Toner transfer etching tip #783

[Mark Hammer]

If one has embarked on the path of using toner transfer to etch your own boards, you have no doubt seen many times the advice to use fine steel wool or very fine emery paper to buff the copper side so that it shines.  The surface of the copper needs to be smooth to assure that the toner adheres to it and comes off the sheet when you wait for it to cool down, and peel it away, rather than remain on the sheet.

But is that enough?

Having made myself a bunch of more complex boards recently, I have come to the conclusion that it isn't.  So what more needs to be done?  Take a clean tissue, paper towel, or similar, and clean the surface of the buffed copper with some alcohol.  No matter how shiny it can appear, there can be invisible residue left over from the buffing, and "finger juice" from holding the board down while you buff it.  The alcohol will remove those, and you may be surprised by how dirty the tissue/towel you wipe the board with will be.  Removing ALL possible barriers between the toner and the copper will help towards a more efficient transfer.

I've been more satisfied with the boards I've made by adding this step.  The toner sticks more firmly to the copper, and I have MUCH less touching up to do after I've peeled the sheet away; sometimes none at all.  And remember that, if you have to do some touching up of the pattern with a Sharpie or similar, the chances are pretty good you will also inadvertently place more "finger juice" on the board, resulting in poorer disproportionate etches.

So keep a bit of alcohol handy to clean the board before wasting your PnP on it.

[italianguy63]

I use acetone on enclosures with the same effect.  I wipe it down after sanding/buffing, and then after swabbing it off with solvent, don't touch it with the oils on your fingers until after you do the transfer!

MC

[Mark Hammer]

Yep, whatever you use, you want bare metal for the toner to stick to.

[italianguy63]

I also take care not to touch the toner side of the transfer either after it comes off the printer.

[Ben N]

Darn, I missed #782!

[Mark Hammer]

I think that one was "STOP PLAYING WITH IT!!" 

[Ben N]

You're a psychologist, man, do you think you ought to be judging?