Hardening 1,200lbs of lead

[Hiaboo]

I have about 1,200 lbs of relatively soft lead (isotope containers) they will go to about 15 BHN but I want em to be closer to 20..

I was wondering what would be a good way to raise the hardness on the cheap side of things -- I was going to cast/clean them all up in muffins (1lb) to make easy mixings to add tin, etc later.

If I have to add tin, what would be a good proportion? I looked around but could not really find a decent answer.

[Bobby Ironsights]

If you have a hardness tester and a scale, then you could make up a number of small lots one day, and note your proportions on a graph to yield a scale. It won't necessarily be linear so by all means go past what you need to bracket the BHN scale.

After you make the scale, be sure to post it online to save others time. If you just have a scale, then I'd make up a number of small lots of metal, and send them to someone on the board to test them for you.

[Lloyd Smale]

Either add 1200 lbs of linotype or water drop your bullets when you cast them.

[Tom Herman]

And congrats on the isotope containers!
Are they the small ones that are roughly an inch to an inch and a half wide and about 3" long? You should clean up with them on Ebay if they are in good shape.
If you do melt them, I would suggest alloying 50/50 with wheel weights for a good, all purpose alloy.
Tin does have a hardening effect, but it's minor compared to what the Antimony and possibly Arsenic in wheel weights does.
The main effect Tin has is to increase flowability ( better mold fillout), and anything more than 2% is wasted.

Happy Shootin'! -Tom

[sqlbullet]

I have rather some experience with isotope lead. I have a source that works at a hospital. I am able to purchase about 1,000 lbs /month. The lead ranges from small vial containers all the way up to the 30# reactor cores. Some vials are painted, and some are not.

For my son's recent science fair project, we undertook to test the effects of various hardening techniques on the lead. Let me summarize our findings.

We cast 180 samples each at 650°, 700° and 750° as indicated by a lyman themometer from a Lee Production 4 10# pot. The samples were 175 gr SWC TL from a Lee six-cavity mold. At each temp half the samples were air-cooled, and half were water dropped. No bullets were retained during the mold 'pre-heat' period of casting.

The ingots that were replaced in the pot were all made from a single smelting session, from the same component lead. The lead ingots averaged 13.33 BHN on a Lee Tester. Lead was added to the pot after each 180 bullets, along with any accumulated sprue's. The ingots were sorted as to ensure average hardness lead was added each time. The number of each ingot and the sequence it was added was recorded for use in more advanced analysis later (if I have it in me).

Once cast, bullets were divided into 18 groups of 10 bullets. These groups were a control of the air-cooled and quenched at each temp (total of 6 groups), 6 groups that would be annealed for 1 hour in a 350° oven, then air-cooled, and 6 groups that would be heat treated for an hour in a 450° oven and then quenched.

Group 1-6
Cast Temp 650°
1,3,4 air cooled to an avg BHN of 10.53.
2,5,6 quenched to an avg BHN of 25.88
3,5 were annealed to an avg BHN of 10.83 and 10.67 respectively
4,6 were heat treated to an avg BHN of 16.44 and 17.38 respectively

Group 7-12
Cast Temp 700°
7,9,10 air cooled to an avg BHN of 11.23
8,11,12 quenched to an avg BHN of 29.50
9,11 were annealed to an avg BHN of 9.72 and 10.13 respectively
10,12 were heat treated to an avg BHN of 20.46 and 21.83 respectively

Group 13-18
Cast Temp: 750°
13,15,16 air cooled to an avg BHN of 11.77
14,17,18 quenched to an avg BHN of 32.41
15,17 were annealed to an avg BHN of 9.86 and 10.37 respectively
16,18 were heat treated to an avg BHN of 24.87 and 25.33 respectively

The average weight of the samples ranged from a low of 172.08 (Groups 1,4) to a high of 173.66 (group 18).

I have retained the samples, and intend to test them again for age-hardening and final diameter and length.

Hope this helps.

[Ugly Dwarf]

.... For my son's recent science fair project, we undertook to test the effects of various hardening techniques on the lead. Let me summarize our findings.

We cast 180 samples each at 650°, 700° and 750° as indicated by a lyman themometer from a Lee Production 4 10# pot. The samples were 175 gr SWC TL from a Lee six-cavity mold. At each temp half the samples were air-cooled, and half were water dropped. No bullets were retained during the mold 'pre-heat' period of casting....

sqlbullet,

That was a well timed post for me.

I was just about to come on here and ask about the effects of casting temp to final hardness. A quick search took me to this.

Your figures confirm my recent experience that casting at higher temps will yield more hardness, both air cooled and water dropped.

Thank you.

Dwarf

[Willbird]

That is really odd that a higher casting temp made the alloy behave so much differently. I wonder what pushing up the heat treat temp would do ???

it looks to me as though a 450 oven is not nearly hot enough to heat treat bullets . I did a batch at 400 and it did diddly to them, as far as I can tell by mashing them base to base with air cooled bullets from the same metal it did nothing as far as hardening.

