Airbrush,
I've never done any figures, but here's how I fill bad seems on aircraft/autos:
- if it's really bad, stuff some scrap plastic or filler in the seam and glue it in place
- I use squadron putty (white or green, but I've heard the tamiya stuff works the same way) and then fill the seam rather 'crudely'. I usually wipe the excess off with my finger and let it dry for 3 or 4 minutes.
- then, I take a cotton swab and dip it in some nail polish remover (I use Cutex and it is acetone free.) The 'excess' filler will slowly wipe away with the cotton swab and you won't damage any of the surrounding plastic. The nail polish remover will slowly dissolve the stuff you don't want. You can even 'smooth' over the joint with the wet cotton swab to get a nice finish.
- Some cautions: I had a bad experience with one type of nail polish remover once, so test it with the putty to make sure it's compatible.
- I have no idea whether or not the figures you are doing are made of the same type of plastic that my aircraft and auto kits are. Test out the materials on some scrap pieces from the same kit before you try it on the real thing!!
The real beauty with this is that you can remove the excess filler without damaging the surrounding details. The swab and polish remover just removes a little of the putty at a time, and doesn't damage the underlying details (like sanding would.)
M.