Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "d1camero" <a8723@...> wrote:
>
> Hi all,  I am building a tube guitar amp PCB.  It requires heavy
> copper on thick boards.  I would like to use 1/8" boards, but cannot
> find any locally.  Anyways, here are my plans:
> 
> Toner transfer method using Phoenix TTS paper (all I can get here in
> Canada).  Then I plan to etch using MG Chemicals Sodium Persulphate
> and hand agitation.
> 
> Is this reasonable for this thick of copper, or should I try a
> different method.  Any hints, tips, or related sites would be
appreciated!
> 
> thanks
> Don
>

Hi Don,  I haven't tried TT on anything heavier than 1oz but with my
results I believe it would work well on 2oz boards, especially for
something like a guitar amp with wider traces.  I use Ferric Chloride
to etch mine and even left in for too long, the toner is still solidly
adhered to the board,. It takes some good scrubbing to remove it even
after all of the etching is done (I use fine steel wool with alcohol
to strip it off and polish up the copper - works great).

I haven't tried the Sodium Persulphate but I did try Hydrochloric Acid
twice and it does attack the toner after a while. The board needs to
come out as soon as etching is done or the toner starts to lift. I'm
not sure if it would hold up for a 2oz etch or not. And I'm not sure
where the Sodium Persulphate is compared to these others.

Here's one tip for 1/8" boards, do 2 1/16 inch single sided
boards and bond them together with epoxy (or maybe even contact cement
would work).

Phil
KA0HBG