arcane art form. Far more technical than most of us here or using toner transfer method.

Some advantages: photoresist is protected from handling by a thin plastic layer. It is removed when you are ready to develop so that you can't scratch or lift off during handling and exposing.

For photoimaging, they also sell stoufer exposure gauge to help you get the right exposure.

------------
For now I think I have Pulsar toner transfer system working well enough. Don't need to use lot of pressure. Too much pressure causes the toner to "bleed" on the edges. temperature to melt toner is around 100C anything more and the toner becomes too thin and the image "bleeds"/run.

I may still switch over to puretch. Don't need to keep printing images for multiple board. higher resolution for use with TQFP with 0.5mm pitch. Pulsar is near the limit for 0.5mm pitch.

Ms. Smilingcat,

It looks like very interesting stuff. What bothers me is they said
"affordable price" yet don't list the price. That usually means it ain't
that affordable. So what DOES it cost?

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of smilingcat90254
Sent: Tuesday, January 08, 2013 6:13 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] photo resist. Slightly different material.

Some of you have complained that the resist lifts off or gets damaged during
handling. laying of the transparent image, static electricity causing the
resist to lift off with the image, vacuum bagging causing more surface
scratch and so on.

and the use of chemicals.

I just recently ordered a material called puretch from only US distributor.
claims that the film is good down to 1 mil resolution provided your image is
that good.

links to the US distributor: www.capefearpress.com/puretch.html
youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s

another link:
http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html

Developer used is sodium carbonate (do not get it confused with sodium
bicarbonate which is baking soda)

capefear press has some good information on how to expose without creating
shadows and the lamp recommended. Good solid information. Application at
capefearpress is not electronics but rather arcane art form. Far more
technical than most of us here or using toner transfer method.

Some advantages: photoresist is protected from handling by a thin plastic
layer. It is removed when you are ready to develop so that you can't scratch
or lift off during handling and exposing.

For photoimaging, they also sell stoufer exposure gauge to help you get the
right exposure.

------------
For now I think I have Pulsar toner transfer system working well enough.
Don't need to use lot of pressure. Too much pressure causes the toner to
"bleed" on the edges. temperature to melt toner is around 100C anything more
and the toner becomes too thin and the image "bleeds"/run.

I may still switch over to puretch. Don't need to keep printing images for
multiple board. higher resolution for use with TQFP with 0.5mm pitch. Pulsar
is near the limit for 0.5mm pitch.





------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links

<http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html>
http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html



The price is on the bottom of the page. The cost is 24" x 10' for $78 (60
Euro). It costs 5.4 times as much as photoresist available on Ebay. I
computed 5.4x using the resist I purchased which is 8.3" by 9.7' DuPont
MM540 for $14.49.



Jeff



_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Rick Sparber
Sent: Tuesday, January 08, 2013 8:40 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: RE: [Homebrew_PCBs] photo resist. Slightly different material.





Ms. Smilingcat,

It looks like very interesting stuff. What bothers me is they said
"affordable price" yet don't list the price. That usually means it ain't
that affordable. So what DOES it cost?

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com>
[mailto:Homebrew_PCBs@yahoogroups.com
<mailto:Homebrew_PCBs%40yahoogroups.com> ]
On Behalf Of smilingcat90254
Sent: Tuesday, January 08, 2013 6:13 PM
To: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com>
Subject: [Homebrew_PCBs] photo resist. Slightly different material.

Some of you have complained that the resist lifts off or gets damaged during
handling. laying of the transparent image, static electricity causing the
resist to lift off with the image, vacuum bagging causing more surface
scratch and so on.

and the use of chemicals.

I just recently ordered a material called puretch from only US distributor.
claims that the film is good down to 1 mil resolution provided your image is
that good.

links to the US distributor: www.capefearpress.com/puretch.html
youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s

another link:
http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html

Developer used is sodium carbonate (do not get it confused with sodium
bicarbonate which is baking soda)

capefear press has some good information on how to expose without creating
shadows and the lamp recommended. Good solid information. Application at
capefearpress is not electronics but rather arcane art form. Far more
technical than most of us here or using toner transfer method.

