Some More Information About TIN in Your Minies

[Southron Sr.]

I also posted my question about adding a small amount of TIN to my lead pot and learned some new facts:

(1) A very small amount of Tin in your Lead will slightly lower the melting temperature of the otherwise "Pure Lead."

(2) The reason Tin works so well in casting is that a little bit of Tin in your molten Lead alloy (the alloy composed of otherwise "Pure" Lead and small amount of Tin) will reduce the "Surface Tension" of the molten lead alloy. This in turn will allow the, molten Lead alloy to fill out your mould cavity better. Hence, better bullets.

(3) For the "Tin Trick" to work, your pot temperature has to be LESS THAN 750 Degrees F.

(4) Bullets cast from a Lead/Tin alloy will actually "soften" a bit more after ten days "Curing Time." However, they will never be "softer" than Minies cast out of "Pure Lead.

(5) A small amount of Tin in your Lead/Tin alloy WILL NOT make your Minies "Too Hard" for best accuracy.

So, there you have it....to misquote a song from the old Mary Poppins movie: "A little bit of TIN will make the Lead Alloy go down better in the Bullet Mould..."

[DAVE FRANCE]

Hi Southron,

About your message.

(1) A very small amount of Tin in your Lead will slightly lower the melting temperature of the otherwise "Pure Lead." True. Lead melts at 621 f, tin melts at 500. As tin is added it lowers the melting point from the 621 to 500 where there is no lead, just tin.

(2) The reason Tin works so well in casting is that a little bit of Tin in your molten Lead alloy (the alloy composed of otherwise "Pure" Lead and small amount of Tin) will reduce the "Surface Tension" of the molten lead alloy. This in turn will allow the, molten Lead alloy to fill out your mould cavity better. Hence, better bullets. True!

(3) For the "Tin Trick" to work, your pot temperature has to be LESS THAN 750 Degrees F. I don't understand this one. You need to keep the mold hot enough to get consistently good bullets. that temperature will be different for differnet bullets and molds. If you set your pot for one temperature, it will vary as you cast and add lead.

The last time I cast bullets I got the temperature to 850 in the pot I was casting from. I had cast from a 4 cavity mold the time before. Quite a few of the bullets did not fill out well or were too light. So I experimented for my own sake. I also used a second pot that I just melted lead in. I would take hot lead from pot 2 to replenish pot 1.

To start I cast from pot one, and added 2 one pound ingots after I cast two pounds of lead. I kept a thermometer in the pot I cst from and the lead went down to below 750 and stayed there as long as I continued casting. I separated these bullets from the ones I would cast later.

I heated the pot I poured from to 850. I started making bullets again, but when I had used about 2 pounds of lead, I added lead from the pot I melted lead in. And I added lead ingots to the pot I melted in. The temperature of the lead in the pot I poured from went down. It did not go down nearly as much as it did the first time when I added ingots. And the lead temperature would heat up again very quickly, although it never got as hot as the 850 where is started.

I separated the bullets to collect the bullets in 4 piles, one from each cavity in the 4 cavity mold. later I weighed the bullets, and they were very consistent.


I saw something on the internet about a test someone did, in which he kept a lead-tin mixture at the highest temp his pot would reach. I think it was over 850. Over a period of days he cast a few bullets every day. Keeping the lead hot, did not affect the lead hardness he got. I think that heating lead-tin to 850 does not cause a problem unless the mold is too hot and leaks lead.

(4) Bullets cast from a Lead/Tin alloy will actually "soften" a bit more after ten days "Curing Time." However, they will never be "softer" than Minies cast out of "Pure Lead. I think that is backwards. I have two books about casting. they both say the lead will get harder after they are cast, and it takes a few days to reach the greatest hardness. NRA CAST BULLETS covers that on page 102

(5) A small amount of Tin in your Lead/Tin alloy WILL NOT make your Minies "Too Hard" for best accuracy. That is true most of the time. But if the lead you start with has too much impurities, it may push it over the edge to being too hard.

I cast bullets off and on for three days with two 4 cavity molds I bought from Lyman. I was very happy with the speed that was possible and the quality of the bullets I made, but I would have to cast much slower if I had used just one pot. I shoot thousands of 44 caiber and 38 caliber bullets per year now, and using 4 cavity molds makes it possible to cast all the bullets I need in just a few hours.

David

[Southron Sr.]

Dear David:

THANKS for the information in your post above. The more I think about it, the more I believe that after "curing" bullets with a slight amount of Tin would actually be harder. Those bullets I cast for the Nationals with the small Tin content still shoot GREAT and they are long since "cured."

Sounds like you are going to a lot of HARD WORK casting the bullets you need. May I suggest you get a Master Caster. I can easily cast 300 .45 Long Colt bullets per hour using a double cavity Lyman mould I have modified to work on my Master Caster.

Casting bullets by hand is 16th Century technology-the Master Caster is 21st Century technology:

www.magmaengineering.com/products/master-caster

[DAVE FRANCE]

Dear Southron,

I think you mentioned the Master Caster before, and I looked at on the internet.

I'm retired and I don't mind spending the time casting by hand. I spent more time casting years ago than I do now. I wouln't buy one unless I was casting a lot more bullets than I do.

A Master Caster would have been of more use to me in the seventies and eighties that it would now. If I was shooting more than I do now, and could use cast bullets for modern rifles, I might buy one.

Thanks for the information,


David

[Ken Hansgen, 11094]

Q: What IS a "small amount" of tin (how much compared to how much lead)?

[DAVE FRANCE]

Ken,

In the NRA Cast Bulets handbook (page 102), it shows a graph showing hardness of lead-tin versus percent tin. For 0% tin (pure lead) it shows a hardness of Brinell 5. And for 1% tin it shows a hardness of about 7. 7 is probably as hard as you want to go. I measured the hardness of bullets I used after I bought a hardness tester. I found a few that were 8, but most were softer than that.

If you start with lead that has impurities, espcially antimony. 1% tin might be too much to add.

Antimony hardens lead faster than tin does. The same graph shows a hardness of 8.5 for 1% antimony. So if you buy soft lead that has a very small amount of antimony, adding 1% tin would be too hard for Minies.

I tried adding tin to lead for Minies one time with a mold that did not fill out well with just soft lead. I added about 1% tin, but the Minies were too hard and I did not try them. Probably other skirmishers will have experience that is helpful.

I bought the NRA Cast Bullets book for $1. It was part of a lot of reloading equipment and books that had been sold by the widow of a shooter. I'll have to leave it to some worthy shooter in my will, even thought most of the cover was chewed off by my dog. It has many articles in it about casting.

Good Luck!