Springy lead alloy?!!!!

[303Guy]

I bought some srap lead. Nice and clean rolled a nd squashed and cut unto useable sizes. Exept for one piece. So, out with the hammer to make it fit the pot. But this stuff vibrated like a sping when struck:!: It's lead sheeting. But when cast into boolits, it turned out to be about as hard as lead pipe mixed with lino. But mostly it is tough and malleable. It weighs the same as purer lead.

This is how it behaved in fine sand (slow to fast).

http://i388.photobucket.com/albums/oo327/303Guy/MVC-574F.jpg

Curious!

[leadman]

Looks like it makes a perfect boolit!

Expands yet stays together, just what ya want.

[lwknight]

Maybe it was heat treated with a little arsenic in the mix. Once you melted it , thats all history.
Just a guess.

[runfiverun]

some extruded leads have antimony in them.lead can be extruded into pipe and have 3-5% antimony in it.

[303Guy]

It does seem to be a perfect lead boolit alloy. The problem is, how will I get some more when this lot is used up? It may be a little too hard for reliable expansion at sub-sonic velocities but I'm sure as going to try it! (On game, that is).

Is it possible that the rolling into sheet process gave it its 'springy' properties?

I haven't tried heat treating it nor annealing it either, but I will.

There is so much about lead and its alloys I don't know or understand - it's quite fun! n:mrgreen:

[303Guy]

Another crazy lead alloy. This time of my own creation. (Not sure what's in it!)

This boolit has a fairly soft front section and a harder rear section. It's caused by a differential cooling rate of the mold.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-226F-1.jpg

A fired one. Here the difference in hardness is quite evident.

http://i388.photobucket.com/albums/oo327/303Guy/MVC-010F-1.jpg

The boolit just happens to have been knurled after seating (for lube purposes - being lube-grooveless).

[303Guy]

Tried oven heat treating this 'springy' alloy. Heated four boolits in oven and held at temperature for a spell then took out two and water quenched them. They hardened as expected. I let the other two cool down slowly in the oven. This should soften them right? (Did on another alloy). Not these. They hardened as much as the water quenched ones! ...??? What gives? Not hot enough?

[runfiverun]

you need to heat them to just short of the slumping temp and hold there for an hour.
the slump temp should be around 400 F depending on the tin in the alloy.
then quench all at once.
now here is where things get strange you didn't have any arsenic in the alloy so it didn't react to the heat treating.
arsenic and sulpher are like a catalyst, to the heat treating.
when you work lead it gets softer .
i think of lead as the opposite of brass, you heat and quench brass it softens, you heat and quench lead antimonial arsenic alloys they get harder.
you work harden brass,you work soften lead.

[303Guy]

you need to heat them to just short of the slumping temp and hold there for an hour.
the slump temp should be around 400 F depending on the tin in the alloy.I didn't heat them enough, then.

[crabyx78]

I wonder if the Arsenic in some lead is bad when heated and how could you tell
if the lead had any in it.
Or at what ratio it might be . Just curious.

[454PB]

Which brings up a question:

When I started heat treating 30 years ago, I kept the boolits in the oven at 400 degrees for TWO hours. That was the recommended procedure way back then.

So how come you can melt a pot of WW alloy, cast and water drop, and get up to 30 BHN? From melting the pot of alloy to dropping them into the water takes maybe 30 minutes. I've used an infrared thermometer, and I know the boolits are below 400 degrees when they leave the mould, and have only been at that temperature for 20 minutes or less.

[rob45]

I wonder if the Arsenic in some lead is bad when heated and how could you tell
if the lead had any in it.
Or at what ratio it might be . Just curious.

Welcome to the forum!

Arsenic is beneficial to heat treating bullets.

As far as what lead has it?
Wheel weights have it. Commercial shot has it. Quite a bit of unknown "scrap" that has been mixed with various lead sources is likely to have it.

Lead that has been sourced from refined lead and made to a specification is less likely to have it. This can include the typemetals, certified pure leads, etc. It all depends on the original source of the lead.

Arsenic is your friend when water-dropping or heat treating for hardness, and the percentage of arsenic needed is less than one half of a percent.

Here is an informative article:
http://www.lasc.us/HeatTreat.htm

Again, WELCOME.

Good Luck.