Some advantages: photoresist is protected from handling by a thin plastic
layer. It is removed when you are ready to develop so that you can't scratch
or lift off during handling and exposing.

For photoimaging, they also sell stoufer exposure gauge to help you get the
right exposure.

------------
For now I think I have Pulsar toner transfer system working well enough.
Don't need to use lot of pressure. Too much pressure causes the toner to
"bleed" on the edges. temperature to melt toner is around 100C anything more
and the toner becomes too thin and the image "bleeds"/run.

I may still switch over to puretch. Don't need to keep printing images for
multiple board. higher resolution for use with TQFP with 0.5mm pitch. Pulsar
is near the limit for 0.5mm pitch.

------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links





[Non-text portions of this message have been removed]

Yes E-bay is cheaper.

At Capefear, cost for 10' x 24" film is $59.00 with S/H I think it was. they have much smaller size for sampling but it is pretty pricy!! $19 for 12" x 24".

I pay premium over E-bay because I prefer to have a "regular" supplier. It's the reason I order from DigiKey, and buy Tektronix and HP equipment.

My sample order from Capefear came very prompt. Well packed, looking very reputable.

I do not care for grey market items or suppliers where you can't trace back.

As a reference of how I view things: Some of my cutting tools are cobalt steel with TiN coated material. Not some high carbon steel. Tools themselves, I prefer Dewalt, Bosch, Makita... Prefer it is MADE IN USA or Germany or Japan and not just the label saying USA/German/Japanese company. Most recent outburst was over 6-32 tap. Ordered a replacement tap. Broken one was a cheapie from Craftsman high carbon steel. Flute on the tap was cut so irregular, one of the cutting surface was less than 1/32" wide. Replacement is a cobalt steel, TiN coated 6-32 H3 tap from Ghurring. cost is about $15.00 each.

Been looking for a lathe and mill and I think I'm going to invest in Taig. Not so hot on Smithy or Grizzly. Both are not that accurate. I used Smithy and wasn't impresed. Even their technical spec was bit of a yawn.

smilingcat,

--- In Homebrew_PCBs@yahoogroups.com, "Jeff Heiss" wrote:
>
>
> http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
>
>
>
> The price is on the bottom of the page. The cost is 24" x 10' for $78 (60
> Euro). It costs 5.4 times as much as photoresist available on Ebay. I
> computed 5.4x using the resist I purchased which is 8.3" by 9.7' DuPont
> MM540 for $14.49.
>
>
>
> Jeff
>
>
>
> _____
>
> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Rick Sparber
> Sent: Tuesday, January 08, 2013 8:40 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: RE: [Homebrew_PCBs] photo resist. Slightly different material.
>
>
>
>
>
> Ms. Smilingcat,
>
> It looks like very interesting stuff. What bothers me is they said
> "affordable price" yet don't list the price. That usually means it ain't
> that affordable. So what DOES it cost?
>
> Rick
>
> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com
> ]
> On Behalf Of smilingcat90254
> Sent: Tuesday, January 08, 2013 6:13 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] photo resist. Slightly different material.
>
> Some of you have complained that the resist lifts off or gets damaged during
> handling. laying of the transparent image, static electricity causing the
> resist to lift off with the image, vacuum bagging causing more surface
> scratch and so on.
>
> and the use of chemicals.
>
> I just recently ordered a material called puretch from only US distributor.
> claims that the film is good down to 1 mil resolution provided your image is
> that good.
>
> links to the US distributor: www.capefearpress.com/puretch.html
> youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s
>
> another link:
> http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
>
> Developer used is sodium carbonate (do not get it confused with sodium
> bicarbonate which is baking soda)
>
> capefear press has some good information on how to expose without creating
> shadows and the lamp recommended. Good solid information. Application at
> capefearpress is not electronics but rather arcane art form. Far more
> technical than most of us here or using toner transfer method.
>
> Some advantages: photoresist is protected from handling by a thin plastic
> layer. It is removed when you are ready to develop so that you can't scratch
> or lift off during handling and exposing.
>
> For photoimaging, they also sell stoufer exposure gauge to help you get the
> right exposure.
>
> ------------
> For now I think I have Pulsar toner transfer system working well enough.
> Don't need to use lot of pressure. Too much pressure causes the toner to
> "bleed" on the edges. temperature to melt toner is around 100C anything more
> and the toner becomes too thin and the image "bleeds"/run.
>
> I may still switch over to puretch. Don't need to keep printing images for
> multiple board. higher resolution for use with TQFP with 0.5mm pitch. Pulsar
> is near the limit for 0.5mm pitch.
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

