Press-and-Peel(tm), photoresist, Sharpie, nail polish...
I have used this method for etching some fairly fine lines when fabricating a microstrip microwave filter using Tom Gootee's method linked to below. My two cents on this is the fact that the type of toner you use matters. In an admittedly small sample set of two different printers, the genuine HP microfine toner performed far better than the generic toner that was installed in a second printer that we tried. We used the Staple's glossy inkjet paper, and with the HP toner, it worked quite well.
Also, the etching solution of 1 part muriatic acid to 2 parts hydrogen peroxide is worlds better than the ferric chloride solution as it is clear and doesn't stain everything it touches. It is also available locally (hydrogen peroxide is in every drug and grocery store, muriatic acid can be found at almost any hardware store).
Thankfully, we worked in a school lab that had access to pure acetone for cleaning off the traces, so we didn't have to resort to foul-smelling nail polish.
Toner Transfer Tip and Tricks From around the World
Leave you tips and tricks here, it is ok if you found it on the web ( give the reference if you have it ) or if you picked it up somewhere else even figured it out yourself. ( if you have a long write up do not leave it here, make a new page and link to it )
Experiment with paper, I use magazine paper, keep shifting around to find the right stuff. You want a glaze ( usually clay ) so the toner will transfer, and soluble paper so you can easily remove it. Right not mu favorite it the RISDI catalog. If the paper is too thin it may jam in the printer ( check printer settings by the way ) Some have suggested attaching ( perhaps just by folding the leading edge over ) it to standard paper as a carrier to get it through the printer. There are of course photo papers for laser printers and stuff made just for toner transfer.
A roller may help focus pressure especially at the edges. Has to be done while hot. One way I have seen is to put a dowel ( perhaps several ) under the board and roll back and forth on that.
A couple of layers of paper towel as padding between the board and the iron can help even out the pressure and improve adhesion at the edges.
Electric Grill as Ironing Board
I russ_hensel was having trouble getting enough heat. My breakthrough was to use a temperature controlled electric grill ( great for pan cakes by the way ) set for 350 and iron as usual.
Remember high temperature is required
This is not like ironing a shirt, the thing has to get hot, move the iron slowly or almost not at all. Pressure is good, experiment to find out how much.
The edges are usually the problem focus your attention there, if you get the edges you will probably do fine on the center with only minimal attention there.
- Direct Etch PCBs These guys are selling a product for toner transfer, might be good or bad, ( how about a review by a user? ) but in any case they also have a bunch of very useful tips.
- DIY Printed circuit board A video, pretty good.
- Printed Circuit Boards for the Masses A pretty quick tutorial.
- Episode 15 PCB Etching A video, the safety warnings are a bit over the top.