I am to the stage of casting the keel for my project. Please comment
on my proposed method of making the mold:

--make a male plug out of styrofoam with a thin coat of bondo for
fairing and smoothing.

--coat the plug with half a dozen thin coats of no texture drywall
mud.

--suspend the coated plug in the mold box and surround with cement.

--burn out the styrofoam and bondo, leaving a smooth female mold for
pouring the lead into.

note: I have never cast with sand and have no desire to learn
another new skill.

TIA mm