Ms. Smilingcat,

If you want to talk metalworking, that is my primary hobby (since
electronics was lost as my hobby when I started to get paid to do it back in
1973). I have a RF30 mill, and Atlas/Craftsman lathe, homemade drill press
and shaper from my own castings, plus lots of homemade hand tools. But this
is OT so contact me directly. I look forward to hearing from you.

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of smilingcat90254
Sent: Tuesday, January 08, 2013 8:29 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: photo resist. Slightly different material.

Yes E-bay is cheaper.

At Capefear, cost for 10' x 24" film is $59.00 with S/H I think it was. they
have much smaller size for sampling but it is pretty pricy!! $19 for 12" x
24".

I pay premium over E-bay because I prefer to have a "regular" supplier. It's
the reason I order from DigiKey, and buy Tektronix and HP equipment.

My sample order from Capefear came very prompt. Well packed, looking very
reputable.

I do not care for grey market items or suppliers where you can't trace back.


As a reference of how I view things: Some of my cutting tools are cobalt
steel with TiN coated material. Not some high carbon steel. Tools
themselves, I prefer Dewalt, Bosch, Makita... Prefer it is MADE IN USA or
Germany or Japan and not just the label saying USA/German/Japanese company.
Most recent outburst was over 6-32 tap. Ordered a replacement tap. Broken
one was a cheapie from Craftsman high carbon steel. Flute on the tap was cut
so irregular, one of the cutting surface was less than 1/32" wide.
Replacement is a cobalt steel, TiN coated 6-32 H3 tap from Ghurring. cost is
about $15.00 each.

Been looking for a lathe and mill and I think I'm going to invest in Taig.
Not so hot on Smithy or Grizzly. Both are not that accurate. I used Smithy
and wasn't impresed. Even their technical spec was bit of a yawn.

smilingcat,

--- In Homebrew_PCBs@yahoogroups.com, "Jeff Heiss" wrote:
>
>
> http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
>
>
>
> The price is on the bottom of the page. The cost is 24" x 10' for $78
> (60 Euro). It costs 5.4 times as much as photoresist available on
> Ebay. I computed 5.4x using the resist I purchased which is 8.3" by
> 9.7' DuPont
> MM540 for $14.49.
>
>
>
> Jeff
>
>
>
> _____
>
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Rick Sparber
> Sent: Tuesday, January 08, 2013 8:40 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: RE: [Homebrew_PCBs] photo resist. Slightly different material.
>
>
>
>
>
> Ms. Smilingcat,
>
> It looks like very interesting stuff. What bothers me is they said
> "affordable price" yet don't list the price. That usually means it
> ain't that affordable. So what DOES it cost?
>
> Rick
>
> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com
> ]
> On Behalf Of smilingcat90254
> Sent: Tuesday, January 08, 2013 6:13 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] photo resist. Slightly different material.
>
> Some of you have complained that the resist lifts off or gets damaged
> during handling. laying of the transparent image, static electricity
> causing the resist to lift off with the image, vacuum bagging causing
> more surface scratch and so on.
>
> and the use of chemicals.
>
> I just recently ordered a material called puretch from only US
distributor.
> claims that the film is good down to 1 mil resolution provided your
> image is that good.
>
> links to the US distributor: www.capefearpress.com/puretch.html
> youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s
>
> another link:
> http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
>
> Developer used is sodium carbonate (do not get it confused with sodium
> bicarbonate which is baking soda)
>
> capefear press has some good information on how to expose without
> creating shadows and the lamp recommended. Good solid information.
> Application at capefearpress is not electronics but rather arcane art
> form. Far more technical than most of us here or using toner transfer
method.
>
> Some advantages: photoresist is protected from handling by a thin
> plastic layer. It is removed when you are ready to develop so that you
> can't scratch or lift off during handling and exposing.
>
> For photoimaging, they also sell stoufer exposure gauge to help you
> get the right exposure.
>
> ------------
> For now I think I have Pulsar toner transfer system working well enough.
> Don't need to use lot of pressure. Too much pressure causes the toner
> to "bleed" on the edges. temperature to melt toner is around 100C
> anything more and the toner becomes too thin and the image "bleeds"/run.
>
> I may still switch over to puretch. Don't need to keep printing images
> for multiple board. higher resolution for use with TQFP with 0.5mm
> pitch. Pulsar is near the limit for 0.5mm pitch.
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and
Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>
>
> [Non-text portions of this message have been removed]
>




