Homebrew PCBs

On 07/07/2013 12:31, Kerry Koppert wrote:
> I am trying to produce a small PCB for a SMD pic16f628a-i/so using
> chinese blue dry film photoresist. The exposure seems to work fine using
> a bank of uv leds and the photoresist turns a nice darkish blue around
> 30-45 secs of exposure. I am trying to develop using washing soda (I
> forget the exact strength but I think it was 200g in litre of water). I
> am having difficulty getting this process right. Either some of the
> unexposed photoresist does not come off (particularly between close
> tracks) or some of the exposed photoresist lifts if I leave it longer.
> Anyone having experience with this process willing to comment on what I
> may be missing.


I don't think that washing soda (sodium carbonate) will work, you sodium 
hydroxide. That's what I use - 2 teaspooons per litre.

Leon
-- 
Leon Heller
G1HSM