The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Da Man"
Subject: Re: homemade uv exosure unit
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
X-MIMEOLE: Produced By Microsoft MimeOLE V5.50.4910.0300
Date: Tue, 24 Dec 2002 23:37:28 GMT
NNTP-Posting-Date: Tue, 24 Dec 2002 19:37:28 AST
I just use an over head projector. I lay the artwork on the window and place
the PCB on top of that. Make sure it's aligned properly, slap some weight on
top to keep the PCB tight on the artwork. Turn the lamp on. Exposure times
can be as short as 45 seconds. I usually expose for 1.5 minutes. Works
awsome, and since the rays are well controlled and spreading in, due to the
frenzel lens below, very sharp images always result. The only problem is
vert large boards can't be done.
The scary part is how much UV people are staring into when they use overhead
projectors :-( Makes me want to wear sunglasses to block the UV when using
them. At least it's mostly long wave UV. Makes me wonder about all the UV
all the halogen bulbs give off commonly in use, and if they cause any long
term exposure problems like cateracts.
BTW, overheads usually use halogen bulbs with special well focused
filaments, rated at 350 - 500 W. A light box could be made with halogen
bulbs, BUT making a safe box that can handle the really high temperatures,
and protection from exploding bulbs is much more complex then using simpler
light sources. A overhead also has the advantage that all most the light
goes out a window not much bigger then then a sheet of paper.
"Leon Heller" wrote in message
> "Spehro Pefhany" wrote in message
> > On Thu, 19 Dec 2002 18:58:21 -0000, the renowned "Leon Heller"
> > wrote:
> > >
> > >I just checked the ones I am using in my home-made unit. They are 8W
> > >Sylvania Blacklite 350. I'm in the UK, so they are 240V.
> > Is there actually any difference between lamps intended for 240V or
> > 120V markets? I had the impression only the ballasts would be
> > different.
> I think you are correct.
> Leon Heller, G1HSM
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup