Posted by: Wayne | January 8, 2011

Not Your Mother’s Meatloaf

Thursday after the posting, I added a bunch of screws into the sides of the lead cutout.  Friday evening I was able to get the bottom of the board shaped.  I also was reminded that power tools allow me to make mistakes much faster.  There are now a few small divots from the planer that will need to be filled with thickened epoxy before fiberglassing.

This afternoon, I tackled the task that I had been dreading: pouring molten lead into the cavity in the centerboard.  I bought a cheap roasting pot to melt the lead.  This was recommended as a nice meatloaf pan by the cashier at the store.  No meatloaf today; sorry!  I also sacrificed a pair of old welding gloves.  I took a piece of scrap plywood and screwed it FIRMLY to one side of the hole.  Then I dragged our propane-fueled camp stove out of the basement and fired it up.  While this was starting to heat up, I set the centerboard on a couple of blocks of wood and leveled the top of the hole.

Heating up the lead for the pour.

It took maybe 15-20 minutes to melt all 20 pounds of lead (about what I was expecting).  It was also relatively simple to pour the lead.  I was a little surprised by how much the lead bubbled after pouring.  In hindsight, this was probably caused by smoke trying to escape through the molten metal.  It was not a problem, but it seemed a good time to step back for a moment.  In future, I will try using a propane torch to pre-char the surface of the mold.

There goes the first pour.

After the pour, I used some of the remaining lead topping off the lead after it settled down.

Topping off as the lead settles into place and shrinks.

After this was finished, I used a donated spoon to very gently skim and smooth the surface of the metal.

Smoothing the surface of the lead while it starts to cool.

After the newly poured block of lead was fully solid (though still hot enough to boil off snow), I moved everything into the garage and closed the door.

One freshly cast lead block cooling off.

Since the pictures were taken, I have removed the plywood from the  other side of the board.  It is well charred where the lead came into contact.  I can actually see the grain of the plywood in the lead on the other side of the board.

All told, I am quite pleased with the way this turned out.  I still need to use thickened epoxy to fill the random nicks and dings in the board.  I also need to finish cleaning up the trailing edge where the foil shape ends at the top.  Then it will be time for fiberglassing.  After that point I will set this thing aside for a while.

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Responses

  1. Well done. My lead pour didn’t go nearly as well. I was worried about singing my centerboard so I made a wooden mold and poured the lead into it, but the joints in the form weren’t tight enough and the lead leaked out and went everywhere! Next try I uses some aluminum bowls from some old camping gear as a mold and that worked well. Congrats on a sucessful pour!

    • Joel:

      I was more worried about the mold leaking. I think I used 28 screws to hold a 6 by 8 inch scrap of 1/4″ plywood to the back of the board. In hindsight, I probably should have pre-charred the wood with a propane torch. When the lead was added, the wood started smoking; the effect was similar to a rolling boil in a pot!

      Good luck with the rest of your build!


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