Just made my first PCB using the bubble etch tank I made last weekend. Photos and associated ramblings at...
This was done using the Press'N'Peel laser printed transfer film sold by Maplin in the UK. The process is about as simple as can be: print the pattern, heat the board-and-film sandwich, peel off the transfer, etch the board.
It certainly seems to work, although I can't say my first result is pretty. That said, I may have over-etched somewhat, with the result that some of the resist was undercut.
The etchant I used was the powdered Sodium Persulphate from Maplin (4ukp for enough to make a litre). Using it was no problem at all - only took a few seconds of stirring with a plastic rod to dissolve most of the powder, and a few seconds more in the tank with the air running sorted out the rest. I liked the fact that this stuff is almost as clear as water - very easy to see what was going on. Looking at the bottle, I notice that now has a slight blue tinge - something to do with the copper absorption?
I got the temperature wrong when I mixed up the water, with the result that I had 35 Celsius rather than the 50 I was after. I put the lid on the tank and stuck it in the microwave - about 2 minutes at 1/2 to 3/4 power (in 20 second bursts with temp readings taken each time) brought it nicely up to 50 degrees. The aquarium thermometer was over-reading by 2-3 degrees compared to the digital thermometer. By the end of the etching session (say, 15 minutes in total), the tank thermometer showed a drop of about 4 degrees.
I found that the board moved around quite a bit in the tank, and had settled such that some of it wasn't getting hit with the bubbles - after about three minutes, one half of the board was clear, while the other was still covered in copper. Jiggling it about about a bit had the remaining copper removed in another minute or so. I think I'll try some different basket designs, and maybe come up with a way of stopping boards sliding about.
Overall, I'm very pleased, not simply because the Press'N'Peel seems to have worked at the first attempt, but because this is the first PCB I've ever made! :-)
The home-brew bubble etch tank seems to work a treat - just need to come up with a better basket. Handling the tank was fine - tipping it up to empty the etchant into a container was easy, and the airstone retainer did its job perfectly.