Homebrew PCBs

I've just bought a ballast to go with a mercury lamp I bought on Ebay. I've 
just connected them up and the lamp is working OK. I rather stupidly put it 
on the bed with a dressing gown over it to keep the cat away, smelt burning 
a few minutes later and found the lamp had burnt the duvet cover and the 
dressing gown. 8-(

Next step is to remove the outer envelope and do some test exposures. I'll 
rig up a suitable box to keep the UV away from me.

Leon
--
Leon Heller, G1HSM
Suzuki SV1000S motorcycle
leon.heller@...
http://www.geocities.com/leon_heller

do not remove the outer envelope. first make test exposures (with envelope).

Leon Heller <leon.heller@...> wrote:          

Next step is to remove the outer envelope and do some test exposures. I'll 
rig up a suitable box to keep the UV away from me.

Leon
--
Leon Heller, G1HSM
Suzuki SV1000S motorcycle
leon.heller@...
http://www.geocities.com/leon_heller 



         

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

At 03:47 AM 10/13/2006, Leon Heller wrote:
>I've just bought a ballast to go with a mercury lamp I bought on Ebay. I've
>just connected them up and the lamp is working OK. I rather stupidly put it
>on the bed with a dressing gown over it to keep the cat away, smelt burning
>a few minutes later and found the lamp had burnt the duvet cover and the
>dressing gown. 8-(
>
>Next step is to remove the outer envelope and do some test exposures. I'll
>rig up a suitable box to keep the UV away from me.

Couple of things: make sure that the phosphor is on the inside 
surface of the OUTER envelope.  That pretty much guarantees that the 
inside bulb is clear, and thus emits UV.

The reason I mention this is that I now see Mercury Vapor bulbs with 
a clear outer envelope.  Box usually mentions that the bulb is "UV 
safe" - this means that the inner bulb doesn't emit UV.

The other important thing is: that inner bulb needs to run hot.  The 
existing outer envelope provides thermal insulation so that the inner 
bulb can operate at the design temperature.

I wound up enclosing the inner bulb within a Hammond die-cast 
aluminum box about 4" x 4" x 7".  A large hole on the bottom allows 
the UV to escape, a mechanical shutter (motor driven) covers the hole 
until the timer switch is hit.

The enclosure allows the bulb to operate near its design temperature: 
its air-tight other than the single large hole facing downwards.  I 
find that the bulb takes 5 to 10 minutes to come up to operating 
temperature before I use it (don't really pay much attention to it: 
the electronic ballast I use sort of squeals until the bulb reaches 
operating temperature).

The whole thing works well - I'm on my 2nd bulb now.

dwayne

-- 
Dwayne Reid   <dwayner@...>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax

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

From: "Dwayne Reid" <dwayner@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, October 13, 2006 5:25 PM
Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure


> At 03:47 AM 10/13/2006, Leon Heller wrote:
>>I've just bought a ballast to go with a mercury lamp I bought on Ebay. 
>>I've
>>just connected them up and the lamp is working OK. I rather stupidly put 
>>it
>>on the bed with a dressing gown over it to keep the cat away, smelt 
>>burning
>>a few minutes later and found the lamp had burnt the duvet cover and the
>>dressing gown. 8-(
>>
>>Next step is to remove the outer envelope and do some test exposures. I'll
>>rig up a suitable box to keep the UV away from me.
>
> Couple of things: make sure that the phosphor is on the inside
> surface of the OUTER envelope.  That pretty much guarantees that the
> inside bulb is clear, and thus emits UV.
>
> The reason I mention this is that I now see Mercury Vapor bulbs with
> a clear outer envelope.  Box usually mentions that the bulb is "UV
> safe" - this means that the inner bulb doesn't emit UV.

Yes, I checked that.

>
> The other important thing is: that inner bulb needs to run hot.  The
> existing outer envelope provides thermal insulation so that the inner
> bulb can operate at the design temperature.
>
> I wound up enclosing the inner bulb within a Hammond die-cast
> aluminum box about 4" x 4" x 7".  A large hole on the bottom allows
> the UV to escape, a mechanical shutter (motor driven) covers the hole
> until the timer switch is hit.

That's a good idea, I think I'll do the same. I've got a ceramic socket for 
the lamp.

Leon
--
Leon Heller, G1HSM
Suzuki SV1000S motorcycle
leon.heller@...
http://www.geocities.com/leon_heller

Hello Leon,

  Friday, October 13, 2006, 11:47:42 AM, you wrote:

> I've just bought a ballast to go with a mercury lamp I bought on Ebay. I've 
> just connected them up and the lamp is working OK. I rather stupidly put it 
> on the bed with a dressing gown over it to keep the cat away, smelt burning 
> a few minutes later and found the lamp had burnt the duvet cover and the 
> dressing gown. 8-(

> Next step is to remove the outer envelope and do some test exposures. I'll 
> rig up a suitable box to keep the UV away from me.

> Leon
> --
> Leon Heller, G1HSM
> Suzuki SV1000S motorcycle
> leon.heller@...
> http://www.geocities.com/leon_heller 


  PLEASE DO NOT BREAK THE OUTER GLASS!

  You  will end up with lot of shortwave UV AKA UV-C. Photoresists are
  sensitive  (peak)  arround  340  nm  AKA UV-A. Also with outer shell
  removed,  you  will  generate  lot  of  ozone (O3) which reacts with
  haemoglobine  in  your  red  blood  cells  and other cells that need
  oxygen can not use in 'cause it's not O2.

  UV-C  can produce severe skin damage and is 'tethal' to your retina.
  Irreversible sight damage.

-- 
 Best regards,
 Zoran A. Scepanovic
 zastos@...

