I have a lead counterweight that I attach to the aft end of the
OTA of my six-inch f/8 Astro-Physics refractor, to move the
center of gravity that way and reduce eyepiece travel during
use. (Christen triplets are heavy -- without the weight, the
tube balances closer to the sky end than to the focuser).
I made it by casting 15 pounds of lead ingots into a small-size
bread tin. I left the cast lead in the tin -- it just about
filled it -- and cut a piece of plywood to fit over the top
of the tin. The plywood is caulked in place, and 1/4-inch
bolts go through the lead and attach to a spare tube ring
I had handy. The result is a nice, compact, heavy lead
counterweight with no lead exposed.
-- Jay Freeman