Given I only managed to get nine reasonably acceptable front plates of the 15 I need out of yesterday's batch, I knew I needed another batch of photo-etched plates for my NVA T-72s. I managed to get the batch running today and made a few adjustments along the way to hopefully get a better result, and thankfully I did actually manage to get that better result. I believe all twelve of these will work, so I'll be able to pitch a few of the more over-etched examples from the previous batch!
This batch worked so well it managed to almost keep the whole set of sprues. There appears to be one spot where the etching solution bled through on the top left example, but with a little filler that one should work just fine too!
This time I used a longer exposure time (12 minutes instead of 10) to better expose the resist. I also adjusted my exposure lamp to hopefully provide more even light coverage. I also backed off on the concentration of the developer, and left it in the developer a shorter amount of time. The etching took a bit longer as I was reusing the same etch solution, which they say is good for multiple runs, and I spent more time double checking it.
I had thought to use some thicker metal for future projects, but looking at the edge creep on these, I wonder if it wouldn't be counterproductive as I can get undercut (wet etches are by there very nature isotropic) - so I may even to thinner on future projects.