Home brew PCB Advice

Caveat: I usually do one-offs using point-to-point perf board or stripboard (using the Veecad stripboard layout program).

That said, I've had pretty good success with the toner tranfer method using a hot roller GBC brand laminating machine and the Pulsar "toner transfer system" paper.

Surface prep is obviously very important but there's also the interaction between the toner, the paper and the surface. Until you get the hang of it, you might want to start with the Pulsar paper (Digikey carries it) and they try out some of the other types.

I've had very good luck with it, so long as I followed instructions. As for smudged traces, first make sure that you're using the right paper. Use the EXACT Staples paper that is recommended. The only time I've had any smudges when using that paper is when I was doing very small boards, in which case I had to press down with the iron, but not rub around with it. With boards of more normal sizes, I've had no problems.

If the toner is lifting up, you need to:

1. Make sure you're using the right brand of printer. I've only tried HP and Brother, the Brother failed miserably (as so many others have reported), the HP works well.
2. Make sure that you're cleaning the board well beforehand with the scotchbrite, then cleaning with acetone.
3. Make sure that you iron it well.
4. Soak it for a long time. Peel back a layer or two of paper, then soak it some more.
5. Make sure that you have two parts hydrogen peroxide, one part muriatic acid - NOT the other way around.

If "bubbles" are lifting up the toner (probably the paper wrinkling up from the cooling, lifting the toner with it), then my guess is that you're not getting #2 or #3 right, although #5 can cause it as well.

The "white fog" is, indeed, the final layer of paper. On the traces, it won't hurt anything - it will actually add a slight bit of resist. In between traces, it can make things a little slower, especially in the smaller gaps. You can usually work nearly all of it off with your finger, and I use the tip of an x-acto to get the last few bits that seem to stick.

Within two or three successful PCBs, you start to get a real feel for the process, and you get much quicker at it. I helped a coworker make one today, and it was a piece of cake. It was a controller board for a MAME cabinet, so we put a nice little Galaga screen-shot in a blank area of the board, and it came out even better than I had expected.

BTW, the clear tops that come on spindles of blank CD/DVDs make very good tubs for etching, particularly the tall ones from 50-packs. It gives you enough room to submerge the board nicely, and give it a good swirling without worry of spilling.

In my experience, the single most important thing to get right, is the choice of paper. It must have a very smooth surface, and also be easily dissolved in water. Finding paper with either property is easy, but finding a paper with both properties is much more difficult. The good news is you don't have to etch to test if the paper is good. Just try some paper, and if does not work, remove the toner with Acetone and try another type of paper.

I have good results with paper from a mail order catalog. The paper is semi-glossy and very thin. I have to tape it to a sheet of normal paper to get it through the printer without jamming. This paper actually works better for me than expensive, purpose-made paper.

There are three reasons for this:

1: Too much pressure on the iron. You will squish the toner out. 2: The paper moves while ironing. 3: Too hot an iron. Will make the toner too liquid, and increase the risk of squishing or moving.

You did not get the toner to stick to the copper. Possible causes are:

1: Not smooth enough paper. 2: Too low temperature. 3: Pressure not even enough. 4: Copper not clean enough.

Yes, I think so, too. Your paper may be too water resistant. Since you also have problems with bubbles, you may want to try a different paper.

I use a couple of drops dishwashing liquid in the water. It seems to help the water soak into the paper. Luke warm water seems to further improve soaking. Don't use hot water, as that will soften the toner.

To get the final paper residue off, I use a soft toothbrush. If the toner has adhered well, and the water is not too hot, the toner is surprisingly tough.

I use a liminating machine instead of an iron. Mine is only just hot enough, so I have to leave it on for a while before I start, and I run the board through several times in different directions.

--
RoRo

Some tips from James Meyer, Michael Colasono, et al:

*-etchant-off-*-*+consistent+acetone+steel-wool-is-not-recommended+teaspoon+greenie.meanie+spoon+microscopic-roughness-*-improves-adhesion+pink.haze+oxidation

Re: Webb's "Pulsar":

Thanks everyone for your advice. The Pulsar site has lots of good techniques I'll try.

I'm using the staples brand picture paper that goote recommends on his site (Staples "photo basic" "gloss"). The only thing I can think of is I've been getting my printouts from "kwikcopy" a local copy outlet. I don't know the name and model of the laser printer they use, but this may be part of the problem.

Would the "Hewlett Packard LaserJet 1018 Monochrome Laser Printer" found here

be a good choice. What would you recommend from your experience in the ($100-250 price range).

