For those that water quench PC'd boolits, how do YOU do it?
Last time I used alloy @ Bhn of 9.5 and had a bit of leading in the bore.
Trying to have an expanding hunting boolit for the 300 BLK.
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For those that water quench PC'd boolits, how do YOU do it?
Last time I used alloy @ Bhn of 9.5 and had a bit of leading in the bore.
Trying to have an expanding hunting boolit for the 300 BLK.
If I'm heat treating the boolits, I heat them to about 450*F for at least an hour in a convection toaster oven. I remove them, ESPC them and return them to the oven. I reset the oven to 400*F and cook the powder coated boolits for 10 minutes once it reaches temp and immediately quench in a 5 gallon bucket of ice cold water (with ice)(or snow in the winter). A 50/50, Pb/COWW+2% Sn alloy with a BHN of 10-12 will heat treat this way to 22-24 BHN after 5+ days aging.
Heat treating does not make the alloy more brittle, it will retain the original characteristics of the alloy making heat treating a great option for hunting. The addition of too much antimony or tin will make the alloy brittle.
Yes.....by dropping immediately after PC bake in ICE water, you can get SOME of the hardness. Not all of it because you are only heating to 400F and not at casting temp right out of the mold.
I cast and PC everything subsonic somewhere around 9-12 Bhn with no leading ever.
Oven heat treating is well regarded as being much more consistent than water dropping from the mold. Using 400*F, the same as the cure temperature of the PC, it just takes longer to age after to get to it's full hardness potential.
So either methods will produce the same hardness? It just has a different time span to reach the hardness?Quote:
Oven heat treating is well regarded as being much more consistent than water dropping from the mold. Using 400*F, the same as the cure temperature of the PC, it just takes longer to age after to get to it's full hardness potential.
Yes, sort of. Water dropped boolits (from the mold) will have a larger BHN spread. See this for more...
http://www.lasc.us/HeatTreat.htm
Interesting. Thanks for the link.
Borg - I've been using Isocore in my BO, AC with 0.025#CuSO4 per alloy#. I add 0.07# shot per alloy# and WQ for the 308. Both are supers. No leading. HiTek gold or PC for the BO, PC for the 308. I'm finding a month cure time min. gives best results. I found that without Sn hardness increased very rapidly, like a week. Cu & As are both grain refiners, As seems to speed the process, Sn appears to slow down, Cu makes them much tougher. More alloy testing to do but I push the PB BO near 1800 , 308 near 2500, near MOA when I do my part.
If you are trying to harden the entire boolit, it may help, but I believe the PC typically is 22-28 BHN already. The Sherwin Williams paint I've used states that it has a cured hardness of "H-2H" pencil hardness.
http://castboolits.gunloads.com/show...=1#post2933043
Think of it like an M&M getting hit with a hammer in your chamber. What's going to happen? The harder your boolit is, the better it can resist getting deformed when shot at higher pressures and velocities..
I don't even bother with all this anymore. My hottest .357 magnum loads don't lead in a 16" barrel and all I do is cast, drop in the bucket (just to hurry them cool so they don't deform when dropped), coat, and bake them. The temps during baking I'm sure ruin the quench and yet they shoot just fine. If you are still getting leading then for one reason or another your coating is failing due to a rough barrel or they weren't coated correctly. I think the hottest I've done so far is .308 with jacketed load data and there was zero leading.
Gonna get my star working and do a composite projectile - hitech, blue star lube, & plain base gas chec. I can , l get social security first of august. Time in shop, yay! I have to figure out how to do star, only used it for sizing hitech up to now.
my novice channel;
http://youtu.be/UozyDZ-44Q4