Make sure you set aside a good bit of time. It takes probably about 1-2 hours for everything to melt. THEN, it's gonna take at least 4-5 hours to pour it into the mold. I wouldn't use a tube any bigger than 5" in diameter (the size would be preferable, but it would take forever to harden/pour). Both of mine are 4", and they seem to work fine.
The best way to do it is to pour about 1-2" deep at a time (I use a soup ladle, and usually pour 1.5-2 full scoops at a time), put it in the fridge, and let that layer fully harden. Then pour the next layer. If you pour in a bunch at a time, the top will harden first, then when the center hardens, it will shrink, causing a deep hole in the center. I've done it that way a few times, and it's OK, but you have to save enough at the end to fill in the hole. Also, realize that what you pour into the hole will in turn shrink, and then you'll have to fill in THAT hole.
Basically, just don't pour the whole lot into the tube at once, or you will be remelting it.
Edited to add: Also, if you do use the fridge to cut down hardening times, make sure you let the tube sit out at room temperature for about 3-4 hours (overnight would be ideal) to come back to room temperature before shooting. I haven't tested the tube cold, but for comparability's sake I think we should, if at all possible, keep tests equal. I would think cold wax would be less fluid, and could affect the bullet's expansion mechanism, and/or penetration depth.
Also, try to keep the melted wax temp as low as possible, as it will keep your hardening wait times to a minimum. After heating the water in my "double boiler", I adjust the stove to medium until the wax starts melting quickly, then I lower it to just above its lowest setting to keep it fluid.
Last edited by 21Carrier; 05-12-2011 at 02:22..