Oil hardening boolites

[tayous1]

I wanted to ask has anyone tried to oil harden there boolites? I'm guessing lead acts like other metals and I found when I was forging knives that oil hardening was one of the best ways to harden the metal you just heated the oil up a little till it was warm and the place the blade in it and let it set and cool.

Anyone tried this or should it be tried?Just thought I would throw this question out there and see what you all had to say about it. Thanks

[sirsloop]

issue I could see is you will need to completely clean the boolits afterwards or you will screw up your powder charge. I guess if you had a shop parts washer or something that would be pretty easy. For the trouble it would probably just be easier to add a percent or so of antimony and call it a day.

[Defcon-One]

1.) You probably ought to heat the knife blade, too!

2.) I suspect that Lead does not reach temperatures high enough that the oil would be of benefit or even necessary.

3.) We chill our water to get the greatest effect from water dropping, so heating the oil might be couter productive.

4.) As stated above, there is the clean up issue. I'd rather just dry wet ones off, or use a tougher/harder alloy to start with. Skip the hardening all together. Besides, I'm the guy who always says that it doesn't really work, anyway.

Maybe there are a few reasons why nobody has tried it.

DC-1

[btroj]

Water works and is far easier to remove from bullets when done.

[sqlbullet]

Slowly heating lead, and more specifically, slowly cooling lead, will remove any hardness gained by quenching or heat treatment.

What you are describing sounds more like tempering to me than hardening. It has been many years since my materials classes in this area, but as I recall you harden steel by quenching it, usually in an oil. Then you remove any brittleness by tempering it. Depending on the steel alloy you need to heat to specific temps to make this work.

The elements of lead alloys that would make them brittle are easy enough to mitigate. Just cut the antimony and quench away.

[DeanWinchester]

I don't believe it would help you at all. Oil is used with certain steels to control the speed at which it is quenched. Added carbon might be absorbed according to some. I dunno if I buy that or not.
Lambs blood has been used by sword makers for years because it does not remove heat as fast as water.
Heat treating is all about controlling your material at the molecular level.
When hot, the molecules are in an excited state. Quenching essentially locks them in place. When you heat treat tool steels, you harden pretty close to as hard as the steel can go, then by controlling the draw temp and time, you control the hardness.

Lead never reaches anything like the temps steel does so there's little risk in quenching too fast.

Always something that bugged me too. I've read of people heat treating their boolits in an oven by heating them and letting them cool. This is not heat treating it as I understand it. I spent 13 years in tool & die. I ain't smart but I understand a little of it. You cannot harden anything without a quench. Oven treating boolits could normalize them I suppose. You could also (in theory) take a water quenched boolit, heat it in the oven and let it cool slowly to make them softer. But I digress.


Basically, kudos for thinking out of the box, but oil quenching lead would be a messy waste of time.

[tayous1]

I understand what you are all saying just thought of that when I found one of my bar stock of O-2 oil steel. So again tell me if I'm wrong if I'm wanting to harden my boolites I would water cool them? I ask because I was water cooling my 45 HP and was told that water cooling them would not do a thing to make them harder. I'm looking for a BHN of 10 or 11 using range scrap also have some pure lead that I was going to add 5-6% tin. Any thoughts on this? I'm not wanting the hard 18 or the HP will not expand also don't want to go to soft.

[dikman]

Waste of time, all you would end up with is boolits coated in oil, although I suppose it could save on lubing them.......

As for using lamb's blood to quench blades, I suppose it might work. Then again, knifemaking is replete with stories of smiths of old using all manner of secret quenching methods to give their blades magical properties (blood, urine, goat's milk, only under a full moon etc etc). One story is that Japanese smiths quenched their swords by shoving them into the bodies of condemned criminals! Good luck on that one, the steel would end up pretty useless as a sword! Water will give the hardest quench, in general, but if you use the wrong steel it can also crack it, which is why oil is mostly used as the shock of quenching isn't as great as using water. Japanese swordsmiths use water, but by coating the blade in clay they have learned, over several hundred years, how to control the quenching to also temper the blade at the same time. Very clever.

But I digress. If you want to harden boolits, drop them, while hot, into water (iced water, if you want to). Anything else will be a waste of time. (We are talking alloyed lead here, I assume - won't do much on pure lead, although I can't see why anyone would want to anyway).

[tayous1]

Waste of time, all you would end up with is boolits coated in oil, although I suppose it could save on lubing them.......

As for using lamb's blood to quench blades, I suppose it might work. Then again, knifemaking is replete with stories of smiths of old using all manner of secret quenching methods to give their blades magical properties (blood, urine, goat's milk, only under a full moon etc etc). One story is that Japanese smiths quenched their swords by shoving them into the bodies of condemned criminals! Good luck on that one, the steel would end up pretty useless as a sword! Water will give the hardest quench, in general, but if you use the wrong steel it can also crack it, which is why oil is mostly used as the shock of quenching isn't as great as using water. Japanese swordsmiths use water, but by coating the blade in clay they have learned, over several hundred years, how to control the quenching to also temper the blade at the same time. Very clever.

