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Etching your own boards

Started by cbg Rick, January 01, 2019, 08:03:01 PM

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cbg Rick

I'm looking for input on how you guys make your "one off" circuit boards.
I've been messing with a chip amp. I built it on a breadboard then on perfboard, now I want to etch my own circuit board. Back in the  day I used the rub on stencils from Radio Shack to etch my own boards. Searching the internet I see the stencils are still available but the reviews are less than stellar and I could only find 2 different suppliers of the rub on style stencils (both with bad reviews) I did a quick search and found a "how to" on using a printer, transfer paper and heat to put the circuit layout on the copper clad board. Just wondering what options are out there to make a "one off" circuit board. 

galaxiex

I use a laser printer and heat transfer method.

It can be tricky and sometimes takes me a couple tries to get a good transfer.

The trick seems to be using the right type of paper and the heating time/pressure. (old fashioned household clothes iron)

Some folks use glossy brochure paper, but you can buy special transfer paper.
I got some from ebay (China) that works ok.

I don't do enough one off boards to justify the more expensive options, such as the photo resist boards.
Might yield more consistent results tho....
If it ain't broke I'll fix it until it is.

phatt

+1 what *galaxiex* posted. :dbtu:

I'm doing a pedal PCB right now so I'll try to get some pics of the process in the next week or so.

Adding my experience,
I found my wife's house and garden magazines are made of thin but Glossy paper. whatever you use the surface has to be glossy.
I started by using expensive photo paper but it takes hours to soak the paper off. Magazine paper rolls off in warm water in less than 5 min.

Find pages with only print avoid pages with lots of dark print pictures as some of the solid colour will transfer and muck up the result. plain printed words only.

Yes you will need to experiment with paper and also the printer settings.
Your printer settings should allow you to print at full ink density, you want as much ink as possible. Beware of cheap refills as the ink may not be up to the task.
Other setting might be, Improve fine line resolution.
In my case I also set for *Thin paper*

The pcb is cut to size and all edges filed so that there are no burrs on any edges. the copper is then scrubbed with kitchen scour, not new ones they are too aggressive. Dry the board ,, then wipe with Acetone.

I then sellotape the printout down on the Blank,, tape the corners down hard onto a clean laminated particle board.
With iron on high Gently slide the iron across the surface until it starts to stick. once it starts to stick then I carefully lay the iron down flat and press hard for 30sec,, lift and turn, press again. Keep turning the iron as mine has the element in the middle so the heat is not even. So I have to move it around. if the pcb is large you may have to do this a lot to get all the ink to melt and adhere to the copper.

A 70x30mm PCb will need about 3~4 minutes to melt the ink well.
Iron on hottest setting, Linen.

Then drop it in cold water so the ink will set hard,, now dunk in warm or hot water and the paper will start to wrinkle and you will then see the track through the paper.
After about 3min you can gently lift the paper.
Some times it just rolls off but do it slowly and keep dunking as you do.

Some paper will stay on the pcb so you will need to gently rub it off ,DON"T use your fingernails roll it off with the flesh of you finger/thumb.

Next step is touchup any missing bits with oil based ink pen (Dalo pen)
Then you etch,,
when done Acetone off all the ink.
Now if you are hand drilling I lightly centre pop all the holes before drilling with Dremmel or similar.

I use a 1mm drill (you can go down to .8mm but they break real easy).
Tape down on flat board and drill holes.
to de-burr all the holes after drilling I just scrape a steel rule across all the holes, work a treat.

Just one more thing about the software side,,,
If it's diy at home build find global setting in you CAD program and setup the track widths and pad sizes.

Most of these programs are *Assuming* we are all building mother boards and preset pads and tracks are tiny. Don't even think about trying to home build with tracks thinner than say .5mm as you will fail.
avoid ground fills as this can lead to problems if the ink gets so hot it spreads a little and any track that is close by will get bridged.

Anyway If I think of anything else I'll add later,, got to go to bed sometime.
Phil.

cbg Rick

Thanks for all the info!  :dbtu:

cbg Rick

I remember using a Sharpie black magic marker to fill in traces. I have seen recomendations to use oil based pens, do oil based pens work better than the regular permanent markers? I am just trying to gather info before I attempt etching my own. My plan for my first attempt is to draw the traces with a Sharpie and see how well that works before I tackle learning to use a CAD program to draw the circuits. 

cbg Rick

I did a test with 3 different pens, a cheap permanent marker, Industrial Sharpie and Sharpie oil. The industrial Sharpie worked best. The etchant ate through the cheap marker and I couldn't control the oil Sharpie, no fine lines with it. If I can figure out how to post pics I'll post the results.

edvard

I've used some thinned-down model paint and a dip pen with very good results.  Speedball "B" series or Cartographer nibs.  Sharpies always drove me nuts, though my first Big Muff box was done with a sharpie.  I drew the circuit, waited for it to dry, and drew over it to get better coverage.  Sometimes, drawing over it would erase the original, so I'd have to re-draw the trace and do a second coat with a lighter hand. 
With the dip pen and paint, I never had to re-draw any, and the traces were solid.  Depending on the nib size, I could do thick, thin, or medium lines as needed.  I used two different sizes of pencil eraser as a "stamp" to make off-board wiring pads; big pads for pots, small pads for other wires.

phatt

Oh I now see what you are trying to do,,
Don't put your self through hell,, go get software and learn how it works. :tu:

http://diy-fever.com/software/diylc/

It's freeware it's not bad for small stuff like fx pedal circuits.
I did try it long age when it was basic but It has been greatly improved.
The learning curve will not be as hard as some of the higher end CaD programs.

I use Kicad (Also free) but that is vastly more complex and a steep learning curve. xP

If you do want to hand draw,, use a lead pencil to do a draft of the tracks,
you can easy rub out mistakes.
Then when it's right you just follow the pencil lines with a Dalo pen.
Dalo pens are designed for the specific purpose of making PCB's, ask at you local electronics store. They might be called some other name where you live.
Marker pens used to be all Oil based but hard to find now.

If you want to DIY your own circuits my advice is bread board everything first.
And test and re test it to make sure it's going to work *With Your Gear* before you go off make pcb's.
Tiss all to easy to get impatient and just assume that your build is going to sound as good as the utube demo,, often played through $$$$ amps giving a false impression of how it sounds.
Phil.