Work on the boat has gone in fits and starts. I’ve started on leeboard guards, and my sail is 3/4 complete. I even made a tapered mast blank during my vacation and have been reconditioning an old Holsclaw trailer. But all work and no play is limiting my progress and I doubt that the boat will make the water this year.
One thing that did go right … I cast a lead weight into the rudder. For the Mayfly, the rudder blade hangs free so that it will kick up when it strikes an object. However, the free wooden blade would float in the rush of passing water, so it needs several pounds of lead to keep the blade in place.
The cut rudder with a metal backing plate.
Bottom view of lumber and shims holding backing plate.
Note the anchoring screws and chamfered edges.
To prep the rudder, I drew in the lines for cutting a square hole, then drilled two corners with a 3/8-inch bit. I stuck a sabre saw through the holes and cut the edges, then used a rasp chamfer them. Theoretically, this would allow the molten lead to form a lip, which would hold the lead in place . I also installed some 8 x 1 wood screws in the corners of the hole to anchor the lead in place.
The big challenge was to source some lead. Three pounds plus were required, the amount prescribed for filling a square void 2 x 2.5 x 1 inch. I scoured Home Depot and the Wal-Mart fishing section for something big and cheap . . . No luck. I called a large marina with a reputation for casting lead keels . . . No callback. I did find 5 pounds of “lead wool” in the plumbing section of a large lumberyard, but the price tag encouraged me to look further. Finally, I did what Jim recommends in his book – I stopped by my mechanic, who handed me a 20-pound can of old wheel weights. Thanks to the good folks at Bill’s Ineffable Auto Rehabilitation, I was in business.
Back home, I used a magnet to differentiate lead weights from ferrous metals, then pinched each with cutting pliers to confirm that they were soft lead. I then cleaned all the grease off with brake cleaner. I threw what I thought I needed in a coffee can, making sure that too was metallic – many newer ones are mylar-covered cardboard. I broke out a single burner camp stove, fire extinguisher and a few other items to make a suitable makeshift foundry in my yard. A colossal set of pliers to grab the hot can, some safety goggles, and I was good to go.
I let the weights dry in the sun while I made preparations. I did not want water anywhere near this operation for fear the molten lead would splatter or explode from steam expansion. While they were drying, I clamped a fairly rigid piece of decorative metal to the underside of the rudder, backed it with a wood board and clamped it in place on a portable workbench. I had to shim one edge of the metal to match the faired curve of the rudder, lest molten lead escape thorough the gap.
Finished pour, before shaping.
Time to fire it all up, I set the can on the Coleman burner. Half-throttle and 5 or 6 minutes were all that was needed. I stayed back avoid the smoke and fumes. When the lead had melted, I grabbed the can with the big pliers and whisked it to the rudder. The volume of molten metal was just enough to fill the void in my rudder, plus a bit for a meniscus, and it all solidified just as the pour finished. Luckily, the un-melted steel wheel clips stayed in the can. Couldn’t have planned it better.
Note that I “planed” the casting with a Stanley Surform to flatten it flush with the rudder surface, pressing hard. This produced shavings that were easy to collect. Be advised, dry sanding this stuff would be a bad idea.