Homebrew PCBs

Ok I have had enough tonight of TT


I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
pic and some transistors)

I can buy the developer for £1.20, I can get a 8*4 board for £1.20, so
for £3.60 I can get everything, except a source of UV..........

I have heard that outside in sunlight can work, any truth in this?
anyone else do this?

I have never done UV before, so have no idea on where to go with
exposure times etc.

I happen to have a 9w UV light on the garden pond to kill algae, can
that be used (badly!)




-- 

Lez

Anyone any comments on the UV lamps on ebay for drying nail varnish?

seach on ebay with "UV nail lamp"


Or what about those CCFL lights to put inside the PC case to jazz it
up, is the UV from them a possible good exposure source?

The exposure is fairly critical, especially if your film doesn't have
very high contrast. You can use sunlight but it is very hit-and miss.
You need bright sunlight and a completely cloudless day. Your UV light
may work but exposure time may be quite long.

Either way you need to work out the exposure time. I use pre-sensitised
board but you can use the same technique if you use spray photo-resist.
Take a strip of board and use a knife to cut the plastic light proof
coating into about 5 - 10 strips. Peel off the first strip, place some
blank film over the board and expose for 1 minute. Peel off the next
strip and expose for a minute. Repeat for the rest of the strips. Now
develop the board. You should now be able to work out how much time is
needed to completely expose the resist. You want the minimum time to
completely expose the board.

If you are not used to the process now print one board to check you have
got the exposure right. Like anything it takes practise to get
everything right. By the way, is the \ufffd1.20 board paper or fibreglass? I
would recommend using fibreglass even if it is a bit more expensive. It
is a lot more rugged and the tracks are less likely to lift when you
solder it.

Les




Lez wrote:

> Ok I have had enough tonight of TT
>
>
> I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
> pic and some transistors)
>
> I can buy the developer for \ufffd1.20, I can get a 8*4 board for \ufffd1.20, so
> for \ufffd3.60 I can get everything, except a source of UV..........
>
> I have heard that outside in sunlight can work, any truth in this?
> anyone else do this?
>
> I have never done UV before, so have no idea on where to go with
> exposure times etc.
>
> I happen to have a 9w UV light on the garden pond to kill algae, can
> that be used (badly!)
>
>
>
>
>

I don't see why one of those nail lamps wouldn't work for small boards.
You do need some method of holding the film firmly against the  board.
Any gap between the board and the film will cause undercutting and poor
definition.

Les

Lez wrote:

> Anyone any comments on the UV lamps on ebay for drying nail varnish?
>
> seach on ebay with "UV nail lamp"
>

On 02/02/07, Leslie Newell <lesnewell@...> wrote:
>
>
>
>
>
>
> I don't see why one of those nail lamps wouldn't work for small boards.
>  You do need some method of holding the film firmly against the  board.
>  Any gap between the board and the film will cause undercutting and poor
>  definition.
>

I've noticed they also sell replacement bulbs, much cheaper than the
real type of bulb, in a pack of 4.

I may try sunlight first, I only need to make 2 boards with the same
design 6 times on each,  I'm in a rush for these but once done I may
not need another board until about 6 month from now.........

For what I have spent on trying to do this, and thw eeks of trying
things, I could have had them done at one of those china fab houses
and still had change...........

My holding out came from the saying of give a man a fish and he eats
for a day, teach him to fish....
Wished I'd ordered pizza.


Lez

----- Original Message ----- 

From: "Leslie Newell" <lesnewell@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, February 01, 2007 11:56 PM
Subject: Re: [Homebrew_PCBs] Photo exposure


> If you are not used to the process now print one board to check you have
> got the exposure right. Like anything it takes practise to get
> everything right. By the way, is the \ufffd1.20 board paper or fibreglass? I
> would recommend using fibreglass even if it is a bit more expensive. It
> is a lot more rugged and the tracks are less likely to lift when you
> solder it.

I use paper/fibreglass composite board as it's much easier to cut and drill 
than FR4. Copper adhesion seems about the same.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

>
>I use paper/fibreglass composite board as it's much easier to cut and drill
>than FR4. Copper adhesion seems about the same.

Leon, could you let me know how the paper/fiberglass is?
Two layers or how?
Copper is on what layer?
Cristian

On Fri, 02 Feb 2007 07:41:37 +0100, Cristian <bip@...> wrote:

> Leon, could you let me know how the paper/fiberglass is?
> Two layers or how?
> Copper is on what layer?
> Cristian


Just another board material, the copper is still on the outside.
You can see descriptions here:
<http://www.felsweb.com/lam_faq.htm#B>

There was also a good page here, but some incompetent webmaster broke the  
web by thinking he just had to change something:
<http://www.hta-bi.bfh.ch/E/ecad/PCB-Shop/route-pcb/standards_N.htm> maybe  
you can find the page again.

ST

----- Original Message ----- 

From: "Cristian" <bip@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, February 02, 2007 6:41 AM
Subject: Re: [Homebrew_PCBs] Photo exposure


>
>>
>>I use paper/fibreglass composite board as it's much easier to cut and 
>>drill
>>than FR4. Copper adhesion seems about the same.
>
> Leon, could you let me know how the paper/fiberglass is?
> Two layers or how?
> Copper is on what layer?

It's compressed paper in the middle, with thin fibreglass on both sides, and 
copper on one or both sides. It's available from Mega Electronics and 
Farnell.

