Any hardware store, e.g. Lowe's or Home Depot. It will come in a tube labeled "epoxy putty." It's basically a clay stick made with an inner and outer section. Cut off a piece and shape it with your hand - I like to make snakes until it becomes a uniform color. Once it's the same color throughout, i.e. light gray, you can use it for your application.
Originally posted by LUCA: Yep.
You can be Phil too if you'd like.
until it becomes a uniform color. Once it's the same color throughout, i.e. light gray, you can use it for your application. 
You can be Phil too if you'd like. 
