Heat treating 'curing' period.

[JeffinNZ]

Team.

How long from the time the bullets hit the water ex the oven till maximum hardness?

I am finding it is taking the best part of a week to reach peak. Alloy is clip on WW with approx 2% tin based babbit oven heated.

[Pat I.]

Either I'm good, lucky, or full of **** but my heat treated bullets reach full hardness over night. A couple of things to try is to either add a few lbs more of WW to dilute the babbit down to about 1% or add about 5% chilled shot to the mix. I don't know what temperature you're heat treating at but I just set my toater oven at 440 degrees using a decent thermometer and the WW's read a BNH in the low to mid thirties after a one hour soak and letting them sit over night.

[Bass Ackward]

Jeff,

There are several variables in heat treating, but the two biggest are the antimony percentage related to tin and the temperature vs the quench time.

Generally the higher the the antimony percentage, the harder the bullet and the faster. If tin percentage actually gets higher, than the antimony, then it won't HT well and you will end up with soft spot formations. The final bullet may not be any harder than if it were AC.

You can control final hardness with temperature and quench time. The downside is that the final hardness time is lengthened the lower the resulting temp at the quench is.

[dubber123]

Jeff,

There are several variables in heat treating, but the two biggest are the antimony percentage related to tin and the temperature vs the quench time.

Generally the higher the the antimony percentage, the harder the bullet and the faster. If tin percentage actually gets higher, than the antimony, then it won't HT well and you will end up with soft spot formations. The final bullet may not be any harder than if it were AC.

You can control final hardness with temperature and quench time. The downside is that the final hardness time is lengthened the lower the resulting temp at the quench is.

Bass, I read that last sentence 4 times and can't quite get a handle on it. Do you mean the faster your alloy heat treats, the quicker it will become soft?

[testhop]

thanks I am more confused than before i use ww and h t then dont worry about it till now

[Pat I.]

If what your doing works for you and you haven't worried about there's no sense starting now. Heat treating a junk of lead isn't very complicated and there's no reason to have to know the atomic structure of the various alloying components to make it work.

There's a lot to be said for simple mindedness and I'm living proof.

[Ricochet]

My impression (without a hardness tester) is that by 4 days they're about as hard as they're going to get. And plenty hard enough to shoot the next day. The Metals Handbook says quenched type metals hit peak hardness at 6 days, but the process can be sped up (at a slightly lower peak hardness) by aging at room temp for 2 hours and then reheating to 85°C (185°F) for 1 hour. Then they're ready to go.

[JeffinNZ]

My impression (without a hardness tester) is that by 4 days they're about as hard as they're going to get. And plenty hard enough to shoot the next day. The Metals Handbook says quenched type metals hit peak hardness at 6 days, but the process can be sped up (at a slightly lower peak hardness) by aging at room temp for 2 hours and then reheating to 85°C (185°F) for 1 hour. Then they're ready to go.

Indeed. 4 days seems very near full hardness.

It would appear that since I commenced to adding my babbitt alloy to the clip on WW the hardest I can get them now is low 20's. As it happens that is fine but for future reference I will not batch all my clip on WW with the babbitt added.

[38 Super Auto]

Do you guys size/lube your bullets within a few days after casting or wait until they have hardened out? Is there noticable difference in sizing effort?

I never have really thought about it. I usually size/lube them when I need to load.

:Fire:

[JohnH]

My impression (without a hardness tester) is that by 4 days they're about as hard as they're going to get. And plenty hard enough to shoot the next day. The Metals Handbook says quenched type metals hit peak hardness at 6 days, but the process can be sped up (at a slightly lower peak hardness) by aging at room temp for 2 hours and then reheating to 85°C (185°F) for 1 hour. Then they're ready to go.

I'm certainly in no position to question, nor to take to task, but since when does type metal have any arsenic except by chance, and since when was quenching type metal a practice? I always thought one of the purposes of eutetic linotype was that its melting and solidification was seperated by only a few degrees. As well, the hardness of linotype is for practical purposes immediate and is not dependant on any kind of heat treat.