But I digress. If you want to harden boolits, drop them, while hot, into water (iced water, if you want to). Anything else will be a waste of time. (We are talking alloyed lead here, I assume - won't do much on pure lead, although I can't see why anyone would want to anyway).

Funny if the oil coating would act as a lube? Kill two birds with one stone!


I'm using range scrap right now and have 150 lbs of pure lead or so the Ebay ad said! I was looking at a 5 to 6% tin mix to the pure lead. Just leave the range scrap as is and water cool them!

I see that you also enjoy forging!? I miss that so much it has been 10 years since the last time I forged a knife I miss it so much the smell of the hot metal and the coal burning! Metal being forged or made it to something just smells so nice! Love it and miss it so much!

[madsenshooter]

Oven treating and quenching does a lot more than what some realize. I've shot oven treated bullets at over 2300fps from a 1/8 twist rifle with decent accuracy. Here's some good reading on the subject. http://www.lasc.us/HeatTreat.htm

[txnative1951]

Here's one article on heat treating lead:
http://www.lasc.us/heattreat.htm

I seem to remember hearing that lead does not act like steel. If you heat it and slowly cool it, it hardens instead of softens. I just water drop my bullets though. It makes them harder and they cool off quicker so that I can handle them sooner.

[dikman]

Not according to that reference you give. It confirms what is said here, that heating and rapid cooling is how you harden lead alloys (as long as they contain antimony). Brass, on the other hand, is the opposite to steel when it comes to hardening/annealing it.

Tayous, I don't do a lot of forging, but yeah, there is something almost primal about the smell of a hot coke forge and working with hot steel. It's one of those things that I decided I wanted to learn how to do - forge a knife blade. Once I learned how I sort of lost a bit of interest, although I have made a few letter openers by forge-welding chainsaw chains. As you probably know forge-welding is arguably the hardest thing to learn to do, and I felt quite pleased with myself once I'd learned how. I do find the forge very handy for other metal-working projects (great for bending lumps of steel!) and use my portable one for melting my scrap lead!!

By the way, your range scrap should be hardenable, but just adding tin to pure lead probably won't do much as far as being able to harden the resultant mix - you need the antimony in it.

[tayous1]

How much antimony should I add to get the BHN I'm looking for?

[dikman]

Look at the sticky's at the top of this subject. There's a lead alloy calculator that you will find very useful, I think.

[sirsloop]

Funny if the oil coating would act as a lube? Kill two birds with one stone!

The oil would foul up your powder leading to inconsistent charges. Same reason you wipe lube off the bottoms of boolits.

[fatelk]

Just for stupid curiosity, I've wondered about quenching them in liquid nitrogen, but only because I have access to plenty.

[bangerjim]

Whatever happened to good olde H2O??????????????????????????????????????????????? ??????????????????????????


banger

[dikman]

Obviously not high-tech enough these days [smilie=1:.

[geargnasher]

As I understand it, oil is sometimes used to quench steel because it absorbs heat and cools the steel more quickly than water. For the mildest quench, lime is used because it insulates better than air.

A cool oil quench may harden boolits more than water, but the difference between ice water and warm water is very little in my experience. The lead/antimony alloy takes a few weeks to get hard after the quench anyway, and is much more affected by the presence of grain refiners such as arsenic or sulfur than by quench medium temperature.

Pure lead and binary lead-tin alloys won't quench-harden.

To get a bhn of 10 or so, a half-percent antimony and a good water-quench is all that is needed. Most mixed range scrap that includes some jacketed cores and/or commecial cast boolits along with the .22s and buckshot will quench to 15 or better.

Gear

[longbow]

Oil is used for quenching some steel alloys because it does not quench as fast as water so tends not to cause cracking in those steel alloys. You want the fastest quench possible with lead (alloyed lead that is) to get maximum hardness. Also, as has been stated water is a lot easier to remove than oil.

Chilled oil might work as well as water but would have to be removed before loading so no benefit overall.

Wheelweights tend to be around 4% to 5% antimony and boolits cast and quenched will be harder than air cooled for sure. 8% antimony is about as much as is useful. Oven heat treating is more effective than water dropping.

Longbow

[bangerjim]

Oil is a mess. I use both water and oil hardening steel in my shop to make tooling.

Water boils off and forms a layer of steam that insulates the VERY VERY hot glowing red steel. Oil does not and cools faster/better. But the austenitic/martensitic phases of OH and WH steels are based upon the specific alloys of metals and other elements in the steel formulation. You do not water harden oil steel and vice versa.

You are wasting your time trying to oil harden lead alloy boolits! Water is and always has been the preferred medium for hardening Sb alloys of Pb.....if you are so inclined.

bangerjim

[JSnover]

Lead hardens and softens at such low temperatures compared to steel, there's no point in using oil for a slower quench.