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Press-n-Pray

Started by ErikMiller, November 19, 2003, 11:40:53 PM

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ErikMiller

Or Press-n-Swear. Anyway, I took another crack at Press-n-Peel Blue, taking into account suggestions from the forum and the instruction sheet that comes with the product.

Scrubbed PCB copper with abrasive cleanser.
Rinsed well and fully dried, handling only by edges.
Good print to the matte side of the PnP.
Preheated iron to a measured 315 degrees (the instructions call for 275-325).
Set timer to 2 minutes.
Put a sheet of paper between the iron and the PCB to help the iron slide better and diffuse the heat.

Here are the results:


No, the image is not blurred (check the edges of the PCB); that's how badly my transfer came out.

It looks to me as if the iron was too hot (although I followed their instructions) and that the stuff smeared around on the copper while I was heating it.

Usually with manufacturing processes, I get better results each time, but with this stuff, each time seems to be more frustrating.

Any hints, suggestions, whatever? At $2 a sheet, this stuff is not cheap enough to keep throwing away.

computerjones

did you cool the whole mess before pulling?  looks like the ink might have been still hot when you pulled it off.  it should take the blue with it leaving a clear spot on the plastic base.  also it looks like you got a bit of smearing from moving the iron side to side.  try just pressing down only.

best luck

Joe Davisson

This is how I do it:

1. Set iron to 3/4 high. Too high and the film will warp.
2. DON'T use paper between. You want to see what's going on.
3. Briefly hold iron in one place, to "tack" down a spot.
4. Apply LIGHT pressure and move iron around, using mostly the tip area at first, then the edges of the iron. Take your time, there is no time limit.
5. After a while, the artwork will begin to show through the top darker. This is your indication that it transferred. At this point the artwork can smear, so be careful.
6. When fully transferred, let it AIR-COOL for a few minutes, then peel it back slowly. Touch up errors with a Sharpie, then etch.
7. Remove resist with acetone.

It really is a good product but I admit it can be frustrating at times. You basically have to let the iron do the work. Use the darkening of the artwork as your visual aid and don't worry about time or heavy pressure.

Due to the warped appearance of your transfer sheet I think you might be using too much pressure, despite the heat setting. It does take some practice. I would highly recommend printing a bunch of smaller boards on one sheet, cut them out and practice transferring them separately, instead of wasting a whole sheet at a time. Then you'll have 20-30 practice runs available to help you learn. You can always erase the board with acetone and start over. Hope that helps.

-Joe

ErikMiller

I think I see a speck of light. Keep a lookout for the transfer ye say.

I'll give it another try.

No paper this time. I though it would keep the surface of the iron from sticking to the plastic.

One thing that I've learned is that the best solvent for getting the resist off is Goof Off.

Rick

Another vote for the power of Goof Off solvent. Does the job in 1/3 the time of acetone.  "Wonderful Stuff" !

For the PNP probs. it does look like either the iron is too hot, or too much pressure is being applied perhaps. I use 1/2 on the iron temp, computer paper on top, smooth flat wood base, gentle rubbing for 3 mins, and quench right away in cold water. I think I have had to redo a board only once in about 3 yrs doing it this way, and I've made lots.
If this doesn't help I'd perhaps try another laser printer to see if things improve as I have never had a transfer that was that smudged using my little dinky Brother laser ptr. and this procedure.

Peter Snowberg

Goof Off is pretty amazing.... If you can't find it, the main ingredient is xylene.

-Peter
Eschew paradigm obfuscation

arielfx

computerjones said ink and I really hope that if you are using PNP you know you can't use ink with it because it won't transfer to the board. You can only use toner when printing on it. you can print with toner using a laser printer or a black and white photocopy machine only.

ErikMiller

It also occurs to me that my iron is an ancient heavy thing. I'll keep a lookout at the thrift stores for a newer lightweight model with the Silverstone coating on the bottom.

The weight of the iron alone could probably smush the image.

Paul Perry (Frostwave)


brett

I got the same results once with PnP as in the picture.  I had left the iron set to "cotton" and "steam" (which is fine for my shirts, but way too hot for PnP).  Set your iron to "synthetics" or, if it has four dots at maximum, set it near the two dots.  You can get good results at quite low temperatures.
Brett Robinson
Let a hundred flowers bloom, let a hundred schools of thought contend. (Mao Zedong)

Mark Hammer

I hope to goodness no one has their iron set to "steam" when doing this.

