Waterdropping: harden surface only?

[crabo]

I may have been thinking wrong about waterdropping and heat treating. Does waterdropping only harden the outside surfaces of the boolit, or does it harden all the way through?

I am going to cast some boolits for a 45/70 Guide Gun, and I read where someone recommended waterdropping 50/50 WW and pure lead. I realize that I had thought that the water dropping hardened deep into the boolit. The poster said that the bearing surfaces would be harder but the boolit would be softer for more expansion. (my paraphrase)

If I had a hardness tester, I would run some tests to see. Any thoughts?

[JRW]

Just thinking out loud as it were, but even using a hardness tester, how would we know how deep the treatment would be? I would think one might have to section the specimen to get to the core of the boolit. Just my thoughts, Jim

[rhead]

If you section the bullet to measure the hardness on the inside you will work harden the alloy to some extent. The interior of the bullet will cool slower than the outside which will alter the hardness some.
Water dropping improves the performance in some of my guns and detracts from the performance in others. If this is because the interior of the bullet is not as hard as the outside there is still nothing I can do about it.
Try some and try some oven treated also it may improve your results. Are you wanting more penetration or more expansion at a given velocity?

[Bret4207]

Based on what I've seen, it SEEMS to harden more than just the outside as expansion is slowed appreciably.

[XWrench3]

maybe i am just dumb, but isn't the outside what we are really interested in?? getting the boolit out of the barrel, without leaving big streaks of lead behind was what i thought the purpose of tempering the boolits was all about. well that, and lubing the boolit.

[44man]

The surface cools faster and hardness will reach a certain depth but never the center. If the boolit is hot enough when water dropped there will be little difference between it and oven treated. The only thing oven treating does is to make the boolits more even.
Not important as long as the rifling engraving is done on harder lead. Engaging the rifling will soften the surface but as long as initial engagement keeps the boolit from skidding, from then on it is not too important.
Lead does not work harden, it will soften. All you need is a start.
If this is not enough, a harder alloy is called for. Keep pushing and a copper jacket is needed.
Copper is great, it allows a soft expanding lead to be used. Since we are casters, the job can get tough to balance the job the boolit is asked to do.

[felix]

Remember the rule: faster the cooling, the harder the object. We are talking the difference between 600 and 300 degrees. Therefore, smaller diameter boolits will have the best chance to harden all the way through significantly. ... felix

[243winxb]

These tests revealed that the hardness was essentially uniform throughout. Info bottom of page for oven heat treating/water drop. http://www.freepatentsonline.com/5464487.html

[runfiverun]

brass work hardens lead work softens.
you anneal brass to make it softer and "anneal" lead to make it harder.
if you want a waterdrropped boolit to mushroom you heat soften the nose it returns the alloy to it's original state.
you do it like annealing brass in a pan of water,basically. except you don't tip the boolits over or you just water quenched them again.

[felix]

Lots of stuff said on that freepatentsonline page are distinctly NOT correct. ... felix

[MakeMineA10mm]

Lots of stuff said on that freepatentsonline page are distinctly NOT correct. ... felix

Not to mention they are talking about cold-swaged (presumably pure, or nearly so) boolits, and basically the oven-heat-treating method vs. water-dropping.


I would theorize that depending on bullet diameter vs. temperature of boolit when dropped vs. temperature of the water vs. (etc.), that most water-dropped boolits have varying degrees of hardness through their depth, with the softest part being in the middle and the hardest part being along the outer surfaces; however, diameter and temperatures will cause this to vary A LOT. Really skinny boolits, like .258" rifle boolits may be fairly consistent in their hardness throughout, whereas a .512" boolit may be as soft as air-cooled in the center after being water-dropped. All depends...

