Homebrew PCBs

Dang, I've still got that autotitrator...thought maybe I had found a
use for it.

I do have a student grade burette which I used once right after I got
the CuCl solution working. But since it continues to work I haven't
bothered with it.

If etch time is the dependent variable, what independent variables
might be involved? Temperature, molarity, and SG?

We know that temperature increases shorten etch times, but they also
introduce problems such as fuming. So what is your guess about how the
others interact and how would you check the hypothesis out? (Assuming
temperature and agitation and amount of air are held constant.)

Grant

--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@y...>
wrote:
> grantfair2001 wrote:
> > 
> > I built an autotitrator with a chemistry student some years back. It
> > used a syringe pump driven by a stepper. We were dropping NaCl
> > solution into silver nitrate IIRC (I supplied mechanical/electronic
> > assistance, he did the chemistry). The probe was expensive but he
> > borrowed it from the school. Would there be a probe which would
> > detect the endpoint in this case? Or would visual inspection be just
> > as good - in terms of time required?
> > 
> 
> I can't think of anything quicker simpler than titrating with a pipette 
> or a long length eye dropper. The good news is we only need a ball park 
> figure of acid and it seems anything > 1M is good while < 0.1M is
not so 
> good.
> See if you can get a long eye dropper that has a measuring mark about 
> half way up. Just take one sample of etchant into a glass jar, with
some 
> water, then using same eye dropper take one sample of 1M NaOH. Drip
into 
> glass gar until copper precipitate forms. Note relative how much NaOH 
> was used and thats your approximate acid molarity.
> 
> Adam