Getting tired of the old iron-on transfers - HOME BREW PCB WOES

[Kevin Mitchell]

Long story short - all of my home-brew boards have been made with iron-on toner transfers that were printed to magazine pages and chemicaly etched. The results have always been hit-or-miss for me as I haven't nailed down a consistent strategy for toner transfers. More of a iron and pray style.

Well I'm sick of it and I need something more easy going. I'm considering building a UV box and trying out photo-etching or maybe giving PnP sheets a try. Maybe in the summer I'll build a PCB CNC in the garage but in the meantime I'd like to do what I can to make this process more easygoing to obtain adequate results - instead of spending hours on and off cleaning, prepping and ironing with no cigar.

-KM

[Mark Hammer]

Over the past year, Kevin, I have found that my traditional buff-with-superfine-steel-wool-until-shiny approach to copper-board preparation was insufficient.  I now make a point of wiping down the surface with isopropyl alcohol prior to attempting to transfer toner, and have had much better success.

The problem is that "finger juice" is not always visible to the naked eye.  One can quite unintentionally leave a film residue on the copper that impairs toner transfer and adhesion to the copper.

[Kevin Mitchell]

I do wipe em' down! Also sand with finishing sandpaper - like 1200 grit or so. It's more of not knowing when there's enough heat or too much and the toner either doesn't stick on some corners or smudges. There seems to be constant variables - the room temp, PCB size, PCB thickness & material, type of paper holding the transfer.

Also results vary depending on what printer I use for the transfer image. I like using my office machine at work as the prints are more heavy but I don't always have access to it! Really need a laserjet at home.

After years you'd think I'd stabilize my technique  Perhaps it's all of the considered variables that make it such a headache for myself. Consistency seems to be a pipe dream.

Also; happy 1000th post to me 

-KM

[Marcos - Munky]

Have you tried cold transfer using acetone? Print the layout the same way you do for iron transfer, clean the board the same way. Scratch the back of the paper so acetone can go deeper inside of it. Put the paper and the board one facing each other, the same way you do for iron transfer. Then drop a little bit of acetone in the middle of the paper, and spread the acetone using your fingers or something cylindrical like a cup or a aerosol deodorant. Apply some force, you don't need to worry if it's much force (unless you spread the acetone with a glass cup). Let it dry, repeat. Let it dry again, then wet the paper and remove the paper the same way you do for iron transter. I got good results this way, some transfers I got better results with iron and other I got better results with acetone. Just a tip, it works better for layouts printed a few days ago than for fresh printed layouts.

The next step I suggest is to try pnp/dry film. I got great results from it using cheap dry film from aliexpress and improvised stuff, but I found out I had to experiment a lot to find the exposition time and distance between the light and the board, and coudn't do big transfers using my setup. But the last boxes I posted on "etched enclosures" and "1590a builds" were all done using dry film, and I got pretty good results that way.

Also, happy 1k post 

[davent]

I've done photosensitive boards for years and my only lights have been regular fluorescent tubes, under the cabinet lights in the kitchen, my shop lights. Just get the board an inch or so from the light and you're set, exposure takes longer but i could print my art expose the board, develop and etch a board in under half an hour.


Photobucket pictures show up for me...
https://www.diystompboxes.com/smfforum/index.php?topic=77252.msg633846#msg633846

dave

[Kevin Mitchell]

Have you tried cold transfer using acetone?

I've seen videos of folks doing that with nail polish remover. Might give this a shot!

Just printed my transfers to thick-stock coated paper. It's been a while since I've used anything besides magazine paper so hopefully this goes smoothly. Think I had switched over to magazine stock after a lot of trouble transferring to enclosures which has many other complications involved (a big surface to heat up!). But like everything else I do, it's a hit or miss 

I've done photosensitive boards for years and my only lights have been regular fluorescent tubes, under the cabinet lights in the kitchen, my shop lights. Just get the board an inch or so from the light and you're set, exposure takes longer but i could print my art expose the board, develop and etch a board in under half an hour.