------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links

The resist is interesting indeed. It develops in 5 seconds with a 1000w
light. It does use the same 1% solution of sodium carbonate for developing
as other resist brands.



They instruct exposing and then developing as normal. They say then to
expose it again to harden it further. I never thought of the extra
hardening step. I will use it.



The instructions say to use a spray bottle or lawn pump sprayer to apply the
developer saying it will strip unexposed resist easier without abrading
exposed resist. If a spray bottle can be used for applying developer, could
it work etching? Has anyone ever tried it?



Jeff



_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of smilingcat90254
Sent: Tuesday, January 08, 2013 8:13 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] photo resist. Slightly different material.





Some of you have complained that the resist lifts off or gets damaged during
handling. laying of the transparent image, static electricity causing the
resist to lift off with the image, vacuum bagging causing more surface
scratch and so on.

and the use of chemicals.

I just recently ordered a material called puretch from only US distributor.
claims that the film is good down to 1 mil resolution provided your image is
that good.

links to the US distributor: www.capefearpress.com/puretch.html
youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s

another link: http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html

Developer used is sodium carbonate (do not get it confused with sodium
bicarbonate which is baking soda)

capefear press has some good information on how to expose without creating
shadows and the lamp recommended. Good solid information. Application at
capefearpress is not electronics but rather arcane art form. Far more
technical than most of us here or using toner transfer method.

Some advantages: photoresist is protected from handling by a thin plastic
layer. It is removed when you are ready to develop so that you can't scratch
or lift off during handling and exposing.

For photoimaging, they also sell stoufer exposure gauge to help you get the
right exposure.

------------
For now I think I have Pulsar toner transfer system working well enough.
Don't need to use lot of pressure. Too much pressure causes the toner to
"bleed" on the edges. temperature to melt toner is around 100C anything more
and the toner becomes too thin and the image "bleeds"/run.

I may still switch over to puretch. Don't need to keep printing images for
multiple board. higher resolution for use with TQFP with 0.5mm pitch. Pulsar
is near the limit for 0.5mm pitch.





[Non-text portions of this message have been removed]

This material might work for etching numbers on the outside diameter of a
disk. Hmmm. Anybody tried that?

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of smilingcat90254
Sent: Tuesday, January 08, 2013 6:13 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] photo resist. Slightly different material.

Some of you have complained that the resist lifts off or gets damaged during
handling. laying of the transparent image, static electricity causing the
resist to lift off with the image, vacuum bagging causing more surface
scratch and so on.

and the use of chemicals.

I just recently ordered a material called puretch from only US distributor.
claims that the film is good down to 1 mil resolution provided your image is
that good.

links to the US distributor: www.capefearpress.com/puretch.html
youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s

another link:
http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html

Developer used is sodium carbonate (do not get it confused with sodium
bicarbonate which is baking soda)

capefear press has some good information on how to expose without creating
shadows and the lamp recommended. Good solid information. Application at
capefearpress is not electronics but rather arcane art form. Far more
technical than most of us here or using toner transfer method.

Some advantages: photoresist is protected from handling by a thin plastic
layer. It is removed when you are ready to develop so that you can't scratch
or lift off during handling and exposing.

For photoimaging, they also sell stoufer exposure gauge to help you get the
right exposure.

------------
For now I think I have Pulsar toner transfer system working well enough.
Don't need to use lot of pressure. Too much pressure causes the toner to
"bleed" on the edges. temperature to melt toner is around 100C anything more
and the toner becomes too thin and the image "bleeds"/run.

