Homebrew PCBs

Russell Shaw wrote:
>>Phil wrote:
>>
>>
>>
>>>Very nice site!  It would have been very helpfull when I was trying CuCl.
> 
> 
> ...
> Adam Seychell wrote:
>  > Thats interesting your experience were different than what I measured in
>  > my test. The bubbles agitation for my test was very vigorous, so maybe
>  > that had something to do with it. The FeCl3 was full strength as sold
>  > industrially (sp.gr=1.47), the AP was 200g/l almost fresh (very faint
>  > blue color due to previous tests). For AP I was getting about 9 minutes
>  > with 1oz copper at 42\ufffdC. 5 minutes sounds fast! Two possible reasons:
>  > you unknowingly have "1/2 oz" PCB material, or the ferric chloride you
>  > were using was for some reason not very potent which made it slow in
>  > comparison. I'm equally curious becuase it could mean my test results
>  > are botched.
>  >
>  > If you have access to a micrometer caliper, you can peal copper away
>  > from the board using a heat gun and pair of pliers, burn off the
>  > remaining epoxy stuck to the back of the foil, and measure its thickness
>  >
>  > Adam
> 
> Ferric chloride works faster if it is diluted with water (to 1 part or 2
> parts water). A properly cleaned 35um copper pcb should etch in 5 minutes
> at room temperature with gentle/moderate bubble agitation.
> 

yep, 5~6 minutes sounds ok for FeCl. But I didn't think AP at 45\ufffdC 
wouldn't be that fast as Phil is finding, maybe at 70\ufffdC however.

> http://www.jtbaker.com/msds/englishhtml/f1060.htm

Thats a good link on FeCl. They say diluting 1 part FeCl (sp.gr 1.47) to 
  2 parts water doesn't effect etch rate. I didn't try diluting it. I 
can't be bothered repeating all the experiments again :(.

Adam