*********
To estimate the time it takes to do a task:
 estimate the time you think it should take, multiply by two and change the unit of measure to the next highest unit.
 Thus, we allocate two days for a one hour task. 
*********

Please be advised what was said may be absolutely wrong, 
and hereby this disclaimer follows.  
I reserve the right to be wrong and admit it in front of the entire world.



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

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

From: "Zoran A. Scepanovic" <zastos@...>
To: "Leon Heller" <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, October 14, 2006 6:31 PM
Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure


> Hello Leon,
>
>  Friday, October 13, 2006, 11:47:42 AM, you wrote:
>
>> I've just bought a ballast to go with a mercury lamp I bought on Ebay. 
>> I've
>> just connected them up and the lamp is working OK. I rather stupidly put 
>> it
>> on the bed with a dressing gown over it to keep the cat away, smelt 
>> burning
>> a few minutes later and found the lamp had burnt the duvet cover and the
>> dressing gown. 8-(
>
>> Next step is to remove the outer envelope and do some test exposures. 
>> I'll
>> rig up a suitable box to keep the UV away from me.
>
>> Leon
>> --
>> Leon Heller, G1HSM
>> Suzuki SV1000S motorcycle
>> leon.heller@...
>> http://www.geocities.com/leon_heller
>
>
>  PLEASE DO NOT BREAK THE OUTER GLASS!
>
>  You  will end up with lot of shortwave UV AKA UV-C. Photoresists are
>  sensitive  (peak)  arround  340  nm  AKA UV-A. Also with outer shell
>  removed,  you  will  generate  lot  of  ozone (O3) which reacts with
>  haemoglobine  in  your  red  blood  cells  and other cells that need
>  oxygen can not use in 'cause it's not O2.
>
>  UV-C  can produce severe skin damage and is 'tethal' to your retina.
>  Irreversible sight damage.

It will be mounted in a light-tight box.

Leon

On Sat, 14 Oct 2006 19:51:57 +0200, Leon Heller  
<leon.heller@...> wrote:

>
> It will be mounted in a light-tight box.
> Leon


But in case it does no good (or little good) what is the point in breaking  
the envelope?
Does it really speed up exposure that much?

ST

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

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, October 14, 2006 8:01 PM
Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure


> On Sat, 14 Oct 2006 19:51:57 +0200, Leon Heller
> <leon.heller@...> wrote:
>
>>
>> It will be mounted in a light-tight box.
>> Leon
>
>
> But in case it does no good (or little good) what is the point in breaking
> the envelope?
> Does it really speed up exposure that much?

Everyone else using them does it. It will also help with collimation as it 
will be more like a point source. The high-speed exposure units used by PCB 
manufacturers use much more powerful mercury arc lamps with special optical 
systems consuming 3.5 kW or more and delivering 15 mW/sq cm of UV at the 
PCB!

Leon

"envelope or not?" poll question.

Leon Heller <leon.heller@...> wrote:  ----- Original Message ----- 

From: "Stefan Trethan" 
To: 
Sent: Saturday, October 14, 2006 8:01 PM
Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure


> On Sat, 14 Oct 2006 19:51:57 +0200, Leon Heller
> wrote:
>
>>
>> It will be mounted in a light-tight box.
>> Leon
>
>
> But in case it does no good (or little good) what is the point in breaking
> the envelope?
> Does it really speed up exposure that much?

Everyone else using them does it. It will also help with collimation as it 
will be more like a point source. The high-speed exposure units used by PCB 
manufacturers use much more powerful mercury arc lamps with special optical 
systems consuming 3.5 kW or more and delivering 15 mW/sq cm of UV at the 
PCB!

Leon 



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

I've used a 400 watt hi-bay lamp (480V ballast) without an envelope 
since 1973 - same bulb still going strong.  Just keep it in a complete 
enclosure with a slot to insert the PCB sandwich.

Norm

guja wrote:
>
> "envelope or not?" poll question.
>
> Leon Heller <leon.heller@... 
> <mailto:leon.heller%40bulldoghome.com>> wrote: ----- Original Message 
> -----
> From: "Stefan Trethan"
> To:
> Sent: Saturday, October 14, 2006 8:01 PM
> Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure
>
> > On Sat, 14 Oct 2006 19:51:57 +0200, Leon Heller
> > wrote:
> >
> >>
> >> It will be mounted in a light-tight box.
> >> Leon
> >
> >
> > But in case it does no good (or little good) what is the point in 
> breaking
> > the envelope?
> > Does it really speed up exposure that much?
>
> Everyone else using them does it. It will also help with collimation 
> as it
> will be more like a point source. The high-speed exposure units used 
> by PCB
> manufacturers use much more powerful mercury arc lamps with special 
> optical
> systems consuming 3.5 kW or more and delivering 15 mW/sq cm of UV at the
> PCB!
>
> Leon
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs 
> <http://groups.yahoo.com/group/Homebrew_PCBs>
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> <http://groups.yahoo.com/group/Homebrew_PCBs_Archives/>
> Yahoo! Groups Links
>
>
> ---------------------------------
> Get your own web address for just $1.99/1st yr. We'll help. Yahoo! 
> Small Business.
>
> [Non-text portions of this message have been removed]
>
>  


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

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

From: "Norm Stewart" <w6nim@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, October 15, 2006 1:36 AM
Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure


> I've used a 400 watt hi-bay lamp (480V ballast) without an envelope
> since 1973 - same bulb still going strong.  Just keep it in a complete
> enclosure with a slot to insert the PCB sandwich.

The high-power exposure units use special "short arc" lamps, which emit a 
lot of UV at the correct frequency. They give a very intense point source, 
which is ideal, but are not very easy to use having very high trigger 
voltages and high operating temperatures. They can also explode 
unpredictably and have a short life. It would be nice to have one of those, 
but they are simply too dangerous, even for me. 8-)

Leon