I may still switch over to puretch. Don't need to keep printing images for
multiple board. higher resolution for use with TQFP with 0.5mm pitch. Pulsar
is near the limit for 0.5mm pitch.





------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links

The Puretch pricing is here:

http://www.capefearpress.com/order.html

and with shipping the results are, in USD$:

Square feet US Canada Elsewhere

2 $19
20 $59 $69 $86
100 $226 $238 $255

They are marketing a film "originally designed for PCB manufacturing":

http://www.capefearpress.com/puretchpcb.html

So I guess this is Riston or some equivalent material. Perhaps the
24.75 inch (628 mm) width of the material they sell would be a clue as
to its real nature.

The Riston MM540 I bought from eBay is still available from the same
source in the Czech Republic:

http://www.tech-place.com/pyralux/23-photosensitive-film.html

318 x 2000mm. This is a good quantity for my needs. An advantage of
this is that I know exactly what the material is. The datasheet and
processing instructions are here:


http://www2.dupont.com/Imaging_Materials/en_US/tech_info/product_selector.html


- Robin

I have a Pan American Tool cobalt drill set. Like yours, real cobalt steel,
not Chinese stuff, but not TiN coated. What brand of drills do you have?



Tektronix over Agilent and Lecroy? Just kidding;)



Jeff



_____

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of smilingcat90254
Sent: Tuesday, January 08, 2013 10:29 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: photo resist. Slightly different material.





Yes E-bay is cheaper.

At Capefear, cost for 10' x 24" film is $59.00 with S/H I think it was. they
have much smaller size for sampling but it is pretty pricy!! $19 for 12" x
24".

I pay premium over E-bay because I prefer to have a "regular" supplier. It's
the reason I order from DigiKey, and buy Tektronix and HP equipment.

My sample order from Capefear came very prompt. Well packed, looking very
reputable.

I do not care for grey market items or suppliers where you can't trace back.


As a reference of how I view things: Some of my cutting tools are cobalt
steel with TiN coated material. Not some high carbon steel. Tools
themselves, I prefer Dewalt, Bosch, Makita... Prefer it is MADE IN USA or
Germany or Japan and not just the label saying USA/German/Japanese company.
Most recent outburst was over 6-32 tap. Ordered a replacement tap. Broken
one was a cheapie from Craftsman high carbon steel. Flute on the tap was cut
so irregular, one of the cutting surface was less than 1/32" wide.
Replacement is a cobalt steel, TiN coated 6-32 H3 tap from Ghurring. cost is
about $15.00 each.

Been looking for a lathe and mill and I think I'm going to invest in Taig.
Not so hot on Smithy or Grizzly. Both are not that accurate. I used Smithy
and wasn't impresed. Even their technical spec was bit of a yawn.

smilingcat,

--- In Homebrew_PCBs@yahoogroups.com
<mailto:Homebrew_PCBs%40yahoogroups.com> , "Jeff Heiss" wrote:

>
>
> http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
>
>
>
> The price is on the bottom of the page. The cost is 24" x 10' for $78 (60
> Euro). It costs 5.4 times as much as photoresist available on Ebay. I
> computed 5.4x using the resist I purchased which is 8.3" by 9.7' DuPont
> MM540 for $14.49.
>
>
>
> Jeff
>
>
>
> _____
>
> From: Homebrew_PCBs@yahoogroups.com

<mailto:Homebrew_PCBs%40yahoogroups.com>
[mailto:Homebrew_PCBs@yahoogroups.com
<mailto:Homebrew_PCBs%40yahoogroups.com> ]

> On Behalf Of Rick Sparber
> Sent: Tuesday, January 08, 2013 8:40 PM
> To: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com>

> Subject: RE: [Homebrew_PCBs] photo resist. Slightly different material.
>
>
>
>
>
> Ms. Smilingcat,
>
> It looks like very interesting stuff. What bothers me is they said
> "affordable price" yet don't list the price. That usually means it ain't
> that affordable. So what DOES it cost?
>
> Rick
>
> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com

<mailto:Homebrew_PCBs%40yahoogroups.com>

> [mailto:Homebrew_PCBs@yahoogroups.com

<mailto:Homebrew_PCBs%40yahoogroups.com>

> ]
> On Behalf Of smilingcat90254
> Sent: Tuesday, January 08, 2013 6:13 PM
> To: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com>

> Subject: [Homebrew_PCBs] photo resist. Slightly different material.
>
> Some of you have complained that the resist lifts off or gets damaged

during

> handling. laying of the transparent image, static electricity causing the
> resist to lift off with the image, vacuum bagging causing more surface
> scratch and so on.
>
> and the use of chemicals.
>
> I just recently ordered a material called puretch from only US

distributor.

