Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "lnphoenix" <Lnphoenix@...> wrote:
>
> I'm about to make a microwave test PCB for the first time, using tone
> transfer. The PCB size is about 4"x4" with the bottom layer is served
> as a ground plane. How do I mask the bottom layer so the copper
> remained intact during contact with ferric chloride? Vaseline? Masking
> tape? Huge tip marking pen? Some kind of chemical etching resist?
> 
> TIA
> Lanny
>

I use transparent contact paper (it's really not paper but a plastic), 
it's a lot easyer to remove than tape and does not seem to leave much 
residue behind. Get the kind that is normally used to line kitchen 
cabinets with. You just need to make sure the edges a well sealed to 
the PCB.