Salt Etching, successful proof of concept

 Woohoo! Took a bit of time (most of that was waiting on my dry film to arrive), but I have a test of salt etching that I'm happy with. :)

I had one limited result test earlier today, my first go with the dry film. I was using a single-layer toner onto tape transfer as a mask, and the toner from my printer prints too thinly to be a decent mask. Plus the image that I was attempting to use was too ambitious for a first go:

My printer gave out reasonably sharp detail, which I was happy with, but the post-exposure results on the aluminium came out too blotchy (as in, the parts covered by the toner should have been a uniform colour, but were not). The result was that when I put it through the soda wash, the solution wasn't strong enough to remove the bits that were supposed to come off, and making it stronger took off the bits that were meant to stay.

Simple solution, get it all off and try again. For my next attempt, I made a much simpler mask with some bold text.

This gave a much cleaner result after the initial exposure. Removing the fill with the soda wash produced a very clean result.

Finally, into the salt water and electricity bath to etch the aluminium. I wasn't too sure how long to leave it in there for (should have timed it!) but I wanted it to be deep enough to be a decent etch, but shallow enough that it didn't start going sideways under the fine details (like the middle bits in the A's and the R's). I kind of winged it (and kept pulling it out to check it) and after it looked about right, it was moment of truth!

With this process, you can put it back into the salt water to keep etching if you think it needs to go deeper, but once you start taking off the resist - you'll never get another layer of resist back on there! So get it right the first time.

I'm pretty happy with how that came out! :D

The process is rather brutal on the metal, so I'm not sure how fine detail will work out, but I'm hoping that I'll be able to have a go tomorrow. I figure one more test with fine detail to see how that goes, then I might have a crack at a real task. Fingers crossed!