[canyon-ghost]

I water dropped some 7mm bullets, 135 grain Lymans. If this sets your mind at rest, here's my little experiment to see how much harder they are. I left one out just air cooled, and took one from the water bucket. Hit both with an 8# sledgehammer, about the same impact. The aircooled bullet collapsed about to the middle, bent and deformed. The water quenched bullet deformed the nose about the first 1/4 inch- that's hard! All this was done right after the pour, neither could have been more than 2 hours old.
You can't tell the inside from the outside with a sledgehammer although it may matter if you leave all the bullets in the water until after the casting session. Point is, they are really hard. No way to tell how the center is effected. May be harder than the original air-cooled anyway.

[Marlin Hunter]

When I water drop from the mold I get between 18 and 20 BHN with WW and the Lee tester. If I oven treat the same boolits again at 400F I get 12 BHN. I don't know if that is right?

one time I cast some boolits from a 850F pot and water dropped into a 5 gal bucket. after running 3/4 of the pot, I pulled them out and they looked like small silver bananas. The water could not cool them fast enough and when they hit the bottom they bent because of the soft interior.

[canyon-ghost]

:coffeecom Here's the trouble spot, all my old tee shirts end up going into that 5 gallon bucket, I have to squeeze the air out of them and they sink to the bottom. Exactly two tee shirts per bucket. The other thing you can try is using a couple of cheap, oversized sponges on the surface. They float and you can let the bullets roll off of them into the water.

Oven heat treating is done with air cooled bullets. Find the right temperature some rainy day when you've got 3 or 4 hours to mess around. Set the temp around 410 and clip a bullet in some needle nosed vice grip pliers. If it slumps before an hour is over, or shows any signs of melting, it's too hot. You need a wire basket to spread bullets out in. Throw another bullet in the basket. My upper limit showed first as shiny spots on the bullets from the basket, had to cut the heat down twice. Oven ht is supposed to give the lead more time to re-align. So, one hour hot in the wire basket, quenched in cold water immediately.

In either case, the bullets must be cast wheelweight (not pure lead) and air-cooled. You cannot heat lead twice without losing the temper instilled the first time. Lead always returns in hardness to it's initial cast state when heated.
Hope that Helps
Ron8-)

[KYCaster]

This looks like a good place to ask some questions I've had on my mind for a while without hijacking a thread.

As I understand it, Pb, Sb, Sn combine to make precipitation hardening alloys...similar to most tool steels. At different temps the alloys have different crystal structures, some of which are harder than others.

The reason the crystal structure changes is that the molecules of the various metals will move(migrate) within the metal as the temp changes. At temps near the melting point of the alloy, the molecules are relatively free to move around in the crystal. The purpose of the fast quench is to change the temp faster than the molecules can move, thereby locking the molecules into a harder crystal structure that is not natural for the lower temp.

Naturally, the surface of the boolit will cool faster than the core, causing a difference in quench rate from outside to center, resulting in (?) a difference in the hardness from surface to core. I'm making an assumption here because, as stated in an earlier post, cutting to the core of the boolit will change the hardness so any subsequent hardness measurement would be meaningless.

In addition to hardness, which most of us are familiar with, other properties of the alloy include ductility, elasticity, toughness, elongation and probably some others I'm not familiar with. There are some alloys that have become "industry standards", like "Teracorp Magnum Bullet Alloy"(92-6-2) and "Lyman #2" (90-5-5) developed to take advantage of different properties of the alloys. And one member here (sorry, I don't remember who...and I'm too lazy to do a search) has determined that 92-4-4 is the optimum alloy.

Now, from a previous life in industry, I know that steel manufacturers make different alloys for specific applications and have developed heat treating procedures to take advantage of the unique properties of the alloys...

...Which leads to the questions I have.

Is there similar information available for boolit alloys? Are there any metalurgists or chemists here who know where to find the info?

Since I'm fairly certain that the answer to those questions is no, is there anyone here who could tell me if it is even possible to define those properties...(what's the best alloy/heat treat for 30 cal expanding boolits at 1800 fps?).

Assuming the info isn't already availale, is there anyone here who could design the tests to determine the properties of various boolit alloys...(ductility, toughness, elasticity, etc.)?

And...would it even be worth the effort?????

So, what do you think????