Leon

--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
>
> Ok I have had enough tonight of TT
> 
> 
> I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
> pic and some transistors)
> 
> I can buy the developer for £1.20, I can get a 8*4 board for £1.20, so
> for £3.60 I can get everything, except a source of UV..........
> 
> I have heard that outside in sunlight can work, any truth in this?
> anyone else do this?
> 
> I have never done UV before, so have no idea on where to go with
> exposure times etc.
> 
> I happen to have a 9w UV light on the garden pond to kill algae, can
> that be used (badly!)
> 
> 
> 
> 
> -- 
> 
> Lez
>



Mercury vapor bulbs will work the best and give the fastest exposure.
Another way is to get a cheap 500 watt quartz halogen work lamp and
use it for UV exposure. They cost about $8 to $10 USD. May work even
faster if you remove any glass filter lens as this may block some of
the UV. I tried it once and it took 2 minutes at a distance of one
foot. The etching resist was negative acting dry film. Positive resist
will take much longer.

This is the cheapest way of making a box that I found.

Going to make a box when I've moved.

Hope it helps.

Richard

--- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@> wrote:
> >
> > Ok I have had enough tonight of TT
> > 
> > 
> > I need to get 10 little 2 inch * 2 1/2 inch boards done. (only 
holds a
> > pic and some transistors)
> > 
> > I can buy the developer for £1.20, I can get a 8*4 board for 
£1.20, so
> > for £3.60 I can get everything, except a source of UV..........
> > 
> > I have heard that outside in sunlight can work, any truth in this?
> > anyone else do this?
> > 
> > I have never done UV before, so have no idea on where to go with
> > exposure times etc.
> > 
> > I happen to have a 9w UV light on the garden pond to kill algae, 
can
> > that be used (badly!)
> > 
> > 
> > 
> > 
> > -- 
> > 
> > Lez
> >
> 
> 
> 
> Mercury vapor bulbs will work the best and give the fastest 
exposure.
> Another way is to get a cheap 500 watt quartz halogen work lamp and
> use it for UV exposure. They cost about $8 to $10 USD. May work even
> faster if you remove any glass filter lens as this may block some of
> the UV. I tried it once and it took 2 minutes at a distance of one
> foot. The etching resist was negative acting dry film. Positive 
resist
> will take much longer.
>

Or you can try

http://www.scienceprog.com/pcb-exposure-using-uv-light-led-box/

This does work, just need to make a pcb first

Richard

--- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@> wrote:
> >
> > Ok I have had enough tonight of TT
> > 
> > 
> > I need to get 10 little 2 inch * 2 1/2 inch boards done. (only 
holds a
> > pic and some transistors)
> > 
> > I can buy the developer for £1.20, I can get a 8*4 board for 
£1.20, so
> > for £3.60 I can get everything, except a source of UV..........
> > 
> > I have heard that outside in sunlight can work, any truth in this?
> > anyone else do this?
> > 
> > I have never done UV before, so have no idea on where to go with
> > exposure times etc.
> > 
> > I happen to have a 9w UV light on the garden pond to kill algae, 
can
> > that be used (badly!)
> > 
> > 
> > 
> > 
> > -- 
> > 
> > Lez
> >
> 
> 
> 
> Mercury vapor bulbs will work the best and give the fastest 
exposure.
> Another way is to get a cheap 500 watt quartz halogen work lamp and
> use it for UV exposure. They cost about $8 to $10 USD. May work even
> faster if you remove any glass filter lens as this may block some of
> the UV. I tried it once and it took 2 minutes at a distance of one
> foot. The etching resist was negative acting dry film. Positive 
resist
> will take much longer.
>

On Thursday 01 February 2007 18:25, Lez wrote:
> Ok I have had enough tonight of TT
>
>
> I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
> pic and some transistors)
>
> I can buy the developer for £1.20, I can get a 8*4 board for £1.20, so
> for £3.60 I can get everything, except a source of UV..........
>snip<
30 years or so ago I made a BUNCH prototype boards both at home and at work 
using #2 photofloods (IIRC 300W). A sheet of plate glass to hold the film in 
contact with the board. IIRC the light was about 6" from board. I'm really 
fuzzy here, but exposure was in the order of 5-10 minutes. The #2 was a 3400 
degree kelvin incandescent bulb used heavily in photo studios back then.  
Quartz halogen was just showing up back then, so I never tired them, but heat 
might be a real problem.

-- 
Keith Bowers - Thomasville, NC

--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
>
> Ok I have had enough tonight of TT
> 
> 
> I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
> pic and some transistors)
> 
> I can buy the developer for £1.20, I can get a 8*4 board for £1.20, so
> for £3.60 I can get everything, except a source of UV..........
> 
> I have heard that outside in sunlight can work, any truth in this?
> anyone else do this?
> 
> I have never done UV before, so have no idea on where to go with
> exposure times etc.
> 
> I happen to have a 9w UV light on the garden pond to kill algae, can
> that be used (badly!)
> 
> 
> 
> 
> -- 
> 
> Lez
>


Hi Lez,
I used to do photo all the time. It's easy once you get the times
down. I used the positve board stock as the process is easier and the
results were excellent. Sunlight is a fairly poor source but cvan be
used. First boards I did were on an overhead projector. I want to
think for about 8 minutes (maybe 10, but I think the 10's were a
little overdone). Any halogen buld is actually a good source of UV so
you could probably expose them under one of those 300w halogen
worklights (just make sue there is no UV coating on the glass).