Arsenic is the metal that creates hardness in lead on heat treating, one needs about 1/2 of a percent (.005% or .08 of an ounce per pound) to get the effect. (I'm willing to bet we are dealing with far less than that in WW) In my experience, testing with one of Buckshots hardness testers, I reach 30-32 BHN overnight when oven treating simple WW with a 1 hour soak @425 dF. The factor I have found that most effects the hardness reached when heat treating is the time from oven to water. A matter of seconds is the difference between 30 BHN and 20 BHN. It is this that one almost never gets above 18 BHN when dropping bullets from the mold into water, but then generally 18 BHN will get us by for most shooting needs and is quite satisfactory. If you are not reaching full BHN then there are only two sources of fault, time or lack of arsenic

[Ricochet]

As I've babbled on about endlessly it seems, no added arsenic is necessary for precipitation hardening of lead alloys, and antimony will do fine all by itself. According to the Metals Handbook,"chill casting" is the norm for the hard type metals. The Brinell hardnesses listed in that book are for quenched and aged alloys (heated to 455°F for 1/2 hour and quenched in cold water), and there's extensive discussion of their hardening and softening which I've typed and posted elsewhere on here recently.

[JohnH]

Ricochet, It would be Wrong of me to say I'm not arguing, I am; not with the Metals Handbook, but with what they propose we do.

It may be that in a type setting situation there is used a chill process, but in our backyard, spare rooom, garage setting environments, who does that with type metal? (or any other for that matter) Far more to the point, who amoung us is going to not only heat treat our alloy but will then reheat the metal for yet another heat treating period just to make bullets that are usable in two hours? I wonder just how much of such a proceedure was followed in the print shop.

I'm of the firm belief that the more involved a proceedure becomes, the more likely that a human will find a way to circumvent it. We're shooting bullets, not setting type, why would I or anyone use a two step heat treat when a one step will give the results we're after. For that matter, why would we heat treat at all if there was no need?

When I began casting, linotype was readily available, and was the metal of choice for making rifle bullets. Some pistol shooters were using, but mostly those using autoloaders and magnum revolvers. When Veral Smith introduced his book "Jacketed Performance with Cast Bullets" heat treating WW was a novel idea. There really was no need for it. Prior to that time, every year the local papers would sell off their lino as they replaced it with fresh metal in the print shop. I remember the adds for it running in the "Athens Banner Herald". Ain't no need for heat treating lino, cast it one weekend, shoot it the next. No big deal.

Not so today, linotype is relatively rare, and quite expensive as compared with WW. We shoot WW because we are human, and as I said, humans will do anything to make something less complicated, in this case it's less complicated to obtain WW and heat treat it than to obtain linotype.

In reading all of Jeffs posts, he doing the human thing, mixing his babbit with WW to either make the metal usable or to streach it's use and is otherwise doing what he's been doing, heat treating, but getting a different result than normal. His reaction is again quite human..."That didn't work, I'll not use the babbit anymore"

I'm not sure that what we do in our back yards is more than remotely similar to what can be found in industry/professional publications. The fellas who put that book together would prolly have been horrified by the idea of mixing that babbit and WW, and couldn't imagine why anyone would have done so. I wonder what kind of alloy they would have suggested for boolits, perhaps we should find it more than interesting that the mass produced cast bullet industry standard is an alloy of about 1% tin, 6% antimony and 93% lead.

I'm not saying there is no use for such information, but at what level is the information useful beyond something to know? A hardness tester, pencil and paper will tell far more of what we are doing, and be far more useful than a book. I'd have never known how useful a tester was till I had one, but many get along with out it, so do I for the most part, so once again, how much do we really need?

K.I.S.S. Keep It Simple, Stupid (I tell myself this often) Jeff, Keep a good record of what you do with that babbit, in fact you may want to create a couple of different alloys with it to see how they harden and shoot, but I'd suggest that those be experiments kept seperate from your regular shooting alloy till you have a good understanding of how the babbit alloys and reacts.

