Welding and fabricating thermoplastics

[obseq]

Does anyone have experience in welding and/or fabricating thermoplastics?

I am looking to experiment with a few possibilities, (extremely thin layers, in sheet form):

-Perforated Polyethylene
-Perforated Polycarbonate
-Perforated Polypropylene
-Nylons, et cetera

While all of the above thermoplastics are available in solid sheet form, I suspect that the perforated sheets will better lend to layering and subsequent sanding down down to an even, matte surface.

If anyone has insight into appropriate tools and methods, I would appreciate it!