When I started using PnP, I placed a sheet of teflon (you can buy it in sheet form from industrial plastics places) between the iron and PnP.  This was partly to provide some insurance for both the PnP and the iron since I had no idea what to expect.

Turns out the teflon was not necessary and in fact made for a poorer transfer since I ended up applying too much heat and the traces splatted out.  Nowadays I just set the iron (with NO water in it) for "wool" or "cotton" setting, make sure the board is on a sturdy hard flat surface, usually a piece of particle board, and iron away, giving little breathing spaces for the board/PnP to not heat up too much.  As my grandmother taught me in preparing crepes for blintzes many years ago, sometimes it's what's underneath that makes all the difference (she moved them from the frying pan to a mesh ironing board with a dish towel covering they could "breath" through in order to keep them supple).

screamer

I use P-and-P all the time and i had no problems
I do same thing than Joe Davisson (posted earlier).
When the board is hot, i lift the plastic sheet a little bit and if the circuit is well printed then i take the board and put it under cold water flow in the sink for a couple minutes. When the board is cold i remove plastic sheet carefully.

Best luck to you

Ed G.

Something doesn't look right on that copper. Unless I'm seeing things, it appears the toner on the copper came out black. It should come out blue.
Also, after ironing the transfer on, the toner separates from the plastic, leaving clear plastic where the traces were once you pull it away.
The whole point of the PNP blue is that the blue stuff helps the toner 'pull away' from the sheet easily.

I know this may sound silly, but are you sure you printed the pattern out on the correct side of the PNP material?

The reason I say this is because I used to use overhead transparency sheets to try to make pcb's, with very little success. The toner sticks to the plastic too well, and the result looked very similar to what you have there. I also see that the plastic was heated enough to wrinkle up a bit. Never did I have to apply that much heat.

I really think you may have put the toner on the wrong side. The PNP should release the toner much easier than that, and it should be blue.

Hope you figure it out. Once you get the hang of it, PNP blue really does turn out some very professional looking results.

Ed G.

Something doesn't look right on that copper. Unless I'm seeing things, it appears the toner on the copper came out black. It should come out blue.
Also, after ironing the transfer on, the toner separates from the plastic, leaving clear plastic where the traces were once you pull it away.
The whole point of the PNP blue is that the blue stuff helps the toner 'pull away' from the sheet easily.

I know this may sound silly, but are you sure you printed the pattern out on the correct side of the PNP material?

The reason I say this is because I used to use overhead transparency sheets to try to make pcb's, with very little success. The toner sticks to the plastic too well, and the result looked very similar to what you have there. I also see that the plastic was heated enough to wrinkle up a bit. Never did I have to apply that much heat.

I really think you may have put the toner on the wrong side. The PNP should release the toner much easier than that, and it should be blue.

Hope you figure it out. Once you get the hang of it, PNP blue really does turn out some very professional looking results.

Skreddy

You can tell by the direction of the smearing (on the left side, it's smeared on the left; on the right side, it's smeared on the right) that the blurred image was caused by too much heat causing the plastic to SHRINK.

I think Mr. Hammer's iron might be a little cooler than yours (and mine too, as I notice a little shrinking at the 'wool' setting last time I did a transfer), so consider setting your iron at 1/2 to 2/3 the temperature you used last time.

We are heating a plastic material, so use the appropriate setting (e.g. nylon, rayon, synthetic) on the iron to avoid overheating/burning/melting/distorting the plastic.

Since it appears to me that the shrinking takes place during the heating process and not the cooling-down process, the cold-water quench probably won't help this particular problem (although it probably wouldn't hurt either).

ErikMiller

Okay, big THANKS to Joe Davisson for his advice.

Yes, obviously my iron was too hot, although I started with the recommendation that came with the product, 275-325. That may be what it says on THEIR iron, but to my thermometer, 225 was more like it.

What finally worked was doing as Joe said and pressing a little bit at a time, and watching for the image to show through black. When a trace stands out shiny black, it's adhered to the copper. At that point, it needs no more heat. The trick is knowing what to look for. With the paper on top, and laying the whole iron on, I couldn't see anything.

I mostly took the tip of the iron and kind of dabbed at it. No sideways sliding. That's the motion we are used to with clothes irons, but it doesn't work well with this.

When it looked like all the traces had adhered, I quenched it under cold water and slowly peeled. There were two pads I had to touch up with the Sharpie, but this time the doughnuts actually had holes in them and I didn't have to scrape between the radial electrolytic cap pads.