Jerry

[snaggdit]

:coffeecom Here's the trouble spot, all my old tee shirts end up going into that 5 gallon bucket, I have to squeeze the air out of them and they sink to the bottom. Exactly two tee shirts per bucket. The other thing you can try is using a couple of cheap, oversized sponges on the surface. They float and you can let the bullets roll off of them into the water.


Or you could live in the north woods and cast in the winter. I fill my pail half full of water then scoop up a pile of snow and add it to the pail. I water drop through the snow and it keeps the water COLD and the boolit has to melt it's way through. Never a deformed boolit;)

[NuJudge]

For alloys, don't think in terms of hardness, think in terms of hardenability. The faster the quench removes heat, the greater the response to the quench.

I've never seen any tables of response to various quenches for Lead, much less tables for differences in response to a quench for various alloys of Lead. One would have to work with far more carefully controlled, and expensive, materials than I am willing to. The materials we work with are typically scrap, with all kinds of odd tramp elements in it probably causing all sorts of odd responses.

As noted above, the speed of quench slows down toward the center of a part. To look at response to a particular quench, for materials that don't have the peculiar characteristics of Lead (recrystallization temp being at room temperature), one sections the part, polishes the heck out of the cross section to remove the area of work hardening near the surface, etch with an appropriate acid, then takes microhardnesses and photomicrograps of crystallographic structures from the surface to the core. For Lead, one probably would have to work with a bullet in a lab well below freezing: section a bullet, polish away the cold work, etc.

There's not a lot of Lead metallurgy materials out there. From the limited materials I've come across, Lead-Tin-Antimony is supposed to get some hardening from Tin atoms substituting for Lead atoms in the Lead crystal lattice, and a lot from Lead-Tin-Antimony precipitates. More than a small percentage of Tin has no added effect through substitution. Hardness from precipitates has maximum effect when the precipitates are in a particular size range, but also increases with more precipitates, so is much more complicated. I have also read of improvements in hardness from Arsenic, the description being that it makes grains size smaller. I am not aware of any alloying element that causes a useful change in crystallographic structure such as Martensite in Steels.

There has been a lot of work on determining the ability of different quenches to induce a response with other metals. Varying the temperature of water is not supposed to change the rate of heat removal and therefore the response to quench much, but adding a lot of salt does. The problem with bullets is that may put salt in your bore.

There probably is a Doctoral thesis somewhere on all this, but it would be a lot of specialized and expensive work.

CDD

[canyon-ghost]

I thought about that last night after I logged off. Yes, I live where the city is on well water so, even in Summer it's only about 50 degrees. It's pretty cold compared to the outside temperature. That makes a difference too, the bullets cooling before getting to the bottom of the bucket.

As far as heat treating different alloys goes, the reason it isn't done is because it's possible to get them too hard. And, wouldn't heating bullets for an hour be about all you'd want to do? If they end up at 30 bhn, then they are too hard except for paper, or possibly would disentigrate on impact. But, that's just what I've been told anyway.

Also, Lyman shows Arsenic, Antimony and Tin to be the alloying factors with lead that makes it possible to heat treat bullets. Pure lead containing a small amount of arsenic will heat treat too.

[243winxb]

Water drop harding alloy needs 2% antimony. Grain-boundary strengthening or Hall-Petch strengthening makes the bullet harder. The more antimony the faster the bullet will reach it full hardness level. Smelting produces many different metals, check the metal weight. % in my link above. Swaged or cast, dont matter, heat treating/water drop still works if antimony is in the alloy. Its a proven fact oven treating gives more balanced harding from bullet to bullet, then just droping from the mould. Large amounts of tin is not needed or wanted in water dropping. For air cooled 2% tin is needed for velocity over 900fps. Why > Lyman>
While antimony is used to harden the bullet, the mixture of tin is critical, for while antimony mixes with lead in its molten state, it will not remain mixed when it solidifies. If tin were not added, we would have pure antimony crystals surrounded by pure lead. A bullet of this type , while it feels hard , would certainly lead the bore and eliminate all potential for accuracy.. In a lead-tin-antimony mixture, the antimony crystals will be present just the same, but they will be imbedded in a lead-tin mixutre. As the bullet cools the tin will form around the antimony-lead keeping your bullets from leading the bore. Obturate simply means to fill or plug. Cast bullets take the rifling by a process called swaging, same as a jackted bullet. This is why all cast bullets are sized groove diameter or .001" or more larger. Lyman #2 alloy will work with any cast bullet. No water dropping needed. Casting for more than 30 years. Just how i see it. IMO. http://i338.photobucket.com/albums/n420/joe1944usa/th_castbullets.jpg (http://i338.photobucket.com/albums/n420/joe1944usa/castbullets.jpg)

