Annealing lead

[stuart cee dub]

Question for the forum :

Is it possible to control the cooling of lead or to heat treat it to effect it's hardness?

I recall years ago in a cast bullets annual that there was an article about hardening lead .
Can one soften a bullet during the molding process?

[Harnic]

I don't believe so Stuart.  You can heat treat wheel weight alloy because of the Arsenic content, but while I'm not a metallurgist, I'm pretty sure lead in unaffected by the rate of cooling.

[Dphariss]

Question for the forum :

Is it possible to control the cooling of lead or to heat treat it to effect it's hardness?

I recall years ago in a cast bullets annual that there was an article about hardening lead .
Can one soften a bullet during the molding process?

Not that I know of.
 Some rifles will shoot hard lead as well as soft.

Dan

[The other DWS]

There is a cast bullets forum on yahoo somewhere.   Heat treating cast bullets is fairly common among those who use cast bullets for precision shooting in Cast Bullet Assoc competition in the plain-base matches,  BPCR, and modern Schuetzen (ASSRA/ISSA etc.)

 In Schuetzen we tend to use very low percentage tin/pure lead alloys.  25 or 30 to one.  Just enough tin to give complete filling in some of the old turn of the century multi-diameter bullet moulds.  We also use dead soft alloys since we mechanically pre seat the bullet into the throat of the chamber before inserting a primed and charged cartridge case.  Old time muzzle/breech loading schuetzen experts also used dead soft alloys since they were in essence muzzle loading a lubricated, very tightly fitted, bullet, sans patch of course, (using a carefully fitted false muzzle and a mechanical starter for ultra-precise alignment) down to the mouth of a plugged case, which was then removed, and a primed charged case inserted.

There is some evidence that lead, unless it is laboratory-pure quality, almost always has some other elements in the mix.  Any impurities can contribute to varying degrees of hardness. Certainly most scrap lead has been melted and remelted who knows how many times. Whether it is enough to influence ballistics, by changing the the weight or penetration because of hardness in all truth is probably pretty moot.  Since in most cases the ball is bore diameter or less and it is the patch that engages the rifling, the harness of the lead in that regard is immaterial--it seem to me.

Lead bullets and balls can be dropped into a bucket of cold water (making @!*% sure it won't splash into your melting pot) and you will get a (modestly) harder ball or bullet   ---"chilled shot".   Some schuetzen and BCPR guys chill their bullets if they are pushing velocities a bit and want to avoid overdriving the rifling and getting leading as a result

 By the same token you can reheat a bullet and let it air cool and it will anneal/soften it somewhat.   I make up batches of my schuetzen bullets during the winter. I sort them by weight and store them in a freezer,  which is supposed to stabilize or at least slow any alloy drift.  then a week or so before a match I'll take a couple hundred out and put them on cookie trays and heat them to about 350 for half an hour or so and then let them air cool then pan lube them.  In theory that should give me a reasonably uniform alloy temper bullet to bullet.   I'm not sure it affects my scores, but there are a LOT more issues involved than my bullet alloy and temper

[Daryl]

There is a cast bullets forum on yahoo somewhere.   Heat treating cast bullets is fairly common among those who use cast bullets for precision shooting in Cast Bullet Assoc competition in the plain-base matches,  BPCR, and modern Schuetzen (ASSRA/ISSA etc.)

 In Schuetzen we tend to use very low percentage tin/pure lead alloys.  25 or 30 to one.  Just enough tin to give complete filling in some of the old turn of the century multi-diameter bullet moulds.  We also use dead soft alloys since we mechanically pre seat the bullet into the throat of the chamber before inserting a primed and charged cartridge case.  Old time muzzle/breech loading schuetzen experts also used dead soft alloys since they were in essence muzzle loading a lubricated, very tightly fitted, bullet, sans patch of course, down to the mouth of a plugged case, which was then removed, and a primed charged case inserted.

