BHN still climbing

[Hayfield]

I've been smelting WW, lead and 25:1 alloy this winter to get started with my casting for this years shoots. I try to get way ahead as I don't care to cast in the hot summer months. I did 125 lbs of WW in Dec and I was checking the hardness. 13.5, same as my batch last winter after 30-60 days. Since I had everything handy I checked a few leftover ingots from last winter. 16.5! I rechecked them all, 16.5. I rechecked my old lead, 5.5. I rechecked my old 25:1, 9.0 on the dot. I smelt in 100 lb batches for the purpose of uniformity and I use at least 25% of the last batch in the next batch. I use a thermometer (600^) and I clean my stock prior to smelting. What's up with this 16.5 thing? I wish I had some bullets left to check.

[Hayfield]

I downloaded the Java thing according to instructions and I still can't get into that chat thing. P@#$ me off. Gives me a 'server busy try later' error.

[grumpy one]

My WW are only 2% antimony, and should be about 10-11 BHN I guess. In practice they average 10.6 BHN after 2 weeks, but after a year they average 14.9 BHN. I don't know what causes this, other than it must be slow precipitation-hardening, but I have no good explanation for why other people don't seem to be experiencing it to a similar extent. Cooling rate may be a factor - in other words, mould temperature.

[randyrat]

Smelting in the winter months. In a way your water quenching your alloy with the cold weather. I get the same thing when i smelt in the cold weather. You pour in a cold mold and it cools real fast, what is happening is your quenching the surface of the alloy and it gets harder. Remelt it in the summer with a warm mold and retest it after a week or so and you'll get a different reading of hardness. Thats my guess. Or possibly you have some real hard WWs?

[runfiverun]

you could have easily air quenched them its almost as good as water quenching.
i try to run my lead and mold as cold as i can and try to keep them at this constant
and get the boolit out of the mold as fast as possible, by blowing a concentrated fan on the mold. i have noticed i get almost 2 bhn harder boolits this way.

[Hayfield]

Thanks guys. Cold weather quenches them makes sense. I am casting in the barn and there is no heat in the barn. I'm using Ly #2 for most of my bullets and I just tested last years batch, 15.5 still. I'm going to move some equipment up to the garage where there is heat and smelt some up and let them sit till next year and test then. I'm not going crazy over it but I did want some experienced opinions. Appreciate the help.

[Ricochet]

Might have something to do with pouring into cold ingot moulds.

[randyrat]

One other point, you never test bullets by testing the nose, not accurate measurment. So when you test an ingot your testing the alloy that touches the mold similar to the nose of the bullet. Its not very accurate to test ingots or at least it is not from my experience. It my be more accurate to file the top of the ingot a 1/4"( i'm guessing 1/4") then test, you may get a better/consistant measurment.

[Hayfield]

Randy, another good point. I've pondered that file thing on occasion but I've been too lazy as you know what a pain it is to card that file every 1 or 2 passes. Guess I'll bite the bullet so to speak and do just that. And I'm cheap too so I'll card the file over a dish to save the lead.