Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Mark Lerman <mlerman@...> wrote:
>
> The silver acetate seems to go for about $2 USD per gram from 
> "legitimate" sources, less from ebay. 

Is that lab grade or technical grade?  There's a HUGE price 
difference between the 99% purity stuff, and the 99.9% purity 
stuff.  :-)

For that matter, has anyone researched how to produce Silver 
Acetate themselves?  It's probably a lot more complex than 
simply dropping some Silver coins into a bottle of vinegar.

Ok, having looked it up on wikipedia, it looks like there's a
three step process (Silver + Nitric Acid->Silver Nitrate + 
Sodium Carbonate -> Silver Carbonate + Acetic Acid -> 
Silver Acetate.).  That's not too complex.  I think the real
problem with the cost is that the price of Silver is rather 
incredible at the moment.

> They mix 1 g with 2.5ml of ammonium hydroxide plus .2ml formic 
> acid. Assuming you can get 2 ml of ink from the mixture and that 
> the cost of the ammonium hydroxide and formic acid are negligible 
> (???),  the cost would be about $1 USD/ml. 

Ammonium Hydroxide is simply ammonia in water.

Formic Acid isn't too hard to synthesize (via a couple of routes),
so it should be reasonably cheap.  Don't get it on you.  It's
the active ingredient in bee and ant stings.

> Since you are only drawing traces, it shouldn't be too 
> expensive, especially if you can reuse any ink wasted in head 
> cleaning. Anyone interested in a group buy of the chemicals?

I doubt that the cleaned ink from the head could be reused.  But,
a little care in batching up the plots could minimize waste.

> Mark

Dave <- Not a chemist, but I occasionally bathe in H2O!