Ben Jackson wrote:
On 2006-12-30, ken scharf wrote:
I've heard of people designing their own pc boards using laser printer
output and iron on toner for resit. I've tried this before but with
'bleeding' of the toner during application I don't think I can get
better than 50 mil trace separation.

Print your design on some kind of clay coated paper (people have
used everything from magazine pages to photo paper intended for
inkjets) and look at the print with a loupe. Cheap laser printers
will produce a result full of pinholes. A nice Xerox will make a
good, solid black. I haven't had any trouble with toner melting
or running. In fact, once you transfer it onto the PCB it's hard
to get off!

If I try designing boards for SMT
parts I'll probably have to farm them out to a professional house, but
this can be expensive for making but one board. (Unless you plan on
writing a QST article and selling the extra boards....).

You've got to pick the right board house for each order. Some, like
batchpcb.com, are particularly cheap if you want few, small boards.
They don't have setup fees or even per-board fees, only a per-order
charge. But their $2.50/in^2 grows faster than some other places
which have bigger minimum size boards/minimum orders.

My problem with the iron on transfers wasn't being able to print thin,
close spaced lines on to the transfer medium. The problem was that when
ironed on the toner lines 'spread out' so adjacent lines touched. Also
a problem was timing just how long to leave the board in the soup to
etch. I did heat the etchant up first and used an IR lamp to try and
keep it warm, but even so the thin close spaced traces were close to
being over etched long before larger and wider spaced traces were
'done'. (maybe a problem with 'Radio Shack' etchant?)