How much magnum shot per lb. isotope?

[UNIQUEDOT]

How much magnum shot per lb. of isotope to take advantage of quenching? I think i read somewhere that an ounce per pound would get enough arsenic in the mix?

[Defcon-One]

Updated per DrB's comment, Fryxell does say not more than 0.1% required.

It's the antimony that let's you water drop harden and you have that already, you can ad As up to 0.10% to enhance the process. I use 4% Sb, 1.25% As, as the content of Magnum shot, that is what Lawrence shot is supposed to contain. (Arsenic content in shot can vary.)

To get 0.10% Arsenic in your Isotope Lead for better Water Quenching:

Mix 10 lbs. of Isotope Lead (1% Sn, 3% Sb, 96% Pb) with 0.9 lbs. (14.4 ounces) of Magnum Shot. You should get an alloy of around (0.92% Sn, 3.08% Sb, 0.10% As, 95.90% Pb). That's 1.44 ounces per pound, so 1 ounce per pound might do it!

- Antimony provides hardness and the ability to harden through heat treatment.

- A small amount of Arsenic (which in and of itself doesn't harden the alloy appreciably) significantly enhances the heat treat-ability of the mix.

I'd also add about 1/4 pound (3 ounces) of 50/50 solder to get the Tin up to 2%, but that is your call.

FYI: Wheel Weights have .17% Arsenic on average!

[DrB]

Fryxell's book says more than .1% arsenic is unneccessary for quench hardening... but I haven't yet seen a characterization of quench hardening rate vs. arsenic content (perhaps it's farther in than I have yet read).

If someone wanders through with the answer (what's the function of arsenic concentration vs. hardening rate/eventual hardness) I'd really be interested in that answer.

I'm sitting on a about a half ton of isotope lead, and I've been hardening using rotometals super hard and shot. I've noticed that I still get quench hardening even with really small amounts (a scant handful in a 20 pound pot) of shot. This makes me wonder if maybe rotometals superhard has arsenic in it to start with?

If RM superhard doesn't have arsenic in it, seems to me it should! I'll send an email to RM and inquire.

Best regards,
DrB

[UNIQUEDOT]

Updated per DrB's comment, Fryxell does say not more than 0.1% required.

It's the antimony that let's you water drop harden


I read in one of my Lyman's and also in another publication that antimony only allowed so much hardening from quenching and arsenic was required for water hardening? I will have to see if i can dig those books out. Perhaps the arsenic is already alloyed in the antimony?

[DrB]

So, yes, the antimony rod/needle crystals are supposed to have a hardening effect in the soft lead matrix (I haven't read the primary source material yet, just second hand accounts). As I understood it, however, the arsenic promotes crystallization of the antimony out of the alloy solution. EDIT/ Wiljen's excellent article linked below states that arsenic acts as a grain refiner (smaller crystals), and thereby hardens the alloy.

Supposedly, it doesn't take much arsenic at all to do this. The arsenic enables quench hardening. Without the arsenic, my understanding was that water quenching wouldn't result in greater hardness of the antimony bearing alloy.

<snip>

[tonyjones]

At the bottom of this page is a link to the LASC Cast Bullet Notes. Under the index to all articles you will find an article by Wiljen; The Myth of Arsenic. You will also find info on Superhard and recipes including adding shot to add arsenic to your mix.

Tony

[DrB]

EDIT/:

So I had trouble finding wiljens article that TJ was referencing, but then was able to find the below via google: http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBUQFjAA&url=http%3A%2F%2Fwww.castpics.net%2Fsubsite2%2FGen eralReference%2FThe%2520Myth%2520of%2520Arsenic.pd f&rct=j&q=arsenic%20myth%20lead%20hardening&ei=Rw8hTv32HMWEtgfV59G4Aw&usg=AFQjCNFBWHQMj3Oc6qzRo0KbLCy7s2sWBg&cad=rja

All right, wiljen's article is outstanding (thanks TJ!)... in it Will tested lead alloy with arsenic at .02%, and reported what I would consider to be normal hardening with water quenching. Nice work... he also points out that a trace amount of Sulphur accomplishes comparable results.

RE superhard, here's the link TJ's referencing:
http://www.lasc.us/SuperHard.htm

TJ -- this article doesn't say anything about Superhard having arsenic, which according to rotometals it does. Given how very little arsenic it apparently takes based on will's study (the variation in required amount among other sources I found confusing), I'll bet you do not need lead shot when using superhard at all. When I get around to making a batch with isotope lead, superhard, and tin sometime soon I'll post my results, if someone else hasn't beaten me to it.