There is some evidence that lead, unless it is laboratory-pure quality, almost always has some other elements in the mix.  any impurities can contribute to varying degrees of hardness. Certainly most scrap lead has been melted and remelted who knows how many times. Whether it is enough to influence ballistics, by changing the the weight or penetration because of hardness it all truth is probably pretty moot.  since in most cases the ball is bore diameter or less and it is the patch that engages the rifling the harness of the lead in that regard is immaterial--it seem to me.

lead bullets and balls can be dropped into a bucket of cold water (making @!*% sure it won't splash into your melting pot) and you will get a harder ball or bullet   ---"chilled shot".   some schuetzen and BCPR guys chill their bullets if they are pushing velocities a bit and want to

 By the same token you can reheat a bullet and let it air cool and it will anneal/soften it somewhat.   I make up batches of my schuetzen bullets during the winter. I sort them by weight and store them in a freezer,  which is supposed to stabilize or at least slow any alloy drift.  then a week or so before a match I'll take a couple hundred out and put them on cookie trays and heat them to about 350 for half an hour or so and then let them air cool then pan lube them.  In theory that should give me a reasonably uniform alloy temper bullet to bullet.   I'm not sure it affects my scores, but there are a LOT more issues involved than my bullet alloy and temper

Good info, DWS - I wondered, back in the late 70's when I was heat-treating WW alloys for my centrefire big bores, if the 'alloy drift over time' could be stabilized somewhat by freezing and then re-tempering to obtain even hardness of alloy - you've answered my question.  The rifles I shot didn't seem to care, but I wasn't in an accuracy game with them.

[stuart cee dub]

Great and useful information DWS .

I have read that the Bevel brothers had tried wheel weight lead without ill effect in some of their testing in Muzzleblasts.
A good friend of mine with a well stoked  PRB .40 cal used wheelweights for lead and won plenty of shoots.

In my hunt for lead I have accumulated a strange collection... scrap sheet lead, '' internet''  ingots  and dug range lead.
 My smoothbore doesn't seem much care what it throws nor does my PRB rifle.
 But everything I have ever heard is that Minnie balls need to be really soft .

 What I am reading here is that I may get some help from simple heat  treating but there is no guarantee  that will dramatically lower the hardness of any of my ''mystery'' alloys, but it may soften them a bit .

What I am concluding is that  if I am to shoot mystery lead I had best have an intermediary sorting .

Can anyone recommend a brand of lead hardness tester?
 
 

[Daryl]

Stuart - the LTB Lead Hardness Tester is one of the very best you can buy.  It gives a direct readout in Brinel hardness.  LTB is Lead Bullet's Technology - owned by Veral Smith- texas, I believe.  He is a regular at the cast bullet association's forum.  Also, he is the maker of fine custom bullet moulds.

[The other DWS]

you might also check out the lead hardness tester product from Cabin Tree    http://www.castingstuff.com/  The schuetzen guys think highly of it.   Lee precision also has a version that uses a loading press in some way.

wheel weight is normally considerable lighter than pure lead as well as being harder. however it is also a highly inconsistant alloy since it is constantly being recycled and some bullet casters have had major problems with contamination from some of the newer eco-friendly un-lead ones completely ruining a whole big plumbers batch pot full of alloy.  For sure steer clear of any with adhesive backs--and even that may not keep the bad stuff out.

Since most wheelweight is lighter that an equal sized ball of pure lead it will not only be harder but it will fly faster and flatter with a longer point-blank range which might be an advantage in a paper target match at unmarked distances.

One additional comment,  at one time I acquired a bunch of actual lino-type machine bar ingots and several cartons of other "printers alloy" metal type.  some was incredibly hard and light--on the 100 yard pigs it'd shatter and hardly move them (in a HOT load in a super 14 TC)  Linotype not bad but the wide range of propriatary printers metal makes them REAL iffy for muzzle loaders.

With Minie' type bullets I'd use either pure dead soft lead since skirt expansion without splitting is critical.  I will try some later this month with schuetzen alloy 24 or 30 to one PURE lead to tin since it may fill out the mould a bit easier than PURE lead.

  with patched round balls, as long as they are sub-bore diameter, you can use anything within reason,  and some not--from perfectly round stones to glass eyes I'd imagine .   As long as the patch it the only thing in contact with the barrel walls.

[northmn]