[454PB]

However, arsenic is not required for heat treating. I have mixed linotype and pure lead 1 to 3 and water dropped. The result is over 25 BHN.

[runfiverun]

the way i make out the water dropping is it hardens the antimony crystals in place at the outside of the boolit.
the alloy of Sb/Sn migrates in the alloy as it ages for the first few days like 7-10.
the waterdropping concentrates the Sb/Sn in the outer layers concentrating it there effectively turning a 1/3 alloy into a 3/9 alloy in the outer parts of the boolit and leaving the center part softer.
this would easily explain the softening of waterdropped alloys over a period of time. it returning to the original alloy bhn] and why re-heating it and allowing it to air cool will return it to it's alloy bhn.
heat treating and waterdropping are two different things.
if you heat to say 350 then waterdrop you have just made that batch of boolits very uniform in hardness as long as they are from the same alloy. bhn around 20
heat treating is holding your boolits to a temp just below slump stage untill they have heated all the way through to a near melting state then cooling naturally and slowly.bhn is generally near 25-28.
or then waterdropping for a bhn in the mid- high 30's.
these numbers are for a ww based alloy.
as 303 pointed out above a rapid air cooling can produce a harder boolit also it's the speed of the cooling that will affect the outer parts of the boolit.
in heat treating the entire boolit is affected in the rapid cooling the outer parts of the boolit are affected. results are achieved both ways but.....
one is more effective in a hunting situation and one will respond better to much higher pressures.

[rob45]

Which brings up a question:

When I started heat treating 30 years ago, I kept the boolits in the oven at 400 degrees for TWO hours. That was the recommended procedure way back then.

So how come you can melt a pot of WW alloy, cast and water drop, and get up to 30 BHN? From melting the pot of alloy to dropping them into the water takes maybe 30 minutes. I've used an infrared thermometer, and I know the boolits are below 400 degrees when they leave the mould, and have only been at that temperature for 20 minutes or less.

You have obtained 30 BHN by water-dropping?
I have heard of people getting higher results before, but the best I have personally obtained by water-dropping WW is around 20 BHN, usually closer to 18.
If I want the really high numbers like 30, I have to oven HT.



Key to all of it seems to be:

1. Inconsistencies in testing for BHN. One person's test method may reveal a result of 18 BHN, while another person testing the same sample may obtain a result of 22 BHN simply due to
a. test equipment/method being employed, and
b. operator technique (After all, two machinists can use the same micrometer to measure the same object, yet may still get different measurements!)

2. "Time is of the essence." When the hardness test is employed has a direct result on the result obtained, as arsenical/antimonial alloys possess the property of age-hardening. Is the sample being tested after 1 day, 7 days, 2 weeks? Several factors effect not only the maximum hardness attainable but also the hardening curve (the time required to obtain that hardness), including but not limited to:
a. percentage of antimony
b. percentage of tin
c. the presence of arsenic- The jury is still out as to whether arsenic actually contributes to increased maximum hardening; rather, the most notable benefit is that it seems to allow the same level of hardness with decreased amounts of antimony upon heat treating. The presence of arsenic is why your wheel weights, with only @3% antimony (Sb) can be hardened considerably more than linotype with 12% Sb. In addition, I believe that it has been fairly well established that the presence of arsenic seems to have the benefit of greatly impacting the rate of hardening. In other words, arsenic allows maximum hardness to be attained in a shorter period of time.
d. I have also discovered that the phase of the moon and direction of the tide may have an impact on final results, as does the way I hold my tongue.:mrgreen:

Personally, I prefer oven HT over water-dropping (WD,WQ?) from the mold if I'm striving for a maximum hardness application.

Were I simply casting for a high pressure handgun cartridge (454 Casull, 475 Linebaugh, etc.) where volume requires convenience, I would WD. To me, such applications require more attention to other details in the load chain besides maximum and consistent hardness; therefore, the reduced precision of WD seems to be of no major detriment. In addition, I am one of the overwhelming percentage of shooters that is forced to realize that no matter how good or bad my bullet/load is, it already exceeds my shooting skill.