My actual setup after that was a single blacklight bulb inside of a
curved reflective cover. This woked great & exposure time was only a
couple of minutes. My understanding is the blacklight flourescents are
ideal for pcbs. There coated to emit in the UV region. I also heard
the germ killer lights are no good, Wavelength is to short for pcb.

For the pcb setup I had a piece of plywood and a small sheet of glass
(from a picture frame). Lay the board on the plywood, the artwork on
the board, and the glass over the artwork to keep it pressed down
tight. Under the uv lamp for just a couple of minutes and good to go.

New setup is with 2 15w uv tubes (the smaller ones, 18" T12 I think is
what they are ... I have to check). Going to mount these into a nice
case and set up for photo again. I have a few TT tricks from here I
want to try too but the paper scrubbing one is not my favorite idea of
fun and laminators are out of the picture for me (only have room for
so much stuff).

I'll post when I get some results.  Bert

Don't bother with UK sunshine - unless you only want to
make boards for a few minutes on one morning a year.

Its far too unpredictable: your tests, and your production
pcbs are likely to be inconsistent.

Now, if you moved near the equator, or went for a holiday
up a mountain in the Azores or Canary Islands it might
be different - but you know they won't let you take your
chemicals on the plane :-)

Previous discussion here suggests that you don't need
far UV. (The fact that "UV" LEDs work tends to confirm.)

An ordinary fluorescent tube (or Compact Fluorescent?)
seems to have UV enough. Exposure time was fairly long
but bearable - of the order of 10min @ 10cm.

[There's more stuff on types of tube in the archive.]

When making an exposure test strip, be sure to give the
lamp a couple of minutes to warm up. Fluorescents don't
like the cold, so don't do the experiment in a very cold
place.

[For a production run, the warm-up time can be incorporated
into your standard exposure, but for your test strip it is
important that each exposure step gets the same intensity.]

Don't switch off between test steps either: if you can't quickly
uncover the next step, cover the lamp. A photographer would
use a density wedge or a sliding mask.

The exposure steps should be in a geometric progression,
not a linear one. This will not only give you equal increments
in step density over the linear exposure range but also span
usefully a greater range when the correct exposure range is
unknown  When making the exposure steps, the times
should be in the ratio: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
which will give steps of "half a stop". Choose an initial time
so your best guess of the correct exposure time lies in the
middle of the range.

[You may have seen this range of numbers on the aperture
ring of a camera lens, where they give steps of "one stop",
halving in exposure because they measure F/diameter and
lens aperture area varies as diameter squared.)


Regards, LenW

Hi
I have given up on TT, so I am gonna try photo
method. How do do the artwork(photo mask)?
By that I mean what sort of transparency, printer etc?
Jeri 

-----Original Message-----
From: bertd.geo@...
To: Homebrew_PCBs@yahoogroups.com
Sent: Fri, 2 Feb 2007 9:24 AM
Subject: [Homebrew_PCBs] Re: Photo exposure


--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
>
> Ok I have had enough tonight of TT
> 
> 
> I need to get 10 little 2 inch * 2 1/2 inch boards done. (only holds a
> pic and some transistors)
> 
> I can buy the developer for £1.20, I can get a 8*4 board for £1.20, so
> for £3.60 I can get everything, except a source of UV..........
> 
> I have heard that outside in sunlight can work, any truth in this?
> anyone else do this?
> 
> I have never done UV before, so have no idea on where to go with
> exposure times etc.
> 
> I happen to have a 9w UV light on the garden pond to kill algae, can
> that be used (badly!)
> 
> 
> 
> 
> -- 
> 
> Lez
>

Hi Lez,
I used to do photo all the time. It's easy once you get the times
down. I used the positve board stock as the process is easier and the
results were excellent. Sunlight is a fairly poor source but cvan be
used. First boards I did were on an overhead projector. I want to
think for about 8 minutes (maybe 10, but I think the 10's were a
little overdone). Any halogen buld is actually a good source of UV so
you could probably expose them under one of those 300w halogen
worklights (just make sue there is no UV coating on the glass).

My actual setup after that was a single blacklight bulb inside of a
curved reflective cover. This woked great & exposure time was only a
couple of minutes. My understanding is the blacklight flourescents are
ideal for pcbs. There coated to emit in the UV region. I also heard
the germ killer lights are no good, Wavelength is to short for pcb.

For the pcb setup I had a piece of plywood and a small sheet of glass
(from a picture frame). Lay the board on the plywood, the artwork on
the board, and the glass over the artwork to keep it pressed down
tight. Under the uv lamp for just a couple of minutes and good to go.

New setup is with 2 15w uv tubes (the smaller ones, 18" T12 I think is
what they are ... I have to check). Going to mount these into a nice
case and set up for photo again. I have a few TT tricks from here I
want to try too but the paper scrubbing one is not my favorite idea of
fun and laminators are out of the picture for me (only have room for
so much stuff).

I'll post when I get some results. Bert


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

On 02/02/07, Len Warner <novost@...> wrote:
>
>
>
>
>
>
> Don't bother with UK sunshine - unless you only want to
>  make boards for a few minutes on one morning a year.

lol your right their.


>  An ordinary fluorescent tube (or Compact Fluorescent?)
>  seems to have UV enough. Exposure time was fairly long
>  but bearable - of the order of 10min @ 10cm.

