For my boat's ballast, I got all the scrap lead I could find, but it wasn't quite enough. So I broke down
and bought four 25 lb. bags of #4 lead shot. I got it at an outdoor store, and since no shipping was involved,
it was cheaper than mail-order recycled shot. It comes in plastic-lined cotton sacks, and I wasn't
comfortable leaving those in the potentially damp bilge. I bought a yard of Phifertex mesh fabric to
make replacement sacks. This material is fairly cheap, strong, extremely easy to sew, and has lot of marine uses.
I made the new sacks a bit bigger than the sacks the lead came in. Each one was made from a 16x16" piece of material
with a 1/2" seam allowance. The thread is nothing special: nylon upholstery thread we had lying around. If i
were doing it again, I might make the sacks a little bit smaller, maybe 15x15".