16-1

[PopcornSutton]

When using wheel weights or linotype made from real type, it's fairly understandable that you will get crud floating to the top once fluxed. And it keeps coming up during a casting session. There isn't anything particularly "pure" about them.

I bought some 16-1 from a well known supplier, and you can get a certification of it if you pay for it. My question is, I still get the grey crud floating up from what I assumed was controlled components. And I started this in a new-to-casting pot which I scrubbed completely clean.

I also thought the grey stuff was antimony, but there isn't supposed to be any in there.

[Dusty Bannister]

You have fluxed (not sure what you used), but what did you use to reduce the oxide back into metal?

[gc45]

15-1 16-1 or more correctly #2 Lyman. - In my shop are several pallets of the stuff, bought years back from local non-ferrous company who, in my opinion makes very good quality melts for any and all customers from marine to shooting sports. When I flux, there is minimal junk floating about and oce spooned off I get great bullets. I also mix it 50-50 with pure as possible lead and for a softer bullet in my handguns of 1000fps or less.

[PopcornSutton]

I used beeswax to flux.

[gc45]

i too use Beeswax for fluxing.

[huntinlever]

I don't think that's impurity, I'd say it's tin oxide - which needs to be reduced and incorporated back.

Edit: Missed a couple posts above. Yes, I'd say that's tin oxidation and not likely from impure alloy.

[PopcornSutton]

Having never heard of doing anything other than "normal" fluxing, what and how is used to correct this?

[Larry Gibson]

That "crud" on top of each alloy is simply oxidized alloy. When you flux it will mix right back into the alloy.

The crud is the same alloy as still molten. It is not tin separating from the alloy.

As mentioned, what is happening is what will happen. Just learn to flux as we all have.

[huntinlever]

That "crud" on top of each alloy is simply oxidized alloy. When you flux it will mix right back into the alloy.

The crud is the same alloy as still molten. It is not tin separating from the alloy.

As mentioned, what is happening is what will happen. Just learn to flux as we all have.

Oh, I didn't know that. I'd thought somehow the tin was preferentially oxidized, and so losing it would mean losing a percentage of tin in the alloy as cast. So, it's just pure loss, then - no changes in terms of content to poured alloy?

[Larry Gibson]

Oh, I didn't know that. I'd thought somehow the tin was preferentially oxidized, and so losing it would mean losing a percentage of tin in the alloy as cast. So, it's just pure loss, then - no changes in terms of content to poured alloy?

None at all. Once the tin is mixed into solution with the lead it will not be separating from the lead during any kind of normal casting operation. As mentioned the "scum" that forms on top is the same alloy that is just oxidized.

[huntinlever]

None at all. Once the tin is mixed into solution with the lead it will not be separating from the lead during any kind of normal casting operation.

Great to know. Thanks Larry.

[RickinTN]

You have to reduce the scum back into the mix, not just flux. It is a chemical reaction, not physical. There is a difference in reducing and fluxing.
Good Luck,
Rick

[huntinlever]

You have to reduce the scum back into the mix, not just flux. It is a chemical reaction, not physical. There is a difference in reducing and fluxing.
Good Luck,
Rick

This is my confusion, I guess. If we are reducing oxidized material back into the mix, but the oxidized material is the same content, though oxidized, as the molten content - there's no real issue in terms of cast alloy, right? I.e., to make it obvious, say the only "crud" is 100% oxidized tin. That would mean the molten mass is now significantly lower in tin and you will be casting a much softer alloy than 16:1, so it's critical to reduce the tin back into the molten mass.

But if the crud is nothing more than oxidized 16:1, the only benefit of reduction would be to limit yield losses in total, right?

[white eagle]

I just skim it off and discard it

[Larry Gibson]

The use of some "fluxes" are also excellent "reductants" to remix the oxidized alloy back into the mix. Beeswax and paraffin are two. They work quite well with alloy that is already smelted. While they will flux the oxidized alloy back into the mix and bring debris to the surface, they won't separate many impurities from the mix as will a true reductant. Something as simple as sawdust is an excellent reductant and flux and is best used outdoors when smelting material initially such as COWWs.

When fluxing the alloy in the Mag20 I drop a piece of beeswax (about marble size) onto the alloy and then 2 or three wooden matches. The matches ignite and reduce the smoke/smell of the beeswax 95+%. The alloy fluxes excellently and with the matches I like to think I'm get a good redux also. Maybe not but it's worked for me for many years.

[missionary5155]

We also use beeswax and once it smokes light it afire. We also stir with a dry wood stick.

[Froogal]

When using wheel weights or linotype made from real type, it's fairly understandable that you will get crud floating to the top once fluxed. And it keeps coming up during a casting session. There isn't anything particularly "pure" about them.

I bought some 16-1 from a well known supplier, and you can get a certification of it if you pay for it. My question is, I still get the grey crud floating up from what I assumed was controlled components. And I started this in a new-to-casting pot which I scrubbed completely clean.

I also thought the grey stuff was antimony, but there isn't supposed to be any in there.

I have the same problem with 1-20 lead, also from a well known supplier. I just skim it off and discard it, otherwise the crud accumulates around the pour spout and then drip, drip, drip.

[gwpercle]

That "crud" on top of each alloy is simply oxidized alloy. When you flux it will mix right back into the alloy.

The crud is the same alloy as still molten. It is not tin separating from the alloy.

As mentioned, what is happening is what will happen. Just learn to flux as we all have.

And as long as you keep the metal molten ... the heat will form more oxides and it will float to the surface ... it never stops and it has nothing to do with the lead and tin or where you bought it . When casting from a 20 lb. pot with a Lyman spouted ladel , I will do 3 -4 quick beeswax fluxes and skim the top during the course of a casting run .
And the higher the heat ... the more oxides will form .
Gary

[Tripplebeards]

It also happens to me when I have my pot temperature turned way up. The hotter it gets the quicker I get crud. Just oxidization is everybody else has said. I just keep scraping it off every so often.

[popper]

I just scrape it off and save it for the next melt. Beeswax flux used here.