Homebrew PCBs

ronpriest2000 wrote:

> it is a device that can be fitted to a soldering iron 
> that allows one to tin a PCB evenly and works I believe by capillary
> action.
> Cant seem to find any info on them at all in the UK

Why not immersion tin chemistry? It works really great, with beautiful
and reliable results.  Is as simple as a acid dip (10% sulfuric or
hydrochloric), tin dip and hot water rinse.

The chemistry is really simple. See
http://books.google.pt/books?id=m8sJBIMtETgC&pg=PA318&lpg=PA318&dq#v=onepage&q=&f=false
Personally i only have mixed tin chloride, sulfuric acid and thiourea in
a past job trying to save money from the expensive tin kits from
bungard. Later found those tin kits are tin sulfate based. But still,
worked really great and i didn't look bad in there.

Unfortunately, these simple mix only last 2 weeks if keep dark and
without air. The Fluoroboric mix seems to last months. Others are based
in Sulphonic salts. You can see pics from Dj Deloire website but he
don't use the acid dip ending with a kind ugly black finish instead of a
shiny as silver finish.

I wish to try it at home with pure tin bars, from the hardware store,
doing electrolise in sulfuric acid and mix thiourea. But i still didn't
find a local chemistry store to buy thiourea. There are Silver cleaning
products based on thiourea but they are almost as expensive as the tin
kits. I guess i will order thiourea by mail like the previous time.