On Thu, 26 May 2005 11:28:21 +0200, Thomas <
teecee@...> wrote:
> I was at a machine shop here in Jakarta several weeks ago and they do
> selective plating etc for Aircraft parts, they had also repaired
> an Engine Block in a camshaft bore using a Coloidal Copper solution
> (IIRC) applied with Electrolysis,
> my first thought was to use this solution to plate via holes also, but
> of course the hole must be conductive for this to work so maybe
> the conductive silver pen will have to be used first to get the process
> working. I dont know about the price but looking at the amount
> they chew through 1liter would last me a long time if it worked ok.
> http://www.brushplating.com/
> Thomas
Well, hole wall activation is apparently the hardest part of it all.
Silver paint costs like 1eur/g, so it is relatively expensive. there is
much cheaper conductive graphite paint, and ideas if that can be used for
hole wall activation?
Even if that works i am not sure it is suitable for my style of making
pcbs, which is quick and cheap.
Toner transfer is not really compatible with THP, because it can't tent
the holes. What you'd have to do is transfer the negative (which raises a
number of problems in itself), and then plate with tin, which in turn
requires a change of etchant to sulphuric/H2O2 instead of CuCl.
Considering the work you need to add (2 plating baths, more complicated
etchant, wall activation), and the costs, i will rather stay with using
pieces of wire for vias. I mean, unless you do it for the advantage of
having a PCB in an hour, financially it does not seem justifyable to make
homebrew PTH boards. The prices for boards are incredibly low nowadays...
ST