> claims that the film is good down to 1 mil resolution provided your image

is

> that good.
>
> links to the US distributor: www.capefearpress.com/puretch.html
> youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s
>
> another link:
> http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
>
> Developer used is sodium carbonate (do not get it confused with sodium
> bicarbonate which is baking soda)
>
> capefear press has some good information on how to expose without creating
> shadows and the lamp recommended. Good solid information. Application at
> capefearpress is not electronics but rather arcane art form. Far more
> technical than most of us here or using toner transfer method.
>
> Some advantages: photoresist is protected from handling by a thin plastic
> layer. It is removed when you are ready to develop so that you can't

scratch

> or lift off during handling and exposing.
>
> For photoimaging, they also sell stoufer exposure gauge to help you get

the

> right exposure.
>
> ------------
> For now I think I have Pulsar toner transfer system working well enough.
> Don't need to use lot of pressure. Too much pressure causes the toner to
> "bleed" on the edges. temperature to melt toner is around 100C anything

more

> and the toner becomes too thin and the image "bleeds"/run.
>
> I may still switch over to puretch. Don't need to keep printing images for
> multiple board. higher resolution for use with TQFP with 0.5mm pitch.

Pulsar

> is near the limit for 0.5mm pitch.
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and

Photos:

> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

[Non-text portions of this message have been removed]

Really good information


Sent from my iPhone

On Jan 8, 2013, at 10:25 PM, "Jeff Heiss" <jeff.heiss@...> wrote:

