Lead-Tin alloy ratios

[.22-10-45]

I have mixed lead-tin alloys from 40-1 thru 20-1 for black powder & target smokeless loads..but for some reason,:oops: my brain can't seem to figure out how to do this: I have 10lb. of 40-1 lead-tin alloy. This is 2.5% tin/97.5% lead. How much tin must I add to equal a 30-1 lead/tin alloy of 3% tin/97%lead. I would like to have the math formula. Thank you!

[Alan in Vermont]

The formula is right there in front of you, 30 of A to one of B. At least that's how I see it. Where I lose it is I see the percetages as being right for your 40-1 alloy, 2.5/97.5 but that is not what you get if you mix something, 40-1

As far as 30-1, the real percentages come out to 3.26% Sn/96.74% Pb.

It's awful easy to get way too far into numbers with this stuff. I have access to a bunch of certified alloy 3.5% Sn/96.5% Pb. That's close enough to 30-1 and easier to say/type.

[.22-10-45]

What I was looking for was...what must I do to alter my 40-1 lead tin alloy to the harder 30-1 lead tin alloy? Sorry for the confusion. Thanks.

[Yodogsandman]

Add an additional .5 % Sn, that's 350gr for 10 lbs. That will get you close nuff.

[bangerjim]

Don't forget about the FREE alloy mix calculator spreadsheet on here! I'm amazed at the countless number of people that have never even heard of it.

It will answer all you what-if questions on alloy mixes and hardness.

Do a search in the white box above.

bangerjim

[runfiverun]

umm 40 to 1 is just that,, 40 lbs of lead and 1 pound of tin.
you actually end up with 100 lbs of lead and 2.5 pounds of tin [not 2.5% tin] for 102.5 lbs of alloy total.

to save the math use the alloy calculator Jim mentioned.
off the top of my head you need to add 25% more tin to make 30-1 from 40-1, and you gotta double it to make 20-1.

[30Carbine]

http://castboolits.gunloads.com/attachment.php?attachmentid=45784&d=1341560870 here is the calculator it is you friend..

[.22-10-45]

Ok thanks..I found the calculator. Getting back to original question of how to convert 10# of 40-1 lead/tin alloy to 30-1 alloy...The only form of tin I have is 50-50 solder in bar and wire. If I add tin to 40-1 alloy..I also will be adding lead..which I already have too much of..what to do? Thanks!

[RogerDat]

Alloy Calculator. Makes this easy.

You put your weight of 40 to 1 into the alloy calculator then add different weights on the 50/50 solder line. When you try the solder weight that shows the correct values for the tin and pb column you have it.
As far as 30-1, the real percentages come out to 3.26% Sn/96.74% Pb.

Say you enter 20# on the 40:1 alloy line then you enter .5 on the 50/50 solder line. If the totals at the bottom show too little tin (less than the desired 3.26%) then you increase the .5 to .75 or 1 pound. When you get too much solder so that the tin column reads more than 3.26% then reduce the amount of solder entered.

Your total is high on tin then you reduce the solder amount entered, low increase the amount entered, soon you will have it bracketed ( x amount is too little solder but y is too much) then try amounts between those two until you get it spot on.

Just play with the amount of 50/50 you enter with a set amount of 40:1 and watch the totals at the bottom of the alloy calculator as you adjust the solder. Will all make sense pretty quick. Have to do this all the time for scrap I get that has odd amounts of alloy, just try different amounts of other stuff I have until it gets to what I want for totals.

If you know that 10 lbs. of 40:1 and x amount of solder makes 30:1 then you can double it to make 20 lbs. or cut the amounts in half to make 5 lbs. In short you will have a recipe for turning 40:1 into 30:1 using 50/50 you can save those number for later re-use. Try entering 14 lbs. of 40:1 and .25 in the alloy calculator. For odd decimal amounts you may need to go to an online decimal pounds to ounces calculators or charts. My scale is in oz. the alloy calculator is in decimal pounds so if you alloy calculator works for my desired alloy at .375 pounds I need to convert that to 6 oz. in order to weigh it. http://www.metric-conversions.org/weight/ounces-to-pounds.htm

[.22-10-45]

Got it! Thanks everyone.

[Bruntson]

My thanks too, I learn something new every day from this forum. :-D

[alfloyd]

.22-10-45
If you will add 1.75 ounces ( 0.11 pounds ) of 50/50 solder to your 10 pounds of 40 to 1 alloy, you will have an alloy of 30 to 1 lead to tin.

Lafaun

[RogerDat]

I should add that a lot of the time it is easier to adjust the base lead than the solder/pewter. The material you are using 10# when changed by a pound or two makes much smaller change to final alloy than a change to the solder or pewter.

Can do it either way, I just find playing with the "big" amount easier than the fraction of a pound part of the equation.