Now that seems a good idea, if 'standard' white tubes work, then all I
need is some 'energy saving' lights, usually about 8 or 11 watt, and
about £1 in netto, 4 of those, in four holders, and a wooden box,
change from £10, not £105 for action mans sunbed from maplin, should
be fine for 8*4 inch board


>  The exposure steps should be in a geometric progression,
>  not a linear one. This will not only give you equal increments

Now I should have thought of that, insyead of 1m , 2m etcm as I used
to take photo's for a hoby many years ago, thanks for remonding me.


-- 

Lez

>  By that I mean what sort of transparency, printer etc?

Actually thats a good question, I'd not given much thought to that, I
only have about OHT sheets left, and those are for inkjet, and I'd
sooner use the laser as toner will give more contrast, so I need to
buy some OHT sheets for the laser.

Lez

What sort of inkjet have you got? Epson Durabrite ink produces very good 
quality prints. For some reason red seems to work best. I find toner 
tends to end up a bit grey.

Les


Lez wrote:

>>  By that I mean what sort of transparency, printer etc?
>>     
>
> Actually thats a good question, I'd not given much thought to that, I
> only have about OHT sheets left, and those are for inkjet, and I'd
> sooner use the laser as toner will give more contrast, so I need to
> buy some OHT sheets for the laser.
>
> Lez
>

On 02/02/07, Leslie Newell <lesnewell@...> wrote:
>
>
>
>
>
>
> What sort of inkjet have you got? Epson Durabrite ink produces very good
>  quality prints. For some reason red seems to work best. I find toner
>  tends to end up a bit grey

Its the flat feeding 900, that I'm now told does not do durabrite, but
I have a cx3200 that I think does, but both have got cheap dye carts
in as they currently get worked to death by the kids printing pictures
to stick into their school work..........

I have the HP4l, has thick toner, getting worried it may need filling
one day....

>
>  Les
>
>
>  Lez wrote:
>  >>  By that I mean what sort of transparency, printer etc?
>  >>
>  >
>  > Actually thats a good question, I'd not given much thought to that, I
>  > only have about OHT sheets left, and those are for inkjet, and I'd
>  > sooner use the laser as toner will give more contrast, so I need to
>  > buy some OHT sheets for the laser.
>  >
>  > Lez
>  >
>
>
>
>                   



-- 

Lez

>It's compressed paper in the middle, with thin fibreglass on both 
>sides, and copper on one or both sides. It's available from Mega 
>Electronics and Farnell.

How well can it handle "baking" in a TO?

--- In Homebrew_PCBs@yahoogroups.com, "Leon" <leon355@...> wrote:
>

----- Original Message ----- 

From: <laxt57@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, February 02, 2007 3:44 PM
Subject: Re: [Homebrew_PCBs] Re: Photo exposure


Hi
I have given up on TT, so I am gonna try photo
method. How do do the artwork(photo mask)?
By that I mean what sort of transparency, printer etc?

I get very good results with an HP Deskjet 5940 and Mega Electronics Premium 
Jetstar film. The film is expensive so I cut a piece slightly larger than 
the PCB and stick it to a sheet of ordinary A4 paper with masking tape.

Leon

----- Original Message ----- 

From: "derekhawkins" <eldata@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, February 02, 2007 4:27 PM
Subject: [Homebrew_PCBs] Re: Photo exposure


> >It's compressed paper in the middle, with thin fibreglass on both 
>>sides, and copper on one or both sides. It's available from Mega 
>>Electronics and Farnell.
> 
> How well can it handle "baking" in a TO?

It seems OK, but I've only tried it a couple of times.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

At 7:52 am ((PST)) Fri Feb 2, 2007, Lez wrote:

>On 02/02/07, Len Warner <novost@...> wrote:
> >  The exposure steps should be in a geometric progression
> >  [snip] When making the exposure steps, the times
> >  should be in the ratio: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
>
>Now I should have thought of that, insyead of 1m , 2m etcm as I used
>to take photo's for a hoby many years ago, thanks for remonding me.

Also, it's probably less stressful on the experimenter
to _cover_ the board in steps, rather than uncover it.

This is because it gets the 'fine detail' of the short
exposures out of the way first and the longer ones
do not require such precise timing. Otherwise, your
stress builds up as you proceed ;-)


Regards, LenW

I may be wrong, but that looks like the aperture series.  Time should be a simple series of multiples of some base time like 30 seconds, one minute, etc.  No?

  ----- Original Message ----- 
  From: Len Warner 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Saturday, February 03, 2007 12:48 AM
  Subject: [Homebrew_PCBs] Re: Photo exposure


  At 7:52 am ((PST)) Fri Feb 2, 2007, Lez wrote:

  >On 02/02/07, Len Warner <novost@...> wrote:
  > > The exposure steps should be in a geometric progression
  > > [snip] When making the exposure steps, the times
  > > should be in the ratio: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
  >
  >Now I should have thought of that, insyead of 1m , 2m etcm as I used
  >to take photo's for a hoby many years ago, thanks for remonding me.

  Also, it's probably less stressful on the experimenter
  to _cover_ the board in steps, rather than uncover it.

