I use tire weights also but I start by making a balsa wood plug like for instant the v shape for the bow or the stern for sides I make long and shor strips primer paint and then wax them make a balsa box about 1" all the way around center the plugin the box and pour plaster of paris over be shure to make the box 1" hire than the plugfill it to the top of the box make sure u put a slite angle on the plug it will com out real easy turn and slitely tap my molds after a few years are still fine I have and old hot plate and cast iron pan to melt the tire weights and por the melted lead into the mold when cooled down turn over and they will fall out do it out side the fumes will make u brain dead wear a mask a good one word of caution some of the newer weights are not lead and won,t melt with the hot plate or even a propane torch lots of work but if u build a lot of ships balasting is a lot easer good luck
Lead wheel weights are being replaced by zinc and iron ones. Best way to tell is to try bending the wheel weight with pliers. If it bends easily, it's lead. If it's magnetic, it's iron. If it's neither one, it's zinc.
