Making PCBs with a pen

[Wendymott]

I found that the quickest way to harden inks etc is to use the domestic oven...I turn it on (gas) on low light, no higher, let the oven warm up until the flame reduces, leave on 5 mins, then turn off....... pop in the item and leave till cold. This works equally well with paint too.. If too big for the oven, as my Hammerlund HQ170 case was, pre heat the case with a hot air gun, spray paint and leave......voila..
PS don't let the wife catch you.. haa haa...
Regards
Wendy G8BZY

[caliskan]

Hi, I think it is better idea to go with the professionals for the prototype boards rather than the making the PCB’s at home because it is very hard to handle the SMT components at home and even some are very small and difficult to solder and that is why, I always prefer to go with professionals.

[Bazz4CQJ]

But....that is the first step on the route to buying the complete item from the professionals. That said, no, I don't make my own transistors

[G8UWM-MildMartin]

Regarding UV photo resist PCBs, 35 years ago a friend and I successfully used them by taping them onto an ordinary (5' ?) fluorescent tube for half an hour or so before etching.
(I had the local chemist's last bottle of ferric chloride at the time and she said it wasn't used much in modern medicine, long before they became pharmacists...)
There is a more recent method using a laserjet (H-P 4 or 5 or similar) printer onto a magazine page then ironing it to transfer the toner onto the PCB, though I haven't tried it.
(I'd be happy to print on mine if it would be any help to anyone.)
I have mentioned the very friendly & helpful professional company that does PCBs for Work from Gerber files or 30-odd-year-old artwork peeling off original acetates and did the Sussex PCBs from the late Mike Rowe's (Swordholder's) .pdf before, so I won't again in case it sounds too much like an advert.

[kellys_eye]

I recently (yesterday) made a pcb using the toner transfer method.

The best paper to use is the shiny backing paper from self-adhesive labels - I have a load of old CDROM printable labels (blank) that I just strip the sticky paper off. The backing passes through both my colour laserjet and mono kyocera without problem and the toner can, if you're not careful, just wipe off the paper with a finger, it's that 'loose'..... which is a good thing.

I then pass the pcb material ON ITS OWN through a laminating machine set to its highest temperature. Three or four passes gets the board nice and hot.

Use sellotape (other tapes are available....) to fix the toner print to the board and pass it through the laminator another four or five times depending on how hot yours gets.

The paper peels away perfectly leaving the toner stuck like brown stuff to a bed sheet.

I made a load of SO18W-to-DIP adapter boards using this method and all the traces came out clean, no undercutting etc, after etching. Considering how thin the tracks were I consider the method very successful indeed.

When you've done the toner transfer method successfully just once you're very tempted to throw every pcb layout you can find under the laminator! It's very, very easy and, using the sticky-backed label backing paper, very cheap!

One thing to be aware of is that the backing paper CURLS quite readily after being printed on so cut your pcb layouts from it as soon as it's been printed and/or use something soft/flat to keep it from rolling up.

[Tim]

Can you till get that etch resist tape? I think there used to be a rub down transfer too.

Originally Posted by jay_oldstuff

I have used nail varnish for pcb etching for many years, it works fantatically well. My method is to coat the pcb with masking tape draw the tracks on the masking tape then cut them out with a scalple, i then romove the masking tape where you want the copper to remain then paint over with the nail varnish, allow to go off then pull away the remaining masking tape and then etch as normal then use nail varnish remover to get the nail varnish off. the results can look very good.

What a brilliant method! I wish I had thought of it.

the ink had a certain (almost certainly toxic) pleasant smell which I've never forgotten.

Ha Ha. Mmmmm I remember that too!

[DragonForce]

Bowood electronics sell Dalo etch resist pens - although to be honest, I've found that permanent CD marker pens are perfectly suitable provided you follow a few simple rules:

1) Make sure your board is clean BEFORE you put the pen anywhere near it. This cannot be over-emphasised.

2) When you draw your traces, do it slowly, give the ink time to flow from the pen's tip onto the copper. Too fast and you'll have an uneven coating of ink, and the FeCl3 WILL etch through that.

Use a bit of green scouring pad to clean your boards before and after, ink will not stick to dirty copper, even if you think "It's clean enough", it almost certainly isn't unless you've gone over it with a greenie.

[M0XNA Neil]

I use one of those car paint touch-up paints which have a fine screw on top and fine brush. It dries really evenly like a layer of plastic and comes off easily with a scourer to leave really good copper tracks.

Neil

[paulsherwin]

For anyone uneasy about braving the cosmetics counter to buy nail varnish, Poundland sell it.

[dominicbeesley]

I've done a good number of pcbs, hand drawn and printed now using a lashed up dental UV LED stuck to the inside of a computer PSU case. I tend to make smaller boards but I'm sure it would work if it were mounted a bit higher. (More info here: http://vintage-radio.net/forum/showt...&highlight=led). I'm sure you can probably get those UV leds cheaper these days. The other advantage is that they are soft UV so you don't need to worry too much about arc-eye.

I tend to expose for 2-3 minutes, it doesn't seem to matter much - but I do use decent quality FR4 boards from Farnell such as 320-4911. I then etch with relatively weak Ferric chloride. I reuse the chloride, when its getting tired I add some more crystals until its getting fairly soupy.

Occasionally, especially with hand drawn boards, one part of the design starts to get over-etched whilst another areas is not ready. I tend to move the board around and agitate the etchant above the area where it needs to work harder.

I've used both Steadler Lumocolor and Sharpies, the Steadler ones seem to give better coverage. For intricate designs I've found printing onto transparency paper with an ink-jet gives excellent results so long as the transfer is held tight against the pcb. Either do this by wrapping in a freezer bag and sucking all the air out. Or, my usual way, placing heavy nuts and washers on "dead" areas of the transfer to hold it down.

With the transparency print I've managed to make successful PCBs with quite thin tracks (down to 0.25mm). It's best to keep thinner tracks away from the very edge of the PCB though as that tends to etch quicker.

I've recently bought a Laser Printer and will be giving that a go soon.