cast boolit tempering

[RoninDelaware]

Mixed reviews on tempering soft lead. No hardness tester here. Wheel weights and soft roofing lead, are my stock. Now I have heard casting the boolit in the mold and dropping into a bucket of water will temper them and make em hard. ( make far enough away to NOT MIX WATER AND HOT LEAD!!! )But, is oven treating , make them harder?? 450 degrees for 30 minutes, and then I hear 450 degrees for an hour, before cold drop immersion. What works well for you guys?

[Yodogsandman]

I like 450*F-465*F in a convection toaster oven for at least an hour at temp and then quickly quenched in ice cold water (with ice). Here's a great article about heat treating...

http://www.lasc.us/heattreat.htm

[gwpercle]

What are you trying to achieve and with what caliber.
I used to think hardness was the answer to everything...but that's wrong. What I've learned is fit of the boolit is king. A lot of ground can be covered with 50-50 clip on wheel weights and lead, air cooled, they harden some after a week or so.
Found this mix better than straight WW boolits in my 30-30 rifle and now use it for 38 special, 357 magnum , 9mm luger , 45 acp and 41 magnum cast boolit loads.
One thing about water dropping, if you size them you cold work the bullet surface...this softens it back to where you started. So if you quench them, shoot them unsized.
Gary

[David2011]

Hi Ron,

Welcome to CastBoolits! Please read the LASC information. It's a great source of information. You'll learn that the alloy needs antimony in order to benefit from water dropping; otherwise you're just making hot boolits cool and wet. Some wheelweights have a little (0.25%) arsenic which is also a hardening agent responsive to quenching. Pure or near pure won't harden by water dropping. Water dropping doesn't temper. It only hardens. No need to temper (also known as draw) lead. Steel is drawn or tempered after hardening to keep it from being too brittle, as in the case of a knife blade or screwdriver tip.

That said, what are you casting for that requires a hard alloy? Because commercial casters promote "hard cast" many people assume they need hard boolits. If you're shooting .38 Special, .45 ACP, .45 Colt, .44 Special or other low pressure cartridges you don't need hard boolits. Even .357 and .44 Mag don't need super hard boolits unless you're trying for hyper velocities.

David

[Yodogsandman]

One thing about water dropping, if you size them you cold work the bullet surface...this softens it back to where you started. So if you quench them, shoot them unsized.
Gary

Sizing can be done prior to oven heat treating and lubed after HT using the same die or .001" larger. I've sized after HT, too and don't notice any difference except in the resistance in cycling the handle from the boolits hardening up. If I do size after, I try to do it ASAP, within the first day before they harden up much. I also only size after HT if I'm only sizing like .001" or so.

[Wayne Smith]

Mixed reviews on tempering soft lead. No hardness tester here. Wheel weights and soft roofing lead, are my stock. Now I have heard casting the boolit in the mold and dropping into a bucket of water will temper them and make em hard. ( make far enough away to NOT MIX WATER AND HOT LEAD!!! )But, is oven treating , make them harder?? 450 degrees for 30 minutes, and then I hear 450 degrees for an hour, before cold drop immersion. What works well for you guys?

One problem here guys - "soft lead" don't temper at all. You need a trinary alloy to accomplish that, at least with water dropping or oven treating.

[bangerjim]

I seriously doubt you need reeeeel hard lead.

As said above, fit is far more important than the olde school thing of hard lead. If you do not have a tester, use the artist pencil method outlined on here. It is a SWAG but better than nothing.

I PC all my slugs and never worry about hard lead. I mix my alloys for what ever hardness I need aircooled. As said, pure lead will NOT harden. You need As & Sb to do that. Read....read...read.

Do not be afraid of dropping boolits right out of your mold into water! I do it all the time. Not for hardness gain, but to have cold boolits when I want to touch them. I have a large cake pan with a towel in it full of water that I just turn to the side and drop them in. Water is not magically drawn to the lead in your casting pot! And the temp of the dropped boolits is NOT molten. Again....read.......on casting techniques.

