cmk
09-20-2018, 03:31 PM
I've read stickies, and tried a bit of googling, but there are just too many possible varieties, so I thought it prudent to ask.
Before even getting ANY casting gear, I came across a guy who was parting with some lead/alloys at a reasonable price. It all came in form rather large bricks 30-50 lbs each. As I have now started smelting it into smaller ingots, I have made some interesting discoveries regarding one of the alloys.
It melts a really(?) low temp, fully liquid at 350F / 175C, but below that it was getting slushy. Not much oxidation forming on the surface (but then again, it was not running particularly hot, say 450-480F). Poured some ingots and as they were cooling/solidifying, it seemed like it was it was actually two (or more) distinct metals, i.e. like mercury floating 'through' the otherwise solidified ingot when tilting the mold back and forth. Don't really know how to describe it better than that. And it takes a long time to solidify fully. A couple of minutes at least.
Once fully solid on the surface I turned the mold upside down, and it dropped out quite nicely, but leaving slight smears in the mold as it was probably quite close to the melting point for one of the metals. Came out sort of shiny on the surface, but quickly (1 minute) turned into a frosty white colour,
Interesting thing is that the original brick looked and felt more like pure lead, i.e. dull gray and easy to dent with a light hammer blow, but in its new ingot shape it is slightly a different story It seems a little harder, and when water quenched, it seems a little harder still. I have no equipment to do any real BHN test. It will scratch with a nail (carpentry, not finger), but it's possible to polish away the 'frosting' with a nail (finger variety). That area then stays shiny for at least a week (maybe forever - time would tell).
Is there any way to figure out what it is? Or could anyone come up with a guess? Or some other type of test that could be done to determine its contents? Since I don't yet have a bullet mold, I cannot accurately measure shrinkage compared to a pure lead bullet or something like that. The one remaining brick has a density of 11.89 if that can help determining things.
EDIT: I realize now that such a density would higher than pure lead, and there was probably something wrong with my calculation/measurement. Unless there is tungsten or uranium in the mix. But that would not explain the low melt temp. /EDIT
I contacted the seller and he did not really know either (he got it from work, but I don't quite recall what he said he worked with), but he admitted it was a bit hard to cast with, and he had himself mixed it with ~30% pure lead for more reliable results.
Anyone up for a guess?
Thanks in advance.
cmk
* Edited for factual errors
Before even getting ANY casting gear, I came across a guy who was parting with some lead/alloys at a reasonable price. It all came in form rather large bricks 30-50 lbs each. As I have now started smelting it into smaller ingots, I have made some interesting discoveries regarding one of the alloys.
It melts a really(?) low temp, fully liquid at 350F / 175C, but below that it was getting slushy. Not much oxidation forming on the surface (but then again, it was not running particularly hot, say 450-480F). Poured some ingots and as they were cooling/solidifying, it seemed like it was it was actually two (or more) distinct metals, i.e. like mercury floating 'through' the otherwise solidified ingot when tilting the mold back and forth. Don't really know how to describe it better than that. And it takes a long time to solidify fully. A couple of minutes at least.
Once fully solid on the surface I turned the mold upside down, and it dropped out quite nicely, but leaving slight smears in the mold as it was probably quite close to the melting point for one of the metals. Came out sort of shiny on the surface, but quickly (1 minute) turned into a frosty white colour,
Interesting thing is that the original brick looked and felt more like pure lead, i.e. dull gray and easy to dent with a light hammer blow, but in its new ingot shape it is slightly a different story It seems a little harder, and when water quenched, it seems a little harder still. I have no equipment to do any real BHN test. It will scratch with a nail (carpentry, not finger), but it's possible to polish away the 'frosting' with a nail (finger variety). That area then stays shiny for at least a week (maybe forever - time would tell).
Is there any way to figure out what it is? Or could anyone come up with a guess? Or some other type of test that could be done to determine its contents? Since I don't yet have a bullet mold, I cannot accurately measure shrinkage compared to a pure lead bullet or something like that. The one remaining brick has a density of 11.89 if that can help determining things.
EDIT: I realize now that such a density would higher than pure lead, and there was probably something wrong with my calculation/measurement. Unless there is tungsten or uranium in the mix. But that would not explain the low melt temp. /EDIT
I contacted the seller and he did not really know either (he got it from work, but I don't quite recall what he said he worked with), but he admitted it was a bit hard to cast with, and he had himself mixed it with ~30% pure lead for more reliable results.
Anyone up for a guess?
Thanks in advance.
cmk
* Edited for factual errors