Avian Non-Sag Epoxy is a 2-part epoxy glue with filler, so it can also be used as a putty. It is made for repairing wooden and steel boats, and seals cracks and damage in damp or wet conditions.
How to use: clean off dust, dirt, oil and loose material. Mix resin and hardener 1:1 until even, spread it on, and wipe off excess while wet. Use within 30 minutes of mixing.
Leave at least 4 hours before sanding. Avoid rough handling until fully dry, about 24 hours or overnight.