Changing 1:20 alloy into 1:16

[broken-mold]

I have several pounds of 1:20 alloy (as well as 1:30) but need some 1:16. I plan to order some 1:16 soon but can I make 1:16 from 1:20 simply by adding a few percent of tin to the 1:20 (or 1:30)?

[BK7saum]

Yes, you can, but I have to ask...What will 1:16 do for you that 1:20 will not?

We are talking 4.76% tin vs 5.88% tin if you are considering a 20 "to" 1 amd a 16 "to" 1 ratio.

For a 1 in 20 at 5% and a 1 in 16 at 6.25%, i really do not knownwhat the advantage the extra 1.25% tin provides. Tin is a poor hardener compared to other alloy additives. Just curious.

[Tatume]

There is an Excel spreadsheet available on this forum that allows you to change components of an alloy and see the characteristics. It is very good, and fun to play with as well.

[broken-mold]

Yes, you can, but I have to ask...What will 1:16 do for you that 1:20 will not?

We are talking 4.76% tin vs 5.88% tin if you are considering a 20 "to" 1 amd a 16 "to" 1 ratio.

For a 1 in 20 at 5% and a 1 in 16 at 6.25%, i really do not knownwhat the advantage the extra 1.25% tin provides. Tin is a poor hardener compared to other alloy additives. Just curious.

1:16 is specified for Trapdoor Springfield boolits.

[broken-mold]

There is an Excel spreadsheet available on this forum that allows you to change components of an alloy and see the characteristics. It is very good, and fun to play with as well.

I saw that but don't have Office loaded yet so figured I couldn't use the spreadsheet.

[dondiego]

Don't bother........

[Tatume]

I saw that but don't have Office loaded yet so figured I couldn't use the spreadsheet.

You can get the freeware Open Office, https://www.libreoffice.org/

The spreadsheet is really good and worth the effort.

[JSnover]

Yes, you can, but I have to ask...What will 1:16 do for you that 1:20 will not?

We are talking 4.76% tin vs 5.88% tin if you are considering a 20 "to" 1 amd a 16 "to" 1 ratio.

For a 1 in 20 at 5% and a 1 in 16 at 6.25%, i really do not knownwhat the advantage the extra 1.25% tin provides. Tin is a poor hardener compared to other alloy additives. Just curious.

I don't know what the OP needs but there was a thread recently where this came up: A boolit cast from 1:20 may slump a bit when fired. If it's good long-range design, it just might not shoot well in his rifle at long range. The same boolit cast from 1:16 will reduce that likelihood. Within 200 yards he might never know the difference.

[Tatume]

Yes, you can, but I have to ask...What will 1:16 do for you that 1:20 will not?

We are talking 4.76% tin vs 5.88% tin if you are considering a 20 "to" 1 amd a 16 "to" 1 ratio.

For a 1 in 20 at 5% and a 1 in 16 at 6.25%, i really do not know what the advantage the extra 1.25% tin provides. Tin is a poor hardener compared to other alloy additives. Just curious.

There are two common methods of calculating dilutions, the dilution ratio and the dilution factor. In this example, the dilution ratio would combine one pound of tin with 20 pounds of lead, resulting in 21 pounds of alloy (and similarly for 1:16). The percentage of tin in the alloy would be (1/21)x100% = 4.76%.

However, this is not the method used to calculate bullet alloys, which uses the dilution factor instead. In the 20:1 example, one pound of tin would be combined with 19 pounds of lead to produce 20 pounds of alloy containing 5% tin.

In fact, both methods actually use volume and not weight. However, the density of tin and lead are close enough that weight can be substituted will only a small error.

[Larry Gibson]

I don't know what the OP needs but there was a thread recently where this came up: A boolit cast from 1:20 may slump a bit when fired. If it's good long-range design, it just might not shoot well in his rifle at long range. The same boolit cast from 1:16 will reduce that likelihood. Within 200 yards he might never know the difference.

^^^^^ Exactly

Frankford Arsenal did extensive testing of alloys back "in the day" and found the 16-1 alloy to be the best for the 45-70 giving the best accuracy over longer ranges. It's what I've also found [rediscovered] with my own TD service cartridge equivalent loads.

