Halestrom.net

last modified: Saturday 18 June 2016
author: Hales
markup: textile

Simpler PCB etching/making techniques for simpler boards

Normally I use a toner-transfer technique to mask my PCBs before etching. It's quite a bit of effort to go to if I only want to make a simple board, however.

Background for the task at hand

I needed to make a board to hold a fuse and some terminal blocks. My pre-drilled veroboard would be perfect, but I wanted to have some better isolation across the board (ie remove the copper from large areas of it).

Presumably the techniques on this page work the same on ordinary copper clad board too. Please excuse some of the blurry photos.

Method 1: Drilling the the copper out

Slow. Difficult. Annoying. Probably weakens the board considerably. I didn't get any further than this.

Method 2: Nail polish

Nail polish does not get dissolved by my etchant.

First I marked out the copper I wanted left using a permanent marker:

Then I painted this will green nail polish. The polish mixed with the marker and required a couple of coats, taking quite a bit of time. It also liked to go everywhere you didn't want it, so I had to clean up its edges with a knife. It also smells.

Result after etching:

Not bad. Unfortunately I then have to deal with the nail polish. Acetone dissolves it:

Now I have to deal with getting rid of a pot of ugly acetone, nail polish and permanent marker mixture. Yuck. Onto the next alternative!

Method 3: Cut tape

I covered the copper side of the board with a single piece of duct tape and poked my components through to make some holes:

From this I could judge what tape I wanted to cut off using a stanley knife:

I covered the other side of the board with another piece of duct tape before etching to make sure that the acid did not attack from behind. I also poked the holes in the tape gently closed: this seemed to be good enough of a seal during the etching.

Beautiful.

Obligatory tentacles

Found growing on the steel lid of my etchant jar:

It's taken many months for them to get this big. I should have left them alone.


leetfrog - Friday 5 May 2017

Hey, this is an awesome idea ! have you had any good projects with this method ?

Hales - website - Saturday 6 May 2017

Not quite yet. I have not made a PCB since last year, nor needed something with high-voltage isolation like this for a while. I'll throw a picture of where this board ended up, it's an interesting box that supplies power to a very large toroida transformer I've used in a few projects here. I expect it will hold up for a long time.

My latest project on this blog (my adjustable bench power supply) did originally have a thrown-together mains board, but this ended up getting replaced by the switch and fuse holder integrated into the box I found.

I still do however have some nice large jars of blue/green used etchant lying around. I might make a post about trying to electroplate the copper acetate out sometime soon. I tried plating some aluminium once before -- which didn't go well. Apparently you need the plating metal to be somewhat electro-similar to the metal you are plating onto, otherwise you just dissolve everything :P But I did manage to partially copper-plate a cupronickel coin.

I've been trying to find a practical use for copper plating for the past year, but I've come up short. I think I'll dedicate a single piece of copper board to it purely for the purposes of cleaning up/safely disposing of the used etchant.


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