printed circuit board exposure
ka4hjh at gte.net
Sun Jan 2 05:13:44 CET 2000
The most convenient thing is an exposure frame. Check out
Here you will find the plans for a really snazzy one (using commonly
available stuff), as well as just about everything else you might
need for fabricating PCB's (tanks, aereators, etc.). This place is a
goldmine of info.
> Don't even bother with exposing to sunlight-the insolation of UV is too
>variable based on air density/water vapor.
I've had success using sun exposure with Kepro's laminated film
system, but there are limits:
1. The sun has to be out
2. The amount of UV varies a lot. The peak is in the middle of the
day. When the sun is lower in the sky (early/late in the day, or in
the winter) the amount of UV-B drops off considerably. Fortunately,
this system produces a latent image on the resist so you can tell if
you got the exposure.
I got good exposures in October and early November in about 50 seconds.
>As for halogen lamps, in
>order to get UV out of them you have to remove the quartz glass (as on a
>halogen work light), and then the device becomes quite dangerous in terms
>of UV exposure.
Just like any old sunlamp (you don't see many of those for sale
anymore). I don't know what that transparent material is, but it's
not pure quartz, as that transmits UV. The "bulb" itself is quartz.
Terry Bowman, KA4HJH
"The Mac Doctor"
More information about the Synth-diy