With some of my Revell kits of older vintage. (real old molds like the 1/426 Arizona) i've used this quite a bit to fill gaps. It's real easy to use, doesn't shrink unlike Tamiya putty (although Tamiya is better for some tasks) and is real easy to use to make custom pieces and fill large gaps. Be sure to mix both parts REALLY well though so that you don't get soft spots.