And there is a definite difference between "tempering" and "hardening". (did I mention reading?)

Unless you are shooting 4K FPS souper-loupers, I seriously doubt you need anything beyond 12 Bhn. (COWW's). PC them and get by with even less hardness! But you have to tell us what you are doing, are trying to accomplish, and with what guns.

Have fun

bangerjim

[blackthorn]

Normally, we do not think in terms of‘annealing’ lead; however there will be times when you want to adjust the BHNof your bullets to suit a specific purpose. Quenching into a bucket of water straight from the mouldworks well to harden your bullets, but it is impossible to produce absolutelyconsistent bullet to bullet hardness simply because of the external/humanfactors, i.e.; casting rhythm, fluctuation of mould block temperature, mouldblock temperature/alloy temperature ratio, material of blocks etc. If you want something between eleven BHN(normal for ACWW) and thirty BHN, and prefer to stick to using WW alloy, thenwater drop your bullets and ‘draw’ (temper) the alloy back to whatever BHN youneed. Success with respect to the finalhardness will be the combined result of experimenting with temperature andtiming. After they reach the ‘draw’temperature, they can either be air-cooled or quenched in cold water on removalfrom the oven. Here is a chart (you mayhave to adjust this chart for your alloy) that can be used to ‘draw’ yourbullets:



Draw Temperature


Time


BHN




200


1.25 hrs.


26




225


0.75


20




225


1.5


18




237


0.75


18




250


1.5


15




263


1.0


16.5




275


0.75


14.5




288


0.175


12.5


Theabove chart is an approximation using bullets that have beenwater-dropped from the mould, heat soaked in an oven and then quickly quenchedin ice cold water. The BHN of anyspecific alloy will depend on its constituent makeup so it may fall between,above or below the chart BHN and you will have to adjust the timing based onwhat your hardness tests, on your alloy, indicate. The point is, ‘drawing’ will bring all ofyour bullets back to the same temper as long as the bullets are already harderthan the target BHN. Note:each ‘new’ batch of alloy has the potential to heat treat differently than anyother batch, depending on its constituents.

[pls1911]

Try a batch of 50/50 wheel weights to roofing lead. I too use that combination, along with abit linotype, babbit lead and mystery metal/pewter.
Depending on your wheel weight alloy, you'll need to adjust the wheel weight up to the point of getting significant Heat treating effects.
Too little antimony, tin, and arsenic (trace) and your boolits will not harden beyond the as cast state.
When you get to the minimum "sweet mix" you'll get 20-27 BHN with a nominal 450 degree, one hour cook and ice water quench.
I backed off of 465/470 degrees to 450 after a few batches had to be recast due to slumping.
Trust me.... after you get to 20-21 BHN, any harder bullet is of little benefit, and 450 degrees will get you there without the downside of pushing the envelope with an "unknown" alloy.
A nice characteristic of a heat treated low antimony mix is that while "hard" for shooting purposes, the alloy is not brittle like linotype, but retains enough plasticity to hold together on impact.
I size after heat treating, but use oversized dies... .312 for 30 cal and .460 for .458.
This practice precludes work-softening of the bearing surface.
Pistol bullets I no longer size, as I find no difference in accuracy for hunting purposes.
Having said that, a favorite .30 cal is SEACO #316 gas checked which casts about .313... the bearing surface is sized down, but I still get 2000 fps, no leading and great pig killing performance in a 30-30.
The best advice I ever heard was this: Cast, shoot, inspect, adjust, repeat... and smile every time you pull the trigger, even though what at times can be frustrating mysteries.
Have fun and keep us posted.

[bhn22]

Here's former member CBRicks experiences with heat-treating cast bullets: http://www.lasc.us/HeatTreat.htm

[whisler]

What do you mean "former member CBrick"? What happened to Rick? Sure hope we didn't lose another great contributor!

[bhn22]

His last post was 2/23/15. His username is still valid, but...

[dragon813gt]

He and a few others left for a forum they created themselves.