Homebrew PCBs

Hello Everyone,

First of all I thank people of this forum for contributing wealth of knowledge here, I am really amazed.

I am exploring possibilities to use "Gum bichromate" method (Gum + potassium bichromate) to develop PCB (Printed circuit boards). Basically to transfer circuit from transparent sheet to the copper-cladded-board treated with gum-bichromate.

My sole concern is about safety. It is well informed all over Internet that chromate compounds are deadly dangerous (for both use and disposal).

1) I would like to know is there any alternative which is more safe, easily available and economical when compared to potassium/ammonium bichromate? I don't want to go for toner transfer or dry film option, only photo-resists.

2) Secondly, do these bichromate remain dangerous/harmful after they are UV-exposed and developed with water? The harden material which remains after development, is that still hazardous?

Feel free to provide your views.

Regards,
Motif

Motif,

Look here,

http://tech.groups.yahoo.com/group/Homebrew_PCBs/message/26532

and in particular at this patent,

IMAGE-FORMING PROCESS 5556735 (Google Patents)

The only sensitizer, other than one of the dichromates, that an individual can buy is diazo. I don't know if diazo will work with gum, but it does work with PVA/PVAac emulsions. Search for Speedball Diazo. There are a lot of patents for sensitizers, but you need a PhD in organic chemistry to understand them.

Baxter

> 1) I would like to know is there any alternative which is more safe, easily available and economical when compared to potassium/ammonium bichromate? I don't want to go for toner transfer or dry film option, only photo-resists.
>

Thanks a lot Baxter, really appreciated your help..

Regards,
Motif


--- In Homebrew_PCBs@yahoogroups.com, "bebx2000" <bebx2000@...> wrote:

>
> 
> 
> Motif,
> 
> Look here,
> 
> http://tech.groups.yahoo.com/group/Homebrew_PCBs/message/26532
> 
> and in particular at this patent,
> 
> IMAGE-FORMING PROCESS 5556735 (Google Patents)
> 
> The only sensitizer, other than one of the dichromates, that an individual can buy is diazo. I don't know if diazo will work with gum, but it does work with PVA/PVAac emulsions. Search for Speedball Diazo. There are a lot of patents for sensitizers, but you need a PhD in organic chemistry to understand them.
> 
> Baxter
> 
> > 1) I would like to know is there any alternative which is more safe, easily available and economical when compared to potassium/ammonium bichromate? I don't want to go for toner transfer or dry film option, only photo-resists.
> >
>