Flying with loose weights or a scuba belt is scary; imagine what will
happen in a crash. Loose weights or a scuba belt will make any crash
even worse.
Our club was in the same situation a few years back. We had two ASK
21s and we had lost all but one of the factory weights and we gained a
new member who was 112 pounds.
I cast two 13.5 pound weights for each ASK 21 to replace the 12
original factory weights. The description of how to do it sounds far
worse than it actually was.
I first used our one remaining factory weight to make a wood replica
that was the shape and size of the intended new 13.5 weights. I then
shaped a band of 2” copper flashing around the wooden form and screwed
the ends together with #6 screws. I then unscrewed them, removed the
wooden form, and screwed the ends together again. This copper form
will become the mold and final outer surface of the weight.
I then set this copper band on a sheet of heavy duty aluminum foil,
and folded the foil up the sides of the copper so it looked like a
bowl the shape of the intended weight.
To create a bolt-hole, I used a copper 1/2” pipe that is 2 1/8” long.
To keep the pipe upright during the casting, I drilled a 1/2” hole
1/8” deep in a board using a forsner bit. I put this board in the
bottom of a pail. I positioned the copper/aluminum form over the
board so that the hole would be in the proper place. I then pushed
the copper pipe through the aluminum into the 1/8” deep hole. I then
carefully poured sand around the outside of the copper form.
I then poured the molten lead into the copper form. The outer copper
sheet and the copper pipe remain and become part of the final product.
The board will get charred with each casting, but I cast 4 weights
using one board.
The aluminum foil is VERY important. I first thought I could do a
sand casting and the copper would hold the sand back while I did the
pouring. Well, the molten lead flowed under the copper band, into the
sand and I had a real mess after that. The aluminum foil creates a
bowl that prevents the lead from flowing out into the sand.
The bolts are 8mm x 160mm. They can be purchased at
www.mcmaster.com
I made a large wooden knob over the hex bolt head for easy turning.
You might come up with your own idea on what is the easiest for your
talents.
Then, the most important part: I made two boxes to hold the weights.
That way the weights have a "home" for storage. Without the boxes, it
is very tempting to lay the weights on the ground where they are
removed between flights. That is how we lost the original factory
weights.
If you want photos, let me know.