Min tin for good mould fill

[dogdoc]

What have you guys found to be the minimum amount of tin to add to a mix for good mould fill out? I think I might have read 1% somewhere but what are your experiences? Thanks
(I have some range recovered lead that is soft and likely has little to no tin)
Dogdoc

[Mal Paso]

1% is good

[StuBach]

In my experience it depends on the mold and material. My big iron mold (HG 130) has pretty decent fill out with hot SOWW with no tin added (0.25-0.5%) but my more square cut brass molds need more tin to get good fill out. Usually around ~2% (calculated) or more.

[rancher1913]

I do the trial and error method. some of my molds require no tin at all and some, like the russian frag slug need quite a bit. tin is to valuable to use if you dont need it.

[lightman]

I would say minimum would be around 1/2%. 2% would be better.

[dtknowles]

It depends on the mold block and cherry. I think brass and aluminum molds need more tin and bullets with fine details need more tin. It is easy to cast round balls with no tin.

Tim

[Conditor22]

It actually depends on how hot the alloy and the mold are.

IF you want good fill out at lower temperatures, -- you need more tin

COWW + 2% is good for most of what ails you

I cast my pewter into .5 oz boolits and will toss 1 0r 2 into the pot if I'm not getting good fill out at the temperature I want

[Retumbo]

It actually depends on how hot the alloy and the mold are.

IF you want good fill out at lower temperatures, -- you need more tin

COWW + 2% is good for most of what ails you

Pretty much my standard

[bangerjim]

Yes.........the temp of the alloy and the mold make a big difference in fill-out. Sn lowers the surface tension and allows the mix to flow into the nooks and crannies better, especially at lower temps.

I use 2% Sn in everything, but I have hundreds of pounds of pure Sn. It is very expensive today. Most I have I got for 50¢ to $1 a pound back in the good olde daze. (where DID they go???????????????? )

Play with your temps B4 investing a ton of money in Sn. You may not need it.


banger

[Larry Gibson]

I have some range recovered lead that is soft and likely has little to no tin

If the range lead is mostly from 22LR and jacketed handgun bullets it probably contains 1 - 3% antimony and little to no lead as mentioned. What you want to do is balance the amount of tin to match that of the antimony so the sub metal SnSb is formed. That sub metal will mix in with the lead and stay in suspension during the cooling/hardening process in the mould and after. Suggest you first try adding 1% tin then cast some with the alloy temp at 700 - 725. You should get good fill out but if the cooled bullets have any "frosty" spots or slight indentations that is caused from the antimony not in composition with the tin hardening before the lead does. If that occurs then simply add 1/2 of 1% incrementally until the bullets come out completely filled out and shiny.

The quick answer with range lead if there is any "hard" commercial cast bullet alloy is to just add 2% tin.

[rockrat]

I get decent fill out with my 44's with Isotope lead which IIRC, has 1% tin. When I blend alloys, I strive for about 1.5-2% tin

[Rcmaveric]

I have found adding tin may sometimes help. But I have found some mystery alloys to still be stubborn.

What does help it turning up the heat. Maybe cast a little faster to keep the mold hotter. Last resort run the mold really hot and tap it on board when the sprue is still molten. Pour and let it fall a few inches. Then watch the sprue turn from shinny silver to crystallize silver or dull silver. Then cut and drop the bullets.

Develop a system by trial and error to see what works for you. Adding tin doesn't always help and is costly.

The typical advice of 2% tin is becuase thats the point of diminished return is hit for tin affecting melt point and flow. While more could help it won't help nearly as much.

If I have tin I will use it. Add 1% and if still having issues, then add another 1%. If I don't have tin, I dont really sweet it. I just cast with the pot hotter. I most often don't have tin.

Getting into the realm of ternary alloys could lead you down a rabbit hole some swear by. Not something I or am an expert on but I believe its equal parts Tin and Antimony.

There is a reason why Lyman 2 is so popular and so was Linotype.

Sent from my SM-N970U using Tapatalk

[Shuz]

Down thru the years, I have had good results with aluminum, brass and steel moulds with 1% tin added to clip on wheel weights..

[DGV]

If you have cast with 20-1or even 16-1 you know how easy it is to make good boolits. Yes, Tin is expensive, but it makes it so easy to cast good boolits. nothing wrong with 4-5 % Tin in the pot.

[ShooterAZ]

Most of my molds will cast quite well with just 1% tin. I do have a few molds however that have sharp cornered driving bands, lube grooves, or boolits like the louverin designs that a little extra tin really helps with fillout. 2% is good for those, though on occasion I've added more.

[dogdoc]

Thanks. Will try 1 to 2 percent depending on results. 10 bucks a pound makes one stingy

[Tim357]

Short, fat pistol boolits with large lube grooves tend to need less tin than do the long, skinny rifle boolits with several narrow lube grooves. The tin, as stated above, reduces surface tension of the melt, allowing the melt to fill the small spaces in the mold.

[Lloyd Smale]

minimum is zero. Ive made thousands of perfect bullets out of pure lead.

[GhostHawk]

I like 1% tin added to my alloy. Which is normally roughly 50% COWW and 50% Range Scrap or other soft lead.
So if I have 50 lbs of COWW, 50 lbs of scrap soft lead, I add 1 lb of tin. Be it Linotype, or melted pewter.

[Larry Gibson]

Thanks. Will try 1 to 2 percent depending on results. 10 bucks a pound makes one stingy

It only seems expensive. That one pound of tin at 1% will do 100 pounds of alloy. At 2% (3.2 ounces per 10 lbs of alloy) it will do 50 pounds of alloy. With either % that's a lot of bullets. Today, 10 bucks doesn't get a whole lot but, to me, 50 or 100 pounds of bullet really good bullet alloy is a lot.