Press 'n Peel laser PCB's opinions

Press n Peel works well, it does have some issues with fine pitch artwork. But I've done 2 sided boards with good results. For fine pitch artwork I tried the iron on foils with better results, but they tend to stretch on larger boards.

Cheers

I've used it but not recently, having become a convert to the low cost commercial board services.

PnP is nice in that it eliminates the "soak and scrub" steps required of methods that use inkjet photo paper, glossy magazine pages, or the paper sold directly as toner transfer paper. Once the PnP has fused with the PCB blank, just let it cool and peel off the backing.

Surface prep is critical. The blank must be completely cleaned of oxides and contaminants, like fingerprints. And cat hair...

The toner is also critical. Some laser printer toners just don't transfer well while others are easy. Refilled cartridges may also be chancier. If the board is clean but the toner doesn't transfer then you may need to use another printer/copier. I'd imagine that you can get an idea of how well your toner will transfer by just printing any image or text onto a transfer-friendly paper (a glossy, clay coated magazine page) and trying to fuse it onto a cleaned blank.

One thing to consider is moving to 31 mil (1/32") blanks instead of the more common 62 mil (1/16"). Home-brew boards are usually small enough that the mechanical strength of thicker boards is offset by the ease of cutting (regular scissors will work, no scoring or grinding required) and the reduction in dust the from holes.

If you DO move to 31 mil, then you may want to think about using a laminating machine as the fuser instead of a hot clothes iron. The stack height of a 31 mil board, plus the PnP and a backing sheet will often be within the capacity of a laminator. It may take a couple of passes but you'll be using a consistent pressure and heat with each run.

Get a few sheets of Mylar... It has worked for us..

But one thing to note, I have found that on any approach that you use, if you don't first heat the board a little in a toaster oven or hot air gun prior to applying the image to the clad, you may get spotty results here and there..

The heating does 2 things, dries the surface and gets it hot so the toner can stick better.

I have done this with direct paper on the board with great results. Just soak off afterwards. But photo inkjet (glossy) is my primary paper, from printer to board.

Has anyone tried running the paper through the printer twice, eg. over-printing the image, to get more laser toner onto the paper?

Could be a registration problem, but may be acceptable for larger patterns. A few tries and one is bound to be close.

Claus Jensen

I never got PnP to work reliably and consistantly. Maybe I was doing something wrong. And when I needed smaller detail, PnP became more of a hassle. I now make boards by laminating a photosensitive film and photoexposing.

Where do you get the film from?

I get excellent results (down to 8/8 mil) with the standard photo-etch process.

Leon

Though it is not discussed in your link or Gootee's page it has been=20 reported to help when you have large copper areas.

That does not work well with my cheap Brother printer, the printer seems to have issues aligning the sheet in the same place each time.

But in any case, I usually have good luck on a single pass..

How hard is it to apply to the copper? It's about a 50% savings over buying presensitized boards. If it's pretty easy to use then it's a significant savings.

And I assume it works pretty good?

I find it easy..

I squeegee the film on small boards using my drivers license card.

Yes. Under 4x magnification etched pcb traces look sharp.

Soon I'll be trying a 'low haze' transparency film which may reduce the exposure time when using a 50W halogen.

I have a different brand, but I've found a method that's pretty reliable. I hacked a laminator to run at 240 degrees F instead of it's default 320 F. I cut a piece of paper a little wider than the PCB and a few inches longer, and tape the leading edge of the film to the paper, with the PCB between them, and the extra paper ahead of it. I tape two paper tabs to the trailing corners of the film. When I put the paper into the laminator, I have time to lift the film up off the pcb using the tabs, and pull it tight, before the film hits the rollers. The tabs let me hold the film tight and off the pcb even when the film has entered the laminator. I've found that this method replicates what the big fabs do, and seems to be very reliable about not getting air bubbles or wrinkles.