Bill

[454PB]

The isotope containers I've used seemed identical to WW alloy. They cast the same and hardness tested the same. Apparently the ones you have are slightly harder.

While heat treating will harden the boolits, it won't do any good for hardening the entire 1200 pounds at once. Heat treating has the disadvantage of changing over time. The boolits take a while to reach full hardness, and they eventually resoften.

If you are determined to harden the alloy all at once, then either do as Lloyd says and mix it with linotype, monotype, or foundry type, or find some antimony.

Personally, I would harden it in smaller batches as needed for the individual situation. 20 BHN is pretty hard for anything but rifle paper punching.

[Hiaboo]

sqlbullet - Fantastic! Looks like I'll be quenching it, I'm surprised about the large difference of hardness between quenching and air cooling.

Tom Herman- They are the little ones up to the huge 32 pound reactor containers.. I have quite a bit of the little ones.

Forgot to add, I will be mostly using this in my 30-30 and .357 lever guns - pushed by 8gr of unique - 172gr flat nose.

[Ugly Dwarf]

One thing I've read (I believe it was here) was some talk about heat treating and effects on accuracy.

IIRC, the author discussed different hardness bullets having different POI with all else being the same. He found good grouping with each batch (same hardness), but large open groups when mixing bullets from different batches (different hardness).

I would interpret that to mean it is important to keep your casting temp fairly consistant through the session (and from session to session). Just a thought.

[leftiye]

If they run BHN15, they aren't pure lead - and so they should heat treat. Try that first before you alloy. A little heat is cheaper by far than a lot of heat and linotype, and tin would be to alloy.

[sqlbullet]

Smelted some new aquisitions yesterday. Among this new lot were some iodine containers of a shape I had not seen before (about 100#'s of them out of the 1800#'s I got).

These are purple or blue. Purple are 3.5" in diameter, blue are 2.5". Both are 4" tall. Melt 75° to 100° above the rest I got (615°-630° rather than 500°-550°). No signs of zinc.

I believe at this point these are pure lead. I have not hardness tested yet, but the absence of eutectic and the darker grey color support this. I smelted two of the lids today in the 400#'s I processed. I am segregating the rest and will smelt them separately, perhaps later today.

However, to the OP: I have every reason to think that if your lead is like these containers, it is pure, rather than an alloy similar to wheel weight.

[Apache]

I have access to (I think?) some of the same type of stuff. I was told they were used for some kind of radioactive type of storage container....apparently for Xray machine stuff?

Can you tell me if they are safe for use?

[Tom Herman]

I have access to (I think?) some of the same type of stuff. I was told they were used for some kind of radioactive type of storage container....apparently for Xray machine stuff?

Can you tell me if they are safe for use?

They should be perfectly safe to use... Medical isotopes are noted for having very short half lives (the amount of time it takes for half of the material to decay).
I think the most common one, Technetium 99, has a half life of something like 6 hours.
Iodine is a bit longer, about eight days for the longest lived one.
Statistically, after ten half lives, the material is considered gone. So, if your containers have been sitting for more than 80 days, consider them radiologically clean.
Good Luck!

Happy Shootin'! -Tom

[Apache]

Thx!!

I'll try some to see how they'll work.

[runfiverun]

the purple/blue ones are probably near pure lead and a bhn of 15 will do what you want already.
i push plain base in my 45 colt lever gun to 1500 easily enough and this is with air cooled ww's.
the harder boolits from the air cooled is caused by faster cooling of the hotter object i call it air quenching.
i have used a fan blowing over ice onto the spot where i drop my boolits ,to get slightly harder boolits at times.

[Hiaboo]

I'll get pictures shortly tonight.

Here it is.

[sqlbullet]

Hiaboo, it looks like you have been in my garage. The only thing I have I don't see readily in your pics are the little green lead triangle halves that fit the rectangular hole in the bottom of those 30lb reactor cores. I even have a bunch of those tan lead buckets.

For our test, I took four of the triangles, along with a lead bucket full to the top with the odds and ends vials. Those were melted. This is usually about 35-45lbs. I flux at this point with saw dust and skim the pot. Then I add a 30 lb core, and cover the pot for about 15 minutes. My cores have little brass fittings in the bottom, which or course float to the top and have to be fished out. I lightly flux again and start pouring.

After 32 ingots, I add another 30lb core. After another 32 ingots, another 4 triangular pieces, bucket of odds and end, and bucket. Then two more cores.

What you have there can be treated basically just like wheel weights.

[Hiaboo]

Awesome. I'm glad to hear that sqlbullet.. I know the guy probably has another 4 tons of this stuff around so i should be getting some more from him later on

I do not have those triangle halves, and I don't think I saw any for some reason? I'll go back and check out what he has, I have to return his pallet anyhow.

[Apache]

Glad to see/hear all this.....those are the exact same things (in the pics) I have access to!!