New alloy

[Tony]

There have been several threads concerning Cu enhanced alloy at the CB forum. Several members from Michigan had done the most experimenting in this area. Cu is a grain modifier in mush the same way as As is. Mike (357Maximun) reported shooting cast bullets with Cu enhanced alloy in his .35 Whelen at the same velocity and accuracy as jacketed bullets. He also reported that damage to deer shot with bullets cast from those alloys was so severe that he dropped the velocity by about 200 fps mv before continuing the practice. badgeredd reported that some of their loads were generating an estimated 50k to 60k psi. Reportedly, bullets from their alloy were holding up to the pressure. edd gave me an alloy recipe but I can't seem to locate it right now.

I'm interested in this topic for future experimentation, however, nothing I'm currently contemplating in the way of shooting cast bullets will get me anywhere near 50,000 plus psi so this is a back burner project as far as I am concerned.

 

[Craig Duncan]

Thanks Warren!
I was getting ready to put in an order with Roto Metals as I'm nearly out of 20-1 after casting 1200 bullets for my wife.
now I can add to that order and start experimenting.

Craig

 

[AKbushman51]

Tony- The recipe I have from Edd was 2.5lbs Pb, 6 Lbs COWW, 1/4 Lb Roto #3. According to Bumbo's calculator the Alloy worked out to Sn- 2.71%, Sb- 2.3%, As-.17%, Cu- .24%, Pb 94.6%. Hope that helps. Can't tell you how it worked out, still testing. Gotta wait for the berms to thaw. bushman

 

[Craig Duncan]

I'd like to thank everyone here for their input.
I placed an order today with Roto metals for a bunch of 30-1, some #2 and a couple of ingots of babbit alloy and pewter alloy.
I'm not sure how I'll blend it all up yet, but I do want to drive some old antique loverin bullets at modern jacketed velocities.

Craig

 

[AKbushman51]

Gentlemen- Been watching this thread on Cu enhanced alloys and on the CB site. Been trying Edd's alloy, but questions arise. Is it Cu+Sn=Sb or Cu+Sb=Sn? When using Edd's alloy I get alot of oatmeal looking dross after just a few casts, flux back in, cast a few more (~10) and same dross appears. I cast at 720 deg (PID controlled pot), and WD. Now I can take that alloy minus the Roto #3 (substitute 95/5 lead free solder) cast all day no problems. Also the Cu boolits take a real long time to harden up, whereas the minus Cu boolits are hardening fast 3-4 days @ 20+ BHN. (LBT Tester).
So is the oatmeal dross just Cu drossing out because not enough to bind to? This situation happens at even higher casting temps (up to 780 deg) only difference is it dross happens faster at the higher temps. I will mention that the COWW is from the same batch, as is the Pb for both Alloys. The only difference is the Roto#3.
Edd's alloy- Sn- 2.71%, Sb- 2.3%, As- .17%, Cu- .24%, Pb- 94.6% (Bumpo's Calculator)
Mod alloy- Sn- 3.06%, Sb- 2.2%, As- .17%, Cu- 0.0% Pb- 94.6% (Bumpo's Calculator)
Is the equation balance that critical? All ingredients are weighed, and COWW were tested No Zn. I've tried all manner of stuff to keep O2 from the top of the melt, to reduce the drossing situation,
at present using lots of paraffin when starting melt, let melt and smoke/burn off till getting a thin layer of Carbon that stays on top. Seems to help a little, but that dross still occurs with the Cu alloy.
Thoughts Gentlemen?
bushman

 

[Rick]

Bushman, I've never messed with copper in the alloy but the only silvery oatmeal I've ever gotten on the melt was Sb, not copper. I've only ever been able to get that rarely and only when the alloy heats up very slowly. With the different melt temps of Pb, Sn and Sb I theorized that the Sb was melting last and forming on the surface.

As a side note sprinkling sawdust on top of the "silvery oatmeal" and it disappeared nearly instantly, didn't even stir yet, just kind of sucked right into the melt. Kind of an amazing thing to see actually.

 

[AKbushman51]

Rick- I'd never thought of using sawdust in my casting pot, (Bottom Pour) in my smelter, yes. Well anyway, I did my paraffin thing, added a little sawdust, it bubbled up a little, and no oatmeal. Go figure. I have no idea what that dross is, but the ash residue kept that oatmeal down to virtually nothing, was able to cast for an hr no problems. Thanks again. bushman

 

[Rick]

Some complain about getting sawdust in the spout of a bottom pour but I can assure you that is impossible unless you physically force it under the melt with the ladle or spoon. That is incorrect fluxing anyway, leave the sawdust on top of the melt and use the spoon to bring up alloy from below the surface and pour it through the sawdust and you will be a happy camper.

 

[Ricochet]

After reading y'all's reports about fluxing with sawdust for years over on CB I've recently started doing it. I like it. Good tip about spooning up the melt onto the sawdust. That's not the way I started, I was trying to stir it down into the metal.

 

[popper]

From Rolf Koring General Manager ECKA Granules Essen GmbH Bearing Technologies Essen, Germany
"Up to a concentration of approximately 0.7 percent, zinc causes an increase of the compressive yield
strength of approximately 1800 psi."
"When increasing the content of antimony, the solubility limit of antimony in tin is exceeded as soon as 8 percent is reached. Cubic SbSn crystals will then form. This does not limit the above statement about the increase of the compressive yield strength, but the cubic SbSn crystals may lead to restrictions in the dynamic impact load of the material"
"Each additional percent of antimony or copper increases the compressive yield strength by about 500 psi."