[1Shirt]

:coffeecomA friend of mine uses a 5 gal pail with a whole lote of wine corks floating on the top, probably about 2 layers of them pretty well wetter soaked. His blts show no deformation, and I had never run into this brfore. Thought it wasn't a bad idea.
As to hardness, I agree with Felix and temp and speed. I cast as hot as possible, as fast as possible, and as consistant as possible. Am thankful for bull plate! It has made consistancy in casting for me a whole lot easier.
1Shirt!

[pdawg_shooter]

maybe i am just dumb, but isn't the outside what we are really interested in?? getting the boolit out of the barrel, without leaving big streaks of lead behind was what i thought the purpose of tempering the boolits was all about. well that, and lubing the boolit.

In that case, paper patch. You can use pure lead and still not get leading.

[5Shot]

I use Wheel Weights with a bit of tin in a Ruger #1, 45/70, and I get no leading without water dropping (Using a Ruger #1 Pressure Load). I don't really think you need to have expansion either, as the bullet going through the critter is HUGE!

I have done oven heating as well, and I had some bullets that shattered when hit with a hammer. You really need to spend a lot of time finding out the right temp. Oven heating is more uniform, since all the bullets are the same temp and the water is the same for all bullets.

When you water drop, it takes a few hours to fully harden the lead, so if you size them right away, the material that work softened will still get a bit harder over night - plus it makes sizing WAY easier.

[runfiverun]

iirc it was Dr. mann that done a ton of studies on lead alloys and their properties it was some time ago 1920's-1940's?
oh yeah her first name was joyce as i recall......
i think she was the first to water quench and heat treat lead alloys at least the first to write about it.

[cbrick]

The surface cools faster and hardness will reach a certain depth but never the center.

A rare occasion I'll disagree with 44man. According the metals industry a lead/antimony alloy when heat treated/quenched does harden all the way through unlike most steels that only surface harden.


you anneal brass to make it softer and "anneal" lead to make it harder.

Anneal always means to soften, doesn't matter if its brass, lead or steel. If you have a lead/antimony bullet that you water dropped (quenched) and its 17 BHN and you now want them 12 BHN, place them in the oven at around 300 degrees long enough to acheive a uniform 300 degree temperature. Turn the oven off and just let them sit there until they are room temp, this is annealing and it softens the alloy.


When I water drop from the mold I get between 18 and 20 BHN with WW and the Lee tester. If I oven treat the same boolits again at 400F I get 12 BHN. I don't know if that is right?

That probably is right. The 400 degree oven wasn't hot enough to achieve full heat treating hardness. You can vary the hardness level of your boolits in this way. 400, 425, 450 etc will all give increasing BHN with lead/antimony alloy.


Oven heat treating is done with air cooled bullets. Find the right temperature some rainy day when you've got 3 or 4 hours to mess around. Set the temp around 410 and clip a bullet in some needle nosed vice grip pliers. If it slumps before an hour is over, or shows any signs of melting, it's too hot. You need a wire basket to spread bullets out in. Throw another bullet in the basket. My upper limit showed first as shiny spots on the bullets from the basket, had to cut the heat down twice. Oven ht is supposed to give the lead more time to re-align. So, one hour hot in the wire basket, quenched in cold water immediately.