Sorry, didn't mean to ramble so much.

[454PB]

Do you guys size/lube your bullets within a few days after casting or wait until they have hardened out? Is there noticable difference in sizing effort?

I never have really thought about it. I usually size/lube them when I need to load.

:Fire:

If you are talking about casting without any form of heat treating, it doesn't matter much when you size them.

When I do heat treating, I size them, then heat treat, then lube. When I quench for heat treating I size them within a few hours. If you do either method and let them age before sizing, not only will they be very hard to size, but they will lose at least some if not all of the hardness you have gained.

[Bass Ackward]

Bass, I read that last sentence 4 times and can't quite get a handle on it. Do you mean the faster your alloy heat treats, the quicker it will become soft?



Drubber,

No. The exact opposite really. The poorer the HT, the faster they soften.

What I get depends on bullet diameter. IF I water droop say 35s, I get 24 BHN out of my mix. If I HT at 450 in an oven, I get @ 24 BHN. If I HT at 425, I get 20 BHN and it takes longer to get that. IF I HT at 400 degrees, then I can get 18 BHN, but it takes a week and you will think that you had a poor HT because three days later none have really hardened yet. AC, it is 14 BHN and contains 2% Sn.

What I am doing is creating a poor HT. Actually, when you lower the temperature, you get a hardness reading on the outside, but the inside is softer because it did not cool as quickly. 30s cool too fast, so they get the same through and through and the numbers are slightly higher than 35s. The numbers for 44s are lower yet with 45s fairly close to those.

[waksupi]

Having done some research on it, lead has naturally occuring arsenic in it, that is not completely removed at smelting. So, the hardening agent is apparently there, with no necessity to add more.

[Pat I.]

While I agree with 99.9% of what JohnH. said I have to disagree with one point. I don't believe it's arsenic that hardens I think it's the antimony, arsenic is the catalyst that gets the the thing going.

[45 2.1]

Something to look at.

http://www.lasc.us/HeatTreat.htm#chart

[felix]

I have never dealt with any linotype that was lino. Close, but no cigar. There has always been some slush stage, however slight. Therefore, I contend when that pot displays a slush stage, the amount of potential hardness increase over air cooled is increased by the same percentage as the slush stage is increased. Pure lino won't heat treat. Pure 63/37 won't heat treat, etc. ... felix

[Ricochet]

JohnH, I'm not arguing against the pour it and try method, because that's exactly what I do. There's no telling what's actually in my bullet metal, which came from sewer joints, lead sheet, drain traps, wheelweights, battery cable terminals, phone cable sheathing, a battery grid here and there, a locomotive ballast weight... Oh yeah, and wheelweights! I've even got some linotype and "plus metal" now!

As for "type metals" and the Metals Handbook, all of our lead/tin/antimony alloys fall into that category as they used it, and wheelweight metal is right in line with the "typical type metal" they showed hardening data for.

Arsenic occurs naturally with the other metals used in bullet alloys and would be hard to eliminate completely if you wanted to. But the cast bullet literature is the only place you find the claim that arsenic is essential to hardening. Doesn't appear in the metallurgical literature discussing the professional heat treatment of lead alloys for things like type and battery grids. That article on heat treating lead alloys from "Key to Metals" that I found and posted several years ago and is cited on the site 45 2.1 mentioned this morning lists arsenic among a long list of metals that will harden lead by solution and precipitation. No suggestion that it's a "catalyst" necessary for hardening by the others.
http://www.lasc.us/HeatTreat.htm#chart

[felix]

I have actually cracked boolits by heat treating them with gas checks applied and crimped into place. The split/cracks occurred immediately when they hit the water. Happened only once. Because I did not remember the alloy composition, I won't attempt that process again. There is no telling what caused that problem: too much antimony? not enough tin? arsenic way too high? too low? ... felix

[Ricochet]

That hasn't happened to me yet, but I imagine it could with any of the more brittle high antimony alloys. Copper's thermal coefficient of expansion's a lot greater than lead, and when it's suddenly chilled that copper check's got to get mighty tight on the base of the boolit.