[wiljen]

Was just reading through and thought I'd add my .02


1.) Antimony creates a harder alloy than lead or lead / tin mixtures alone but does NOT allow for any form of hardening by itself. This can be proven easily as linotype does not contain a grain refiner (arsenic/selenium/copper/sulfur) and will not quench
or heat treat harden at all.

2.) Adding additional material beyond the threshold required to cause the Hall-petch effect is actually detrimental to the process and not something you want unless you are looking for an alloy that can be used to alloy with others. (Thus diluting the material).

Think of this in terms of crystal formation, if you have all the components to make a crystal lattice and you add additional material, it has to either expand the lattice or fit inside it in some way. Once you have enough material to saturate the lattice, the only option is to expand. (This should sound familiar as heat treated bullets also have a habit for growing in size).

In experimentation, I found that all of the grain refiners I played with were roughly equal in performance. The reason arsenic has been the preferred to date is cost. Many sources of lead worldwide are naturally contaminated with some small percentage of arsenic and smelters sell it as is unless the application requires the removal of it to produce chemical lead. So, wheel weight manufacturers didn't add arsenic to the product, they simply bought what was cheap because in their application having some small percentage of naturally occurring arsenic was not a detriment.

Depending on the source of the ore, that percentage can and does vary considerably. Even with that variation, all of those sources are generally considered arsenical lead and all I have played with have succeeded in creating hardenable alloys.

I might talk to my guys at the lab that helped with the analysis during the tests I did for the article and see if they would assay arsenic concentrations for me again for a new series.

In this test, I think start at .05% arsenic and work down by 1:1 dilution with linotype until you don't get hardening and see at what percentage the arsenic is.


Oh, and for the record, the article was originally written for http://www.castpics.net and it plenty of others are there. If you haven't bookmarked it and spent some time there yet, you are missing out on a great resource.

[btroj]

I generally add a handful of mag shot to a pot full and it seems to work fine. I don't think you need that much as Wiljens study shows.
I view this as a good example of "sometimes less is more".

[Defcon-One]

So we are back around a long circle of thought. Still it is clear that Antimony does the work, Arsenic is required to push it all along. The OP knew that all along as he asked, "how much arsenic do I need to add?"

I still say 1 ounce of magnum shot per pound of Isotope lead might do it! He can use 1.44 ounces per pound to get a true 0.10%.

The rest is fun to talk about, but does not change that fact.

Unfortunately, I can quote many articles that say Antimony is required for water quench hardening of lead bullets but they never mention Arsenic at all. Others say it has to be there. This is most likely because I now know that Arsenic is already in most of the metals that we use to alloy for and cast bullets already, either as an additive or more likely, as a beneficial contaminant.

[btroj]

I think an ounce per pound is a good starting point. Like Wiljen said, then go down from there. Don't use any more than is required.
I did find it interesting in Wiljens post that excess As may be a culprit in age growth of some alloys. Could that be why some people have seen this more than others? Or why it shows up only on occasion? Interesting to say the least.

[DrB]

Guys -- I'd just point out, again, that if the OP is using superhard for his alloy with isotope lead he probably can skip the shot altogether... and if it doesn't harden it's an easy fix.

I'll post back here if I get an answer as to how much arsenic superhard contains.

[btroj]

He never mentioned super hard in the OP. He asked how much magnum shot to add to the isotope containers.
I will agree that super hard will add the As needed for heat treating but I prefer to use magnum shot. Easier to get locally, easy to add in any amount needed, and I have it on hand.
In the end we can agree that it take a small amount of As to get hardening. How much is up to you, seems there is none to too much, anywhere in between works.

[tonyjones]

DrB,

I was surprised when you posted here that ROTOMETALS had informed you that SuperHard contained As. I have no reason to doubt you but ROTOMETALS describes SuperHard as 70% Pb and 30% Sb, without mention of As. I had always assumed that a foundry would supply material exactly as described on their site. As we've learned, it is entirely possible for Pb to contain incidental As.

lasc shows a recipe: 15# stick-on WW, 5# lino, 4 oz. lead shot and 9.6 oz. Sn that yields 95.75% Pb,1% Sb, 3% Sn and .25% As. I do not recommend having significantly more Sn than Sb in an alloy but quote their recipe to show how to obtain a usable amount of As in your alloy. lasc states that shot contains .5 to 1% As. Other reputable sources place the percentage somewhat higher, up to 1.5%.

I agree with btroj. Since I load shot shells and always have several hundred pounds of shot under my bench the matter of a source of supply is not an issue. Shot is also a lot easier for me to weigh and add to the mix than dealing with SuperHard ingots at 4 to 5# each.