  This is because it gets the 'fine detail' of the short
  exposures out of the way first and the longer ones
  do not require such precise timing. Otherwise, your
  stress builds up as you proceed ;-)

  Regards, LenW 



   

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

First attempt to post failed:

> From a practical perspective, it does not much matter as you point out. 
> But
> I cut my teeth in a darkroom following the Ansel Adams zone exposure 
> scheme
> of things.  Also, being and engineering type tends to urge the use of
> logical procedures.  If you make the exposure steps meaningful such that
> they realistically relate to exposure, then you wind up with more useful
> information.  It should also be noted that when you move your light source
> twice the previous distance from the exposure frame, you wind up with 1/4
> the exposure (inverse square law).
>
> I still have no idea why he recommended using the if stop ratios for the
> exposure multiples...
>>
>> About photo exposure: i think it matters little how you distribute the
>> series, as long as you end up knowing the ideal time. Finding the correct
>> distribution for least effort seems more of a mathematical or
>> philosophical question. You can always narrow the range down or extend it
>> if you need more data.
>> One thing i noticed is if you do not let the light warm up it may be best
>> to start with the shortest time and cover the PCB up gradually, so that
>> the short times get realistic "from cold" exposure.
>>
>> ST
>

Actually........ there are long established rules for quoting, pre- 
dating the BBS and Internet days.

It's like those rules about not driving through flashing red traffic  
lights in my country. We have a lot of people that never heard of the  
concept when they were younger, and thus we now have a lot of people  
in my town that simply don't follow that old rule either.

;^)

So, here is a link to those nearly forgotten quidelines.......

http://www.dtcc.edu/cs/rfc1855.html

Allow me to quote a couple of those.......

******************
[from] 3.0 One-to-Many Communication (Mailing Lists, NetNews)

If you are sending a reply to a message or a posting be sure you  
summarize the original at the top of the message, or include just  
enough text of the original to give a context. This will make sure  
readers understand when they start to read your response. Since  
NetNews, especially, is proliferated by distributing the postings  
from one host to another, it is possible to see a response to a  
message before seeing the original. Giving context helps everyone.  
But do not include the entire original!

If you should find yourself in a disagreement with one person, make  
your responses to each other via mail rather than continue to send  
messages to the list or the group. If you are debating a point on  
which the group might have some interest, you may summarize for them  
later.

******************

They sure aren't laws. But they sure seem to be good ideas to know  
and follow.

Best to ya'
Mike Bauers
Milwaukee Wi, USA

On Feb 4, 2007, at 10:48 AM, AnaLog Services, Inc. wrote:

> You are certainly a rude lil cuss!  Top posting is not uncommon,  
> and there
> are those who prefer it.  It is simply a matter of taste, and there  
> is no
> "law" on the issue notwitstanding the protestations of the net  
> nannies out
> there.
>
> Those of us with slow dialup connections find looking at posts in the
> archives to be a very painful experience.  So if one were inclined to
> complain, one might point out that you did not include enough  
> information in
> your post to understand what you were talking about.  That is fine  
> in a
> private email, but this is a reflector mailing list, and some fool  
> like
> myself is going to be puzzled.
>
> I am still puzzled.  Why the "f stop" series for step exposure  
> times?  Take
> a look at any adjustable camera.  The aperature follows the  
> convention you
> state, but the shutter speed is a simple progression with each step  
> doubling
> the last.  One f stop change is equivalent to the doubling or  
> halfing of the
> shutter speed.  Simple physics here.  If you are doing a step test to
> determine proper / optimum exposure, then there is no reason to use  
> the f
> stop series as your exposure multiplier.  If you are up to  
> something else,
> then...nevermind.
>
> Syd H. Levine
> AnaLog Services, Inc.
> Phone:  (270) 276-5671
> Telefax:  (270) 276-5588
> E-mail:  analog@...
> Web URL:  www.logwell.com
>
> ----- Original Message -----
> From: Len Warner
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Sunday, February 04, 2007 7:39 AM
> Subject: [Homebrew_PCBs] Re: Photo exposure
>
>
> At 8:23 am ((PST)) Sat Feb 3, 2007, AnaLog Services, Inc. wrote:
>> I may be wrong, but that looks like the aperture series. Time  
>> should be a
>> simple series of multiples of some base time like 30 seconds, one  
>> minute,
>> etc. No?
>
> The post is accurate as it stands: I've explained it all in the  
> thread:
> Lez was accepting my previous advice which I then augmented.
>
> Lez didn't choose to quote all the relevant part of my post and
> I didn't choose to _reinsert_ more than was required to reply.
>
> If it's not in your old email, it's in the archive. I'm not going  
> to repeat
> it for a top-poster who trashes threads instead of following them. ;-)
>
> Regards, LenW

--- In Homebrew_PCBs@yahoogroups.com, laxt57@... wrote:
>
> Hi
> I have given up on TT, so I am gonna try photo
> method. How do do the artwork(photo mask)?
> By that I mean what sort of transparency, printer etc?
> Jeri 
>  
>  


I use a CAD program and a Laser Printer. Makes it easy to make a
positive. Most CAD programs can also generate a negative but good luck
getting that much toner to produce well (loads up the transfer roller
and starts to smudge) not to mention the amount of toner used. I think
to go negative successfully you still need to produce a positive from
the printer and then use a photographic method to make the negative.
This extra step is why I've always used the positive method.
I used an HP Laserjet printer, I set the toner retention to high, and
would print on laser transparency stock (make sure it's for laser
printers so it wont melt when going thru). Even so, there are
sometimes some pinholes. A sharpie marker covers these pretty good , a
dap of black paint with a toothpick is even better. I would guess an
inkjet might work equally well but never tried it. The ink might be
somewhat translucent. For the software I used to use P-CAD and then
Or-CAD.  Getting back into it I'm giving DipTrace a try. The OrCAD
demo can't make a large enough board and I can't afford even their
cheapest package and my P-CAD is an old. So far the DipTrace looks
really good, a great demo package, and their prices are quite
reasonable to upgrade to the full thing. The demo package has
everything but the gerbers but you can print individual layers to make
artwork for the pcb for home use. It's a start anyways.

