Homebrew PCBs

Red Devil no longer makes the 100% LYE crystals (THANK YOU METH HEADS)
there is another brand called "ROOTO crystals of Household 100% LYE 
drain opener" this is what I now use to develop the positive resist 
on GC Pre-Sensitized Positive Acting PCB. Add 300mL of tepid water to 
the developing tray. Stir in 1/2 teaspoon of Sodium Hydroxide (LYE 
drain cleaner). Continue to stir until all of the Sodium Hydroxide is 
dissolved. Place circuit board into the developer and gently rock 
back and forth until all unwanted photo resist has been removed. 
Development should take less than 2 minutes. This method is fast, 
clean, and very cheap.

Ron

P.S. If you do find or have the Red Devil crystals, the mix is the 
same 1/2 teaspoon to 300mL of tepid water.

--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111" 
<javaguy11111@...> wrote:
>
> Drain cleaners like Red Devil or Crystal Drano are sodium hydroxide.
> It my have little metal shavings in it to make it fizz. Since I use 
it
> to strip negative resist, I am not worried about metal shavings. I 
am
> not sure if it would cause a problem with developing positive resist
> as I have no experience with that.
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Ben" <bhleavi@> wrote:
> >
> > Well I needed to make a board this weekend but did not realize 
that I
> > was out of the developer.  I use the M G Chemicals 600 series 
board
> > with positive resist.  Normally use the M G Chemicals developer 
which
> > is Sodium Hydroxide, but can not get it over the weekend.  Never 
have
> > found a place to buy the Sodium Hydroxide without ordering it in.
> > 
> > I tried some Washing Soda but so far it does not seem to do 
anything
> > to the resist.  How strong should the washing soda need to be 
mixed? 
> > or will the washing soda even work on the M G Chemicals positive 
resist?
> > 
> > Ben
> >
>