Wiljen,

I look forward to reading the results of your latest experiments.

Best regards,

Tony

[UNIQUEDOT]

Thanks for helping me to understand this a little better guy's. I have bookmarked castpics and plan to do some more reading. The reason i asked about the mag shot is indeed because i have a lot of it on hand. I have some linotype, but am a bit greedy with it as i am almost out and most of my other lead is either pure or wheelweights that i have added linotype or magnum shot to. When adding mag shot to wheelweights i was in the past just dumping unmeasured amounts in the mix and achieving quenching hardness, but i figure i was wasting a lot of shot to achieve my goal and i remembered reading somewhere that an ounce per pound would work. Does anyone know if a higher antimony content in mag shot also has more arsenic? Some of my shot has 4% and some 5% antimony. I am almost positive that i have some in the shed that was for trap and it stated either 6 or 7%. I will have to look for it and see to know for sure, but i know for a fact that i have some old west coast with 5% antimony on the bags. Also the smaller the shot size the more antimony it contains.

[shotman]

As is a surfactant in the lead. As said very little is needed. It NEEDS to be there for a shotmaker . The isotope will not drop good shot Its hard but dont work for GOOD shot
Pure As, is not cheap last I got was $20 for 5 gm and that is about the size of a 222 bullet. As Wil said it is in WW because they get the cheap to start with. Sulphur has some in it and will work But the smell will run the dogs off .
As far as adding hardness that would amount to about a 22 LR bullet in 50lb. of lead

[Tinbullet]

Does all shot contain arsenic?

[btroj]

I think, not certain at all, that all shot has some As. I don't know if magnum shot has more or not. I think magnum shot has a higher Sb content is all.
Like was said, the As is in the shot to help make the pellets rounder. I can't see why regular shot needs to be less round that magnum.

[DrB]

Whoa, whoa...

Alright, I see what's going on here. You have an antimonial "isotope lead." "Isotope lead" radiation shielding lead that I have used (and have half a ton of I'm sitting on now) has only ever been pure (three 9's, I believe) elemental lead, totally dead soft.

I was trying to figure out what the heck you were talking about with an ounce of magnum shot -- that would provide about 0.2% antimony in an alloy with the "isotope lead" I use. The only reason to even add the shot would be to increase arsenic if you were adding antimony some other way.

An ounce of magnum shot would give you about 0.1% arsenic, and yes, that sounds just fine since you've already got your Sb, and yes, if you've got all that magnum shot around that's a no-brainer.

For me, that would make no sense though -- hence my superhard suggestion.



DrB,
I was surprised when you posted here that ROTOMETALS had informed you that SuperHard contained As. I have no reason to doubt you but ROTOMETALS describes SuperHard as 70% Pb and 30% Sb, without mention of As. I had always assumed that a foundry would supply material exactly as described on their site. As we've learned, it is entirely possible for Pb to contain incidental As
Tony

Tony, if you didn't doubt me you wouldn't have mentioned how surprised you were and the possibility of doubt in the first place. :) You are free to pick up the phone or keyboard and contact rotometals yourself. It ain't hard, and their customer service is good, so you should get a prompt reply, just like I did.

Reality is, that with or without a spec a foundry is going to have a variety of trace elements in varying concentrations in an alloy (a spec just places limits upon their concentration). Without a spec there may be "significant" additional constituents to the alloys... given rotometals reputation and professionalism, I would never expect them to be deleterious to the intended purpose of the alloy. In the case of rotometals superhard alloy, some arsenic is advantageous. 70% Pb 30% Sb is a guideline, and no doubt absolutely correct to the one digit of precision that has been stated.

Best regards,
DrB

[Tinbullet]

So far using a 50~50 mix of lead & linotype with 5% tin does not seem to water harden. I'll add some shot and test again Thanks

[geargnasher]

DrB, I don't know exactly what kind of nuclear medicine containers the OP has, but many of them are NOT pure lead, in fact have a nice blend of a few percent antimony and at least a couple percent tin. Problem is they are short on grain refiners, so a handfull of shot might be the ticket to help hardness and shorten the aging process. I got a couple of "large isotope containers" from one of our vendor sponsors last year just to mess with, and I found that the stuff is wonderful but takes about two months to reach it's (for practical purposes) maximum, air-cooled hardness. My explanation was that it was short on arsenic. When alloyed 50/50 with clip-on wheel weights, that time goes to two weeks.

