Inexpensive & abunduntly available thermal transfer sheet for making PC boards

[tkamiya]

I'm really NOT sure where to put this question.  It's sort of elementary question, so I'm putting it here.

I bought a pack of yellow sheet supposedly for PC board making.  No instructions or specs.  But I know newer way of making PC board is to design it on PC and print on these using laser printer.  Then use hot iron to transfer it to a PC board.

Well....  Laser printers have roller heater to fuse toners.  So I'm afraid it may damage my printer. 

Can anyone comment on this?  I saw few videos and I know the process.  But having no technical info on these scares me.

[KL27x]

That stuff is basically laser printer label backing paper. Lots of people use this stuff with good results. About the worst problem you will find, IMO, is that it's thin and curly, so it can jam in your printer. And some of the toner might not fuse, causing "ghosting" when the unfused toner clings and fuses to the paper on the next go around. If your board is larger than the rollers/fusers in your printer, the ghosting can end up on your pcb print. If it's smaller, then the ghosting can end up on the next thing you print.

In the US, you can buy this stuff called Pulsar from Digikey or Mouser. It's also available at Amazon and places like that, but I think it's usually cheaper from the component distributors. The Pulsar paper is thicker than normal printer paper so it is easy to handle without curling or jamming, the toner fuses completely. It was a water soluble dextrin coating that handles very high temperatures without melting/burning/sticking, and the paper releases in about 10 seconds after wetting it. It costs way more than the yellow paper, but it's still basically nil compared to the time and labor you spend to make a board.

Just keep that in the back of your mind. I wouldn't spend on the the Pulsar until after you prove your method and printer is viable with the yellow paper. I bought that stuff on eBay, myself, just to see what it was. I binned the whole package, but I have already tried laser backing papers and photo papers and magazine papers. There's good reason I use Pulsar, but it boils down mostly to convenience... and maybe the last 1% of results and consistency, but if your process isn't there, then that doesn't matter.

[Zero999]

Many people swear by special papers, my favourite was always magazine paper, but I've found plain old copier paper works quite well.

Why bother etching your own boards? Decent quality boards can be made fairly cheaply nowadays.

[tkamiya]

I only need a very simple board.  My circuit is subject to a lot of changes.  I also don't know how to use K-cad or other CAD software and don't want to learn it at this time for my so simple needs.  I was going to make artwork by hand, scan it, and print it out.

Yes, I know it's not hard.  But learning CAD is not in my motivation.

[Zero999]

I only need a very simple board.  My circuit is subject to a lot of changes.  I also don't know how to use K-cad or other CAD software and don't want to learn it at this time for my so simple needs.  I was going to make artwork by hand, scan it, and print it out.

Yes, I know it's not hard.  But learning CAD is not in my motivation.

How about using strip board? That's what I normally do when I want to make a quick prototype and have no time for a PCB.

I've also cut tracks into copper clad board, rather than strip board or etching it, because it was for a high current design, which needed thick traces. The low power part was done on strip board and connected to it with links.

[quadzillatech]

ive cut isolation tracks in copper clad before using a dremmel and a small bur,seems to work for simple boards.

[xavier60]

Many people swear by special papers, my favourite was always magazine paper, but I've found plain old copier paper works quite well.

Why bother etching your own boards? Decent quality boards can be made fairly cheaply nowadays.

I have tried glossy magazine paper. It would work well except for that the existing printing sticks to the copper as well as the toner.
I'm using coated ink-jet paper.
With my particular printer, a HP 6L, toner deposition is greatly improved when I reduce the moisture content of the paper by heating it with a hot air gun just before printing. The improvement is mainly noticeable in the larger areas where the toner tends to thin out.

[SilverSolder]

+1 for the Pulsar paper, it gives very reliable toner transfers compared to the many other toner methods I have tried. 

I economize on the Pulsar paper like this:

1) Print the artwork on a regular piece of (good quality) paper,
2) Cut out a piece of Pulsar paper big enough to cover just the artwork,
3) Tape that piece of Pulsar paper to the paper, covering the artwork,
4) Run it through the printer again, this time the print ends up on the small piece of Pulsar paper.

By reducing waste like this, it is actually quite economical in use and it isn't worth messing with "lesser" papers.

I find the main limitation of the toner transfer process to be that laser printers don't seem to apply a thick enough layer of toner if you have large areas of copper on large boards.

E.g. a 10 inch by 8 inch boards with lots of very wide high current traces did not work for me, it proved impossible to get the layer of toner thick enough to work properly even though the Pulsar paper transferred all of it to the copper.

The method is super fast and works very well on boards with "normal" sized traces, though.  But for some jobs, the photo resist still comes out to play!

[KL27x]

E.g. a 10 inch by 8 inch boards with lots of very wide high current traces did not work for me, it proved impossible to get the layer of toner thick enough to work properly even though the Pulsar paper transferred all of it to the copper.

