Mould fill-out problems

[calsite]

I've been attempting to cast some 45 LC for a buddy, using his NEI aluminum molds. My pour is almost 100% WW's, and I had great sucess throwing some
.358's from a Lee mould at 725 degrees the same day. When I went to casting the bigger .45 boolits I was getting alot of poor fill out. I was starting to see alittle frosting up towards the nose of the bigger boolits so I was hesitant to turn up the heat anymore. Should I go ahead and turn up the heat or maybe try adding a bit of tin to the mix?????

[Calamity Jake]

Yap turn up the heat a little and you might try smoking the cavities. Seems like, if the mold is made out of alum. it has to have the cavities smoked to produce a good boolet, at lease that is the way it is with me and alum molds.

[calaloo]

Are you sure about your alloy? I once made up some 20:1 alloy using 50:50 solder for the tin.I was using a Hoch nose pour mould in .32 cal. I simply could not get the driving bands or the base to fill out even with high heat which resulted in frosted bullets. The solder was Kester solid core, not junk. That was the last time I used mystery metal in my alloy.

Bill

[calsite]

This alloy was what I had left over in my pot and have had good results using it before. The moulds I was using yesterday (NEI's) plus a brand new Lee .358 were the only things that changed. I started pouring into the .358 and made up some fine looking boolits. The .45 moulds were the ones giving me problems with fill out, and some wrinkles. After I threw 35-40, the noses started looking alittle frosty so I didn't turn the temp. up anymore. I still managed to make 45-60 .45 keepers out of one mould. The other (a soup can custom made .45 mould) was the one that was not wanting to cooperate hardly at all. I'm suspecting temp too low. (hopefully that's it)

[38 Super Auto]

Does your NEI vent OK? I suspect the problem with your poor bullet fillout is one of the following:

1) Mold and/or alloy not hot enough (pre-heat mold more and/or increase lead pot temp.
2) Melting point of alloy is too high (tin will help reduce melting point)
3) Mold not venting properly (poor venting slows down fill of cavity and alloy solidifies before bullet is filled out)

[runfiverun]

if that isn't working put in some tin 1% - 2% will do plenty

[idahoron]

If it is a botom pour pot the hole might be pouring slow. Ron

[beagle]

If it's a double cavity mould, slow down on the casting tempo a little. Your mould blocks may be getting too hot. I've had this problem before with large bullets in DC moulds and large .45 bullets in the small Lyman blocks. I've even had the same problem with a DC 429421 Lyman.

Now, what causes the incomplete fillout, I don't know.

I had Walt Melander at NEI make me a DC .375 mould once with two different designs. One 300 grain and one 320 grain. He fiddled with the computer a bit and said it won't work. You'll get incomplete fill out. I had him make it as I only needed to make one weight at a time. When I got it, it worked fine......until I tried casting with both cavities and I got incomplete fillout. Once, I slowed way down, it worked with both cavities.

Walt knew something about heat dissipation and mould fillout. Had some model or formula worked out on his computer that he plugged weights and diameters in and it gave him a go/no go. Wonder if he passed it along./beagle