Press and Peel Blues

[ErikMiller]

I ordered a couple of sheets of PNP Blue from Small Bear, and I just can't get the stuff to work well.

The resist was going on with the traces too wide, so I cut down on the ironing time, but then it got patchy, and still had the big traces and pads problem.

I've made 6 PCB's with it and they are at the outside edge of usability. I'd probably do as well drawing them by hand with a Sharpie.

This stuff has a great reputation around here, so what are the secrets?

I heated my iron to 300, measured with a thermometer, I put a piece of paper between the print and the iron, I kept the iron moving.

How can I get this to work?

[smallbearelec]

A couple of suggestions (because I also use the material):

--It is important to deburr the edges of the board with a small file, so that the P'N'P makes good all-around contact.

--Believe it when they tell you that the copper surface has to be very clean and shiny. I use a Scotch-brite or similar cleaning pad and a little Comet cleanser.

[Aharon]

Be prepared to waste at least a sheet learning.
Use a small PCB patern so you can get many prints from it.
When you print the PCB on to the Blue do not use the dark setting,use normal,otherwise too much toner will be deposited and it'll bleed.
Here is where the experimenting gets good.The temperature has to be hot enough to transfer the toner but not enough to melt the Blue or make the toner bleed,on my iron is the notch before wool(as you can see this is very scientific!)but it changes with every iron i guess.
I start by making the Blue stick to yhe copper either by preheating the board or just by putting the iron on one half of the sheet  while holding the other half in place (i don't use tape to hold he sheet in place).
Then put the whole iron on top and press firmly but don't put your whole weight on it.I find that sliding  the iron makes for bleeding,I usually lift it and place it on another area,very little sliding if any.
After a while I check by lifting one end of the Blue a little,then another etc and maybe a final press.
Then quench the board in a little bowl of water.Leave it for a couple of minutes and peel.
Fix drop outs with sharpie and scrape minor imperfections with small exacto "knoife".
For a full picture essay (and better explanation)go to Tonepad.com
Aharon

PS:this is by no means THE way of doing it but one way that's worked for me.I usually draw them unles they are too convoluted.

[Mark Hammer]

I second Steve's advice.

I had some trouble with the first few attempts, but I now make sure I attend to all of the listed considerations and it works fine for me every time.

BTW, I also make sure I iron my boards atop a nice stiff piece of wood so there is no buckling under pressure, and make absolutely sure that there is no "finger juice" on the board after going through all the cleaning steps.  It really does need to be like shiny virgin copper for optimum adhesion.  A simple means for assuring this is to fold over a clean piece of paper and handle the board by pinching it between the folded paper halves so your fingers do not come into contact with the copper.

[Jay Doyle]

It is sort of a black art, but after similar frustrating attempts I found that the one thing that did it for me was preheating the board.

[Chico]

I have had what I would characterize as moderate to strong success with PNP.  I mostly do what everyone else here has already suggested.  I apply pressure from the iron perpendicular to the board, careful to lift and set.  On a typical board, I have a few lines that need to be fixed, but for the most part, the system works.  

Another alternative that I am currently experimenting with is the use of a laminator.  I just built several circuits including a simple Bazz Fuzz, a Foxx Tone Machine and a Double D.  I did the layouts in Eagle, and printed on a paper called TTS.  

I purchased TTS at:
http://www.dynaart.com/home.html

I also purchased their laminator.

I printed onto the TTS paper, cleaned my pcb and two passes through the laminator and every board came out perfect.  There was not a single broken line , smudge etc.  Even my pad came out clean.

The TTS paper is about the same price as PNP blue and has the advantage in that it can be used to make dry rub decals.  I still need to experiment with this paper, but it appears to have many uses.  The laminator was expensive, $150 bucks, but to me, transfering the traces was always a hassle.  The laminator is about as convenient as can be and the time from printing out my layouts onto the TTS to the time the boards were dropped into the etch tank was less than 5 minutes for all three boards.

Has anyone else had any experiences with these products?

