New alloy

[Brad]

Copper really does one thing, it adds toughness. Not hardness, toughness. It helps make the alloy handle impact without fracturing well.
I haven't used copper in that low a concentration. I have an inkling that it would work well in an alloy with around 2 % Sb.

 

[Brad]

by the way .. that hollowpoint design you cast and posted pics of is nice. The 3 crimp grooves would give you some definate load versatility

That it does. I seat it long as possible for my Super Redhawk and short as possible for my 444 Marlin.

 

[Warren4570]

444 nice round highly under rated
Thanks for the input so far on this ..appreciate it.
Nowwhile handling impact and helping reduce the tendancy to fracture does the alloy still rivet or mushroom the same way as a non enriched alloy ?

 

[Brad]

I haven't shot enough yet to really know? I would expect similar riveting and possibly a slight reduction in overall expansion. Some of that is dependent upon Sb content, or at least that is my understanding.
I haven't shot much copper added alloy, mostly because of the cost of the copper Babbitt. I'm cheap.

 

[Warren4570]

What temp did you cast at ? Had read that one gent was casting a similar alloy about 700F but it would think that cooking the Sn out of the alloy would then become a concern.

 

[Brad]

I ran it at 725F. It poured fine with the ladle. It might need a bit more in a bottom pour.

 

[Warren4570]

Thanx for that Brad. I am also researching other elements alloyable with a pb sb sn blend looking towards creating a tougher alloy. Mostly out of curiousity more than anything and looking for a better bullet. Creating a blend and testing it is part of the science and the fun of this.
A local supplier that resmelts and recycles battery plate alloy has interesting options with PbSb alloys of various percentages. Leaving the Sn and other elements to be added.
Again most here supply a 92 6 2 or a 91 7 2 alloy .... bit too much Sb I think to not be concerned about brittleness.

 

[Brad]

92/6/2 is easy to cut 50/50 with pure lead. Heck, even going 40/60 would be fine for my needs. Getting the Sb below 3 % makes me much happier for hunting bullets. Heat treating gives me plenty of hardness and accuracy at velocity.

 

[Warren4570]

Does silver add toughness as well ?
Had a line on some Sn Cu Ag solder as well.
That seems like it may be a interesting source of alloying material providing the sought after properties were realized in the end result

 

[Brad]

I don't see silver as a bad thing, other than possibly more expense. It should behave pretty similar to copper based on the periodic table. That is an assumption on ,y part, no experience to back it up.

 

[fiver]

silver adds a hardness similar to copper but is much more soluble.
I'd bet there are a jillion old silver dimes stashed away by some old time casters thinking that one day they'll get around to making an alloy out of them.

copper forms a matrix with antimony similar to the one tin does only it's a stronger bond and won't manifest itself on the surface unless you get the antimony to migrate as well.
a good alloy is one with the antimony content as high [or slightly higher] as the copper and tin added together.

 

[Warren4570]

Fiver / Brad thanks for the input again .....

Well all of this got me thinking and readin ..... alot of reading... love metalurgy but wish I had of gotten more of it in trade school. Find myself relearning a lot of things but that keeps the mind active. The science of this is quite facinating.

The quest for a low SbSn alloy that is very tough and malleable and one that heat treats well is driving this. A super tough alloy as opposed to a super hard alloy. One that can be shoot fairly hot to really hot out of both the 454 cassul and the 45-70. The 350 gr in the 45-70 I am hoping to work up to about 2200fps and eventually a stout 405 to 500 gr load as well (live in grizzly country). I dont think hardball (2-6-92) will get me there and reliably survive the impact.

Not to mention that it helps pass some time at night while working in camp. The opinions of others in a forum such as this also helps as well.

Got into an article on the LASC site and few others about grain refiners ..........sulphur... selenium... arsenic and copper. Silver also happens to be one of those. Found that a lot of lead acid batteries also now contain these grain refiners / property enhancers due to advances in technology and the cost of alloying elements.
So
Ive contacted a battery recyclying facility that resmelts the lead from the battery plates.They recycle the meterial to 99% pure Pb, various 2% + antimony blends and due to the newer technology in low antimony battery maufacture copper seems to be one of the alloying elements as well. It also helps that they can smelt out most of the nasty gasses and other things we would not want to deal with going after these types of lead sources ourselves.

Batteries although different by use need fairly hard plates in order to work and survive their operating environment. Casting alloys for us also seem to be able to take advantage of these advances. As it would seem that a BHN of 12 is possibly common and these alloys also age harden and heat treat well.

In discussion it appears that the sulphur is fluxed out of the alloy as it is reclaimed however that could be added back into it again. Sulphur seems to have wetting properties similar to tin (if I am not getting my wire crossed after all of this reading) and along with the other elements Se As Cu and Ag also has some grain refining properties. It also seems that a lot if the refiners add to both age hardening and the toughness.

