> > I use positive phot-resist PCBs, and I know that you need
> > a UV bulb with a "BL" designation, not "BLB".
> >
> > "BL" lamps have a white coating and appear light blue when operating.
> >
> > The "BLB" bulbs are dark purple and filter out too much of the
> > short wavelength UV. Also, "BL" tubes are not to be confused with
> > the clear "germacidal" lamps needed for erasing JW devices or EPROMs,
> > though I would suspect that the germacidal tubes would work OK for
> > exposing the photo-resist.
>
>         Hello, thanks for the info. The tube I have is a BLB one, I'm
hoping though
> that it will still work but just require a longer exposure time.
> Approximately how long does it take for you with the BL bulb? I haven't
been
> able to find one of that type locally. I did find a tube at a local pet
> store used for reptiles. It states that it emits 30% UVB and 8% UVA. I
> assume this is similar to what you've got (it was white in colour when
off,
> don't know what colour when on). The only problem with it is it's too long
a
> tube and pretty pricey. That's why I want to try to use the one I've got,
> but I don't want to experiment until I know more because of the high cost
of
> experimenting. Thanks, TTYL

BLB tubes are the safest you can use, even if they tripple the exposure
time, they are almost completely harmless.
People are working in disco's every night where they have 20-30W BLB's
running continously.
With good photoresist the time can be seriously redused.  (15 mins with 3x
4w)

    KreAture

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