35 Whelen
07-18-2010, 09:32 PM
A few days ago I smelted about 60 lbs. of WW's. I've read much about of zinc contamination, but figured it was more of an internet "ghost" than a reality. I know the zinc weights exist, but I've never had a problem with them. But, just to be safe, I smelt at around 700° F (Zinc melts at something over 780° F) according to my Craftsman digital meter.
Anyhow, I smelted as usual, monitoring the temp and poured the cleaned WW's into ingots. A few days later, I began casting bullets for the local High Power match. I always flux again after the metal is melted in my pot. I use candle wax and stir the mix with pine door shims. When I scraped the gunk off the top, I got a blob of grey stuff off.
I first used my NOE K-31 180 mould. I didn't examine any bullets closely, and didn't see any problems. Next I grabbed my Lyman 311672 after heating it on top of the pot, I began casting giving the bullets a look at as they dropped from the mould. I immediately began noticing fill-out problems in the area of the lube grooves. I stopped and cleaned out the vent lines. Things seemed better, so I continued casting until the pot was almost empty. I decided to visually sort some of the bullets and began find voids again in the are of the lube grooves. Ultimately, I had probably a 50% rejection rate. This mould NEVER gives me problems and casts very, very accurate bullets.
Later I refilled the pot and cast with a tried and true 311291 single cavity mould. This mould too is very reliable and never gives me problems. But again, i found voids in the bullets. This time almost everywhere.
Does this sound like zinc? FWIW I run my SAECO pot very hot...maxed out in fact as that's always worked best for me.
35W
Anyhow, I smelted as usual, monitoring the temp and poured the cleaned WW's into ingots. A few days later, I began casting bullets for the local High Power match. I always flux again after the metal is melted in my pot. I use candle wax and stir the mix with pine door shims. When I scraped the gunk off the top, I got a blob of grey stuff off.
I first used my NOE K-31 180 mould. I didn't examine any bullets closely, and didn't see any problems. Next I grabbed my Lyman 311672 after heating it on top of the pot, I began casting giving the bullets a look at as they dropped from the mould. I immediately began noticing fill-out problems in the area of the lube grooves. I stopped and cleaned out the vent lines. Things seemed better, so I continued casting until the pot was almost empty. I decided to visually sort some of the bullets and began find voids again in the are of the lube grooves. Ultimately, I had probably a 50% rejection rate. This mould NEVER gives me problems and casts very, very accurate bullets.
Later I refilled the pot and cast with a tried and true 311291 single cavity mould. This mould too is very reliable and never gives me problems. But again, i found voids in the bullets. This time almost everywhere.
Does this sound like zinc? FWIW I run my SAECO pot very hot...maxed out in fact as that's always worked best for me.
35W