JimGnitecki
Member
- Joined
- Mar 28, 2010
- Messages
- 1,258
I was given abouy 50 lb of pure Lead some time ago, and needed a way to make a Lead alloy that would have a BHN = about 12, for use in my Pedersoli Sharps replica. A few weeks ago, someone here on the forum suggested I try using Rotometals "Super Hard" as an alloying ingredient.
Super Hard is a 30% Antimony / 70% Lead alloy that requires a "real" smelting facility to create, since pure Antimony does not melt until you hit 1166 degrees F! Rotometals offers SuperHard in 5 lb ingots, and currently has it on sale at about $24 /lb plus shipping (I live in Canada, so no free freight). It has a hardness of BHN = 36.
An article at the Los Angeles Silhouette Club (LASC) recommends Super Hard very highly for creating alloys of specific BHN targets. And, I checked with Rotometals by phone about how best to break down the 5 lb ingot into manageable chunks of weight for accurate alloying, and was told that I can simply melt the entire 5 lb ingot in a normal "home" casting furnace, as the Antimony-Lead alloy DOES melt at 650F, and "is homogeneous with your base alloy and thus blends in with your melt quickly and easily with your final flux before casting", just as the LASC article states. I melted the entire 5 lb ingot in my Lyman Mag 25 furnace, and poured it into ingot molds in weights ranging from 0.1 lb to 1 lb, so that I could mix up Lead alloys of virtually any Antimony percentage.
I used the "alloy calculator" available at the Castboolits website to determine what percentages of Lead, Tin, and Super Hard would make a suitable alloy. The calculator did all the tiresome percentage calculations. For ease of weighing out the individual components, and to have a large enough batch to reduce any errors due to some remaining earlier alloy in the pot that would not pour out through the bottom valve due to insufficient head pressure, I settled on this cobination for my test alloy batch:
Lead = 10 lb
Super Hard = 1.5 lb
Tin = 0.2 lb
Total = 11.7 lb
Per the calculator, this should produce an alloy that is:
94.4% Lead
3.85% Antimony
1.71% Tin
BHN = 12.6
After alloying these individual component metals in the Mag 25, and mixing throughly, I poured the various sizes of ingots mentioned earlier. After waiting an initial 10 hours to take hardness readings on 2 of the ingots with my Lee hardness tester, and then repeating the testing at 24 hours after the alloying, and then again at 48 hours after alloying, I have found that indeed the BHN test results range from about BHN = 12 to BHN = 13.
Using only "clean" components (Lead known to be relatively pure, Super Hard from Rotometals in The U.S., and Tin from Western Metals here in Canada), there were NO impurities brought to the surface - just a nice shiny alloy surface, making the whole process nicer than when alloying wheel weights.
Super hard is not "cheap", even at the sale price of $24US / 5 = almost $5 per pound US = $7 Canadian, plus shipping. And Tin is remarkably expensive here in Canada right now, costingabout $70 per lb plus shipping. Nevertheless, I calculated that, even with the costly shipping, my cost per FIVE HUNDRED grain bullet is sitll only $.18 Canadian = $.13 US. Right now, I cannot even GET commercially cast 500g bullets, but even if I COULD find them somewhere, they would cost $1.00 Canadian each, plus shipping. And, of course, on commercially bousht bullets, I would have little or no choice on the design of the bullet provided, whereas casting my own, I have found, and now use, the mold whose bullet my Pedersoli likes.
Yes of course using wheel weights would have cut the cost even more, BUT when I asked the manager of my local tire store about current wheel weight availability, he said that for both legal and liability reasons, NO tire stores in Canada now use lead wheel weights. The current universal solution is to use plastic coated stick-on weights of unidentified and varying composition. So, the only Lead wheel weights still available are leftovers that some scrap yards and some individual users might still have (like the 50 lb of pre-1990 wheelweights my buddy gave me). And of course Linotype is similarly now available by only "legacy" sources.
