Re: Achieving a smooth surface with plastiline clay
I use Classic clay in both the soft and hard hardness (it can be ordered through the JMac company or Arizonasculpture.com). The hard isn't quite as hard as Chavant, but it does what I want it to and is easier for me to work with than Chavant. There's no smell to Classic at all, it isn't sticky unless it's too warm, and when you draw a metal tool through it, you get clean cuts with few crumbs. One of my problems with Chavant is that there's a faint whiff of sulphur in even their non-sulphur clay that triggers my asthma. I talked to the president of Chavant about this in Loveland a few years ago, and he said all their clays go through the same presses, so it's possible the clay is picking up just a bit of sulphur from that.
Sorry, got a bit off-topic . . .
To smooth the clay, if it's small enough to fit in my freezer, I'll freeze the part in question then use metal tools on it to get a smooth finish. I also use a scrap of nylon mesh (screen wire, but not metal) to rub over the piece (at room temperature, not frozen) to find where there may be dips or bumps that aren't easily visible. After I fix these, I run the screen mesh over it again to be sure it's all even.
The final step in my process was told to me by my foundry - it's what they do to finish clay. I use a good quality (so it won't shed bristles) oil painting filbert brush and a plastic cup into which I've sprayed some citrus cleaner (Fast Orange is their brand of choice). I paint the citrus cleaner all over the piece, which melts the very top surface of the clay and smooths out crumbs. The rounded shape of the filbert brush means it won't score or gouge the clay and I can really get into the detail to scrub the crumbs out. Then I go over the sculpture again with my finger, rubbing in a circular way to make sure everything's smooth and blended (I usually work it so it doesn't leave a pattern, although there are times I'll use my fingerprints to give texture to a piece). Once the piece has dried, it's ready to go.
I hadn't heard about using chamois on plastilene. I'll have to give that a try!