brnomauser
04-02-2011, 06:03 AM
I've just had my second go at casting with mixed results. As discussed in my previous post - http://castboolits.gunloads.com/showthread.php?t=106134 it appears I needed to flux. I was losing a lot of (I assume) antimony and other wanted impurities from my 50/50 Pb/Linotype. It would just appear on the top as powdery crud.
So this time round, I added some parrafin wax and sawdust and stirred a lot. It didn't seem to be going back in, so I started casting anyway. Bullets were horrible - filled with little black particles and voids. I may have got it a bit warm - When I offered a bit of rolled newspaper it caught alight as soon as it hit the melt. When I added more wax or sawdust it burst into flame. It was going all shades of colour then I suspect I saw the melt start to give off vapours. I killed the fan (it's a coal powerd forge) and left it for a while to let it cool a bit.
Then I skimmed all the crud off - which amounted to a lot and kept casting. Bullets were then absolutely perfect - very well filled out, sharp bases and well defined grooves. But now I'm suspicious they'll be really soft as I suspect most of the hardening impurities have been lost. No more started coming out of the melt at the lower temperatures, but is that because there wasn't any left... It was still casting very nicely even when I tried the newspaper thing again and it hardly charred at all.
Does anyone have any suggestions as to how I can reintroduce the anitimony etc. or prevent it in the future? I have more linotype un-smelted.
I know I should buy a thermometer really but I don't have a spare 50 pounds right now. Also, will it really help with my alloy problem?
I'm not that fussed for these bullets right now as they will be low pressure TB loads in my 243. But I want to get this under control as I'll want some decent hunting bullets that I can drive to reasonable velocites with something like 4895 in my 30-06.
So this time round, I added some parrafin wax and sawdust and stirred a lot. It didn't seem to be going back in, so I started casting anyway. Bullets were horrible - filled with little black particles and voids. I may have got it a bit warm - When I offered a bit of rolled newspaper it caught alight as soon as it hit the melt. When I added more wax or sawdust it burst into flame. It was going all shades of colour then I suspect I saw the melt start to give off vapours. I killed the fan (it's a coal powerd forge) and left it for a while to let it cool a bit.
Then I skimmed all the crud off - which amounted to a lot and kept casting. Bullets were then absolutely perfect - very well filled out, sharp bases and well defined grooves. But now I'm suspicious they'll be really soft as I suspect most of the hardening impurities have been lost. No more started coming out of the melt at the lower temperatures, but is that because there wasn't any left... It was still casting very nicely even when I tried the newspaper thing again and it hardly charred at all.
Does anyone have any suggestions as to how I can reintroduce the anitimony etc. or prevent it in the future? I have more linotype un-smelted.
I know I should buy a thermometer really but I don't have a spare 50 pounds right now. Also, will it really help with my alloy problem?
I'm not that fussed for these bullets right now as they will be low pressure TB loads in my 243. But I want to get this under control as I'll want some decent hunting bullets that I can drive to reasonable velocites with something like 4895 in my 30-06.