Yes! I've been wanting to try that and hopefully transition over. I have a few ideas for my own UV setup. Would also be using it for curing silkscreen emulsion.

Thanks for the suggestions, guys. Going on 6 years on this forum it's about time I nailed this part down. 6 years ago I etched my first Easy Vibe without any experience in electronics, soldering or anything of the sort. Talk about a deep dive.
-KM

[Fancy Lime]

Have you tried cold transfer using acetone?

I've seen videos of folks doing that with nail polish remover. Might give this a shot!
...

Nail polish remover is mostly acetone plus perfumes. Unless you mind if your workshop smells like the sort of motel that has hourly rates only, nail polish remover works well. Just be wary of googles search algorithm when buying online so you don't accidentally buy a Polish nail remover instead.

I have done cold transfers in the past onto aluminium enclosures with some success like this: Place thoroughly cleaned, sanded, steelwooled and de-greased (with acetone) enclosure on a flat surface so that liquid stays on top where you pour it. Cover the surface with a film of 2/1 ethanol/acetone mixture. Place the printout face down in the liquid, making sure not to take too long so that the liquid does not evaporate (which it does quickly in warm weather). Press it to the surface in the right place and see if the whole paper is wetted. If not, pour some more mixture on top of the paper. Place a flat surface (I used a plank of wood) on top of the paper and weigh it down. 10kg or 20lb ought to suffice but the more the merrier. Wait until the liquid has evaporated, which takes a while because it needs to diffuse out through the paper to the sides. An hour was always enough for me. Remove the paper carefully. If all went well, your done.

I have never done this with copper but the instructions originally come from PCB etching, although I cannot remember where I got them from. The 2/1 ratio of ethanol/acetone is just a guideline and may need adjustment to the toner. If the result is smeary use less acetone; if the toner does not transfer but sticks to the paper, use more acetone.

I just looked up what photoresistive boards cost these days and promptly decided not to bother with toner transfer anymore.

Cheers,
Andy

[Mark Hammer]

I've been using the yellow toner-transfer sheets for a few years now, with much success.  The Press-n-peel sheets are much better for things demanding very precise slender traces, given the acetate sheet, and finer particle-resolution of the blue coating.  But these yellow sheets are not only MUCH cheaper than PnP (about 30 cents when I get them),  they are far more precise than photo paper, and I find it much easier to "see" the extent of successful transfer through the backing than is the case with thicker photo paper or might be the case with glossy magazine stock with pictures on both sides.

I used to get the sheets from various Canadian distributors, but my most recent batches have been purchased through Banggood.

[garcho]

I've had consistent success with PnP, light sanding and alcohol (also for cleaning the board :p). If a few traces peel up, the right type of paint marker works just fine, and usually would take only a few minutes (if you're lucky anyway) of touching up.

That being said, I got really sick of going through all the work and having possibly harmful chemicals in the house (depending on how you handle/dispose of them). I started doing the math, and it basically costs the same or less to send gerber files off to a fab house like OSH Park here in the US, for instance. No f'd up printing problems, no ironing, no sanding, no cleaning, no need to buy etchant, F4 copperclad nor PnP, no need to spend time sanding it down and then oops! sanded too much off, no need to spend time going blind checking traces, the fab'd boards have actual copper eyelets instead of pads, etc. I spent as much time on generous forum member Banica's marvelous DIYLC software as I do now on EagleCAD, so that evens out. The only downside is waiting a week or two for the boards to arrive in the mail. I use "busboard" or "protoboard" for simple one-offs, everything else goes off to the fab house. I have cut back significantly on frustration, chemical/fiberglass exposure, and crap laying around my bench. I build more and better devices now. It's worth giving a shot.

[slashandburn]

Probably all in my head but I found 1200 was two fine and led to toner running and smudging under  too much heat. I just hit it with 400 grit and then scrub down with IPA. I've never really had to worry about too much heat from the iron. Lots of pressure, pay attention to the corners and edges, when I think it's done give it another few minutes. The only other variable I can think of is that I use cheap gloss photo paper rather than magazine paper, which is a pain in the ass to peel back off the unscreened areas but has served me fine so far.

