Cast bullets question

[catkiller45]

The way I understand you have to wait three or four days to check the hardness of your bullets I got to wondering suppose after you cast your bullets and they were cool if you set them in the refrigerator say for like overnight and check the bhn how accurate do you think that would be I mean you're not water quenching them they're already cool just a thought any comments appreciate it thank you

[Winger Ed.]

You can check them anytime you want.

However; unless they're pure Lead, they will continue to harden a little bit for about 2 weeks.
If you size a boolit that was cast a few weeks prior- you can often tell its a little harder,
than a fresh one, but it's no big deal.

Personally: I go to great efforts not to overthink, and split hairs over this stuff.
I pick, mix & use the alloy I want for the type of boolit, and don't worry about it.

[243winxb]

Oven heat treating, cool in water, with 2% antimony takes up to 2 weeks, to fully harden. The higher the percent of antimony, the sooner bullets harden.

Cast and dropped on a towel, good to size and load same day. IMO.

Air cooled tin based alloys will get softer over time takes months , years.

[David2011]

Oven heat treating, cool in water, with 2% antimony takes up to 2 weeks, to fully harden. The higher the percent of antimony, the sooner bullets harden.

Cast and dropped on a towel, good to size and load same day. IMO.

Wholeheartedly agree. With the alloy I typically use, it’s important to size the same day or within 2-3 days of casting. Once I let boolits sit for about two weeks. HUGE MISTAKE! They age hardened quite well and it took far more effort to get them through the Star. I had about 500 age hardened .40 cal TCs to size.

[wv109323]

The hardening and sizing of cast bullets over time is usually not a game changer. Depending on alloy you are talking .001" or less and BHN of 1 or 2. Many variables to consider for optiminal performance/accuracy but they can be worked around.

[jonp]

The hardening and sizing of cast bullets over time is usually not a game changer. Depending on alloy you are talking .001" or less and BHN of 1 or 2. Many variables to consider for optiminal performance/accuracy but they can be worked around.

I disagree with this. I've had much more although since trying powder coat it's not an issue

[PBaholic]

The way I understand you have to wait three or four days to check the hardness of your bullets. I wondered if you cooled them in the refrigerator overnight how accurate the BHN would be.

It's not really a question of accuracy, just realize that the hardness of lead alloys continually change over time. The temperature is not creating the hardness, but the crystalline structure solidifying in the alloy, and I'm unsure if it will increase or decrease in a fridge, but that might be an interesting experiment.

You can test hardness after 24 hours, and it'll give you a good idea. Most alloys harden the longer they age, except alloys with high Tin (Sn) and low Antimony (Sb), which lose hardness after 7 days.

Here is the latest data I've composed with my hardness experiment using the stable alloy called SnSb (equal amounts of Sn and Sb). The calc column is out of the Rotometals hardness formula, which most calculators are based on. Note this formula is only accurate in the linear portion of the output, which is between BHN 11 and BHN 15. Above and below that final hardness, it will be inaccurate. I'm looking for an alloy made of lead, Linotype and Pewter, that has a hardness of about 10, so I focused on the lower end of the hardness spectrum.

I use Brinell's method for determining hardness, and my BHN is accurate to about 0.5 below 15 and 1.0 above 15. I've got an illustration that shows my drill press method of this.

[cr445671]

Could any of y'all talk a little more about the relationship between antimony and speed of hardening? I'm using hardball alloy with 6% antimony, what sort of timeframe am I looking at?

[Winger Ed.]

Speed wise, it does all its going to do in about two weeks.
I didn't use very scientific methods, however:
I've sized cast boolits that were about 2-3 years old, and they had pretty much the same resistance
in the sizer as ones that were 3-4 weeks old.

[243winxb]

Could any of y'all talk a little more about the relationship between antimony and speed of hardening? I'm using hardball alloy with 6% antimony, what sort of timeframe am I looking at?

Forming battery grids- https://www.totalmateria.com/page.as...site=ktn&NM=88

The alloy containing 2% Sb clearly does not respond sufficiently to be considered as a possible alternative. (2 weeks) The 4% Sb alloy, however, attains a hardness of 18 HV after 30 min, and the alloys that contain 6, 8, and 10% Sb could be handled almost immediately.

Hardness Stability. For most of the two-year period, the solution-treated specimens were harder than the quench-east specimens. Other investigations have also shown that alloys cooled slowly after casting are always softer than quenched alloys. The alloys with 2 and 4% Sb harden comparatively slowly, and the alloy containing 6% Sb appears to undergo optimum hardening.

