Homebrew PCBs

On 23/08/2011 04:58, thegimp98 wrote:
> I'm just another old guy getting back into making PCBs to support my hobby of vacuum tube amps.
>
> We used to make pcbs when I went to Clemson in the 70s. Spun the boards and poured mask liquid on them to coat them. Dry them and expose to UV with a negative mask. Develop with nasty smelling VOC stuff, and etch with Ferric Chloride.
>
> I picked up some GC positive resist sensitized boards (12" x 12") for $10 each from a local electronics supply. They look like they were hanging on the shelf for 10-20 years.
>
> I tried a UV eraser for ERPOMS with no joy.
>
> Switched to a plant light that I use for sets in the spring, and Bingo!
>
> Sodium Hydroxide developer was Red Devil Lye (I checked the MSDS sheets for proper developer composition and found the web recommendation of washing soda was off base.).
>
> First board is about 90% etched as I type.

The UV eraser uses short wavelength UV, you need long wavelength UV as 
supplied by the plant light.

Leon
-- 
Leon Heller
G1HSM