Explain this to me please....Rotometals hardball alloy

[btroj]

I would not worry about it. Those bullets will shoot thru anything you need them to.
I would mix it with some pure lead just to stretch the allot but that is just me.

[454PB]

That hardball mix is what I use for rifle boolits.......50/50 pure lead and linotype. Air cooled it tests anywhere from 15 to 18 BHN, so 30 BHN after water dropping sounds about right to me.

[Ridgerunner665]

Thanks a million for all the replies...and keep em coming, I'm still learning.

[deepwater]

The casting temperature of the molten lead would not have as much affect on the resulting bullet hardness as would the temperature of the solid bullet when dropped from the mold into the quenchant (in this case tap water) and the quenchant temperature. As the water heats up the cooling effect is slower and the bullets will not be as hard. This is the reason for a big bucket of water compared to a small cup. Salt brine cools faster then tap water and increases the hardening capacity of a material, all other factors being equal. Oils cool slower than water, so are used with materials that may crack if cooled too quickly or to reduce the as quenched hardness.

Any given alloy will solidify at its own liquidus/solidus (phase change) temperature. Hardening from heat treating would be most effective when quenched at the time of the optimum crystal lattice formation which occurs at some temperature range unique for each type of alloy.

Nonetheless, rules of thumb work even with scrap WW of different manufacturers and various solders that may have traces of this or that. You may have had all the stars lined up just right and with your alloy and quenching procedures everything worked out to yield 30 BHN.

[Ridgerunner665]

The casting temperature of the molten lead would not have as much affect on the resulting bullet hardness as would the temperature of the solid bullet when dropped from the mold into the quenchant (in this case tap water) and the quenchant temperature. As the water heats up the cooling effect is slower and the bullets will not be as hard. This is the reason for a big bucket of water compared to a small cup. Salt brine cools faster then tap water and increases the hardening capacity of a material, all other factors being equal. Oils cool slower than water, so are used with materials that may crack if cooled too quickly or to reduce the as quenched hardness.

Any given alloy will solidify at its own liquidus/solidus (phase change) temperature. Hardening from heat treating would be most effective when quenched at the time of the optimum crystal lattice formation which occurs at some temperature range unique for each type of alloy.

Nonetheless, rules of thumb work even with scrap WW of different manufacturers and various solders that may have traces of this or that. You may have had all the stars lined up just right and with your alloy and quenching procedures everything worked out to yield 30 BHN.

I think you may be on to something there...the boolit was HOT when it went into the water (note the estimated alloy temp) and the water was COLD (outside tap, the temperature outside was just above freezing)

[crabo]

Anyone one tested the difference in ice water vs regular temp water? When I first started, I bought 20# of ice and dumped it in a 5 gallon bucket and filled it from the hose. I quit doing that.

[lwknight]

I think you may be on to something there...the boolit was HOT when it went into the water (note the estimated alloy temp) and the water was COLD (outside tap, the temperature outside was just above freezing)

Second on what Deepwater said. The mold temperature and drop temperature has the most effect. Hardness is affected the least by the alloy temperature.

[jtaylor1960]

I use Lyman #2 the 95-5-5 version and I get 20-21 bhn on my water dropped bullets.It must be the extra antimony in your alloy that gives you such a hard bullet.

[RobS]

The boolit's temp hitting the water is the contributing factor to how hard it may become that is fact of course, however alloy temp does have direct correlation. A boolit that is cast at a lower temp where it comes out all shinny and pretty looking we all know has a lower temp vs one that is frosted when released from the mold (assuming we are casting from the same pot of alloy). Two ways to get a frosted boolit is to; 1. cast at a much quicker tempo so the mold heats up or 2. turn up the alloy temp which brings up the mold temp. We know Ridgerunner665 was casting warm. I for one don't like to increase tempo as I don't like to rush so if I need fillout I'll turn up the heat.

[Ridgerunner665]

I don't think they look right all shiny and stuff...LOL.

I like them slightly frosted...like the one in RD's picture....grey, not silver.

[RobS]

Nothing wrong with some frost; my targets have never known the difference.