[243winxb]

https://www.freepatentsonline.com/5464487.html
After 8 days, 1 1/2 months and 2 months, hardness tests were again performed on these samples and these tests revealed that the hardness was essentially unchanged.

At least 25 of the samples which were heated for 5 and/or 10 minutes and then quenched as described above also were sectioned, ground, polished and hardness tested both at the surface and the core. These tests revealed that the hardness was essentially uniform throughout.

The samples which had been hardened as described were also analyzed for metal content and had the following metal content:

______________________________________
metal wt. %
______________________________________

Copper 0.038
Arsenic 0.16
Antimony
3.0
Tin 0.25
Zinc 0.0001
Cadmium 0.0001
Nickel <.0001
Bismuth 0.018
Silver 0.0038
Tellurium
0.0015
Sulfur 0.0005
Iron <.0001
Lead Balance

[cr445671]

Forming battery grids- https://www.totalmateria.com/page.as...site=ktn&NM=88

The alloy containing 2% Sb clearly does not respond sufficiently to be considered as a possible alternative. (2 weeks) The 4% Sb alloy, however, attains a hardness of 18 HV after 30 min, and the alloys that contain 6, 8, and 10% Sb could be handled almost immediately.

Hardness Stability. For most of the two-year period, the solution-treated specimens were harder than the quench-east specimens. Other investigations have also shown that alloys cooled slowly after casting are always softer than quenched alloys. The alloys with 2 and 4% Sb harden comparatively slowly, and the alloy containing 6% Sb appears to undergo optimum hardening.

So after a couple days mine should be good to shoot? That's awesome, I was worried I was forgoing something

[bangerjim]

Hardness. HARDNESS? We don’t need no stinking hardness!!!!! We have powder coating now. I rarely check hardness. I just know if I mix a little of this and a little of that it will be 9-12 hardness. Then the PC adds a layer of protection. I have been doing it that way since 2013 with ZERO leading and no loss of accuracies. I rarely shoot my cast boolits soon after I cast them. The many times sit for 6-8 months B4 every being loaded. Now using my use of 4, 5, and 6 cavities ONLY when I cast, it is generally a thousand or more at one time. A lot more than the 1 and 2 cavity molds of the by-gone days.

[PBaholic]

Hardness. HARDNESS? We don’t need no stinking hardness!!!!! We have powder coating now. I rarely check hardness. I just know if I mix a little of this and a little of that it will be 9-12 hardness. Then the PC adds a layer of protection. I have been doing it that way since 2013 with ZERO leading and no loss of accuracies. I rarely shoot my cast boolits soon after I cast them. The many times sit for 6-8 months B4 every being loaded. Now using my use of 4, 5, and 6 cavities ONLY when I cast, it is generally a thousand or more at one time. A lot more than the 1 and 2 cavity molds of the by-gone days.

Well, it's only because the original poster was asking about hardness. If you want hard bullets, all you have to do is water drop them out of the mold. This will work with any alloy, except dead soft lead, which will not harden at all.

I'm also a PCer, and want to maximize my use of Linotype and Pewter. I've been finding lots of soft lead, but I like to have mine around BHN 10 or so. I'm down to my last 150 lbs of Lino, and want to make it last.

I found that my 99% Pb, 0.5% Sn and 0.5% Sb, shoots perfectly fine PC'd at any age from a days to months.

I love PCing. I can shoot the same gun every week for 6 months, before having to clean it, and I have!!

[JonB_in_Glencoe]

The way I understand you have to wait three or four days to check the hardness of your bullets I got to wondering suppose after you cast your bullets and they were cool if you set them in the refrigerator say for like overnight and check the bhn how accurate do you think that would be I mean you're not water quenching them they're already cool just a thought any comments appreciate it thank you

Have you read "From Ingot to Target: A Cast Bullet Guide for Handgunners" (the free online book).
Chapter 3 is about Alloy Selection and Metallurgy.
http://www.lasc.us/Fryxell_Book_Chap...Metallurgy.htm
* scroll halfway down the page and look for the chart titled "Age Hardening of Tertiary Lead/Antimony/Tin Alloys"

Age hardening of the tertiary alloys is more pronounced in the softer alloys, suggesting that at the higher antimony concentrations precipitation occurs more readily during the cooling process. This age hardening can be accelerated by increasing the aging temperature. In general, measuring bullet hardness 24-48 hours after casting provides the most useful, and timely, information.