I'm close to trying a few things so I'll let you know. Going to throw
the new UV box together this week I think. 
Bert

Hi
Thanks for the info!!!!
Jeri 

-----Original Message-----
From: bertd.geo@...
To: Homebrew_PCBs@yahoogroups.com
Sent: Mon, 5 Feb 2007 9:20 AM
Subject: [Homebrew_PCBs] Re: Photo exposure


--- In Homebrew_PCBs@yahoogroups.com, laxt57@... wrote:
>
> Hi
> I have given up on TT, so I am gonna try photo
> method. How do do the artwork(photo mask)?
> By that I mean what sort of transparency, printer etc?
> Jeri 
> 
> 

I use a CAD program and a Laser Printer. Makes it easy to make a
positive. Most CAD programs can also generate a negative but good luck
getting that much toner to produce well (loads up the transfer roller
and starts to smudge) not to mention the amount of toner used. I think
to go negative successfully you still need to produce a positive from
the printer and then use a photographic method to make the negative.
This extra step is why I've always used the positive method.
I used an HP Laserjet printer, I set the toner retention to high, and
would print on laser transparency stock (make sure it's for laser
printers so it wont melt when going thru). Even so, there are
sometimes some pinholes. A sharpie marker covers these pretty good , a
dap of black paint with a toothpick is even better. I would guess an
inkjet might work equally well but never tried it. The ink might be
somewhat translucent. For the software I used to use P-CAD and then
Or-CAD. Getting back into it I'm giving DipTrace a try. The OrCAD
demo can't make a large enough board and I can't afford even their
cheapest package and my P-CAD is an old. So far the DipTrace looks
really good, a great demo package, and their prices are quite
reasonable to upgrade to the full thing. The demo package has
everything but the gerbers but you can print individual layers to make
artwork for the pcb for home use. It's a start anyways.

I'm close to trying a few things so I'll let you know. Going to throw
the new UV box together this week I think. 
Bert


 
________________________________________________________________________
Check out the new AOL.  Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more.


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

>I would guess an inkjet might work equally well but never tried it.

Inkjet works much better on transparencies.

>The ink might be somewhat translucent. 

Nope! As opaque as it gets, so much so that one can overexpose inkjet 
artwork by several minutes and not see any ill effects. Don't try that 
with laser artwork on transparencies or it will be pitsville (pitted 
copper surface similar to TT boards) after etching.

--- In Homebrew_PCBs@yahoogroups.com, "Bert" <bertd.geo@...> wrote:
>

>Inkjet works much better on transparencies.

Another issue with laser artwork is dimensional accuracy. Boards made 
from laser artwork (whether TT or photo) can have the pads so badly 
misplaced that using CNC drilling becomes a frustrating experience. 
Inkjet artwork is much better in this respect also. The only thing 
laser artwork has over inkjet is smoother edges. These are all best 
case scenarios BTW.

--- In Homebrew_PCBs@yahoogroups.com, "derekhawkins" <eldata@...> wrote:
>

On Mon, 05 Feb 2007 19:05:52 +0100, derekhawkins <eldata@...> wrote:

> Another issue with laser artwork is dimensional accuracy. Boards made
> from laser artwork (whether TT or photo) can have the pads so badly
> misplaced that using CNC drilling becomes a frustrating experience.
> Inkjet artwork is much better in this respect also. The only thing
> laser artwork has over inkjet is smoother edges. These are all best
> case scenarios BTW.


Yes, but some things can be calibrated (skew and stuff). It won't get  
perfect, but combined with adjusted x/y scaling in software you should get  
a printout that does not cause too much trouble. Check the printer service  
manual for adjustments.

ST

>Yes, but some things can be calibrated (skew and stuff). It won't get
>perfect, but combined with adjusted x/y scaling in software you 
>should get a printout that does not cause too much trouble. 

Fiddledeedee, fiddledeedum, waste of time unless a laser printer is all 
you have or you're confined to TT. Photo exposure gives you a choice 
and Inkjet is the clear winner there.

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>

----- Original Message ----- 

From: "derekhawkins" <eldata@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, February 05, 2007 7:55 PM
Subject: [Homebrew_PCBs] Re: Photo exposure


> >Yes, but some things can be calibrated (skew and stuff). It won't get
>>perfect, but combined with adjusted x/y scaling in software you
>>should get a printout that does not cause too much trouble.
>
> Fiddledeedee, fiddledeedum, waste of time unless a laser printer is all
> you have or you're confined to TT. Photo exposure gives you a choice
> and Inkjet is the clear winner there.

I agree. I get much better results with a cheap inkjet printer than I ever 
got with a laser printer.

Leon

What I have found to work best is inkjet transparency film and print 
with yellow ink as it gives better UV filtering than the black ink.

I used a HP CP 1700 Inkjet printer and the HP inkjet transparency film 
with MG Chemical's  600 series boards.

For a example of a etched board the photo on the Home page is one of 
mine.

One problem that I have is that I just changed from Ivex Winboard to 
using DipTrace and right now Diptrace will only print black.  Color 
printing to be available in the next update sometime this spring.  
Diptrace is far better software than Ivex ever was.  


