Homebrew PCBs

mikezcnc wrote:
> Stefan,
> 
> Yes, acetone was etching into the fiberglass. Paint thinner? I'll try 
> it and it probably doesn't smell as bad. I hate acetone!

   Very unlikely.  Fiberglass board is a relatively rough surface on 
small scale and the particles get stuck and the acetone evaporates out.

> 
> The tracks are .015 ie 0.0281 which like you suspected: 0.4mm
> 
> Do you know how I feel now, looking at that board? It would cost 
> probably couple hundred bucks to have it done in an hour. I used to 
> pay much more. The method is just incredible! Oh, how to get that 
> pressure much more repatable and predictable?!!!!! 
> 
> Mike


   Yes it is, the speed and ease is terrific.  Note the problem is 
almost always not enough heat, not pressure, and sounds like it from 
your posts.  If you have too little heat you only get good transfer 
where you press hardest, with enough heat you get good transfer with a 
much wider range of pressure.  Toner melt temps are often 160 deg F not 
130 as you'd mentioned.  Even when the board is hot it's still taking 
heat away, and the iron is on the other side of an insulating sheet of 
paper.  It may take quite a bit more time than what you'd think of as 
hot to actually have the toner up to correct temp.  More heat, medium 
not excessive pressure, and the right paper handling techniques gets me 
good results every time now.  The only thing that gives problems now is 
when I rush a bit much and don't clean the board as well as I know it 
should be cleaned.

Alan