Bad news, Rotometals has discontinued the nuggets

[KnifeMaker]

Michael you probably go by weight when you add tin to a mix by weight don't you?  like 1 gram to a 100 grams for 1% tin

No Wayne, I mix 1/2 lb of tin to 20 lbs of lead tin. I mix it by the pot.
I am completely out of pure lead, and have been for well over a year. Guess it is time to get a couple hundred lbs. 


However, as I recover most of my lead on my range, I just remelt and cast.


Mike

[Wayne52]

Michael I think what I'll do when I mix mine is ad the flakes to a full pot of pure lead then, I'll try doing approximately 1% tin to begin with to see how they turn out.

[Bob Pratl]

Michael I think what I'll do when I mix mine is ad the flakes to a full pot of pure lead then, I'll try doing approximately 1% tin to begin with to see how they turn out.

I have been using 1.5% Tin for all of my cast bullets and now pellets with the exception of BP round balls which was 100% lead. A good source of Tin was Thrift Shop Pewter (95% tin + 5% junk) and 50/50 solder which I had a large roll of. I would use 30 ounces of Lead with 1 ounces of solder(.5 OZ of Tin). I have never casted with 40:1 (2.5%) because 1.5% worked for me.

[HunterWhite]

Wayne, nice,  I have heard of lead shot but I've never seen it.

[KnifeMaker]

Michael I think what I'll do when I mix mine is ad the flakes to a full pot of pure lead then, I'll try doing approximately 1% tin to begin with to see how they turn out.

I have been using 1.5% Tin for all of my cast bullets and now pellets with the exception of BP round balls which was 100% lead. A good source of Tin was Thrift Shop Pewter (95% tin + 5% junk) and 50/50 solder which I had a large roll of. I would use 30 ounces of Lead with 1 ounces of solder(.5 OZ of Tin). I have never casted with 40:1 (2.5%) because 1.5% worked for me.

Wait a minute here, 30 ox to 1 ox is 30-1 which is higher tin than 40-1. Not lower.

[KnifeMaker]

Hunter, the lead shot that Roto is showing is what "They" call lead nuggets. this is not shot. Not what caster call lead shot.


 Real lead shot, or what is used by casters and has been for well over a century is real lead shot. As in Lead shot for shot guns. Usually sold in 25 lb bags, but has become ridiculously expensive in recent years.


Many casters to add hardness would add # 7 1/2 chill shot to the pot. works well. 


When a shotshell reloader orders a bag of shot, it is the 25 lb to 50 lb bags of the shot size they want. You sure would not want to use what Roto is selling for actual shot. Talk about a wild flight pattern.  LOL


Their nuggets are cut sections. where as actual shot is dropped melted, from a good height called a shot tower, into a cooling tank and forms the shot spheres.   

[HunterWhite]

Thanks Michael.

30 to 1, but the 1 is 50% lead, 50% tin.
That's 30.5 to .5. So it's like 1.6% tin.

Those shots were big !

[Wayne52]

I used a 22 gram chunk of tin to about 3lbs of lead, I figure it was probably a tad over 1%.  The pellets came out wrinkle free and about the same weight, I still got more rejects than I should have, I haven't gone for a round two with the tin.  I shot a red squirrel and a chipmunk today with them and I'd say the accuracy is about the same . . . . excellent !!!! They sure look prettier with the tin though

[Wayne52]

I'll bet the pure lead disipates heat in the mold slower than the tin mix.

[K.O.]

Wayne from what I have read the tin starts losing it's ability  to help fill out once temp start getting over about 750*f...

[Wayne52]

I need to get me a pot that I can adjust cause mine is single heat.  Ebay has good deals on them.

[HunterWhite]

I'm sure that you already know this, but The tin lowers the melting point of the mixture.
The melting point of tin is
449.5°F 231.9°C.

The melting point of lead is
621.4°F 327.5°C.

The lowest melting point of tin / lead is 361F, that is 63% tin / 37% lead.

The wierd part is that the melting point of tin/lead ( solder ) is lower than either of the two metals it's made from.

Just 2% tin lowers the melting point 10 to 20 degrees Fahrenheit.

I did find a chart at:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.technic.com/sites/default/files/resources/Solder%2520Alloy%2520Melting%2520Temperature.pdf&ved=2ahUKEwjT2b-y7OThAhUwgK0KHcNjBoEQFjAbegQIAxAB&usg=AOvVaw3FsjWvmQIup7xIyMPsHoyN

[Kinetic45^]

A lot of the temperature we use has more to do with keeping the molds hot enough than the melting point of the alloy.
Is the mold cast iron, brass, aluminium?
How big/thick a block is it for it's heat sink?
How many cavities so filling vs cooling duration on filled n empty cavities.
How big are the cavities/calibur so how much molten lead volume is there to add heat.
Casting rate
Local environment of a hot room or day vs a cold room or day.

Those variables mean you have to use a different pot temp to match the conditions.

A little tin still helps fill out at 850 (you have to cap the melt to keep all the oxygen away so the tin will not be removed by oxidization at that temp) vs pure lead

[KnifeMaker]

The oxygen is a real issue. When using tin, at higher heat, I put borax or Frankford Arsenal powder on top, and don't stir it in as it forms a tight cap on it.




A fellow over on Cast Boolits makes a run of lids for out pots from time to time. I finally got one a few months ago. Makes a huge difference. A side benefit is the lack of air cooling. With pure lead, I can get another 125 F in the melt using the lid.


Knife