Nick,
Assuming it’s a throw bag you’re making, consider using stainless steel shot as the ballast instead of lead shot.—No lead shot, no lead dust to worry about.—In all the older lead shot throw bags I’ve owned, the abrasion of repeated use has turned some of the shot into a powder. Throws that miss the crotch and hit the trunk send up a puff of dust. Shots in the rain that end up in a puddle leave a milky white soup behind. This can’t be good for the environment , the climber, the crew, or the kids of an old throw bag owner.—Little kids seem to explore the world by mouth.—Stainless steel shot doesn’t cost that much, (about $4 per pound), if you get it from an abrasives supplier. The stainless steel shot they sell as a polishing medium, is extremely corrosion resistant. So, you won’t have to worry about it turning into a lump of rust.
Happy Trails,
Paul