I have been using treated lead bullets in my centerfires for the last few years.  When I collected milsurps I liked using cast loads over jacketed to lower the wear.  I have also shot a few deer with cast bullets.  My recipe for my 30-30 is to use chilled birdshot, which contains arsenic, and harden them in an oven at 450 degrees for an hour then drop them in cold water.  The alloy in  chilled birdshot contains about 2% antimony and makes for a soft bullet, but when hardened it is much harder than wheel weight and likely harder than "hardcast" which is about 6% antimony.  WW is more or less 4% antimony.  For a hunting bullet I put the bases in a pan of water and use a torch to heat the noses, which is annealing.  I can drive these bullets at 1900 fps with very good accuracy and no leading.  I have never recovered a bullet as they shoot through any deer, but they are very effective and blow very large holes.  They perform much like a Nosler jacketed bullet wants to.  Pure lead does not temper.  When Rupert made his shot screen in the 1600's he found that he had to use "poisoned" lead or lead with arsenic to get the pellets remotely round.  One technique for making a cast hunting bullet which is a royal PITA is to cast the base out of WW and the nose out of pure lead or lead/tin.  The bullet then can be hardened as described in the oven, but the nose remains soft.  The advantage to this is to drive them at over 2000 fps.  As to Linotype, it is not a recommended bullet for hunting and will not do as well as a tempered bullet.  WW can be tempered harder than Linotype and they are heavier and tougher. Lyno is very brittle and has been known to totally fragment in game animals.  I had hardness charts somewhere, but a tempered WW bullet is like 29 Brinnel where Linotype  might be 20. 

DP

[northmn]

Having trouble with the screen jumping while typing, which means I am getting too long winded.  Addition of Linotype makes bullets brittle as well as hardening them.  Tin helps your cast flow better and also hardens bullets but not to the extent of Lino. Pure lead bears the distinction of being very maleable and does not like to fragment but will flatten out easily.  Tin reaches max hardness somewhere at about 1-10, and 1-16 tin lead was used for some black powder cartridge bullets.  1-20 is very common with some that like to go 1-30 or 1-40.  Tin also makes for a lighter bullet as does antimony.  Target shooters like the hardened bullets better because the bullet retains its weight while still giving the hardness needed to shoot well.  Hardcast bullet alloy is advertised at 6% antimony and 2% tin which is about the alloy content of a good grade of the finer magnum birdshot used for shooting trap. 
If you want to harden a roundball, you can use WW, birdshot, or add tin.  Some add tin for casting but at a level of at most 1-50.  it does not take much to make pure lead cast better.  At ML velocities, most claim WW is plenty hard.  Unless you want to use a very large bore to blow through the heavy bones of a very large African animal, WW would likely be plenty hard.  We had an article a while back where an individual hardened his 50 RB and shot a moose with it with very good results.  I do not remember the alloy, but I do not believe it was as hard as WW but an alloy where the WW was cut by pure lead.  Or you can use chilled birdshot.  Sizes over #6 generally have less antimony than those smaller.

DP 

[Daryl]

Note that hardened or softened lead will attempt to return to it's normal brinel state.  That means, over time, it will harden if it was softened, and soften if it was hardened.  This takes varrying amounts of time, depending on how drastically it was changed.

[The other DWS]

Another thing that can effect pure lead and soft alloys in their use as projectiles is their relative plasticity compared to the harder alloys.  rapid acceleration can cause the soft projectile to "slug out" or "slump" getting shorter and more cylindrical compared to its as-cast shape.
  the old time long range slug gun shooter of the civil war era commonly used a two piece swedged cast bullet with a hard nose portion to preserve its ballistics and a softer back half or third that would squish out to really fill the rifling.
 Cast bullet hunters reverse this.  some will drop a pure lead ball or buckshot in a hot mould and let it melt, then quickly fill the mould with their harde WW type alloy in an attempt to get an expanding soft point  some even developed a 2-mould and swedge process.
I have heard that even our round balls slug out some, if shot with heavy loads and recovered on soft medium or water recovery will show a flattened band around their center and will be shorter than they are wide.  this is good for a hunting round ball since it also expands on impact giving an increaser wound channel for faster bleed-out.

a month or so back there was another discussion and someone posted a great picture of game-recovered round ball that not only showed considerable flattening, it clearly showed the impression of the deer hair.  This is great as far as I'm concerned for deer and smaller game.  However on larger or potentially dangerous game I think I'd want something that got farther in through the hide before it started giving up too much energy----thinking specifically about a thick, possibly dirt and mud filled bear skin.

[Daryl]

a month or so back there was another discussion and someone posted a great picture of game-recovered round ball that not only showed considerable flattening, it clearly showed the impression of the deer hair.  This is great as far as I'm concerned for deer and smaller game.  However on larger or potentially dangerous game I think I'd want something that got farther in through the hide before it started giving up too much energy----thinking specifically about a thick, possibly dirt and mud filled bear skin.

That's exactly what WW balls do from my .69 and my friend's .75.  They penetrate very deeply and the .75's exit moose - every time with heavy loads - something a 300gr.RN ,375mag. fails to do about 95% of the time.

