Homebrew PCBs

Jan and the group,

I'll be glad to do a write up on making plated through holes. How 
much detail does everyone want?  There are about 60 steps to the 
whole process if you break it down. 

I could give an overview of the entire process and then in future 
posts give more details on each step. The hard part of the process is 
knowing what to do when something goes wrong. So another part could 
be a discussion on problem solving.

BTW, the activated solution mentioned is actually a super activated 
palladium chloride catalyst. My shop was the first one in North 
America to install this process in 1990. It was invented by Eric 
Harnden who owns a company called Solution Technology in California. 
I worked with Eric in the early days right after he received his 
patent for this process. We ran his solutions along side our 
electroless copper tanks and found them to be superior. At that point 
we junked the electroless system and converted everything to the new 
process by early 1991. 

At first there was much resistance to using this new method because 
the MIL SPEC at the time only allowed electroless copper. This kept 
the new process out of the big shops but one by one they caught on 
and now Eric has licensed the technology to all the big chemical 
suppliers. The magic ingredient was lignin vanillin extract!! The 
catalyst tank smelled like a milk shake! I'm sure that Eric Harnden 
has made a fortune from his invention.

The idea behind this catalyst was to get such a low resistance 
between the two board layers that the electrolytic copper would plate 
right over the catalyst layer. This eliminated the electroless copper 
part of the process and about thirty minutes of time per load.

I'll write up the basics stating at the beginning and post them over 
the next few days. 

Tom