Homebrew PCBs

Hi,

   Just joined the group, mainly to share this for the moment.  If 
you've tried the laser toner transfer and didn't get near perfect 
results, you should really try it again with fusing it 3 times as below. 
  It seems like this would make the toner stay in the paper and be 
harder to transfer, but it really makes the toner and outer paper 
surface become one, transfer heat to the toner better, and then the 
outer surface tears at the edge of the toner when removing the paper far 
better.  Also seems to dry out or 'burn' the rest of the paper coating 
that doesn't have toner, making it much less likely to stick to the 
board from ironing.  Nearly perfect results and in the etch tank within 
5 minutes of printing, I'm now doing SO and TSOP surface mount boards 
with ease.

   First, take a look here in the PCB folder.  Might want to check in my 
stepper and light folders too while you're there.  I have my own 
intelligent 3 stepper controller and a few hundred stepper motors on 
hand as well.  Also have a homemade CNC driller that reads the excellon 
files from Eagle to drill boards.

http://photos.yahoo.com/alantak69

   Fuzziness is from the camera not doing close focus very well.  Note 
that the toner held the paper to it, the coating seperated at the trace 
edges.  No paper in the holes etc, and an excellent pattern in the trash 
paper as well from the coating left on the paper.  Far better results 
than I'd ever gotten with this method before.  All because I printed a 
couple extra TSOP patterns by running through the printer again.  Didn't 
care if the main board didn't come out, and it ended up working ten 
times better than it ever did before.  This is using the JetPrint Photo 
paper and my HP Laserjet 6l.


   No doubt most of you are familiar with this page:

http://www.fullnet.com/u/tomg/gooteepc.htm

   I could make a useable board following this, but it was a lot of work 
removing the extra paper etc and touching up the board.  Now it is 
simply a matter of a few minutes ironing, then some hot water, then some 
cold water, then peel.  Etching within 5 minutes or so.  My results are 
now super and easy, where before it was a lot of work to get a useable 
board.  It's now so good that I had to share for anyone else not getting 
terrific results..

   Rest of the message is cut and paste from a couple I sent to Tom with 
more complete details:


Hi Tom,

   Might want to try what I've described below, much improved results 
over just fusing once.  Previously I'd assumed that having the toner 
fused as little to the paper as possible would be best, but now I 
realize that the extra fusing makes the rest of the paper much less 
likely to stick.  The below method work about ten times better than it 
ever did before with just a normal print, at least on my HP Laserjet 6l. 
  Results are now as good as any of the films, and no soaking just iron 
then wet then peel.  Actually I'll attach a pic or two, they're small. 
Fuzziness is from too close with a normal camera, the traces are sharp. 
  Note the white fuzz on the toner, not only did the toner stay stuck it 
kept the paper with it, almost no lifting at all.  May want to add it 
into your instructions so people don't start off doing too much work..

Alan

Tom,

   No problem.  I had always assumed that sticking the toner more to the 
paper would be a bad thing, but I happened to have a small test board 
printed that I didn't care if it wasn't perfect when made.  I also 
wanted to make a small test spider pattern for a 8 pin TSOP part, so to 
double up I printed two on unused areas of the same paper.  Also didn't 
care if it peeled a bit, so didn't wait and just peeled after putting 
under water.  Lo and behold it worked much better than ever before, and 
after the fact it wasn't hard to think of a reason or two why that might 
be the case.  Made another board or two now, and trace edges are razor 
sharp now too.  Still get some minor mashing etc if ironed too hard, but 
looks as good as the commercial films, and even they have you soaking 
longer than what I'm doing now.  I hardly even give it time to get wet 
and cool off a bit before I start peeling.  It's quite good at TSOP 
level now, my original boards a year ago could barely even do 16 mil 
traces ok with the same printer and paper.  Just had lots of peeling 
traces and having to pick at the stuck paper surface.  No more 
toothbrush hole cleaning!
   Also not even bothering to iron nearly so completely now, just iron a 
few minutes pressing here and there to change the holes around and it 
works.  Only had a tiny little peel or two on the last board, and I 
really was pushing it and didn't iron but a couple minutes or so, 
nowhere near a thorough job.
   I am abolutely positive the commercial paper people already hate me 
though, I have posted this to several places already, just finally 
getting back to your page.   It was useable before but now it is hard to 
see anyone ever buying a more expensive paper.

Alan