[bob in the woods]

I used to use WW balls in my 10 bore for target shooting, saving the pure soft lead balls for hunting.
After reading posts by Daryl and Taylor, I started using the WW for hunting and love them for bears and moose. I  still use pure lead in my .54 and smaller rifles.

[northmn]

WW is not always as available to every one.  I have a few pounds left, but have not found a replacement source.  There is also an issue of zinc WW getting mixed in.  Adding 50-50 lead solder to a pure lead mix to get a 1-20 or 1-30 alloy like in BP cartridges will also give one a little harder ball.  There was a discussion on this 50 cal and Moose that I brought forward that had excellent information on this.

DP

[Black Jaque Janaviac]

In my experience with casting both muzzle loader and centerfire bullets, pure virgin lead is the softest.   Once you add other metals the alloy becomes harder.

Alloys that contain arsenic or is it antimony? can be quenched for hardness or annealed for softness.  However no amount of annealing will soften a hard alloy to that of pure lead.  Believe me, I've tried.

For the most part the annealing is done to make "uniform" all the bullets of a given batch.  For example, as you begin casting, your pile of bullets will be sparse and they'll cool quickly.  Later, as the pile of lead builds those bullets that drop from the mold will fall amid other still-hot bullets and they'll cool slower.  Annealing them will make a more uniform hardness throughout the batch - it won't soften them to the 5 Brinell hardness of pure lead.

[stuart cee dub]

Black Jaque or anybody ,
I would like to try an experiment .Maybe someone can advise me of the practical end of annealing for softness.I do understand there is hardness drift over time but I am not worried about that at the moment
I have a cookie sheet worth of minies made of some of my softer salvage lead ,an accurate oven thermometer and an oven .
I have use of a lead hardness tester for before and after.
What should I try doing ?


 Regards Stuart

[Daryl]

I would heat them in the oven until they almost slump in the oven - then turn off the oven and let them cool very slowly in the oven. They will soften as much with this method as any other, I assume.

Arsenic is needed to harden lead.  That is why arsenic is added to shot lead before dropping, so it will harden.  the hard shot already has some antimony, but without the trace amound of arsenic, it won't harden - apparently.  Lead WWeights (non sitck-ons) already contain enough arsenic to allow further hardening, but for large game, even dangerous game, further hardening isn't necessary in a large diameter ball.
Stick-on wheel weights as sometimes put on fancy mag wheels, are almost pure lead and will soften a straight WW melt down to 9 brinel or even softer if there are enough added.  For hard bullets, straight clamp-on WW are best - non-zinc, of course.  Some casters find they have to add tin to WW to get them to pour correctly.  I run the lead a bit hotter, and have no difficulty, evenly frosted bullets or balls of uniform diameter result.

[stuart cee dub]

Thanks Daryl !
I will certainly give that a try .

What I was not sure of was how lead ,as a nonferrous metal, anneals .
Since what I have is mystery lead I just need a rule of thumb method to try before I send the lead into either my rifle ball pile (on the hard side ) or  smoothbore pile (pretty darn hard)

I know that with brass, when I wanted to anneal it after work hardening ,anneals just the opposite of steel ,a quick cooling .At lease that is what I was taught to me by a friend of mine who taught me silver soldering and fine metal working .

[Black Jaque Janaviac]

Stuart,

Yes. Pb anneals and hardens similar to ferrous alloys - slow cool to anneal, fast quench to harden.

I have a toaster oven in my garage for annealing.  This isn't the best, but the price was right so. . .

I stand the bullets on a steel sheet with a little space in between each bullet.  Heat to just under slumping which is somewhere around 350 to 400 depending on outside air temps.  You can try one bullet and gradually bring it up to slump by increasing the temp 25* every 20 minutes or so.  Then back it off 25* and fill the remainder of the tray with bullets. 

The problem with a toaster oven is that it can cool quite quickly in a garage in the dead of winter.  So it might be necessary to walk the oven back down to 200* by incremental decreases. 

The best material I've found for soft bullets is plumbers lead, or sewer lead.  It's a little dirty and might be disgusting when you consider how "intimate" it has been with the contents of sewers.  But it is good stuff, let me tell you.  Definitely worth setting aside and using for specific purposes.  Other soft leads like flashing, stick on wheel weights, cable sheathing etc. can have alloy metals like tin or antimony that harden it up a bit.

Honestly I think the best way to deal with lead alloys is to:
A) Sort according to quality before melting.
B) Shoot a number of different guns to make use of the various types of scrap lead
C) Establish some networks with other lead scroungers and trade lead.  For example, fishing jigs and lures do not need to be pure soft lead, so you might trade pound-for-pound wheel weights with pure lead.