In either case, the bullets must be cast wheelweight (not pure lead) and air-cooled. You cannot heat lead twice without losing the temper instilled the first time. Lead always returns in hardness to it's initial cast state when heated. Hope that Helps Ron

Basically correct, bear in mind that home cooking oven temp settings vary considerably, you'll have to experiment with yours. I use a cookie sheet rather than a wire basket and stand the boolits up.

Here is an article I wrote on heat treating that may help explain it.

Heat Treating Lead/Antimony/Arsenic Alloys (http://www.lasc.us/HeatTreat.htm)


...Which leads to the questions I have.

Is there similar information available for boolit alloys? Are there any metalurgists or chemists here who know where to find the info?

Since I'm fairly certain that the answer to those questions is no, is there anyone here who could tell me if it is even possible to define those properties...(what's the best alloy/heat treat for 30 cal expanding boolits at 1800 fps?).

Assuming the info isn't already availale, is there anyone here who could design the tests to determine the properties of various boolit alloys...(ductility, toughness, elasticity, etc.)?

And...would it even be worth the effort????? So, what do you think???? Jerry

I am not a metalurgist but when I became interested in heat treating boolits several years ago I started searching the internet and reading papers from the metals industry. There is collectively a lot of info on lead and lead alloys but it takes a lot of searching and peicing it all together.

Best alloy/heat treat? Lot's of variables, bullet design, distance, target. The harder it gets the less ductile or elastic it becomes, one of the things I did learn from the metals industry is that lead responds to heat treating opposite of steel. If steel is hardened by heat treting it becomes more brittle, lead does not. Heat treating lead will make it less ductile but not more brittle. Boolits are made more brittle by adding antimony.

Boolit casters refer to heat treating as "hardening" the alloy, the metals industry refers to heat treating as "stengthening" the alloy.

Hope this helps,

Rick

[45 2.1]

Quote:
Originally Posted by 44man http://castboolits.gunloads.com/images_acps/buttons/viewpost.gif (http://castboolits.gunloads.com/showthread.php?p=651017#post651017)
The surface cools faster and hardness will reach a certain depth but never the center.

A rare occasion I'll disagree with 44man. According the metals industry a lead/antimony alloy when heat treated/quenched does harden all the way through unlike most steels that only surface harden.

Cast very hot near the frost point and you'll see an almost hard through boolit. Cast at a lower temperature (around 725 degrees) and the hardening will not go to the center. It's a matter of balancing the hardening constituents in the alloy with the temperature they will quench harden at. Get it near the threshold and they will not harden all they through.

[cbrick]

Cast very hot near the frost point and you'll see an almost hard through boolit. Cast at a lower temperature (around 725 degrees) and the hardening will not go to the center. It's a matter of balancing the hardening constituents in the alloy with the temperature they will quench harden at. Get it near the threshold and they will not harden all they through.

That wasn't something I made up or just decided it should be. According to the metals industry papers on the subject HT lead/antimony alloys harden all the way through.

Rick

[Willbird]

brass work hardens lead work softens.
you anneal brass to make it softer and "anneal" lead to make it harder.
if you want a waterdrropped boolit to mushroom you heat soften the nose it returns the alloy to it's original state.
you do it like annealing brass in a pan of water,basically. except you don't tip the boolits over or you just water quenched them again.

I do not agree. The process of annealing usually means heating, then slow cooling.

The only reason we quench brass when annealing it is because we do not want to anneal the whole case, just the mouth.

When you heat a lead/tin/antimony alloy then quench it you are heat treating it, just as if it was steel you are using the quench to "lock in" a state that was created by the initial heating.

So when we heat treat bullets we are not annealing them.

Bill

[45 2.1]

That wasn't something I made up or just decided it should be. According to the metals industry papers on the subject HT lead/antimony alloys harden all the way through.

Rick

Well, I believe you reported what they said, BUT I don't think they gave the heat treat range for their tests nor the heat range at where the alloy didn't harden. You want to try where those ranges meet. Try it out for yourself and see, nothing like experience with something. The smaller diameter boolits need to be closer to the threshold when they are quenched.

