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A friend asked me this question about water quenching pure lead pistol bullets. Would they have a surface hardening enough to drive them faster than if they were soft lead? Would they still retain their soft center to upset and expand like a soft point when an object is hit? Anybody ever come across this type of experiment, or try this procedure? My arthritis won`t let me try casting out in the cold barn till Spring is why I`m asking for some input from this board.Robert
Pure lead has absolutely no ability to harden from any sort of heat treating or quenching. Antimony and tin are the principle elements added to create a harder metal, and antimony allows heat-treating to a greater hardness. Arsenic in small quantities acts as a catalyst in conjunction with antimony, reducing the time to maximum hardness of the alloy from a few weeks to a few days in most cases.
Gear
+1 on what Gear said..........right on:Fire:
Like you, I cast out of doors, in my cast the garage. It is hardly casting season here. I did however get a new mold that is begging to be tried. I'll be casting today.
Shiloh
If you add some magnum shot to your pure lead you can get some hardening from water dropping.
Argghhh!!!!!! NO IT DOES NOT ACT AS A CATALYST. This is another of those things that has gone around the internet a billion times, and nobody ever questions, that is incorrect terminology.Quote:
Originally Posted by geargnasher
A Catalyst is: a substance that causes or accelerates a chemical reaction without itself being affected.
Since hardening is a physical/crystalline shift not a chemical reaction, arsenic cannot possibly act as a catalyst.
Ok, soapbox mode off.
Read http://www.castpics.net/memberarticles/arsenic.htm for more details.
2% antimony or more is needed to water drop harden. 2% antimonal alloys harden in 1 day, reaching full hardness in a week. 6% antimony hardens much faster as little as 30 minutes. .5% tin is plenty in the alloy. The hardness is the same throughout the bullet. Sizing the bullet after water dropping will soffen the surface some.
Quote:
Originally Posted by 243winxb
I gotta disagree with some of this too. Specifically, full hardness within a week. What I found was that full hardness was not achieved for at least 2 weeks and even then some slow hardening continued for several more weeks. I also would question that the hardness is the same throughout the bullet from water dropping as the tests I've seen suggest that the bullet insulates the core while the surface cools much more rapidly resulting in a tough surface with a softer core. Even oven heat treating results in this phenomenon to some degree as it is impossible to cool the metal at the same rate for both the core and surface. This is accentuated in larger boolits with more metal to insulate the deep core.
Will is correct. The hardening-MOTIVATION stops when the "lead" reaches 300F. The motivation comes from the rate of change from the molted state to 300F (or thereabouts, depending on exact alloy). A small boolit, 22 for example, does NOT have to be water dropped to obtain a measurable degree of hardening over time. ... felix
Maybe i should have said they are hard enough to shoot. You did the testing, i sure wont argue with you. Great info by the way. http://www.castpics.net/memberarticles/arsenic.htm As for hardness throughout the bullet i was going by this.http://www.freepatentsonline.com/5464487.html Personally, to much is made of this bullet casting for the average guy. Simple- correct diameter bullet, alloy, lube. For me scrap from the indoor range, sized to the standard dia. for lead pistol bullets, and NRA type 50/50 lube works great. The 30 cal rifles, .310" works in 4 different guns. Maybe not benchrest accuracy, but ok for me. If i can't get the correct dia., i add linotype to make the bullets larger.Quote:
These tests revealed that the hardness was essentially uniform throughout
The question came to me from a friend, yes I do have a friend, in Fla. Seems he came into alot of pure soft x-ray shielding lead and wanted to know if he could surface toughen it by quenching. I told him I didn`t think it would be workable as he wanted it, but I would ask around. So, thanks for backing me up guys.Robert
Just have him mix it with 75% WW and it will make his lead go allot farther and still be close to proper hardness for most needs
Done some testing myself. Just got more confused and now reading this thread, even more so!:veryconfu
This kind of subject is just not good for a scatter-brain like me!:???:
I was trying to soften an alloy I have using a benchtop oven grill. I managed to soften some sample and harden others. At lower temperatures, the samples hardened uniformly, retaining differences in hardness as cast. Hotter and the hardness became uniform. I don't remember the temperature setting that softened the alloy (nor which alloy it was).[smilie=1:
I have mensioned before about an alloy I had created by accident that produced a graded hardness from my nose molds under certain conditions.
Here they are again.
http://i388.photobucket.com/albums/o...MVC-226F-1.jpg GC cast in position.
http://i388.photobucket.com/albums/o...MVC-010F-1.jpg
It's not only one alloy that behaves this way but this one one is very marked with frosting on the softer portion.
The mold that produces this effect. (It also produces a bevel base and hollow nose).
http://i388.photobucket.com/albums/o...osepour303.jpg
303 guy,
that is genius. cooling fins on the base to essentially quench the lead with a chunk of steel around the nose to keep it warm and allow it to slow cool over a long period of time. Do you pre heat the mold to get the nose portion hot then pour? I would imagine that it would take a while for the bullet to get the gradient that you are talking of. Its a very interesting mold design, did you make it your self? Also, how in the world do you cut the sprue and get the bullet out?
Thanks,
Matt
No. You need to used MAGNUM shot, which has antimony & arsenic in it. Chilled shot is soft. Using the two together as a description will confuse people.Quote:
Originally Posted by mooman76
I stand corrected then!Quote:
Originally Posted by anachronism
Tin is good for castability and "strength", (ductility), but I have not noticed that the addition of tin helps with quenching or heat treating hardening at all. Antimony and arsenic are the ingredients that have worked best for me. Most wheel weights have some. Magnum shot is the best source for adding more that I've found. My heat treated WW alloy achieves it's maximum hardness in 2 weeks at about 25 BHN. The addition of a little magnum shot gets the BHN over 30 in one week.
BD
Other brands might be different.Quote:
CHILLED SHOT
(American Standard) with
Equivalent Hardness Factor of:
2% Antimonial Lead All
:smile: http://www.maycoindustries.com/lead_shot.htmQuote:
HIGH ANTIMONY MAGNUM
LEAD SHOT (American Standard) with Equivalent Hardness Factor of:
4-6% Antimonial Lead Alloy
While geargnasher may not be absolutely correct in his choice of words from a chemical aspect; I believe like him that the arsenic is an initiatory element towards the best heat treat ability results.
Arsenic is added to the better makes of shot as a fluxing agent. Arsenic oxidizes to form As2O3 which fluxes the molten surface of the dropped pellet and enhances the spherical shape. Possibly this enhances heat treat ability as well??
Trace amounts of arsenic seem to be in antimony alloys. (like wheel weights) Possibly to remove As for total purity costs more that leaving trace amounts of arsenic in the
alloy.
I'm not sure anyone has heat treated ternary alloys of lead/tin/antimony where the arsenic HAS BEEN TOTALLY REMOVED. It may still heat treat... but I believe trace amounts of arsenic will improve the process.
Eutectic
The report I have from the bureau of mines, says that when mined, lead has naturally occuring arsenic that is not removed in the smelting process.