Ben

--- In Homebrew_PCBs@yahoogroups.com, "Leon" <leon355@...> wrote:
>
> ----- Original Message ----- 
> From: "derekhawkins" <eldata@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Monday, February 05, 2007 7:55 PM
> Subject: [Homebrew_PCBs] Re: Photo exposure
> 
> 
> > >Yes, but some things can be calibrated (skew and stuff). It 
won't get
> >>perfect, but combined with adjusted x/y scaling in software you
> >>should get a printout that does not cause too much trouble.
> >
> > Fiddledeedee, fiddledeedum, waste of time unless a laser printer 
is all
> > you have or you're confined to TT. Photo exposure gives you a 
choice
> > and Inkjet is the clear winner there.
> 
> I agree. I get much better results with a cheap inkjet printer 
than I ever 
> got with a laser printer.
> 
> Leon
>

I have to agree that positive photo method if far easier and better 
than TT.  I read on here what some seem to go thru to do the TT 
method to get good results.  I find the positive photo method much 
much easier.  I guess if you don't do this much TT might be a way to 
go but if you do boards very often and have a place you can setup a 
exposure frame and a etching tank you can produce boards very easily 
with better results.  For most it seems that TT method is hit and 
miss on getting a good board as can be seen in the photo of that one 
post.  I know that there or some on here that seem to really have 
the TT method down and have good results, but I have a idea that it 
took them a while to get to that point too.

Ben

On Wed, 14 Feb 2007 03:17:34 +0100, Ben <bhleavi@...> wrote:

>
> I have to agree that positive photo method if far easier and better
> than TT.  I read on here what some seem to go thru to do the TT
> method to get good results.  I find the positive photo method much
> much easier.  I guess if you don't do this much TT might be a way to
> go but if you do boards very often and have a place you can setup a
> exposure frame and a etching tank you can produce boards very easily
> with better results.  For most it seems that TT method is hit and
> miss on getting a good board as can be seen in the photo of that one
> post.  I know that there or some on here that seem to really have
> the TT method down and have good results, but I have a idea that it
> took them a while to get to that point too.
> Ben


I have spent more time trying, with little success, to get decent  
photoboards than TT, the problems work the other way around too.
I do know what some of the mistakes were, and i have no doubt i could have  
gotten it right if i put in more effort.

For your situation photoprocess may well be better, but there are several  
strong points in favour of TT:

Low cost of PCB material (or no cost and effort of sensitizing).
No shelf-life limit of PCB stock, i do few boards (a couple a week) and  
prefer to buy bulk.
Speed of production (not even with a professional exposure frame and  
developer tank was i able to make small boards faster).
No inkjet required (for me maintaining an inkjet is a nightmare, the major  
annoyance with direct inkjet printing).
No chemicals other than water and etchant required.
Photo paper is only about the same cost as transparencies.
Component legend capability (90% or more of my boards have component  
legend, how would i make that with photo?).

Both processes are reliable, and produce good results. I don't think one  
can reliably predict where someone would have more trouble. You can make  
mistakes with both. The right tools must be used, and the right materials,  
and the right procedure, then both will work just fine, if you do not do  
that both processes will fail just as miserably.

I don't think one should decide which process to use by following a single  
opinion, it is well established here that both methods work and none is  
always easier. I think one should look at the needs (quantity, one-offs or  
series, space, investment, ... many more) and then decide which method is  
more suitable. It does IMO not make much sense to try to get by without  
minimal gear (for example working with a clothes iron is just as  
unreliable as not using a proper exposure device), so one should set up  
properly from the start. Look at it in detail, decide which is more  
suitable for yourself, and then stick with it and get it to work. I don't  
think there is any excuse for not getting either process to work reliably,  
because there are just too many people using them with good results. In  
other words, if it didn't work, it's your fault and not the process. One  
should decide on the merits of the one or the other, not on some worry it  
might not work, both _WILL_ work with enough attention to detail.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Ben" <bhleavi@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "Leon" <leon355@> wrote:
> >
> > ----- Original Message ----- 
> > From: "derekhawkins" <eldata@>
> > To: <Homebrew_PCBs@yahoogroups.com>
> > Sent: Monday, February 05, 2007 7:55 PM
> > Subject: [Homebrew_PCBs] Re: Photo exposure
> > 
> 
> I have to agree that positive photo method if far easier and better 
> than TT.  I read on here what some seem to go thru to do the TT 
> method to get good results.  I find the positive photo method much 
> much easier.  I guess if you don't do this much TT might be a way to 
> go but if you do boards very often and have a place you can setup a 
> exposure frame and a etching tank you can produce boards very easily 
> with better results.  For most it seems that TT method is hit and 
> miss on getting a good board as can be seen in the photo of that one 
> post.  I know that there or some on here that seem to really have 
> the TT method down and have good results, but I have a idea that it 
> took them a while to get to that point too.
> 
> Ben
>

Hey Ben, Thanks for the note on the yellow inkjet for UV ... that's
interesting. I wouldn't have guessed that yellow would be better than
black???

I agree, I've seen some really good TT examples that make it tempting
but it seems a lot of people really struggle with it. I tried it a few
years ago with the Pulsar TT that is easily available from DigiKey. My
results were always about the same, about 98% effective. There were
always a few spots that the toner just didn't bond well to. I also
usually got some etching at the edges. The photo process never did
this and the learning curve is only a couple of boards. Once the
exposure time is dialed in, the rest is pretty straight forward. 

