DIY PCB plated thru holes?

[Tony Clark]

> Any ideas out there on how to do diy plated through holes?  I'm working on a 
> super compact design that is going to require a two sided pcb but I still 
> want them to be DIY. I really don't want to have to solder one side and then 
> the other side.  Any ideas?  I only need about 8 boards, each of which has 
> about 200 holes, so I think it still makes sense for me to do them diy rather 
> than go to a board shop. 

   Hi,

   My advice, go to a board shop.  Places like AP Circuits will get you 8 
boards for probably $100 USD total.  If you think you can drill 1600 
holes, plate them, and then redrill the 1600 holes for cheaper, I'd hire 
you, but I think I'd be forced by law to up your pay to at least minimum 
wage!  :)
   Seriously, plating the holes is a somewhat nasty chemical process.  
Here's a general process list from my PCB handbook.

   1) Cleaner - conditioner
   2) Rinse
   3) Microetch
   4) Rinse
   5) Predip
   6) Activator
   7) Rinse
   8) Accelerator
   9) Rinse
  10) Copper Eletrolytic Flash
  11) Rinse
  12) Dry

   There are a lot of different techniques, but the process list 
looks basically the same.  You'll have to do a lot of work to not only 
mask the board (so you aren't electrolysing the whole board, just the 
pads/holes) but to control the thickness of the copper deposits enough to 
prevent them from coming off when you apply heat to them!
   Again, if you want plated thruholes, go to a shop.  Heck, you've got 
so many holes to drill, that alone will be worth it!   

   Good luck!

   Tony

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