Making PC boards and soldering

Posted: 11/20/2008 5:07:34 PM

From: Escondido, CA

Joined: 2/6/2008

At some point nearly every electronics hobbyiest has made their own pc boards. So how about a little discussion of things you have tried and how well they worked. Also,I have read that there are some "crazies" out there who, not to be held back by this "new-fangled surface mount stuff", have actually been assembling SMT boards with the use of a toaster oven! Got to give them kudos for originality!

Ok here's my experiences:
1. Dry transfer donuts and lines -- worked fairly well, but there does not seem to be anyone selling that stuff anymore.

2. Photo process -- worked fairly well, but messy and time consuming.

3. Iron on -- great idea, I'm just not quite able to get a smooth transfer yet. Working on it though. Latest thoughts: Buying an old electric griddle and using a heavy piece of metal to hold down the blank pc board and artwork.

Has anyone built anything to transfer artwork directly onto the blank pc board? I could see someone clever maybe ripping apart a laser printer to build something.

Etching is pretty simple now. I bought a $40.00 etch tank from Frys that works quite well.
Posted: 11/21/2008 7:13:59 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as . ...................................

Joined: 12/7/2007

"3. Iron on -- great idea, I'm just not quite able to get a smooth transfer yet. Working on it though. Latest thoughts: Buying an old electric griddle and using a heavy piece of metal to hold down the blank pc board and artwork."

I have been making PCBs for prototypes - I nearly gave up with Iron-on, as I could not get good adhesion with the transfer paper and film I was using (Pulsar)... I then tried "Press-n-peel Blue" and it worked perfectly first time - it is simple and robust, and does not require a second step of applying a film. I know others have found the Pulsar system works.. But no matter what I did, the results from Pulsar were never good enough to make a PCB which did not require extensive re-touching.

I bought a panini toaster which I modified - fitted a precision thermal sensor and power controller to each heating element - but this proved to be a bit of a waste of time.. Pulsar would not work, and P+P blue works, but works just as well using a simple iron.. P+P Always gives a good transfer, and temperature does not seem too critical. I probably average about a PCB (100mm x 160mm) per day.

The most time consuming process is drilling the board - Sometimes I use prototyping board like Roth RE200-LF ( which is just holes and pads.. I lay my design out on a 0.1" grid, then copy the track layout onto the board using the Pulsar transfer paper.. This gives a plan which I can follow when wiring the board (I use Road-runner wiring pens).. One can also transfer the component overlay using Pulsar paper.. Pulsar is good enough for this job, and cheaper than P+P.. As no etching is required, and the print is only a guide and not critical. It is easy to solder directly onto toner-coated pads.. but I do not know if this is a possible health hazard.

I HATE SMD! - I have had a batch of small adaptor boards made for the few SMD parts I use, and if I must use any SMD on anything I produce, I will get someone else to assemble it!

"Has anyone built anything to transfer artwork directly onto the blank pc board? I could see someone clever maybe ripping apart a laser printer to build something."

I thought a lot about trying to do something like that - but when I was able to get perfect transfers using P+P Blue, the reason for exploring a complex project like this vaporised!

What I would like, is for someone to produce a conductive solderable ink, which didnt cost a fortune.. I have wondered about the possibility of a highly conductive additive for toner.. If one had highly conductive, solderable toner, one could eliminate the etching process.

Posted: 11/22/2008 6:38:38 PM

From: London, UK

Joined: 6/5/2007

Making PCBs, something I have done many times!
I have heard of machines that “print” the tracks onto a blank board, but the price is way out of the league of a casual user.

The most reliable way is the photo etch method.

I use a UV light box, caustic soda (drain cleaner) and regular etch crystals in a plastic container, normally something from the take away so I can just throw it out when finished.

It can be messy and the chemicals are a bit nasty, but it’s the best way to get consistent results.

Whatever method you choose, remember this:
PCB making is best done when the lady of the house is out and make sure you are finished and have cleared up before she gets back!
Posted: 12/1/2008 6:50:28 PM

From: Escondido, CA

Joined: 2/6/2008

The photo transfer requires a sunlamp or other high intensity light. Mine broke years ago :(

That process gave me about the best results, but it's not the easiest thing to setup and run for the occasional proto PCB that I do. Not to mention that my garage lab is probably already a hazmat disaster without adding even more toxic stuff!

I think there might still be transparency materials available rather than using the glossy presentation paper. It's more expensive, though.


Posted: 12/5/2008 7:23:45 AM

From: London, UK

Joined: 6/5/2007

Yes it does require a UV light box.
You could always buy or make another one?

In times gone by, I have used the photo etch method by placing the mask onto UV board, putting some glass from a photo frame and exposing it to the big orange thing that lives in the sky and sometimes makes an appearance even in London! Not science but it did work.
Have heard of some people using sunbeds in a tanning shop.


Posted: 12/5/2008 2:00:49 PM

From: Escondido, CA

Joined: 2/6/2008

The big orange thing is so fickle :) Sometimes it refused to give me even coverage ... half- exposed board, didn't etch away all that it should, etc.

The artificial big orange thing (i.e. sunlamp) worked great every time.

You can still buy all that stuff, but it makes the boards cost about twice to three times as much as the iron-on methods ... where any old piece of copper-clad will do. And if you are out to make a bunch of prototype boards with a budget of less-than-zero, every penny counts.

Posted: 1/5/2009 8:00:06 PM

From: Escondido, CA

Joined: 2/6/2008

Well the George Foreman grill was a total waste of time, but at least it didn't cost much from Goodwill!

The tried and true iron-on approach seemed to work, but I discovered a few things:

1. The surface under you board needs to be smooth and able to take the heat, but not remove too much of it. My laminate-covered workbench worked much better than a piece of aluminum foil on top of a wood board.

2. While some recommend placing a blank piece of paper on top of the artwork to be transferred, I found it worked best to apply the iron directly on top of the artwork.

3. Patience! and I want it now! You have to set the iron on top of the artwork and give it about minute or 2 to fuse the artwork down enough to continue. But don't walk away because it just might catch on fire! (no, didn't have to put out any fires!)

4. Temperature of the surrounding air. My "lab" is out in a garage separated from the house. It gets damn cold out there (well to us Californians anyway). Even though the transfer seemed to take, if I iron on the pattern when the temperature drops to something in the low 50's high 40 degrees F, the image just won't transfer properly.

5. Don't expect "professional" pc boards. They'll be good enough for prototypes but that's about it.

You must be logged in to post a reply. Please log in or register for a new account.