I used to have this problem, as do many others. But no more. I suspect there are two issues at play that make this pronounced, which I'm thinking it MIGHT not be your printer. My problem disappeared, no change in the printer.

1. the toner isn't fully fused to the board and/or the laser printer pattern is leaving tiny gaps in w/e dot matrix it leaves... due to the mechanicals or software or w/e.  You can see this on the print under a microscope.
2. etching with acid peroxide

I think what happens is acid peroxide will get into any weak point in the resist and undercut like mad, leaving pin holes in your ground pours. I don't use any foil overlay and I get solid pours without any problem, anymore. I'm not sure which of the two is the main culprit,* but my method eliminates both. I fuse the toner to the board at high temp to completely liquify it, and I pre-etch the board so the toner doesn't wander. The "dots" fuse together, but the fidelity remains very good. And I abandoned acid peroxide. Try making a sharpie board in acid peroxide, and you will see the same sort of problem, but even worse! With a proper etchant, the board will be night and day better, and you simply don't spend (waste) time inspecting the board for shorts and broken traces and making repairs.

*I can still see some "spots" on pours after the etching where it looks like the etchant got through gaps in the resist; but they are very shallow/superficial. After a shine with steel wool, they are gone, and I have solid planes and traces with crispy edges. So it might be a matter of degrees. Suboptimal etchants and/or transfer method add up and cause problems on a continuum between "it works" and perfection.

I remember seeing pics of DIY boards that were way better than mine and thinking that it was a matter of practice.** And mine were good enough for what I needed, at the time. Then my needs changed, and the boards didn't get any better with just practice. I didn't luck out and start out making good boards; I started in the gutter, and I have a pretty good idea of what makes the differences.

**Or that the board was cherry-picked out of a dozen! Nope. Every board, every time. And it doesn't take skill or practice. Just the aquisition and application of knowledge.

[David Cutcher CEG]

Hey KL27x
This is very easy to do. This is my 1st post, so I hope the attachment attaches.
This is a scan from my book "Electronic Circuits for the Evil Genius" 2nd Ed 2010.
It's all about clay coated paper. That's why magazine paper works. But the Epson Photo Quality ink jet paper is the best, for the price.
David Cutcher "Certified Evil Genius)

[SilverSolder]

I used to have this problem, as do many others. But no more.

So, if you print e.g. a black filled rectangle the size of an A4 (US letter) page, you would expect it to give a thick (enough) and even coating to be able to protect the copper?

None of the devices I have tried slathers toner on thick enough to make that possible.

[David Cutcher CEG]

Interesting thought. Never had need to do a whole sheet entirely covered. But I have done larger negative areas just to save chemicals. There are always pinholes. This is a method for home, education, and prototyping.  I'm not expecting commercial quality.
For classroom work, I use A4 sheets printed with multiple pcbs within the margins. And a T-Shirt press. I get consistently great results. It's a matter of practice. And don't use the "Save Toner" settings on the printer.

[SilverSolder]

I also get excellent results as long as I don't use large fill areas. 

Printers and copiers definitely put a thicker layer down when there is less area to cover.  Wonder if there is some power limit in generating the static electricity for the roll fast enough, or something like that, when you are printing large areas?

[KL27x]

So, if you print e.g. a black filled rectangle the size of an A4 (US letter) page, you would expect it to give a thick (enough) and even coating to be able to protect the copper?

None of the devices I have tried slathers toner on thick enough to make that possible.

Hmm. I have never tried to print a solid polylgon that large, so I can't answer that... yet. I might have to make a board very soon, so I might give that a try.

Wonder if there is some power limit in generating the static electricity for the roll fast enough, or something like that, when you are printing large areas?

+1. I'm gonna be curious to find out. I'm working on a prototype right now, and if it ends up suitable for DIY, I plan to make it, myself. I'll try this, too. Maybe not an entire A4 envelope, though. 3"x5"?

Hey KL27x
This is very easy to do. This is my 1st post, so I hope the attachment attaches.
This is a scan from my book "Electronic Circuits for the Evil Genius" 2nd Ed 2010.
It's all about clay coated paper. That's why magazine paper works. But the Epson Photo Quality ink jet paper is the best, for the price.
David Cutcher "Certified Evil Genius)

I think I've read some of these books, mate. Cheers. I actually went over to the internet store, found this Epson S041062 and put it in my cart...

And then I get the notification that I purchased this stuff ten years ago. It didn't work for me, then. Although I probably did not try the dish soap trick. Clay coated magazine paper worked pretty good for me. IIRC, this "clay-coated" inkjet photo paper stuck to the board even where there was no toner. Maybe they changed the formula (or maybe they sell a different product in Canada), or maybe I was doing something wrong/different. That was so long ago, I'm not sure if I was still trying to use an iron or if I had a laminator.

