Homebrew PCBs

I agree with all of Stefan's comments completely. I will add to my 
comments that the ironing-on process is the most difficult to get 
consistent. Particularly, I have had trouble around the edges. You 
would do well to read http://www.fullnet.com/u/tomg/gooteepc.htm and 
follow his methods of ironing, basically move slowly and apply heat 
all over the board.

By the way, for the last board I used, I used JetPrint "Graphic 
Image Paper, Gloss Finish" paper. The one that Mr. Gootee indicates 
is 2nd best. I am not near a Staples (I live in very rural Georgia) 
but we do have a Wal-mart which had this paper. I have only used it 
once. It worked pretty well. For the resist image, I tried to follow 
Mr. Gootee's instructions and let the paper disolve, scraping off 
layers slowly. I noticed, however, that it looked like the paper 
would peal off OK without this lengthy process (the way I am used to 
with transparency paper). So when I did the component outline on the 
top of the board ("silkscreen"), I just cooled quickly with water 
and pealed off, just like the transparency paper I am used to. It 
worked great! Mr. Gootee talks about having to get the paper out of 
the holes in the pads, etc., after disolving the paper away. I 
didn't have this trouble. I'm not sure I was doing things exactly as 
he describes.

One thing that I have found that I have not seen others mention is 
that you can have too much toner from the printer. If the toner is 
too thick, then when you apply pressure from the iron, the toner 
will spread out and make the traces wider and potentially touch. 
This is only an issue if you are using very narrow traces. I 
routinely use 12 mil traces and some 10 mil ones on occasion. With 
12 mil separation. If the toner spreads, board is useless. 

I have used 3 different lasers over the years. I especially remember 
on a Lexmark 1650, that I got the best results with the LOWEST toner 
setting. I have a 30-power hand-held microscope with a small light 
(Christmas gift from brother-in-law years ago) that is great for 
looking closely at the paper and/or the board. I experimented with 
various toner settings printing on normal paper. I then looked 
closely with the microscope. What I found worked best was the 
setting where the traces were not totally solid, but made up of 
touching toner particles with some space showing between - not much 
though. I wish I had a way to take a picture through the microscope 
to show. When heated again with the iron, the particles spread and 
formed solid traces. The type of toner particles (fine versus 
coarse) probably make a big difference too.

I now use a Xerox Phaser 6250 color laser. (I haven't tried any 
color but black, however.) The default setting works great on it. I 
have never tried to look at it under a microscope. It just always 
worked so I never experimented.

There are a few things in Eagle that are hard to remember where to 
find, like resizing the restring around the holes. There are a lot 
of little details that eventually get easier to do. I really really 
like Eagle. I will say that.

KT