Sorry for the long time in responding, it's been a little busy around here
I welded these dry. I don't have a TIG, so i took it to the local welding/fab shop and had one of the guys there just fuse the edges with a TIG torch (no filler). I'm undecided on if I'll try the next one wet or not. If I had my little wirefeed welder running I'd give it a shot but all I have for a welder right now is a great big 400/400 AC/DC stick welder, so I can't really do any precision welding to prep stuff.
All of the final welding and drawing on this was done on a 50lb Iron Kiss air hammer while demonstrating in 2" deep mud
You don't need a press to do this stuff. I did need to take very light blows at first, so a hammer with good control is essential, but you can surely do it.
My new forge is almost done, then I'll get to some larger mosaics for fun.
-d