Homebrew PCBs

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.

Cheers.

Gimp

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