So, like it or not, the Lead, Antimony, and Tin we need to make cast bullets are now ALL either hard to get, or very costly, or both. So, products like Super Hard from Rotometals, and Tin from places like Western Metals, are going to become increasingly important to us and our shooter descendants, whether we like it or not.
Jim G
Super Hard is a 30% Antimony / 70% Lead alloy that requires a "real" smelting facility to create, since pure Antimony does not melt until you hit 1166 degrees F! Rotometals offers SuperHard in 5 lb ingots, and currently has it on sale at about $24 /lb plus shipping (I live in Canada, so no free freight). It has a hardness of BHN = 36.
An article at the Los Angeles Silhouette Club (LASC) recommends Super Hard very highly for creating alloys of specific BHN targets. And, I checked with Rotometals by phone about how best to break down the 5 lb ingot into manageable chunks of weight for accurate alloying, and was told that I can simply melt the entire 5 lb ingot in a normal "home" casting furnace, as the Antimony-Lead alloy DOES melt at 650F, and "is homogeneous with your base alloy and thus blends in with your melt quickly and easily with your final flux before casting", just as the LASC article states. I melted the entire 5 lb ingot in my Lyman Mag 25 furnace, and poured it into ingot molds in weights ranging from 0.1 lb to 1 lb, so that I could mix up Lead alloys of virtually any Antimony percentage.
I used the "alloy calculator" available at the Castboolits website to determine what percentages of Lead, Tin, and Super Hard would make a suitable alloy. The calculator did all the tiresome percentage calculations. For ease of weighing out the individual components, and to have a large enough batch to reduce any errors due to some remaining earlier alloy in the pot that would not pour out through the bottom valve due to insufficient head pressure, I settled on this cobination for my test alloy batch:
Lead = 10 lb
Super Hard = 1.5 lb
Tin = 0.2 lb
Total = 11.7 lb
Per the calculator, this should produce an alloy that is:
94.4% Lead
3.85% Antimony
1.71% Tin
BHN = 12.6
After alloying these individual component metals in the Mag 25, and mixing throughly, I poured the various sizes of ingots mentioned earlier. After waiting an initial 10 hours to take hardness readings on 2 of the ingots with my Lee hardness tester, and then repeating the testing at 24 hours after the alloying, and then again at 48 hours after alloying, I have found that indeed the BHN test results range from about BHN = 12 to BHN = 13.
Using only "clean" components (Lead known to be relatively pure, Super Hard from Rotometals in The U.S., and Tin from Western Metals here in Canada), there were NO impurities brought to the surface - just a nice shiny alloy surface, making the whole process nicer than when alloying wheel weights.
Super hard is not "cheap", even at the sale price of $24US / 5 = almost $5 per pound US = $7 Canadian, plus shipping. And Tin is remarkably expensive here in Canada right now, costingabout $70 per lb plus shipping. Nevertheless, I calculated that, even with the costly shipping, my cost per FIVE HUNDRED grain bullet is sitll only $.18 Canadian = $.13 US. Right now, I cannot even GET commercially cast 500g bullets, but even if I COULD find them somewhere, they would cost $1.00 Canadian each, plus shipping. And, of course, on commercially bousht bullets, I would have little or no choice on the design of the bullet provided, whereas casting my own, I have found, and now use, the mold whose bullet my Pedersoli likes.
Yes of course using wheel weights would have cut the cost even more, BUT when I asked the manager of my local tire store about current wheel weight availability, he said that for both legal and liability reasons, NO tire stores in Canada now use lead wheel weights. The current universal solution is to use plastic coated stick-on weights of unidentified and varying composition. So, the only Lead wheel weights still available are leftovers that some scrap yards and some individual users might still have (like the 50 lb of pre-1990 wheelweights my buddy gave me). And of course Linotype is similarly now available by only "legacy" sources.
So, like it or not, the Lead, Antimony, and Tin we need to make cast bullets are now ALL either hard to get, or very costly, or both. So, products like Super Hard from Rotometals, and Tin from places like Western Metals, are going to become increasingly important to us and our shooter descendants, whether we like it or not.
Jim G
