So, here's some etching into the aluminum I did using the vinyl as a resist layer... I tried various combinations of HCl + H2O2 and ended up going with stragiht HCl ( something like 30% pool variety from home depot )...

Here is a freshly laser cut layer of vinyl on top of the adhesive aluminum....on a test plate of glass....

Here is the vinyl bits peeled away to expose the aluminum for etching...(remember this is a negative)...

And here it is after etching.... My first try, so it's a little sloppy and undercut...the goop from the vinyl being cut should probably be removed with goo-gone or something before etching...acetone doesn't work well on the vinyl...

Here's the back... a lot of undercutting...I'll work this out later.. ;)

And this is the light from my monitor shining through the glass plate....

All in all, I think this is a pretty good proof of concept...the resolution on the TQFP32 is pretty good I'd say... Since these pictures have been taken, I refined the settings a little and have managed to make it even better... Keep an eye out!!