> I have a Pan American Tool cobalt drill set. Like yours, real cobalt steel,
> not Chinese stuff, but not TiN coated. What brand of drills do you have?
>
> Tektronix over Agilent and Lecroy? Just kidding;)
>
> Jeff
>
> _____
>
> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of smilingcat90254
> Sent: Tuesday, January 08, 2013 10:29 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] Re: photo resist. Slightly different material.
>
> Yes E-bay is cheaper.
>
> At Capefear, cost for 10' x 24" film is $59.00 with S/H I think it was. they
> have much smaller size for sampling but it is pretty pricy!! $19 for 12" x
> 24".
>
> I pay premium over E-bay because I prefer to have a "regular" supplier. It's
> the reason I order from DigiKey, and buy Tektronix and HP equipment.
>
> My sample order from Capefear came very prompt. Well packed, looking very
> reputable.
>
> I do not care for grey market items or suppliers where you can't trace back.
>
> As a reference of how I view things: Some of my cutting tools are cobalt
> steel with TiN coated material. Not some high carbon steel. Tools
> themselves, I prefer Dewalt, Bosch, Makita... Prefer it is MADE IN USA or
> Germany or Japan and not just the label saying USA/German/Japanese company.
> Most recent outburst was over 6-32 tap. Ordered a replacement tap. Broken
> one was a cheapie from Craftsman high carbon steel. Flute on the tap was cut
> so irregular, one of the cutting surface was less than 1/32" wide.
> Replacement is a cobalt steel, TiN coated 6-32 H3 tap from Ghurring. cost is
> about $15.00 each.
>
> Been looking for a lathe and mill and I think I'm going to invest in Taig.
> Not so hot on Smithy or Grizzly. Both are not that accurate. I used Smithy
> and wasn't impresed. Even their technical spec was bit of a yawn.
>
> smilingcat,
>
> --- In Homebrew_PCBs@yahoogroups.com
> , "Jeff Heiss" wrote:
> >
> >
> > http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
> >
> >
> >
> > The price is on the bottom of the page. The cost is 24" x 10' for $78 (60
> > Euro). It costs 5.4 times as much as photoresist available on Ebay. I
> > computed 5.4x using the resist I purchased which is 8.3" by 9.7' DuPont
> > MM540 for $14.49.
> >
> >
> >
> > Jeff
> >
> >
> >
> > _____
> >
> > From: Homebrew_PCBs@yahoogroups.com
>
> [mailto:Homebrew_PCBs@yahoogroups.com
> ]
> > On Behalf Of Rick Sparber
> > Sent: Tuesday, January 08, 2013 8:40 PM
> > To: Homebrew_PCBs@yahoogroups.com
>
> > Subject: RE: [Homebrew_PCBs] photo resist. Slightly different material.
> >
> >
> >
> >
> >
> > Ms. Smilingcat,
> >
> > It looks like very interesting stuff. What bothers me is they said
> > "affordable price" yet don't list the price. That usually means it ain't
> > that affordable. So what DOES it cost?
> >
> > Rick
> >
> > -----Original Message-----
> > From: Homebrew_PCBs@yahoogroups.com
>
> > [mailto:Homebrew_PCBs@yahoogroups.com
>
> > ]
> > On Behalf Of smilingcat90254
> > Sent: Tuesday, January 08, 2013 6:13 PM
> > To: Homebrew_PCBs@yahoogroups.com
>
> > Subject: [Homebrew_PCBs] photo resist. Slightly different material.
> >
> > Some of you have complained that the resist lifts off or gets damaged
> during
> > handling. laying of the transparent image, static electricity causing the
> > resist to lift off with the image, vacuum bagging causing more surface
> > scratch and so on.
> >
> > and the use of chemicals.
> >
> > I just recently ordered a material called puretch from only US
> distributor.
> > claims that the film is good down to 1 mil resolution provided your image
> is
> > that good.
> >
> > links to the US distributor: www.capefearpress.com/puretch.html
> > youtube videos on the product: www.youtube.com/watch?v=xkGt9nFER1s
> >
> > another link:
> > http://www.polymetaal.nl/siteUK/shopukwork/en-gb/dept_183.html
> >
> > Developer used is sodium carbonate (do not get it confused with sodium
> > bicarbonate which is baking soda)
> >
> > capefear press has some good information on how to expose without creating
> > shadows and the lamp recommended. Good solid information. Application at
> > capefearpress is not electronics but rather arcane art form. Far more
> > technical than most of us here or using toner transfer method.
> >
> > Some advantages: photoresist is protected from handling by a thin plastic
> > layer. It is removed when you are ready to develop so that you can't
> scratch
> > or lift off during handling and exposing.
> >
> > For photoimaging, they also sell stoufer exposure gauge to help you get
> the
> > right exposure.
> >
> > ------------
> > For now I think I have Pulsar toner transfer system working well enough.
> > Don't need to use lot of pressure. Too much pressure causes the toner to
> > "bleed" on the edges. temperature to melt toner is around 100C anything
> more
> > and the toner becomes too thin and the image "bleeds"/run.
> >
> > I may still switch over to puretch. Don't need to keep printing images for
> > multiple board. higher resolution for use with TQFP with 0.5mm pitch.
> Pulsar
> > is near the limit for 0.5mm pitch.
> >
> > ------------------------------------
> >
> > Be sure to visit the group home and check for new Links, Files, and
> Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
> [Non-text portions of this message have been removed]
>
>


[Non-text portions of this message have been removed]

I bought one of those on ebay once.

I made a couple of modifications to mine though. the one i got had 4 bulbs, the two in the middle were level and the ones on the end were lower and placed at an angle. I cut the side sockets out and then cut some new holes for them so that all 4 would be level and superglued them back into place.

The other modification i made was i added a pot. The nail dryer i had came with a 3 position switch (Timed, Off, and On). The timed part was just controlled by a 555 and there were unpopulated spots on the pcb that made it easy to add a pot to change the timing. I found that my boards actually exposed in under one minute when placed inside the dryer (where your hand is supposed to go) when using dry film.

