Be careful. Any filler that is a "one part" (ready to go out of the tube) cures by having a component(usually a thinner of sorts) evaporate. When any material has a component removed, it shrinks. If you use a one part putty, only use thin layers, as it is less apt to shrink. I use either thick superglue, or, a two part automotive filler. Any filler that is two part, cures by chemical reaction, and should not shrink.