[Paul Perry (Frostwave)]

I wonder if the laminator at Kinkos (or similar) would do? at least it would be 100% consistent, if it DID work!

[nightingale]

hello~
i had problems at first also... i was using lava soap to clean/prep the board. it turns out that most soap leaves a "film" behind, that wont let the p'n'p blue transfer to the board...  then i switched to mineral spirits to prep the board, and have had very consistint results ever since...
hope this helps,
~ryanS

[ErikMiller]

Thanks for the suggestions; I have been preheating the board, and also cleaning with a Scotch-Brite pad followed by alcohol to remove and remaining film.

So I think I can rule out surface preparation.

Years ago I used to get great results with presensitized board, but I don't have a darkroom and wanted to try something new.

I'll keep trying, I guess. In my view, if I need to go over it with Sharpie and X-acto knife, something is wrong. Is that too much to ask of this technique?

[Mike Nichting]

hey Erik,
no thats not too much to ask~!! If you are paying premium price for a "special" sheet that is made for this sole purpose then it should work every time.
I really messed up my first couple transfers. I now clean the board like you do and I file the edges so that there are no burrs and I preheat the board and let the PNP stick to it. So far just like everyone else :-)
I then iron using the side of the iron. I don't use the flat surface. I turn the iron up on it's side and slide it around and even use the tip to make sure I hit every trace on the layout. After a minute or so I give it a rest and then come back after a minute or so and start ironing again. I do this 3-4 times and then gently lift the sheet to see if it OK. If it doesn't transfer all the way you can lay it back down and go at it again.
After a few you will start to see that the transfer is sticking and won't have to peel it up to see.

 After all this has been said, are you using a laser printer to print the transfers on the PNP?? If not that might be the problem. Inkjet printers ink is water soluble and won't work at all.
I take my layouts to Office Depot and have them copy the layouts onto the PNP using their good copiers. It costs 7 cents a page so you just can't beat it.
You might want to try a different printer and see if the results are better??


 Anyway, thats my 2 cents.

best of luck Erik~!!

mike N.

[Paul Perry (Frostwave)]

It's a wonder Mark Hammer hasn't written a thesis on the relationship between people & press'n'peel.. some ppl blame the pnp, some blame themselves, some get it right first time, some try 100 times. There's obviously "too many" variables.
What makes a difference? EVERYTHING!

[Bill_F]

I don't like the stuff. I'm using Kodak Ultraglossy photo paper now and it works great. Doesn't seem to be so tempremental.

[ErikMiller]

Thanks for the detailed answer, Mike.

And yes, I am printing on it using my laser printer.

It's a LaserJet IIp, which is standard enough to be like the Telecaster of laser printers.

I'll try another run in a few days and report back. I wonder if it would help to use an iron with a Silverstone coating.

I'd say the stuff needs better documentation, at least. Set the iron to THIS temperature, press for THIS amount of time, etc.

[computerjones]

you might also want to look at the alchohol you are using to clean the board.  many of the products that are sold as rubbing alchohol actually contain oils and fragrence, which can leave a residue.  best luck.

[Paul Perry (Frostwave)]

I'd say the stuff needs better documentation, at least. Set the iron to THIS temperature, press for THIS amount of time, etc.

Absolutely.. but the irons themselves are pretty undocumented! and the person using the iron... using pnp is the only thing that makes playing guitar look easy! Some say to put a layer of paper between the iron & the pnp to even up the pressure.
It is very frustrating to have pnp trouble when there are sites with pics of ppl using photo paper, overheads, avery label bacing etc etc

[Peter Snowberg]

I don't etch my own boards any more, but I have to second computerjones thoughts. Unless you get pure ethly, methyl, or isopropyl (not the 99% stuff even), you can't be sure of the impurities.

I've used LOTS of rubbing alcohols for lightshow purposes and there is an amazing variety in their makeup. Some brands wouldn't work at all for my purposes while others were great, even though they all said the same thing on the package. :?

I would give nightingale's approach a try and use a non-polar solvent like mineral spirits or acetone.

-Peter