I'm also considering purchasing the Pulsar's "toner applicator "(laminator). Could someone recommend a good place to purchase the laminator? Digikey list a non-stock "KIT PCB STARTER W/LAMINATOR" (Digikey part # 182-1024-ND) that includes the laminator 20 sheets of TTS and plus green and white TRF and a couple of ½ OZ boards for $155. They sell the laminator alone in stock for $158 digikey part#

182-1029-ND) go figure.

The Pulsar site is a bit confusing too they show a laminator here

Note the price on the bottom left $129.95, clicking on buy now takes you here

The only toner applicator is listed at $69.95 Is there a difference? I can't even see a picture of the laminator at the second link. Is this the Laminator you have Rich?

Sorry to bombard you with all these questions but if I'm going to purchase this I want to be sure they are the right tools for the job.

Thanks for your replies!

The only problem I ever had with a LaserJet was with one that was ancient. Even with it's RAM maxed out, it wouldn't do a whole board. (The fraction of the board it did before it gave up looked just fine.)

When you are doing your own printouts, you can open the printer's Properties and tell it to put down more toner. The Kinko's guys aren't going to do that

--at least not if you don't specify it.

That's strange, I use a brother and it works just as well as the HP I use to have before it went belly up..

I use glossy photo paper.. Maybe it's a different bother.. model.. I did notice that I had to heat the sheets hotter than I did when I used the HP.. Not sure how that would work on paper because I've never tried the Brother with just paper.. I just happen to have lots of photo glossy (smooth) lying around.

--
"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

Yes, I do it now with Bother Laser printer and inkjet photo glossy paper! (not mat finish).. Also, I use what they call CLover which is used in machine shops to polish up steel for a smooth finish. I use fine sand paper with a dab of clover on it which cleans and smoothes the copper surface to a shine.. Its important for some laser printers to have a smooth surface because of the thickness of the toner and the type of materials that are used in making toners. I use a dry (no water in the iron) and hot to apply it and then lay a weight on it while it cools enough to handle.if it's double sided, I have 2 alignment holes pre drilled in the PC board that match alignment holes in the image..I leave the paper on until i get ready for use. Then I place it in water to release the paper when i get ready for etching.

--
"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

Don't slide the iron (if you're using an iron). Just apply downward pressure and lift/move.

Clean the surface thoroughly first. Use acetone.

You can scrub that off with a toothbrush. When the toner adheres properly, a toothbrush won't take any of it off (any it DOES take off probably wasn't going to work as a mask anyway).

--
Ben Jackson AD7GD

http://www.ben.com/

I think it has to do more (or as much) with the toner formulation as the printing engine. I use an ancient HP-4ML (note the "L" suffix, indicating it's a 300 dpi model) with Xerox-brand cartridges (got a couple on sale a while back). I don't try to go below 0.015 inch rules with that model but that's good enough for my purposes.

Ultimately, AFAIK, all laser toner is basically tiny plastic beads with a pigment filler. The Xerox cartridges produce slightly shinier printing than the original HP toner.

I suspect that any of the GBC "type" of laminator would work. I use the GBC H200, modified as per the instructions on the Pulsar site. An un-modified laminator should probably be used only with 0,031 inch stock vice the more common 0.062 variety (although I see that Pulsar states that 0.062 is okay with their current model). Even after the mods I typically use 0.031 stock; easier to cut & drill, and sturdy enough for small projects (no MIL-STD-901 shock quals required).

The one they show looks like a newer model. Recommend just check the local office supply stores to see what they have. Might as well pick up some laminating pouches, too, if you get the machine. They do make dandy ID and luggage tags. Again, note that "standard" laminators may not do the thicker board stock.

With the Pulsar paper, I generally take about three passes through the rollers to get a good fusion. The biggest benefits to using a laminator vice a hand iron are the uniform heat/pressure application and use-to-use repeatability. It's kind of guesswork with an iron.

The Gootee method works, and works well. You must follow *all* the instructions carefully. I clean the boards first with Brillo, then with copper cleaner. The boards must be 100% clean and free of any chenmical residue. Let me slay some myths that I saw in the thread: I use a Brother laser with great results. I use the iron at the highest setting. I press hard while ironing, and slide the iron around. And I soak in hot tap water.

Fold the paper over the blank so that it cannot move while ironing. Iron for ~5 minutes. Soak the board for ~ 1/2 hour before attempting to remove the paper from it, and peel off only what come off easily, then soak it again, peel some more. Repeat this until you can't rub any more paper off with your fingers - then use a toothbrush.

Ed

In answer to the "other method" question, for one-offs or even several of a simple circuit, I use a Sharpie-type permanent marker and draw the circuit directly. This is much easier than you might think, and very flexible.

Complete info on this, as well as general board-making tips (like using dental burs instead of drill bits, and *diluting* ferric chloride that etches too slowly) at

Best regards,

Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis

Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card!