Gear

[DrB]

Thanks for helping me to understand this a little better guy's. I have bookmarked castpics and plan to do some more reading. The reason i asked about the mag shot is indeed because i have a lot of it on hand. I have some linotype, but am a bit greedy with it as i am almost out and most of my other lead is either pure or wheelweights that i have added linotype or magnum shot to. When adding mag shot to wheelweights i was in the past just dumping unmeasured amounts in the mix and achieving quenching hardness, but i figure i was wasting a lot of shot to achieve my goal and i remembered reading somewhere that an ounce per pound would work. Does anyone know if a higher antimony content in mag shot also has more arsenic? Some of my shot has 4% and some 5% antimony. I am almost positive that i have some in the shed that was for trap and it stated either 6 or 7%. I will have to look for it and see to know for sure, but i know for a fact that i have some old west coast with 5% antimony on the bags. Also the smaller the shot size the more antimony it contains.




So far using a 50~50 mix of lead & linotype with 5% tin does not seem to water harden. I'll add some shot and test again Thanks

Can you guys talking about using "lead" and "isotope lead" please confirm that you are not talking about pure lead, but antimonial lead?

[DrB]

DrB, I don't know exactly what kind of nuclear medicine containers the OP has, but many of them are NOT pure lead, in fact have a nice blend of a few percent antimony and at least a couple percent tin. Problem is they are short on grain refiners, so a handfull of shot might be the ticket to help hardness and shorten the aging process. I got a couple of "large isotope containers" from one of our vendor sponsors last year just to mess with, and I found that the stuff is wonderful but takes about two months to reach it's (for practical purposes) maximum, air-cooled hardness. My explanation was that it was short on arsenic. When alloyed 50/50 with clip-on wheel weights, that time goes to two weeks.

Gear

Thanks Gear -- yeah, I'm guessing TJ at least is talking about antimonial lead "isotope lead." For what it's worth, I started wondering what folks calling it "isotope lead" might mean other than what I meant, and I found a source via google that suggests that something like 1/8th of "isotope lead" is pure elemental lead, and the rest antimonial.

My shield lead is in brick form, about 26 pound per brick, and "brickish" in size. :) It's the pure Pb stuff.

It's still not completely clear to me what the other guys here talking about "lead" or "isotope lead" are using...

I'm pleased at the prospect of only having to use "superhard" and not use any of my shot... but I guess I'm probably only 1/8th of the population out here using this "isotope lead." :)

[felix]

One thing for sure, guys, stuff at three 9s gets us into the lab grade circles. The price for the arsenic as stated by the shotman might be quite low nowadays. I don't know without looking at my catalogs. Aldrich Chemical is a typical supplier for labs and their prices even twenty years ago will make you a true believer in junk acquisitions for shooting back into the ground. I have shot the hospital canister boolits and there is something in it that does make it cast 22 boolits quite well, in fact, exceptionally well. I used my 20 pounds or so up years ago, so todays canisters might be lead as delivered by the likes of Doe Run and others. However, they WOULD alloy it enough to make the canisters without hassle. Consider the dose of isotope given for a PET scan costs the hospital 1800 bucks delivered, so looking at the price of a shipping container means nothing. The cancer cells think this isotope, whatever it is, is pure sugar. Need to research this sometime, but I know it took researchers several years to find this one isotope. ... felix

[UNIQUEDOT]

DrB, I don't know exactly what kind of nuclear medicine containers the OP has, but many of them are NOT pure lead.
Gear

The isotope i have is in the form of a couple cores that i just picked up from starbits on the forum. It definitely has antimony in it.

[tonyjones]

The isotope lead that I'm familiar with is either 96/3/1 Pb/Sb/Sn or 95/2.5/2.5. There may be others but I've yet to encounter them. I believe that these are the containers that the isotopes used in radiation therapy are shipped and stored in.

I believe that the amount of As in lead shot will vary more between manufacturers than between chilled or magnum shot. The Sb content of shot will be 1 to 2% for chilled and 2 to 6%, or so, for magnum. The smaller shot sizes (7, 7.5, 8, 8.5, 9) generally have higher Sb content.

Tony

[DrB]

UniqueDot:

Then disregard all my chatter about "superhard" (I was thinking of pure elemental lead only). You probably just need the arsenic from the magnum shot as has already been pointed out several times. :)

I'm still curious about the actual arsenic content of RM "superhard" for alloying with pure lead, and whether it is sufficient to enable water quenching without any shot, as I expect. I'll post that to a different thread when I get a round tuit. :)

Best regards,
DrB

[geargnasher]

Me too, DrB. Please let us know what Rotometals has to say about the As content of Superhard.

Gear