1.Clean board
2.Shake can before each use.(What I did not do the first few times)
(in the dark with safe light)
3.Tilt board upright on 45 degree angle
4.Spray from right to left working your way to the bottom
5.Blot off excess that runs to the bottom of board
6.Lay board flat to dry. (I used an old hair drier to
dry the board.)
I found I need more exposure time than the instructions in order
to get a good trace.
--- In Homebrew_PCBs@yahoogroups.com, "gmc_za" <gmc_za@y...> wrote:
>
>
> I've started fiddeling around with photoresist spray and developing it
> using caustic soda, and have a few questions as the board is still not
> coming out 100%
>
>
> 1) How thick should the photo resist be sprayed on. After I've sprayed
> it on and its dried you can clearly see the purple film - there's no
> gaps.
>
> 2) After you put the board in CS - how do you know when to take it
> out? I can see the tracks clearly but the pcb is still have a layer of
> the purple stuff on it. Should the purple film vanish completly
> (except for on the tracks)
>
> 3) Which is a better etchent to use - Ferric Chloride (mine works
> really slowly even when heated up - like 30-40mins) or Hydrochloric
> Acid+Hydrogen Peroxide
>
> I've done another board (etched) and the top half of it is perfect -
> nice clear tracks. But on the bottom half none of it is etched. If I
> leave it in too long it starts to eat away the tracks, but still
> doesnt touch the bottom section? Does this sound like too thick spray?