[BABore]

Do you believe everything you read? I'm sure the industry article was based on a standard sample thickness and optimal temperture. That's not the same as casting boolits. Boolit diameter, alloy temp, and how you run the mold all dictate the result. It's much easier to get complete hardening with 22 caliber boolits, 800 F alloy, and a fast casting cadence than with 458 boolits. There are some very real benefits to not having the boolit's core hard.

[cbrick]

Do you believe everything you read? I'm sure the industry article was based on a standard sample thickness and optimal temperture. That's not the same as casting boolits. Boolit diameter, alloy temp, and how you run the mold all dictate the result. It's much easier to get complete hardening with 22 caliber boolits, 800 F alloy, and a fast casting cadence than with 458 boolits. There are some very real benefits to not having the boolit's core hard.

I believe the industry papers on the subject yes.

Only patially true when quenching, not when oven HT where boolit diameter, alloy temp and how you run the mould would have nothing to do with the results.

Rick

[cbrick]

Try it out for yourself and see, nothing like experience with something.

I have oven HT'd many, many thousands of bullets for many years, then tested them in long range handgun grouping, velocity and standard deviation testing looking for cause and effect looking for what works and what doesn't. To a lessor extent in rifles but have run tests on many of these also.

I have run tests on oven temp vs ice water and room temp water, time to acheive final BHN, I even ran a 10 year test on 30 BHN 35 cal 200 gr bullets to see how much they age softened. I have run tests on various oven temps and the resulting BHN. I have run tests on alloy changes and everything else I could think of over the years. Most of the tests were run several times to make sure the results were the same each time.

Yep, tried it out for myself.

Rick

[crabo]

I have run tests on oven temp vs ice water and room temp water, time to acheive final BHN,
Rick

Drumroll! and the results were......? I have often wondered this.

[cbrick]

I got conflicting results with varying the water temp. I had run several tests between cool tap water and water as cold as I could get it with block ice. Each time the results were the same, the final BHN was reached in less time with the ice water though they didn't get any harder. In other words if the final BHN was 18 for the ice water within two days it was also 18 for the tap water but within several days. I initially thought with the very first tests of this I did that they were getting harder, subsequent tests proved this wrong, not harder, just faster.

The conflicting part was this worked each time when using a conventional gas fired cook oven, when I started using the convection oven the water temp didn't seem to make any difference in time to final BHN. Ice water or tap water with the convection oven and the final BHN is reached in the same time.

It also takes a lower temperature with the convection oven to reach the desired BHN than with a conventional oven. Probably due to a more consistent, even heat throughout the oven.

Varying the percent of antimony will effect both the final BHN AND the time it takes to reach the final BHN.

I explained this in this article:

Heat Treating Lead/Antimony/Arsenic Alloys (http://www.lasc.us/HeatTreat.htm)

Rick

[outdoorfan]

I recently have been trying to heat treat some .452 300 grain boolits to 12-14 bhn. It's a 2/1 ww/soft alloy. Well, at 475 degrees, the boolits get real hard real fast (within two days). At 375 degrees, they get to at least 15-16, but it took a week or so to get there. Before I figured that out I kept re-doing the test with a hotter temperature each time. :groner:

Then I remembered a trick I had read on this board that involved heat treating the boolits, quenching, letting them sit for 2 hours, then putting them back into the oven for 1 hour at 200 degrees. That brings them to final hardness pretty much "right now". And that worked for me without waiting a week to see what final hardness they'd finally get to.

Oh, but none of this has anything to do with obtaining a hard jacket and soft core. Oops.

[KYCaster]

Couple of things I'd like to clarify and comment on.

CBrick, thanks for the reply, but I probably didn't make the question clear. I used the 30 cal @ 1800 as an example. The real question is, Is there info available that would tell us what alloy/HT will give our desired expansion in any particular situation. Something similar to load data, like...13gr. of Unique in a 30/30 under a 311041 will result in X fps. So...a 311041 cast of WW and HT to 21 BHN fired from a 12 twist barrel with XXX impact velocity will expand to ??? dia. in wet newsprint.

