Does it mean anything when your sprue falls apart?

[spur0701]

I've been casting .45 and .40S&W using WW, a 20 lb bottom pour Lee pot, and Lee 6 cavaity moulds. I've noticed that when the pot gets to be about half empty when I turn the mould over to give the bottom of the sprue plate a little smack to dislodge the sprue, the sprue just falls off and breaks into pieces. When the pot is full, I have to smack the sprue plate to dislodge the sprue and the sprue stays together. Am I missing something here, is this a temp thing or is the alloy at the bottom of the pot different than at the top?

[LAcaster]

Sounds like you need to let it cool alittle longer, are the boolits frosting bad? Melt is getting hotter use a casting thermometer and adjust your pot temp as it gets lower.

[hammerhead357]

I think the temp. of the melt may be increaseing as the lead level decreases. This results in the sprue not being completly solidified when you are cutting the sprue. I have this happen if I get to casting to quickly or if I am using a higher than normal casting temp.
The alloy should remain consistant from the top to the bottom. I use a stacked pot system where one pot sits on top of the other the top one is the premelting pot and the bottom pot is the pouring pot. I do this to keep the lead level the same in the casting pot. This results in the same head pressure all the time. I don't know if this improves bullet quality or not but I think it does...Wes

[454PB]

Your mould is overheating, cast slower and reduce the pot temperature. When the mould begins to overheat, touch the filled mould bottom to a wet towel to cool it.

[462]

Yep, the pot's too hot... you're cutting the sprue too soon...or both.

[runfiverun]

the pot is runniing hotter and you havent changed anything to counteract it.

[par0thead151]

will this produce unacceptable boolits?

[hammerhead357]

Yes the boolits should be good as long as you are not tearing any lead out of the base, The boolits may be frosted but as long as they are well filled out and this includes the base you should be good to go. Also as pointed out slow down your casting pace in order to allow the sprue to harden properly.....Wes

[C1PNR]

Or maybe add another ingot before you get to the half empty stage. That usually results in a slight cooling of the melt, at least for a little bit.

[Echo]

I have the same problem = I am sure that, in my case. the alloy and/or mold is to hot. When I sense it coming on, I set the unloaded mold on a soaking wet shop towel and let it steam for a few seconds. Have to replenish the agua occasionally, but that cures the breaking sprues.