Getting PNP not to smear/curl?

[rockgardenlove]

Hey, I've been using PNP for the first time(I've done overhead transparencies before.  It works great for the hardest part (getting toner off material), but I've got some problems regarding smearing.  The paper curls up around the edges with  heat when I lay the iron on it...this lifts up.  Then when I try and flatten it out, bubbles get caught underneath.  The edges remain smeared.

Tips?  do I need an iron that can cover the whole board at once or what?

[finkfloyd]

Hi,

It sounds like you are applying too much heat, I use medium-high heat, lowest to medium steam setting (WITHOUT the STEAM on!)

There is a knack to doing this right, you get better and better at it eventually. my first few boards were a failure, and I occasionally get missing or broken traces but I use a sharpie to touch up before etching.


Theres a guide at http://www.tonepad.com/photoessay.asp?photoEssayID=10

[Pushtone]

Yeah sound like too much heat.
I had those issues when using the "cotton" setting.

I use the "polyester" setting with good result, but it takes a little longer.

I let the iron sit over the whole surface for 15 seconds, then rub with the tip of the iron over the traces or art, then another 15 seconds of sitting, more rubbing, sitting, rubbing, douse in cold water.

I also think that it takes more heat/time to apply PnP to an aluminum box than a copper PCB.

Good luck this weekend.

[MikeH]

I was having this problem too.  I've been using lower heat which helps, but my big problem was getting the pnp to stick to the board, so it didn't wiggle when I put the iron on it.  So, to solve that I preheat the board for a minute or so, the I lay the pnp down and quickly roll something across it, like a glass or dowel, to get the pnp to stick to the board.  Then when I put the iron on it, it doesn't move and smudge.

[rockgardenlove]

Thanks, I have been using full heat, as I'm used to doing it with photo paper and transparencies.  I'll try lower heat when I get home. 

I'll preheat the board too, thanks for the guys who suggested I do so.

Thanks very much.

[sfr]

Just starting to read this thread, "preheat" was the first thing that came to mind for me as well, glad someone mentioned it.

If you haven't read the photoessay over at Tonepad about using this stuff, you should check it out at least once.  It certainly helped me.

[Somicide]

my first experience went great, all thanks to tonepad's essay!

[markm]

Just starting to read this thread, "preheat" was the first thing that came to mind for me as well, glad someone mentioned it.

......Strange.
I never pre-heat and get Excellent results.
There's always dozens of methods to acheive the same goal.
(wow, that sounds pretty philosophical)