may smear lead between the blocks and the cutter. It may also cause a cavity in the bullet. If cooling of the sprue takes too long, try touching one edge of the sprue cutter to a wet sponge in a shallow container of water. Moisture on the sprue cutter will evaporate quickly, but be very careful not to allow moisture to be carried into the pot. (This is one of the suggestions from the NRA Cast Bullets publication.) After casting for a time, problems may occur when the mold temperature becomes too hot. The typical problems are frosty appearing bullets and whiskers (caused by some of the melt entering the vent lines of the mold). After casting a quantity of bullets, it generally is necessary to lower the temperature of the melt. Experiment to determine the best casting temperature and strive to consistently keep the mold and melt at the best temperature. Keep the mold and melt temperature from dropping while casting. You can keep them hot by following the suggestions that follow: 1. Cast at a good rate. 2. Limit delays or breaks while casting. 3. Fill the mold and leave the mold where heat from the pot will help keep it hot if a delay is necessary. If possible leave the mold with the tip of the sprue cutter in the melt. 4. Add lead or alloy in one pound ingots after about one pound of the melt has been removed (unless you use two pots ? see item 6 below). If larger amounts of lead are added, the melt temperature may drop enough to cause casting problems. 5. If a bottom pour pot is used, make a steel wire basket that fits into the top of the pot unless you use two pots. Using the basket will prevent cooling the melt that enters the mold from the bottom of the pot and helps prevent the melt from solidifying in the valve. Always keep the level of the melt above the bottom of the basket while casting. Add to the melt by placing ingots in the basket instead of dropping them into the bottom of the pot. 6. The best way to keep the melt temperature high and consistent is to use two pots. Using
Auguest 2021.indd 37
two pots avoids dropping the melt temperature every time an ingot is added and frequent adding of ingots is unnecessary. Use one pot to cast from; use the other pot to melt the ingots and to provide hot melt for the casting pot. If you want to cast lead at 850 degrees, and if you use two pots capable of keeping the melt at 850 degrees, you should have no problem keeping the melt in the casting pot at the desired temperature. Or for casting at a lower temperature, the melt in the casting pot can be kept at a near constant temperature. I use two pots for all my casting. I find it helpful in casting good quality Minies. I use two pots for casting round balls and conical bullets also because of the convenience. Frosty-looking bullets. If the mold and melt temperatures are very high, frosty-looking bullets may result. The frosty look is due to a metallurgical change to the alloy at the outer surface of the bullet. If the thin outer skin is scraped away, the bullet looks normal. Some authorities state they should be remelted. Other authorities state they are more consistent in weight than normal appearing bullets. Cast Bullets, page 137, states that evenly frosted bullets are not harmed by the frosting except for a slight reduction in diameter. I shoot them, but sort them into my second class of bullets along with others that have minor defects. As far as I know, they do not cause an accuracy problem.
8. LEAD POISONING. The NRA publication, Cast Bullets, page 42, has a thorough discussion of this potential problem. To summarize very briefly: 1) Lead poisoning caused by casting bullets is very uncommon. Very long exposure to fine dust is necessary to cause a problem. 2) Use adequate ventilation (a fan, not necessarily blowing through a door or window open to the outside). 3) Keep the temperature of the alloy down to limit vapors. 4) After casting or handling lead, wash before smoking or eating.
9. SOME FINAL COMMENTS. You probably will be able to cast good quality bullets without following all the suggestions in this article. There is some art involved in casting and it takes some experimentation to find what will work best. Skirmish Line Summer 2021 36
8/16/2021 12:11:20 PM
