Mold Temp - Pot/Alloy temp
- Thread starter Rick
- Start date
Thanks Rick,
These probably have a hint of Sb or lino. What happened is I'd ordered pre-cast but they came in BHN of 15 and 18 (2 separate companies). Rather than shoot 'em I melted down to use w/ pure lead after my tin ran out. This batch of 300 were 7 parts lead to one part 18 BHN ingot for a BHN of 11 to approximate the 18:1 recommended for these long nose bore riders (against slumping). One company called their alloy their version of Lyman #2. And I'm gonna be using these harder ingots for a while to use w/ pure lead. Have plenty.
These probably have a hint of Sb or lino. What happened is I'd ordered pre-cast but they came in BHN of 15 and 18 (2 separate companies). Rather than shoot 'em I melted down to use w/ pure lead after my tin ran out. This batch of 300 were 7 parts lead to one part 18 BHN ingot for a BHN of 11 to approximate the 18:1 recommended for these long nose bore riders (against slumping). One company called their alloy their version of Lyman #2. And I'm gonna be using these harder ingots for a while to use w/ pure lead. Have plenty.
James W. Miner
Active Member
They will not age expand unless you have antimony in the mix.
You can feel fairly confident that commercial bullets of 18 BHN does have antimony in them, possibly significant Sb. Mixing 7/1 and still bringing pure Pb up to 11 BHN says they had a fair amount. Lino with 12% Sb is 22 BHN and the commercial bullets being 18 can give an idea. It's possible some commercial casters could be heat treating but I wouldn't think it's common.
Sorry--knew I'd brain-farted somewhere. I used my tin to make 20:1 ingots, and it was this that I combined 7-1 w/ the 18 BHN ingots to reach ( a theoretical) 11 BHN to approximate an 18:1 alloy for the long bore riding bullets. Neither do I have a hardness tester. Sorry for the confusion, but I doubt it changes anything. Thanks everyone.
James W. Miner
Active Member
Adding more tin has little affect on hardness. Just raises cost. BHN is a funny number and there must be 1000 alloys with the same numbers.
Tin is sufficient for our (BPCR) purposes. We never go harder than 16:1 (11 BHN), then up to 20:1 (10 BHN) for most apps. Some folks go softer but doubt I'll ever be one. Now subbing sumthin else for tin is something I've never looked into, but if Sb is gonna keep my bullets max dia then I need to look into it. Thx.
James W. Miner
Active Member
BPCR gets along fine with softer and I use 20 to 1 mostly but have gone 30 to 1. For BP you don't need hard. Tin toughens the boolit. It aids casting too.
castmiester
Active Member
I use a thermometer as a guide to prevent having to readjust the Rheostat. I noticed that it's off considerably, not a ton, but a notch and a half sometimes on my Lyman big dipper. It's not the best and I leave the adjustment alone by just unplugging the unit. So for me it's mandatory for now.
castmiester
Active Member
this is true.... I read from LASC, that if a sprue plate, on a aluminim mould, if not pre heated correctly, (plate side down on a burner or pot), can act as a "chiller". Iron/steel moulds, this is no big deal since both the mould blocks and the sprue plate have similar thermal conductivities and heat up at the same rate
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castmiester
Active Member
I could go along along those lines, with a generous puddle. I found it hard to do on a single and double cavity, due to not joining others as on my 6 cavity Lee. I wonder if thicker plates would work better than original thinner plates in regards to cooling faster. Don't know if my homemade plate of cold rolled flat bar is as good as the RCBS plates I got recently.