Guys I need some help. Given say a 500 grain prue lead bullet from a mould. You throw another from the same mold that is 480 grain of unknown alloy. What is the formula that will give you the lead to tin ratio of the 2nd bullet?
Bob
Lead/Tin Ratio
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bwbayless
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Dave Shaw
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Lead/tin ratio
BWBAYLESS
I think you may have answered your own question, you talk of an unknown alloy. That is the one thing you should allways know.
If you can find a supply of roofing lead - not the Church roof. And a tin (solder / plumers lead) supply, then start with a ratio of 20 - 1 lead / tin then work up from there.
Different alloys will give different weights, but you will know what you started with.
Regards
Dave
I think you may have answered your own question, you talk of an unknown alloy. That is the one thing you should allways know.
If you can find a supply of roofing lead - not the Church roof. And a tin (solder / plumers lead) supply, then start with a ratio of 20 - 1 lead / tin then work up from there.
Different alloys will give different weights, but you will know what you started with.
Regards
Dave
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bwbayless
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- Location: Lebanon, Indian Nations, OK
Dave,
Thanks for the reply. Yes it would be nice to know but like my old Daddy used to say you shoot what you got. It is a little harder than pure lead but shoots nice. I don't actually care what it is now but when I run out I would like to duplicate it. That's the reason I would like to know that formula is and it does exist.
Thanks,
Bob
Thanks for the reply. Yes it would be nice to know but like my old Daddy used to say you shoot what you got. It is a little harder than pure lead but shoots nice. I don't actually care what it is now but when I run out I would like to duplicate it. That's the reason I would like to know that formula is and it does exist.
Thanks,
Bob
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Ray Newman
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pluton
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Lead/Tin Ratio
Hi BWBayless,
In answer to your question regarding the Lead/Tin ratio in your alloy.
You say that a pure Lead bullet casts at 500 grains and your alloy throws at 480 grains from the same mould.
Given the density of Lead is 11.37 grams/cc and Tin is 7.29 grams/cc you can calculate the ratio of the two.
For every grain of Lead you replace with tin the bullet would weigh 0.36 grains less.
Therefore to cast a bullet weighing 20 grains less than one of pure Lead you would need to replace 20 / 0.36 = 55.5 grains of Lead with Tin.
This would give you 445 grains of Lead to which you would need to add 35 grains of Tin to get a 480 grain bullet.
The Lead / Tin ratio is therefore 445 to 35 or 12.7 to 1
All this is of course theoretical and in the real world we all know that not every bullet cast from a mould is identical. The calculation assumes that both bullets ARE identical and that the alloy is a mixture of pure Lead and pure Tin. If there is any antimony (Density 6.68 grams/cc) or other metal in there it would be impossible to calculate the ratio, you would have to have it analysed.
What all this BS means is that you are casting with an expensive alloy at that ratio, most folks on this forum seem to use ratios between 20 to 1 and 30 to 1 for their bullets.
If the alloy works for you then by all means carry on, but don't be afraid to experiment with other ratios, it's all part of learning.
I hope this is useful to you,
Best wishes from a wet and windy England,
Pete Luton
In answer to your question regarding the Lead/Tin ratio in your alloy.
You say that a pure Lead bullet casts at 500 grains and your alloy throws at 480 grains from the same mould.
Given the density of Lead is 11.37 grams/cc and Tin is 7.29 grams/cc you can calculate the ratio of the two.
For every grain of Lead you replace with tin the bullet would weigh 0.36 grains less.
Therefore to cast a bullet weighing 20 grains less than one of pure Lead you would need to replace 20 / 0.36 = 55.5 grains of Lead with Tin.
This would give you 445 grains of Lead to which you would need to add 35 grains of Tin to get a 480 grain bullet.
The Lead / Tin ratio is therefore 445 to 35 or 12.7 to 1
All this is of course theoretical and in the real world we all know that not every bullet cast from a mould is identical. The calculation assumes that both bullets ARE identical and that the alloy is a mixture of pure Lead and pure Tin. If there is any antimony (Density 6.68 grams/cc) or other metal in there it would be impossible to calculate the ratio, you would have to have it analysed.
What all this BS means is that you are casting with an expensive alloy at that ratio, most folks on this forum seem to use ratios between 20 to 1 and 30 to 1 for their bullets.
If the alloy works for you then by all means carry on, but don't be afraid to experiment with other ratios, it's all part of learning.
I hope this is useful to you,
Best wishes from a wet and windy England,
Pete Luton
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bwbayless
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- Location: Lebanon, Indian Nations, OK
Pete,
<< you are casting with an expensive alloy at that ratio>>
Not at all Pete that was just an arbitrary number to work with as I stated in my previous post. I do thank you for your response. Almost 50 years out of school and my thinker is not what it used to be. Finally knocked some of the rust off and got my head around it. I've been casting off and on for 35 years and I'm almost certain I saw a formula for it but so far haven't found it in any of the stuff I have. But I've been wrong once before.
Thanks again,
Bob
<< you are casting with an expensive alloy at that ratio>>
Not at all Pete that was just an arbitrary number to work with as I stated in my previous post. I do thank you for your response. Almost 50 years out of school and my thinker is not what it used to be. Finally knocked some of the rust off and got my head around it. I've been casting off and on for 35 years and I'm almost certain I saw a formula for it but so far haven't found it in any of the stuff I have. But I've been wrong once before.
Thanks again,
Bob