[Tripplebeards]

I’m sure if you look up some of my old posts where I boo-book’s trying to make 16/1 out of pewter and pure lead and came up with basically a 40/1 alloy with my ratio at 7.5 bh. I kept adding more pewter until I got the 16/1 hardness which is around 10 1/2 BH. It took me an eight to one ratio mix. So yes it can be done but I would tell you to test it along the way for hardness like I did.

[Chill Wills]

20 to 1 is 20 parts to 1 part
1 in 20 is 19 parts to 1 part

The same with 16-to 1

Algebra will help find the amount of tin to add. Some of us have not done much algebra since school days. I always have to think a bit before I do one of these conversions.

[Tripplebeards]

It’s easy math until you are using pewter with unknown properties, instead of a 100% ingot, like I do. That’s why I had to end up doing an eight to one mix until I got to around the same “advertised 16/1 true hardness” of 11.2 BH. I kept adding more pewter to my melted mix and then casting a test boolit to check hardness with my lee tester. I would water drop my test boolit and then test it with the lee hardness tester. Hardness didn’t change with my final alloy immediately after hardening, water dropped or not, (which it shouldn’t have) after sitting for a couple of weeks so my pewter must’ve been mostly tin but just not enough percentage to get to an actual 16 to 1 hardness…till I mixed it 8/1.

[Willie T]

Don’t over think this. 1-20 and 20-1 are different. Same as 1-16 and 16-1. I’m guessing you have 20-1 and want to turn it into 16-1. The math is simple. 20-1 has 21 equal parts. 16-1 has 17 equal parts. One of the equal parts of each is tin. Broken down it is something like this.

1. Weigh the amount of 20-1 you want to alter the alloy to 16-1.

2. Divide the weight by 21. That will give you the weight of the 21 equal parts and how many pounds of tin is in your 20-1. Write that number down.

3. Multiply that number by 16 and it will give how many ounces of tin is in your 20-1. Write that down.

4. Subtract the pounds of tin from the weight in pounds of your 20-1. That will give you the pounds of lead in the 20-1.

5. Divide the amount of lead by 16. That will give you the pounds of tin needed for
16-1. Now multiply by 16 and it will give you the ounces of tin needed for 16/1. I did that last bit for illustration to hopefully make it easy to follow. (16-1 alloy is one ounce of tin for every pound of lead, so just hit the easy button there.

Subtract the ounces of tin already in your 20-1 from the ounces of tin required for
16-1. (The weight in pounds of the lead in your 20-1 is also the total weight in ounces of tin needed for 16-1). The difference will give you the ounces of tin to add to your
20-1 to bring it up to 16-1.



In summary: weigh your 20-1 and calculate how much tin it has. Subtract that from your total 20-1 weight to calculate how much lead you have. The amount of lead in pounds is also the total amount of tin needed in ounces for 16-1. Subtract how much tin you already have in the 20-1 from the total needed for 16-1. Add the difference in tin to your 20-1 for 16-1.
I bet the Springfield trap door is fun!
Willie

[Rockindaddy]

You don't need 1-16 for your Trapdoor Springfield. Have been loading and shooting trapdoor Springfields for over 50 years. The softer alloy allows the boolits to upset better in the large overbored barrels. It is my belief that the US Government should have called the new adopted rifle caliber in 1873 the 46-70 as the groove diameters run upwards of .461~.462 I load about 5000 rounds of 45-70 a year feeding a pair of Gatling Guns but the bores require a .458 sized and lubed boolit. However when loading for my Trapdoor Springfield carbine and Cadet Rifle, I have moulds that are enlarged so the boolits can be sized to.461 so they shoot accurately. The hollow base Lee 45-70 boolit seems to work ok too. Remember most scrap lead pipe is pure soft lead. The joints are tin as It melts at a lower temperature than the lead. The old plumbers had to learn how to "wipe" a joint when joining two pieces of pure lead. Weigh the tin joints and weigh the lead pipe to make your alloy.