It sounds like you have already done the work and can answer the question, but what would it require to get the data verified and published. And I already know the answer...it was kind of a silly question....I was in kind of a silly mood. I just wanted to see where it would lead.



I spent quite a few years in industry, working with some engineers who were at the leading edge of their respective fields, and I can tell you for certain that any scientific study that is properly prepared and published will have ALL the variables defined and ALL the procedures documented. Any published papers will very quickly be thoroughly tested by others in the same field and either verified or mercilessly picked apart. Look at the foot notes and documentation, if it isn't complete and verifiable then it's just one man's opinion.

Much of my job involved heat treating. Mostly ferro-magnetic alloys, but also tool steel parts from our in-house machine shop. I've used a wide variety of quench media...water, oils, sand(at various temps), gases(nitriding, carbourizing, inert), and even molten salt(now there's an adventure I'll never forget). I've also done extensive hardness tests and michroscopic examination of all the materials I've heat treated and I can say with confidence that, when properly done, the heat treat will be effective to the core of the material. Now, I have to qualify that by saying that the quench has to be compatible with the alloy. Given the properties of the lead alloys we use, it would be extremely difficult to cut to the core of a boolit without changing the hardness.

Another of my duties was annealing copper tube used to make electromagnetic coils. Copper and its alloys (including brass) are dependant on the quench rate for their ultimate hardness (softness). The faster they're cooled, the softer they will be. Water quenched brass will be softer than air cooled brass. Is it enough to really matter????probably not.

There's a lot to this hobby that most of us don't understand. We really don't have to understand much of it to get good results, but it would sometimes be nice to have some of it documented so it wouldn't be necessary for every one of us to repeat the same experiments.

Anyhooooo....I like to shake the tree occasionally just to see what falls out.

Thanks everybody.
Jerry

[454PB]

I had the same question a while back, so I filed 1/3 of the way through a water quenched boolit that had aged two weeks. It was the same hardness there as on the surface.

[45 2.1]

Yep, tried it out for myself.Rick

Too bad you didn't find it then. Believe what you want and do what you want...........No skin off my nose, but your the looser. Reduce the antimony content and cast at low temperature, then maybe you'll hit it.

[243winxb]

I recently have been trying to heat treat some .452 300 grain boolits to 12-14 bhn. It's a 2/1 ww/soft alloy. Well, at 475 degrees, the boolits get real hard real fast (within two days). At 375 degrees, they get to at least 15-16, but it took a week or so to get there. Before I figured that out I kept re-doing the test with a hotter temperature each time. :groner:

Then I remembered a trick I had read on this board that involved heat treating the boolits, quenching, letting them sit for 2 hours, then putting them back into the oven for 1 hour at 200 degrees. That brings them to final hardness pretty much "right now". And that worked for me without waiting a week to see what final hardness they'd finally get to.

Oh, but none of this has anything to do with obtaining a hard jacket and soft core. Oops. Testing battery grids The higher the % of antimony in the alloy, the faster it reaches full hardness. 2% works, just takes longer to get there.
The alloy containing 2% Sb clearly does not respond sufficiently to be considered as a possible alternative. The 4% Sb alloy, however, attains a hardness of 18 HV after 30 min, and the alloys that contain 6, 8, and 10% Sb could be handled almost immediately.
More on air colded and water dropping here > http://www.keytometals.com/Article88.htm

[cbrick]

Too bad you didn't find it then. Believe what you want and do what you want...........No skin off my nose, but your the looser. Reduce the antimony content and cast at low temperature, then maybe you'll hit it.

??? Find what? Looser of what? What Antimony percentage am I using? What temp am I casting at? Hit what?

Rick

[cbrick]

243winxb, that's correct. The Key To Metals article you placed the link to is one that I qouted heavily in the article I added the link to in post #33 above.

Rick