But what about a pet rifle rig in which I shoot maximum high pressure loads? Surely here is an application where I can take advantage "the best", right? If I determine that increased maximum hardness is required (remembering that not all loads require such hardness), I will oven HT those bullets every time, as the goal in any such application is not only increased hardness, but more importantly, consistency.
By its very application, simple water-dropping presents too many variables.
1. How consistent does the pot maintain the alloy temp? More importantly, how consistently are the alloy percentages maintained through out the casting session?
2. How consistent can one keep the temperature of the mold? Do all bullets solidify in the same time frame?
3. How consistent can one be when dropping the bullets? Can one drop every bullet into the quench medium (water bucket) in the same amount of time? What is happening if some bullets "stick" in the mold, while others drop more quickly?
4. What is the minimum temperature change of the bullet required, and at what rate (how quickly the change must occur)? In other words, if one is casting a substantial amount of bullets, and the quench medium (the water bucket) slowly rises in temperature with each bullet dropped, does this make a difference? If so, at what point (temperature) is a difference realized?

Oven heat treating eliminates those variables.
By using the oven, the entire batch of bullets is allowed to rise to the same temperature, and every bullet is subjected to the same rate of quench.
The result is more consistent BHN from one bullet to the next.
Water-dropping from the mold does indeed increase hardness, but there are times that I have experienced variances as great as 3 BHN within the lot.
Oven heat treating allows those variances to be reduced considerably, usually to the extent that any such variance is either not noticeable, or is so small as to have no measurable effect upon final results.
In addition, oven heat treating allows one to experiment with different temperatures so as to determine if a controlled hardness is possible, whereas with water-dropping we simply just get "harder bullets". Some, including myself, report this ability to reach a "target BHN", while others say it's not possible. As always, everyone's mileage varies.

As I mentioned earlier, I personally have not attained a hardness of 30 BHN simply by WD. If I want to reach that level, I have had to oven heat treat. But for those who may find otherwise, keep this in mind- We each have different alloys, we each have different casting methods and technique, and we each have different methods and technique of testing the final result.

For the more inquisitive among us, here is an interesting thread. It's slightly lengthy, and offers slightly differing opinions ("juicy"!), but offers valuable information.
http://castboolits.gunloads.com/showthread.php?t=67128

Good Luck.

[303Guy]

I don't have a hardness tester but I do have a rough indication meathod of hardness testing. I get widely varying results around the circumference of the boolit. This seems to be from hard spots on the surface. I keep turning and re-measuring until I get repeated softest readings.

This fired boolit shows those surface hardness variations quite nicely.

http://i388.photobucket.com/albums/oo327/303Guy/th_MVC-596F.jpg

I annealed two boolits of different alloy and hardness at 400F and found the hardness reduced in both but curiously, the difference in hardness between nose, middle and base remained the same for both alloys. The bases were hardest and the mid section slightly softer then the noses. These being nose-pour and the base of the mold is much cooler than the the rest of the mold, particularly the nose/top where the sprue funnel is kept hotter to ensure shrinkage filling.

[454PB]

The problem with heat treating is all the variables involved......alloy, temperature of the sample when it hits the water, the water temperature and it's temperature stability, and the test equipment and it's use by the tester.

As an example, I had always accepted the widely published premise that monotype was around 28 BHN, linotype as 22 BHN. I was gifted 2000 pounds of the stuff many years ago, a mixture of the smaller "lines of type", and the large single letter blocks widely defined as monotype. One of our forum members posted that his monotype didn't meet this criteria, and sent me samples. This brought about a flurry of testing, both of his samples and my own. The results showed that hardness of all samples varied wildly from the high teens to 30 BHN. I can only guess at the reasons for that, and my guess is that the people to mixed and reconstituted all the various metals for type probably weren't as concerned with the exact recipe or hardness that we boolit casters are, and neither are the people that make wheelweights.

Without using laboratory certified alloys, temperature measuring equipment, and hardness testers, we are always going to see unexpected heat treating results.

I don't use heat treating much just for these reasons and the fact that I have a good supply of various alloys and alloy components on hand. However, I do like to experiment, and that is why I've invested time in the process. I also agree that the most consistent method is oven heat treating, not water dropping.

I went so far as filing some samples down to two thirds diameter to see what the hardness was INSIDE. I can't say heat treating hardens the full diameter, but the results showed me that they are the same hardness at 1/3 the diameter that they are on the surface.