http://www.delorie.com/electronics/rx/rx-adapters-blank.htmlDid a few things differently, got good results, so it's share time...
This is an 8/8 DS project, 13 mil vias, 38 mil header holes. UV film,
CuCl etch.
What I did differently:
I wet laminated the film - I did dry last time, but that's really only
efficient for larger boards where the extra film you need (to hold
onto it as it's laminated) is worth wasting. This project used up
some 2"x3" scraps. I used the old technique - film on some
transparency sheets, wet sand the copper, rinse everything and stick
together. Squeezed out the water with my thumb, did both sides that
way. Used hot water so the film sticks OK. I'm thinking that film is
better on small boards because it's easier to get the bubbles out.
New trick: run the result through the laminator at 200F (94C) - BELOW
the boiling point of water. No new bubbles! I wonder if remaining
water was forming steam bubbles. The temperature control hack for my
laminator is really coming in handy!
New etch technique: This was a small board, so I unplugged the air
pump in the etch tank and just swirled the board around by hand,
mostly moving perpendicular to the board's surface. I think this
simulates the flow of a spray tank. I did seem to get a faster and
more consistent etch - it took about 4 minutes or so.
Observation: my post-processing scripts increase the copper size a mil
or so to compensate for my process, but this time the copper ended up
a little bigger than planned and I had two tiny shorts - I could have
etched for another minute or so.
Also, this is my first board since updating my scanner. The new
scanner does 4800 DPI. Here's a 2400 DPI scan of one of the boards:
http://www.delorie.com/electronics/rx/scanned-closeup.html (this is
the one with the two shorts, which you can easily find in this photo)
I also discovered that Liquid Tin won't last forever in the tray (even
covered) but does seem to last forever in the original bottles. I
wonder if just adding more water will re-constitute it?