Homebrew PCBs

Stefan,

I would like three issues answered by a chemist and or pharmacist 
(although here I suspect that argument would be made that since it is 
used for rubbing then it must be ok:

1. The web search reveals that IPA causes cancer. We might get into 
semantics on that one, but we should not use an argument of rubbing 
alcohol being healthy, therfeore and the reason being that that 
discussion might turn in to medical subject which I won't get into. I 
know it is carcinogennic and if someone believes otherwise, I can 
respect that.

2. Tinnit says: it contains "acidic tin salts, although it 
doesn'tcyanide or other highly poisonous materials it is a skin and 
eye irritant- do not eat or drink". I realize that keeping it in the 
fridge is not for anybody else than me. Fridge is for food only, but 
since it is my fridge then I issued yself a waver from that otherwise 
strict regulation. Now, Stefan, aside how bad that stuff is to our 
helth, you made me think that if it works on copper traces, will 'go 
into the holes'? I would say it will go into the holes ONLY if the 
holes are copper plated.... But for that is the method of using H2S04 
and CuSO4 with DC current or like Jeremy suggested (better yet) 
use 'flash copper' rather than acidic copper... Tinning with that 
stuff brings awsome results, but there are some rather smallish fumes.

3. I would like a chemist to tell us how does IPA clean, because it 
does not dissolve oils nor fats. And if it doesn't then what kind of 
principle is applied for cleaning with it?

Mike


--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan 
<stefan_trethan@g...> wrote:
> On Fri, 30 Jul 2004 11:12:19 -0000, mikezcnc <eemikez@c...> wrote:
> 
> > Jan,
> >
> > Just a word of comment: I tried the electroless tin and it workd
> > exceptionally well on tinning the PCBs. I was quite amazed how 
well
> > it work, exactly in a kitchen and I keep in tee fridge all the 
time.
> > Life of the solution according to a mfr is six months and the 
cost is
> > low for that amount of time.
> >
> > However, I don't know what the electroless tin does to a hole- 
that I
> > hvent tested but I suspect that unless the hole is copper, than
> > nothing.
> >
> > It wasn't clear from your post if you were talking about tinning 
the
> > copper traces or tinning the thruholes. For traces to be tinned, 
the
> > solution needs to be hot, otherwise it takes very long time. Mike
> >
> >
> 
> The last time i checked all electroless tin used some pretty nasty 
> ingredients
> which i wouldn't want to have in the kitchen or fridge.
> What about yours?
> 
> ST