The lead flashing I ordered a bit ago finally arrived, so I started the build of the centerboard and rudder foils. The kit parts include two halves that must be glued together, after lead weight is added.
Here we are measuring to cut pieces for the centerboard. The lead sheet is 1mm thick, 2.5lb/sq ft. I am installing 8 pieces per centerboard side, 100mm x 400mm each.
Here we are measuring to cut pieces for the centerboard. The lead sheet is 1mm thick, 2.5lb/sq ft. I am installing 8 pieces per centerboard side, 100mm x 400mm each.
Here, I am routing the lead weight cavity in one of the centerboard halves. I had to clamp down each end of the board half to get it flat, because it was bowed such that, when the halves are assembled, the middle of the halves are separated by perhaps 3/4 inch.
I clamped router guide boards for the sides of the cavity, and did the shorter ends free-hand. The cavity will be just under10mm deep. By looking at the reverse (shaped) side of the board half, I could determine from the laminate pattern (sort of like reading tree rings) that the board half was about 14mm thick at the thinnest point in the cavity.
I clamped router guide boards for the sides of the cavity, and did the shorter ends free-hand. The cavity will be just under10mm deep. By looking at the reverse (shaped) side of the board half, I could determine from the laminate pattern (sort of like reading tree rings) that the board half was about 14mm thick at the thinnest point in the cavity.
Test fit of the lead sheets - you have to pound the pile of sheets with a hammer (not while they are in the centerboard though) to get them to lay flat, and with minimal thickness.
Ready for gluing in the lead sheets, rudder on the left. Tape around the cavity perimeter is to make cleanup easier. I brushed the inside of the cavities with straight epoxy, and let that set for 15 minutes or so.
Then, a stack of 8 lead sheets was laid one at a time into the cavity, painting a bit of straight epoxy on the upper surface of each sheet.
After all sheets were in place, I then poured straight epoxy around the edges of the lead until the cavity wouldn't take anymore.
Then, a stack of 8 lead sheets was laid one at a time into the cavity, painting a bit of straight epoxy on the upper surface of each sheet.
After all sheets were in place, I then poured straight epoxy around the edges of the lead until the cavity wouldn't take anymore.
Since I am using multiple sheets of lead, I needed to weight the lead to make sure it didn't want to become "delaminated" while curing.
You can see the rudder getting the same treatment. The centerboard is getting about 17lb of lead total, and the rudder about 2lb.
You can see the rudder getting the same treatment. The centerboard is getting about 17lb of lead total, and the rudder about 2lb.
Cured epoxy on the left. After much work with a scraper, the encapsulated lead and epoxy are flush with, or below, the surface, on the right.
Glue-up of the foil halves. First, applied straight epoxy to both halves of each foil, let sit for 15 minutes or so, and then applied cell-o-fill thickened epoxy with a notched trowel to both halves.
The halves were then joined, placing two locating dowels in holes that had been drilled previously, to provide correct alignment of the halves.
Lots of clamping force to make sure that the bowed halves join together well.
The halves were then joined, placing two locating dowels in holes that had been drilled previously, to provide correct alignment of the halves.
Lots of clamping force to make sure that the bowed halves join together well.
Next up is to sand the ridges off the shaped part of the centerboard, and then apply two layers of fiberglass. This will have to wait a bit, as I am waiting for dynel fabric to arrive. Dynel will be used on the edges of the shaped part of the board for increased abrasion resistance.
Meanwhile, there are more coats of epoxy to apply to bulkheads, and other pars. And fiberglass to be applied to the inside of the centerboard trunk pieces - in a future article.....
Meanwhile, there are more coats of epoxy to apply to bulkheads, and other pars. And fiberglass to be applied to the inside of the centerboard trunk pieces - in a future article.....