[BABore]

I have been burnt several times with both HTWW's and HT'd 50/50 WW-Pb alloy by not waiting for them to cure. This is with both water dropped and oven heat treated. In a rush to the range, I've hardness tested a few bullets, found them to be in the hardness zone expected, and loaded and shot them. In every case I've ran into unexplained flyers in load developement. Wait a week or two and this doesn't happen. Yes heat treated bullets will often show complete hardening after a day or so. But, are you testing them all? At several places on each. For whatever reason, I don't think a batch of HT'd bullets are of a UNIFORM hardness after just a day. If I'm going to be doing load developement I wait at least a week, and prefer two weeks. It's easy to prove it out with your own alloy by doing test groups after a day or two cure, then repeat it two weeks later.

[felix]

BAB, very true. The more accurate the gun, the longer you have to wait for that uniformity between all boolits in the batch. Three days wait are fine for a typical lever, and most military bolt guns. My bench gun typically sees only boolits that are one year plus old. ... felix

[JohnH]

I thought about this alot today, I wish I knew more of Jeffs usual metal and methods prior to the babbit. At this point I think what he may be experiencing is a shift in the slush stage as a result of the the babbit, which would also cause a shift in the hardening curve. The ideal "slush" in HTing WW is that point just prior to slump. Finding this is a tad tricky and being able to handle a pan of slump prone boolits is tricky too. Most of us it seems use a temp fo 425-440 dF. If the alloy is not quite at the slump, it will either not harden to the full expectation or take a bit extra time getting there. I, personally, don't heat treat as a rule, have only done enough of it to get my head around it, I'm prolly the last person to even be responding on this, all my experience with heat treating is with straight WW.

Ricochet, I jumped off before I should have. Reality is, your handbook tells us a great deal about an accepted standard of how to deal with a know group of metals, and shouldn't be discounted out of hand. My appolagies if you felt disrespected, that certainly was not my intention. I think Jeffs problem is far more likely to be our common experience, much as you relate, and the real question here is how to work with unknown alloys to reach a useable alloy.

A case in point...Recently I was given about 70 pounds of metal. At first glance the color and softness to hand of the metal would suggest it is plain lead. There are blocks that have the characteristic blue hues, dull grays and whitish dust of lead. Some has a silvery tone to it. Grab a sliver of if it and it bends readily. Put it on the hardness tester I get 17 BHN! That is exactly the same as a sample of 50/50 solder I have. Do I have one or two metals here? Do I have something else? Just how do I go about mixing it in with my other metals?

It's a puzzle, and without knowing exactly the alloys we are working with, blending them often creates GOK (God Only Knows) and that can create more problems than it solves. I have at hand about 300 pounds of metal I can only identifiy by it's hardness. One day I'm gonna melt it all together and just shoot it, or add 1 pound to 40 of my normal alloy. Otherwise what does one do with unknown but useable alloy especially in these days of increasing difficulty of securing supplies?

[Ricochet]

Melt it, cast it and shoot it, of course!

GOK; I like that! :mrgreen:

[JeffinNZ]

Prior to the babbitt additive I was running straight clip on WW and when heat treating I did so for an hour at about 440F. BHN used to come it at 30+. Now I have added babbitt I heat treat at the same temp for the same time and top out at 23 BHN.

I think there is a lot to be said for Ricochet's "Melt it, cast it and shoot it".

I appear to have opened a can of worms for the forum. [smilie=1:

[Pat I.]

Jeff,

You didn't open anything you just asked a question. If I was to take a stab at your problem I'd say you have too much tin in the mix. Try emptying half the pot and replacing it with straight WW. If you have a couple of shotgun shells laying around take the shot out if them and throw it in for good measure. Don't monkey around when quenching the bullets and see what happens. If you have a hardness tester and decide to try this get a reading sometime the next day and let me know what the hardness is if it's not a problem.