[SilverSolder]

I'm working on a prototype right now, and if it ends up suitable for DIY, I plan to make it, myself. I'll try this, too. Maybe not an entire A4 envelope, though. 3"x5"?

It is pretty obvious on my printer that it considers it a challenge to print a big black rectangle even on plain paper. You don't need to go as far as to actually try to etch a PCB if your printer is anything like mine.  It is much, much happier with line art, even reasonably thick lines.

Would be interesting to try a few experiments to see how many % of a page can be black, and still provide solid toner coating...

[ednspace]

I used to have good luck with Jameco covers

Just recently I tried to make a board and it was just a nightmare. It turns out after looking under a microscope that the toner my printer was laying down was VERY spotty. No amount of tweaking the setting in the print driver seemed to fix things. I eventually traced over everything transferred with a sharpie and got a board but Jeez. With my old laser printer years ago I used to be able to pretty reliably get 8mil traces and 8mil spaces if I was careful.

Only did it this time because the artwork was available but the board files were not and I still had all the materials. In the end it probably would have been faster to redraw it and send it out. Still, it's a great trick to have in your tool bag when you really need it.

Good luck coming up with your system!

[David Cutcher CEG]

Just a comment specific to the Epson Photo Ink Jet Paper.
Get a package and just try my method.  I find it "Student Simple." The two biggest errors are (1)not enough heat, (2) too much pressure as it cools, and squish the toner out.
And yes, it took me a while to perfect this, but it does work. And a 3X5 area should have no problem.
Keep in mind, you are separating the clay from the paper, not the toner from the clay.
I never did have success with magazine sheets. The pages in the mags I bought were just too flimsy. Maybe National Geographic. There's glossy & thick.
David Cutcher "Certified Evil Genius"

[tkamiya]

I really wanted to do it the old fashion way, but materials are so hard to get.  Those die cut patterns and tapes are pretty much unavailable.  So I'm trying to learn Kicad.  I'm sure it's not hard but for a newbie to the modern world, it's a daunting task.

Since one 14pin IC is involved, it's really not practical to dremel the board.

I'm getting tired of making this piece in perf-board, so I'm going to try rolling my own board.

If anyone is curious, I made a 1 pps distribution board.  I will need to make several.  Although it's a simple board, hand-wiring takes few hours.  Circuit changes every time since I keep finding better ways to do it.  That's why I don't want to send it in to be made.  Besides, I used to be a darkroom photographer, so I'm sort of used to the process.

[james_s]

I remember when I was using magazine paper large copper pours would often transfer the image printed on the catalog page onto the copper. Some of the printing inks would fill the pores in the toner and prevent any pitting. The ability to cover large pours depends heavily on the specific printer and the toner in it. Under ideal circumstances I've had some success but these days if I need a board like that I usually send it out.

[KL27x]

I have my prototype board in the tank, right now. I was gonna mock up a large pour test board, but I remembered I have this:

https://www.eevblog.com/forum/reviews/hakko-888d-interface-fixed/msg875006/#msg875006

This isn't huge, but it's maybe a 2" circle that is 90% solid pour. Is this "pitted?" To my recollection, this is 1 oz copper. Not the easy half oz cheater board.

[KL27x]

Why bother etching your own boards? Decent quality boards can be made fairly cheaply nowadays.

Client: Can you make this board?
Me: Probably. What time frame?
Client: As soon as possible
Me: Ok.

Meanwhile, the playoffs are in progress, and the Masters over the weekend. Got family visiting. So I procrastinate for 4 days.
Start the board design last night. Taking dimensions and making a drawing. Start the PCB design this afternoon. Couple hours making custom library parts. 30 minutes to put the schematic together. Print, transfer and etch in an hour. Mostly waiting.

Board is electrically fairly simple. But the position of contacts and placement holes/slots is fairly critical. I printed the dimension layer and slots in 8 mil thick lines. Place a via over the critical hole positions for a center point. Cut and sand the board to the dimension outlines with the disc sander, removing roughly half the copper line. Dremel with cutoff disc to cut the slots. Spend 20 minutes doing the holes. This involves carefully center punching them under the microscope and then referring to the pcb file for the hole sizes. Then picking out the drill bits with a pair of calipers. Cordless Dremel: bzz, bzz, bzzz. Crazy, but the holes and slots and contacts all seem to be perfectly aligned on the first try. Done. Started it yesterday. Client will have the board tomorrow. Upon which he will procrastinate for a week or two before doing anything with it.

I don't really mean procrastinating. We both have plenty of other fish in the fire. I have 4-5 other projects going on right now.

If it checks out, I'll order production quantities with no worries. Really just checking the placement of things. I'll make only minor modifications to the routing and vias for the production version.