I took what you suggested Brad and looked at a 2%-3% Sb alloy into the coversation and it appears that they have a 2.75% Sb alloy available.
This low antimony alloy also has Se (selenium) one of the elements I was looking for.
Se as low as .03% along with the Sb seems to have very positive effects on a lead alloy .
Now I need to figure out at what content As starts to become benefical to a lead alloy.
The Cu content is also one of the things that i am trying to figure out where it becomes beneficial for toughness .05% .1% ? dont know yet still a lot to figure out. (thats where forums such as this help out a lot)

Going to work on this some more over the weekend and send some info to these folks and see what comes of it when I talk to them next week.
The goal so far is a 2-3.5%Sb 2%Sn .05-.1%Cu .03%Se alloy with the balance Pb. May even look at close to equal Sb Sn content. A little more research may help with the other element levels.
The main advantage I have in going this way is that they have a PMI machine there (posistve material identification) so the base alloy is known to start with.
I've used them at work analyzing pipe and weld deposits... quite cool.
From there I can add / remove elements as needed, by blending with Hardball,pure Pb, magnum shot, solder etc.

If anyone thinks that some of the research and tables that I have are useful I can try and sort them out in a useful fashion and post.
Sorry for the long post just found this real interesting and thought I would share it here.

 

[Rick]

It is interesting, thanks for the write up.

From the metals industry papers I've read adding arsenic in percentages over about .5 to .75% won't increase it's effectiveness as a grain refiner. It doesn't take a lot of it, it just needs to be there. Yes most of the elements you mentioned are grain refiners.

 

[Brad]

The guys who have done the most work on Cu alloys found that Sb needs to be pretty close to equal to Sn+Cu. getting too far out of whack in favor of Sn and Cu gave bullets that tended to grow with age.

I have always adjusted my alloys to be as close to that balance as possible. I figure that the guys who had done the most work with it might well know what they are talking about.

 

[fiver]

Arsenic starts working at levels as low as .12 ww's usually contain 0.2[4ish] or more than needed to work however it is more effective at the higher percentage.
sulpher is also a grain refiner and super easy to add, it is also a good cleaner of the alloy and can pull zinc out.
be aware that if you are pulling zinc from an alloy you are also pulling tin along with it.

copper seems to work the best and is easiest to cast with at a solution of 0.3% you can of course add more but it becomes a different set of casting rules at that point.
one of the things I found was I could hold pretty high solutions of copper in a lead alloy if I used about 3 times the amount of Tin in the alloy.
something like 3% copper took about 10% tin.
Tin is also a good grain refiner in a lead alloy if you keep the amounts in the .25% area.

you could make a pretty serious high velocity alloy if you started from scratch and added sulpher/zinc/copper/bismuth/silver/tin and antimony in small amounts [all at or below 1%] except the antimony of course.
cobalt is also something that is a good addition to lead alloys if it's in the super low concentration level area too. [like 0.1%]

 

[Brad]

Just got a message from Edd regarding the copper alloy.
I had it backwards. You want tin to equal copper plus antimony.

When Edd speaks regarding this alloy I listen. He has certainly done far more work with it than I have.

 

[Warren4570]

This is a micrograph of a Pb 2.5Sb alloy and a Pb2.5 Sb .0015Se (selenium) alloy compared. Just to show the refining effect of the added selenium and its effects.
Looking forward to talking to the supplier tomorrow and finding out what they have to say re the alloy make up of the 2.5%Sb alloy they make. Hopefully I will be able to get some good information from them.

Thinking too that even if the Sulphur pulls out a bit of tin and there is some selenium in the mix one would think that effects of the 3 elements together would still have a positive effect on the final alloy.
That and Cu + Sn <= Sb and up to .25As should yield a tough alloy that may suit what I am looking for and may even be good for HV cast bullet shooting.

 

[Warren4570]

Ok ... yes I have read quite a bit of Edd's findings as well and that is some of where this all started .. amongst a lot of other research
it would easy enough to adjust the mix either way ... But if Edd's findings are Sn = Cu + Sb that should be easy enough to do as well.
Cu has an affinity for Sn but will also combine with Sb.

 

[Warren4570]

However isnt the general rule of thimb that Sn not exceed Sb?

 

[Brad]

This alloy is unique. The copper works with the antimony and if there isn't enough tin it gets wonky to cast. Edd says his work has shown that balancing the tin to equal antimony plus copper works best.

He also said we need to not think of copper as adding hardness but rather it adds a toughness that lets it handle pressure better. It can be shot at higher pressures with good accuracy. The added benefit is that the bullets tend to stay together well on impact.