Homebrew PCBs

pork_u_pine2000 wrote:
> 
> I bought about 100 of each of these grades from BestHongKong and they
> seem entirely satisfactory. I was looking at the absorption maxima
> for organic materials (fish-glue gelatin and some of the
> polysaccharide gums) and found that the 390-395 range looked best, but
> all seem to work. I ended up buying some UV strips with 3 LEDS
> mounted on an aluminum carrier that are set up for 12v. They seem to
> produce more output than I would guess. I have more problem with
> overexposure than with underexposure.

BestHongCong looks like the best so far. Their LED's are rated at 11mW 
and don't know what that translates to in mcd. Anyway the specs are 
better than the other two ebay sellers (which I think are identical 
parts from the same factory). I think around 360nm is optimum for 
photoresists as they are normally designed for exposure with the 365nm 
peak from mercury lamps. The 390-395nm cost only an extra dollar or two 
so I'll get those. What did you mean by "390-395 range looked best" ? 
did it have a better light pattern ?

Adam