That said I'm intruiged in all the alternative methods, I etch as little as possible now and when I do I'm confined to the shed. Even still, I'm tired of the filth. Ferric chloride stains like nothing else. Then there's the dust from drilling boards, I'm tempted to jump to somewhere to like oshpark but the price and lead time hardly seems worth it for one off boards.

[Kevin Mitchell]

Yeah I've been using 1000 grit actually.

So... first try with thicker stock glossy paper was a success 
I guess I shouldn't ever complain without trying all options available to me. I feel crazy trying over and over again without the thought of trying a different paper stock.

Now to dial in my silk screening technique. This one is a real PITA without a legitimate rig lol.

Hope everyone is doing well during these times! With everything being so calm I've been finding time to pull a bunch of projects off the backburner.

-KM

[Kevin Mitchell]

Hey 20th time is the charm. Happy I didn't give up lol.

[PRR]

> thicker stock glossy paper

What you want is CLAY.

#1: selected art-books from 1999
#2: Playboy magazine from the 1970s
...
#987+: today's sales fliers.

[Mark Hammer]

I find one of the biggest challenges with iron-on toner transfer is being able to visually verify that the entire layout has been transferred.  With PnP, it is rather easy because the toner+emulsion is thicker than the acetate backing, so the acetate kind of "sags" around the edges of what has been transferred.  Photo paper is one of those take-it-on-faith things, because even with thin photo paper, it doesn't physically deform in any informative way.  Glossy magazine paper, regardless of what it is from, is not assured of being devoid of images on both sides.  That makes it harder to tell, by looking, what has and hasn't been transferred.

That's why I'm lovin' this yellow stuff.  It looks kind of like wax paper and is glossier on the transfer side than the backing side.  I think I paid about 30 cents a sheet.  The only thing not to like about it is that it is A4 format, not 8-1/2 x 11.  So, a little longer, and a little narrower than "letter" size, so you either have to adjust your printer edges, or line up the paper carefully so that it doesn't accidentally go diagonal and bunch up on you.

[davent]

I never did full sheets of transfers, maybe a board or three. I'd first just print the art to a regular sheet of paper then cut a piece of transfer to the size of the image, attach it to the printed paper over the image then run it back through the printer to print the art onto the transfer paper.
dave

[vigilante397]

I haven't done toner transfers in years, but I just wanted to let you know there's a learning curve and a lot of learning from mistakes for CNC etching boards as well

[soggybag]

I bought a desktop CNC mill a couple months ago. Might not be an affordable solution for everyone, I wouldn't have bought it last week myself.

Cost aside, I just made these PCBs last night. Took about 30 minutes to mill the traces, drill the holes, and cut out the boards. The machine will do double sided boards also.

The process is surprisingly easy, the software uses .brd files from Eagle PCB. Just open a .brd file, measure the thickness of your PCB, add 0.3mm for the thickness of the the tape, then double stick tape the board to the bed. The machine prompts you to change tools. I milled these boards with a 1/32" and 1/64" flat end mill.

I also used the machine to mill the boxes.

[Mark Hammer]

Very nice.  I gather it wants at least medium-thickness fibreglass boards?

[soggybag]

You can mill many materials: aluminum, plastic, wax, wood, brass.

For PCBs you can mill FR4, but you need some special equipment to protect against the fiberglass particles. I'm milling FR1 boards which are resin and don't produce hazardous particles.

I've used the mill to mill some 1590B boxes. The bed will handle about 4" by 5" by 2". A 1590 BB is about the limit. You could mill a 4.5" by 5.5" pcb, which is about the limit of what you can make with the free version of Eagle.

The real magic, if there is any, is that you can load a .brd file and start milling without any extra setup or processing. This goes for double sided boards also.

Here is a picture of a box I milled.

[Mark Hammer]

I am very impressed, and very jealous.