Question about tin

[bigborefan]

I purchased some ingots of tin a while back that I was told was tested at 86% tin. My question is that when I tested the hardness of these ingots, they came out to about 14+ BHN. Since pure tin is approx 7BHN, doesnt 14+ sound hard for 86% tin? I tested a bar of 50/50 and it came out to 7.8 BHN which sounds about right. The ingots are about 2 lbs each but when compared to 2 lb ingots of lead, they are larger in volume than the lead ones meaning they are lighter in weight if cast in the same ingot mold. Does this sound right to anyone with knowledge of metallurgy?

[3sixbits]

Maybe 14% Sb is the balance? Find the liquidus temp and record the numbers. Time to make a home made chart. Use this method to establish a guide. Melt pure Pb, Sn, Sb using your own gear at your casting area. find the liquidus temp for a broad range of solders, 95/5, 60/40, 50/50, etc. Only your numbers are important. Do you see where I'm going with this? The trouble with the hardness method is that there are many factors that can influence the hardness. Unless you are using a certified Brinell tester in calibration and you re comparing to other known standards etc, etc, etc.

[bigborefan]

3sixbits, Thank you for your response. I do believe that the remaining 14% of the ingot is SB since that sounds like the only conclusion you can com to if the other 86% is SN which has a BHN of about 7. The method that I use for determining the BHN of my lead is a little unorthodox but very reliable. My linotype is in the 22BHN range while my pure PB is in the 5 range as it should be and my #2 alloy is in the 18 range so I feel very confident in my BHN readings. My main problem is that I was hoping that with the 86% SN content of the ingots, I wanted to add this to pure PB to get a 20-1 or 30-1 mixture for BPCR shooting. If these ingots truely contain 14% SB in them, it will be like adding linotype to PB and ending up with the equal to #2 alloy which is a little too hard for BPCR loads. Also by using your method to determine the alloy of the ingots, SB liquifies at 464 degrees while tin liquifies at 429 so if the whole thing liquifies by 464 dgrees does that mean that there is no PB content in the mix since lead liquifies at 621 degrees?