3 inches of Kneadatite Brown/Neutral Stuff.

Two part Epoxy Putty.

Kneadatite Brown/Neutral is a two-part epoxy/polyamide sealant-adhesive in tape form. It has excellent adhesion to metal. Nicknamed "Brown" by sculptors and modelers, Kneadatite Brown/Neutral is well-known for its long work life, hard cure, non-grainy texture and ability to hold fine detail. Cured models withstand up to 4 vulcanizations. Mixing "Brown" with Kneadatite Blue/Yellow^® ("Green") will increase Blue/Yellow's hardness, and mixing proportions can be adjusted to control curing time.