Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Deepinder Singh" 
> I was thinking of switching over to the toner transfer method but 
was
> curious what is the resolution that people achieve with this 
method -
> i.e. is it suitable for smt. I've heard that the toner spreads a bit
> when heated but not sure how much. 

I normally use 12mil trace-6mil clearance.  You can do this without 
even thinking twice about it and not be very careful during the whole 
process.  I've done 6-6 with good results too, but you do need to be 
quite a bit more careful.  I've had difficulty with these, not 
manufacturing the board, but burning the traces off later  (the glue 
releases the copper under too much heat).  I have noticed that the 
FR4 1oz clad seems more robust than the paper phenol in this regard --
anyone else see this?  <-- That may be more a function of board stock 
brands.  Anyway if a PCB layout needs higher densities, I've tended 
to lower the clearance value rather than the trace.  That said 8-6 
works pretty well, although you do need to be more careful and put 
some toner nearby (ground planes, other signals ) --this tends to 
help keep the paper from pulling off that one lone trace.

I haven't seen too much spreading with the laminator.  I keep my 
printer set to normal rather than dark --if you get the right amount 
of heat/pressure/paper carrier, all the toner will get tranfered.