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First attempt at making ballast molds

For the past few weeks, I've been tinkering on making some male-molds for future ballasts. I've 3D printed two male-molds for Sun Wind HF style torpedo bulbs, one slightly smaller than the other to make a lighter weight bulb if desired. And then also I've worked on a shaped ballast mold for the current Wampum VM that I'm building.

Today, I finally took a big gulp and filled the molds full of refractory cement. Now I'll let it cure for a few days and then attempt to take off the molds and see how they look. Then I'll let the cement cure for a few weeks, occasionally in a warm oven, to fully cure before I attempt to pour lead in them.

My current fear is that the mold for the Wampum has a bit between the two halves that is too close together and may crack off when I attempt to remove the male mold. Fingers crossed that it will come off easily.

Here are two pictures of the molds in boxes that I framed around them. They have also been smeared liberally with Vaseline as a release agent. 

Sun Wind HF RC sailboat lead bulb torpedo

You can see in the picture below that there is very little space between the two molds for the Wampum VM. I'm a bit worried that the cement might crack off when I attempt to remove the mold. For that reason, I'm going to wait several days before trying to remove it. Gulp...

Wampum VM RC sailboat lead ballast

Here are the two molds after being filled with refractory cement. I bought a 25 lb. tub and used it all. It didn't go far, but I had just enough to do the two. I hope that they are thick enough to support their own weight when cured.

RC sailboat lead ballast bulb molds

More later after they have a few days to cure and I try removing the molds. Ugh...



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