I realize the article is about tin Babbitt. We now Sb tends toward brittleness, apparently SbSn does also, Cu increases strength with malleability. My thinking is a fraction of Cu & Zn in low Sb alloy will be strong and tough enough (dynamic impact) & is CHEAP.

I normally use 4/0.5 Sb/Cu @ 2700 165gr GC 308W, 3/0.5/0.5 Sb/Sn/Cu for 145 gr PB @ 2100 in the BO. Shot a 165 TC 40SW 3/0.5 Sb/Cu into a rock pile from 10', recovered looked like a WC & lost < 2% weight. Same boolit went end to end on a 150# hog and broke a leg on the way out. I did cast some 3/2 Sb/Cu that dented a bar of superhard. They shot fine in the BO. I sized immediately, PCd & H.T.d
I generally don't use any Sn, but didn't convert all from the isocore for the BO & 30/30.
Next experiment is to toss some pennies into the pot for the 0.7% Zn, along with the pure to get 2% Sb.
Edit: tried adding the Zn today, got ~ 1 1/2# of stringy oatmeal stuff off the top. Added 4# pure to what remained, used Zepp to de-Zn. Started out with the 308W alloy (~5% Sb, 1% Cu), muffin'd 6#, added 4 pennies, muffin'd out the goop, added 4# pure, Zepp'd, muffin'd another 6#. Left what remains in the pot for 40SW to try.

 

[KHornet]

Would have bought a star a long time ago, but I am cheap, old fashioned,
set in my ways and traditional. Guess that about says it all.

Paul

 

[popper]

Cast some from the remaining alloy, 40sw. Shiny, good fill out, soft, spruce froze almost as soon as I poured. Acts like 60/40 solder but NO tin. Just a few normal hits from a hammer - doesn't pour or act like pure. Weird. Oh, Lee 175 mould, weighs 185. Can't bend the smashed one by hand. pounded another flatter today, ~ 0.020" No signs of frayed edges/scaling. Basically Pb/Cu alloy, very malleable. Might try casting a 185GC with a smidge of 1680 for the BO, just to see what it does. Should be good for low psi BP.

 

[popper]

Shot that alloy today in 40SW, 4.5gr 231, BLL. No leading, no tipping, seemed to go where I aimed. Couldn't tell any difference between the isocore or this alloy. No expansion I could mic from 3/4" fiber backer. Figure I'm close to 30K psi.

 

[fiver]

Popper I'm watching I just ain't got anything to say right yet.

 

[popper]

Cast some WD in 170 & 185 this morning, haven't decided 30/30 or BO. Fill out was excellent, I noticed the PID swung up to 740F. If I get a chance I'll cast a bunch of 165 for 40sw tomorrow. I tried pure with some tin years ago in the 40, results were bad. Don't really know what I have but was pleasantly surprised by the initial results.
Edit: Pounded that piece flatter (0.030"), still no breakage, splits, etc. 2nd coat of BLL is drying on WD 165s that I'll load at max jacketed with 231. Using the BLL as that will give alloy properties - I normally hitek. also doing the 170 & 185 for the 30/30 - pressure is too high with the BO (I think). Not a very good pistol shot but accuracy results @ 7-10 yds should tell the story.

 

[Brad]

Popper, how much root killer is needed to "treat" say 40 pounds of alloy?
I know there isn't an exact answer but I'm curious. I have lots of range scrap crap with about 1.75% Sb and little tin. I'm wondering if a little copper might give me a tougher bullet. The root killer is certainly cheaper than adding Babbitt.

 

[popper]

Add Sn & Zn % = Cu %. Cu replaces Zn/Sn atom per atom. Pure will take 0.3% Cu as solid. I started using 5 x the weight of Zn/Sn of Zep. Cu will alloy with Sb for real hardness, heat treats very well. As example, I used isocore (3%Sb, 1%Sn), added 1% Sn. Used Zep till it wouldn't take anymore so 2% Cu. It shot fine and dented bar of super hard. With higher Sb you could go to 6% Cu.

 

[Tom]

Not having any background in metalurgy, this stuff makes my head swim. I played with Popper's method before but put it aside. I had no idea how much copper I was getting in the mix. Reading the above, I THINK I'm getting it figured out.
Let us say I am trying to get 20 lbs of ww with a copper content of .0024. Would I be accurate in starting with 20 lbs ww, adding .385 oz each of sn and zn, then using 3.85 oz zep root killer to add the cu and remove the added sn/zn? I'm pretty sure this would not be an ideal alloy, but I'm trying to figure out how to quantify the amount of cu added with this process.

 

[popper]

If you add 0.385 oz of tin & zinc you will have 0.77 oz of Cu. in your alloy, no matter how much Zep you add. No matter how much Pb you have. Sorry, tin weighs 2x Cu or Zn. You cannot make sulfuric acid with this process. Sulfur is absorbed by Pb, like using it as a hardener, remedy and you get a sulfur smell.

 

[Tom]

Thanks. I was thinking weight for weight, even though you clearly said molecule for molecule.