[northmn]

Pure lead may develop an oxide coating that is harder, but otherwise it does not appreciably harden.  Lead tempering requires an addition of arsenic which when coupled with antimony can make very hard projectiles.  WW, as has been mentioned will harden over time, which is one reason one may not wish to cast too many at a time.  To anneal you can heat them and let them slowly cool.  I use a kitchen oven on a lined pan and as stated put bullets in at 450 for about an hour (use an oven thermometer). If your bullets require softening they are not pure lead.

DP

[Daryl]

Due to the existance of slightly harder 'chilled' shot - even back in the late 1900's, it could be that to get balls or bullets really hard for high velocity use, the arsenic is needed.  We do know that modern shot has arsenic in it and the addition of bagged shot to the melt allows significant hardening. Tempering, is the drawing of the harness to a certain level.

[stuart cee dub]

NorthMN,
   The lead I have been  using is basically sheet lead from a sound studio a friend of mine picked up for free about 8 years ago . From looking around at commercial lead suppliers while pure can be supplied it goes for a premium. Sheet lead is one of the softer available alloys .While the sheet lead I have  has been uniformly good I am just getting low.
   Frankly there is a strange thrill to scrounging for shooting materials like going  into the local  fabric store to hunt for the perfect patch material . (Maybe it is that frugal Minnesotan in me that likes to eat hotdish too )   
 I have not had any problems from using soft salvage lead to make minie balls using the thumbnail test .But without any real means of determining actual content of the trace minerals I  am looking for  a generic treatment regimen to make them as soft as possible. Afterwards I can test them.
  I just bought a 60 lbs ingot from a retired plumber friend of mine I shoot with. Seems pretty good but I don't think its pure just soft.But it is softer than my internet lead ingots from Iowa which will get used in my smoothbore .
   My thinking is that I should anneal all my minie balls as I start using the new lead  .Sounds like most of you guys do this already for your ''long'' bullets as needed .
Good is the enemy of perfect and I have had pretty good luck with the good so far  .

   

[northmn]

Plumbers lead is pure lead and about as soft as it gets.  However scrounged stuff can contain about anything.   About the only real test I know of is to get something like a lead tester made by Lee or Saeco.  WW is not as hard as some think.  It lists at Brinnel of 9 and 30-1 lead/tin at 9.  The old standard of 20-1 used by BPC shooters is harder.  Pure lead is 5 (10B is not "twice as hard" just like 10 degrees is not twice as warm as 5 degrees)  They claim tin can be removed by skimming without fluxing?  Antimony and arsenic cannot.  So fresh cast balls or minies are about as soft as you will get them.  The best way to keep your supply softest is to cast as you go and not cast up over a years supply and use them the next year. Again pure lead should not harden but a little additive, even 40-1 such as lead/tin alloy can (8B) can harden it a little.

DP

[The other DWS]

Marked and stamped bar solder usually indicates its content. I have acquired some and will use it to mix and blend alloys for my schuetzen match bullets.  Currently I am buying a commercial lab-grade blend in ingots from a fellow ASSRA member who is in the metal trades.   I only worry about annealing my my schuetzen bullets since I tend to cast up large batches during the winter.  I anneal them just prior to a centerfire match so that all the bullets used will have a consistent hardness.
 For patched roundball shooting I'll probably be a bit less critical of the exact alloy, though I may do a couple large batch melts of msc scrap to come up with a reasonably homogenous blend for that purpose.

Sheet lead is fairly pure since it has to be industrially prepared.  Some years back I was fortunate to purchase a whole pallet of plumbers roof flashings from a local plumbers supply house for 10 cents a pound that an ex-employee had toppled and crushed with the warehouse fork lift.  It was made of pure lead.
  A lot of plumbers recycled old lead pipe and other odds and ends and poured it to seal cast iron sewer stacks used in multistory buildings. As a result plumbers ingots can vary in content.  lead wool (like coarse steel wool only pure lead) was also used to caulk those joints but it is pretty uncommon to find since it was pretty expensive.  I've been told that some eastern cities specified it in building codes.
With the increasing values of all scrap metals and the general alarm over the potential environmental toxicity of lead it is getting harder and harder to find, at least at low cost.  most of my reliable sources for scrap have dried up.  I was fortunate to acquire a dozen 20-25 lb lead "casks" and lids that are used to handle and store medical isotopes,  but those are now controlled with deposit and return policies.