I can tell you for sure I'm using 1/1 oz material because I have
weighed it out. I also have a bunch of .5/.5 and it is noticably
lighter. Haven't etched it though. I could have made up a weaker
batch of FeCl. I followed the directions on the package but 12+ mins
at room temp sounds about right for what we are talking. Your AP is a
bit weaker than the literature that came with mine recommends (80% of
mine - 250 g/L).
--- In
Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@y...>
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°C. 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
>
>
>
> Phil wrote:
>
> > Very nice site! It would have been very helpfull when I was
trying CuCl.
> >
> > One question, you have a chart that shows AP as generally having about
> > 1/4 the etching rate of CuCl and worse than 1/5 the rate of FeCl for a
> > given temperature. What was your AP concentration? My experiences
> > with AP and FeCl are significantly different from that. Just
> > yesterday I etched a 2.5"X3.5" DS 1 oz board in 5 minutes. 1 L of AP
> > (250G/L per the directions on the package) heated to about 45C. This
> > etchant is getting a bit old - I've done about 10 similar sized boards
> > in it so it may even be faster with fresh etchant. This was
> > significantly faster than the FeCl etching that I have done at room
> > temp (12-14 minutes at 25C approx from memory). I recall room temp AP
> > took a little longer than FeCl but not appreciably. I'm mostly
> > curious since I'm very happy with AP.
> >
> > Phil
> >