--- In Homebrew_PCBs@yahoogroups.com, "designer_craig" wrote:
>
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "dave_donlan" wrote:
> >
> > Just been looking on flea bay and came across these
> >
> > 36W Nail UV Lamp Acrylic Gel Curing Light
> >
> > has anyone had any experience with these unit for producing pcbs - seem quite cheap might be worth a llok
> > Dave
> >
> I ordered on a while back to make an expousure box. The one I go has 4 U shaped 8W tubes (36W total). As is, it would do a 4x4 board. I figured I wanted a little larger unit so the plan was to go with more tubes in a DIY box. Also wanted the ability to do both sides of the board at once.
>
> The replacement 8W bulbs are quite inexpensive, so I will just buy more bulbs. No need for bulb sockets, just RTV the bulbs in place and solder directly to the pins. The real issue is where to get low cost ballasts. The nail unit I got had one ckt board that powered 4 bulbs, best I could tell there was one main line chopper and 4 bulb current limiting inductors. If you don't want to roll your own ballast just hack some from old CFL cork screw bulbs -- they work fine. FYI inside the blastic base of the bulb each end of the tube has two filiment wires. One wire from each filiment is connected to the pin on the base of the bulb. The ohter filiment pins are joined together with a series capacitor. Thus the bulbs will appear open to dc and an ohm meter.
>
> Craig
>

An old thread but I thought I'd contribute something with my first post. I got one of these UV nail lamps to use for solder mask film - inspired by this: http://www.instructables.com/id/Dry-Film-Solder-Mask/

It works really well. As others have mentioned, the outside two lamps are lower so I removed these to help prevent light getting under the transparency.

I tried it briefly with positive photo resist for board etching but found that the UV output was too high and a normal fluorescent worked better for this.

Fred

Can you tell us what kind of solder mask film have you used? Brand and
model? Cheers.


2013/7/4 fred27murphy <fred27murphy@...>

> **
>
>
> An old thread but I thought I'd contribute something with my first post. I
> got one of these UV nail lamps to use for solder mask film - inspired by
> this: http://www.instructables.com/id/Dry-Film-Solder-Mask/
>
> It works really well. As others have mentioned, the outside two lamps are
> lower so I removed these to help prevent light getting under the
> transparency.
>
> I tried it briefly with positive photo resist for board etching but found
> that the UV output was too high and a normal fluorescent worked better for
> this.
>
> Fred
>
>
>

[Non-text portions of this message have been removed]

It's the same one used in the Instructable but as I'm in the UK I tracked down a European supplier. It's Dynamask 5000 and I ordered a roll from from octamex.de

So far I found it easier to work with than photoresist boards! However I've only used the solder mask on simple CNC-milled through-hole boards.

I managed to get my first SMT board etched last night. The quality is good enough for TSSOP20, but I believe it could be better. I'll let you know how well the mask works for SMT when I get round to soldering it.

Fred

--- In Homebrew_PCBs@yahoogroups.com, Vicent Colomar Prats <vicentecolomar@...> wrote:
>
> Can you tell us what kind of solder mask film have you used? Brand and
> model? Cheers.
>

Thank you for the link, I'm also European, from Spain. I'm interested in
your cnc process. I just tried a 0.2mm v-shaped bit and managed to do a
good job for smd resistors, leds, etc... but not for TQFP or TSSOP. Can you
tell me what kind of engraving bit have you used (angle and size)? Thank
you in advance.



2013/7/5 fred27murphy <fred27murphy@...>

> **
>
>
> It's the same one used in the Instructable but as I'm in the UK I tracked
> down a European supplier. It's Dynamask 5000 and I ordered a roll from from
> octamex.de
>
> So far I found it easier to work with than photoresist boards! However
> I've only used the solder mask on simple CNC-milled through-hole boards.
>
> I managed to get my first SMT board etched last night. The quality is good
> enough for TSSOP20, but I believe it could be better. I'll let you know how
> well the mask works for SMT when I get round to soldering it.
>
> Fred
>
>
> --- In Homebrew_PCBs@yahoogroups.com, Vicent Colomar Prats
> <vicentecolomar@...> wrote:
> >
> > Can you tell us what kind of solder mask film have you used? Brand and
> > model? Cheers.
> >
>
>
>

[Non-text portions of this message have been removed]