Too much tin?

[mto7464]

I was getting poor mold fill out so I added some tin. Problem was, small pot, large ingots. By my best guesstimate I added about 5-8% tin. Bullets came out better as far as fill out but were not as shiney and seemed a little dirty looking. I fluxed it real well too.

[HeavyMetal]

without a picture we're shooting in the dark here (yes this is a pun). Be aware that adding tin to your alloy can lower the melting point and it could be your seeing "frosting"?

We need to know: what was the original base metal, how much, by weight, did you start with. How much tin did you add? Was it pure tin or 50/50 bar solder? How much, by weight, did you add to you melt? Temperature? bottom feed or ladle?

As you can see lots of things could cause your problem. With more info it can be figured out.

[mto7464]

They are frosted in spots, that is what seems the oddest. I used 40/60 solder fromthe radiator shop and I guess added 1lb to 5lbs approx. I was laddling. Base metal WW. Temp?

[44man]

Too much tin will not hurt anything, it is just a BIG waste of a precious metal. You have other issues to solve for a bad boolit. I would take all of that mix and add more WW's or pure lead to make use of the wasted tin.

[BABore]

Too much tin will not hurt anything, it is just a BIG waste of a precious metal.

I would agree with that if you only have a lead tin alloy. Once antimony enters the mix, you can get an imbalance. Did it myself not too long ago. 357Max poisoned his alloy with too much tin as well. The bullets go from nice and shiny to gettin ugly, dirty spots on them. Add back in a bit of WW's or Pb and it goes away.

[cbrick]

heavyMetal and 44man are both right.

As a suggestion I highly recommend getting a lead thermometer. It will answer many questions so you won't be "shooting in the dark" quite so much. Can boolits be cast without one? Yes, of coarse but it's kinda like trying to avoid speeding tickets on the freeway with no speedometer.

Rick

[grumpy one]

Any lead alloy containing both antimony and tin, with the tin exceeding the antimony, will contain crystals of tin, which the RCBS Cast Bullet Manual describes as "soft spots". If the tin content is less than the antimony content there will be crystals of antimony, but not of tin. Frances Weaver said that the pseudo-binary line (where tin and antimony are precisely equal) "may be said to divide the the ternary system into two parts. Each of these parts may be considered as a ternary system, so that the whole is composed of two ternary systems ..."

In practice all of the useful ternary alloys are on the left (low tin) side of the pseudo-binary line. That is not to say that alloys right on the pseudo-binary line may not have special advantages. There is much work to be done on this.