I like the one tip of printing 2 artworks and then stacking them. I'm
going to give that a shot with the laser. Should eliminate pinholes
100%. Going to try the 

btw - Just switched to DipTrace myself. So far I like it. If you
really wanted yellow, there's a program out there called GC-Prevue.
It's a gerber viewer (the viewer is free) and I think it would allow
selecting different colors for printing. Only hitch is it requires a
gerber and there's no gerbers in the free DipTrace.
Bert

I have done the stacking of two black artworks, does work but can be 
a pain to get lined up and all.  Also tried printing sheet twice 
which sometimes lined up good and sometimes did not, normally took 
several trys to get one to come out with the double printing.  Once 
I started printing in yellow ink it works Great.  Yes you can kind 
of see thru the yellow ink but it is a filter to UV.  Also set 
printer for Best printing and if you can adjust the amount of ink 
used set it to max if you can.


Ben



> Hey Ben, Thanks for the note on the yellow inkjet for UV ... that's
> interesting. I wouldn't have guessed that yellow would be better 
than
> black???
> 
> I agree, I've seen some really good TT examples that make it 
tempting
> but it seems a lot of people really struggle with it. I tried it a 
few
> years ago with the Pulsar TT that is easily available from 
DigiKey. My
> results were always about the same, about 98% effective. There were
> always a few spots that the toner just didn't bond well to. I also
> usually got some etching at the edges. The photo process never did
> this and the learning curve is only a couple of boards. Once the
> exposure time is dialed in, the rest is pretty straight forward. 
> 
> I like the one tip of printing 2 artworks and then stacking them. 
I'm
> going to give that a shot with the laser. Should eliminate pinholes
> 100%. Going to try the 
> 
> btw - Just switched to DipTrace myself. So far I like it. If you
> really wanted yellow, there's a program out there called GC-Prevue.
> It's a gerber viewer (the viewer is free) and I think it would 
allow
> selecting different colors for printing. Only hitch is it requires 
a

> gerber and there's no gerbers in the free DipTrace.
> Bert
>

I agree one should decide which method fits their needs, and that 
will depend on a number of things, as how many boards do you make, 
do you make a number of the same board, available space, etc. If you 
are making a number of the same boards then the same transpancy can 
be used over and over and over. 

Myself I like the positive photo method, where as Steffan (hope a 
spelled it right) likes the TT method and seems to get very good 
results from it.  I make a lot of the same boards over and over 
where as I think Steffan may do more one of a kind boards.

Either process takes time to learn the different exposure times or 
amount and time of heat.  Type of printer you have, and what paper 
works best with your printer and your transfer method that you have 
decided to do.  If you have a laser print TT most likely is your 
best bet.  If you have a good inkjet then positive photo method 
maybe your best bet.


Ben

 

> I have spent more time trying, with little success, to get decent  
> photoboards than TT, the problems work the other way around too.
> I do know what some of the mistakes were, and i have no doubt i 
could have  
> gotten it right if i put in more effort.
> 
> For your situation photoprocess may well be better, but there are 
several  
> strong points in favour of TT:
> 
> Low cost of PCB material (or no cost and effort of sensitizing).
> No shelf-life limit of PCB stock, i do few boards (a couple a 
week) and  
> prefer to buy bulk.
> Speed of production (not even with a professional exposure frame 
and  
> developer tank was i able to make small boards faster).
> No inkjet required (for me maintaining an inkjet is a nightmare, 
the major  
> annoyance with direct inkjet printing).
> No chemicals other than water and etchant required.
> Photo paper is only about the same cost as transparencies.
> Component legend capability (90% or more of my boards have 
component  
> legend, how would i make that with photo?).
> 
> Both processes are reliable, and produce good results. I don't 
think one  
> can reliably predict where someone would have more trouble. You 
can make  
> mistakes with both. The right tools must be used, and the right 
materials,  
> and the right procedure, then both will work just fine, if you do 
not do  
> that both processes will fail just as miserably.
> 
> I don't think one should decide which process to use by following 
a single  
> opinion, it is well established here that both methods work and 
none is  
> always easier. I think one should look at the needs (quantity, one-
offs or  
> series, space, investment, ... many more) and then decide which 
method is  
> more suitable. It does IMO not make much sense to try to get by 
without  
> minimal gear (for example working with a clothes iron is just as  
> unreliable as not using a proper exposure device), so one should 
set up  
> properly from the start. Look at it in detail, decide which is 
more  
> suitable for yourself, and then stick with it and get it to work. 
I don't  
> think there is any excuse for not getting either process to work 
reliably,  
> because there are just too many people using them with good 
results. In  
> other words, if it didn't work, it's your fault and not the 
process. One  
> should decide on the merits of the one or the other, not on some 
worry it  

> might not work, both _WILL_ work with enough attention to detail.
> 
> ST
>

>I have done the stacking of two black artworks, does work but can be
>a pain to get lined up and all. Also tried printing sheet twice
>which sometimes lined up good and sometimes did not

This couldn't be an Epson inkjet. If it is then you aren't using the 
right transparencies. If it isn't then it could also be a transparency 
mismatch. I can see somebody needing to do the above with laser 
transparency artwork but not inkjet unless something was terribly wrong.

--- In Homebrew_PCBs@yahoogroups.com, "Ben" <bhleavi@...> wrote:
>