wrote:
I'm 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

First of all, you don't burn Styrofoam, you melt it with solvents.

Lead melts around 700F.

How big is the ballast?

How big is your melting pot?

What kind of material handling equipment do you have to handle 700+F
lead and keep it molten during the pour?

How many 1,000,000 BTU burners do you plan on using? You will need
several that can operate for several hours.

How long do you think this project will take?

It will be a long day, at best.

How long do you plan on allowing for cooling this ballast?

It will take several days.

IMHO, you are a disaster waiting to happen.

SFWIW, poured a 20,000 lb INTERNAL ballast.

Did it safely, but wouldn't even consider pouring an external ballast.


Lew
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