Not fluxing alloy melt ?

[hemiallen]

I saw a posting that stated that they had Linotype biscuts, dross'd but not fluxed.

I have always heard the proper tecniw=que when you melt any alloy for use OR to cast into biscuts you HAVE to flux to get the Tin and Antimony back in solution, then dros which is hopefully just oxides.

If you don't flux, don't you end up with a softer alloy because you remove some of the hardening alloys? Ingots look shiny, but I think not fluxing is bad???

Thanks

[BOOM BOOM]

HI,
I believe you are correct. Fluxing is so easy & simple to do why would anyone not do it?

[Bret4207]

Lean/tin/antimony alloys are supposed to be true alloys, they don't separate once combined under normal conditions. Fluxing is as much cleaning the mix as it is anything else. You have carbon helping the oxides ( the dross) recombine with the mix, helping the debris like dust, dirt and rust from the pot float to the top and loosening anything sticking to the pot.

Removing the dross but not fluxing is fine I guess. I'm not sure how much alloy you are losing, but I do know if I fill a 10 lb pot with dross and flux it really well I wind up with a good amount of alloy when I'm done. Fluxing is pretty darn simple- stir the mix with a stick. Why WOULDN'T you do it?

[hemiallen]

Thanks for the information.

Interesting on stirring with a stick, does it have to be a stick with a lot of pitch, or is it the carbon from leaving the wood in long enough to burn the wood that acts to flux the alloy?

I think overheating the alloy, ie more than needed to melt the metal, contributes to the alloys seperating and moving to the top as they arfe lighter ( less dense) than the pure lead.

Not sure why the seller stated NOT FLUXED, seems like a bad sales pitch to me.

[Bret4207]

The metals DO NOT separate in a true alloy which as I understand it is what were dealing with. Want to prove it? Set your pot to around 700 degrees and walk away for 8 hours. See if all the tin is on top when it cools, it won't be.

Just stir with whatever stick is handy and dry. Paint sticks, dowels, scrap wood, anything works.

[masscaster]

Depends on whay is gonna be cast. My plumber's pipe and flashing never gets fluxed, and the dross is kept in a special can. Since the "soft" lead is cold stirred to remove most antimony, zinc, and some other metals except tin. Then it's heated to about 725 and a bit of crushed charcoal is added to oxidize lighter material, this is scrappy dross.
The first skim in my special can waits til it's full, and i'm gonna be doing WW's for bullets, then on it's lonesome it's remelted, de-zinced as best as possible, and put in bars for a WW hardener. The latter is always fluxed at second hot stage.
Jeff @ Forefather's Casting

[hemiallen]

The metals DO NOT separate in a true alloy which as I understand it is what were dealing with. Want to prove it? Set your pot to around 700 degrees and walk away for 8 hours. See if all the tin is on top when it cools, it won't be.

Just stir with whatever stick is handy and dry. Paint sticks, dowels, scrap wood, anything works.

Ok

So what is the metal that I pick out of a melting pot, clip on wheelweights smelted to be poured into ingots ?

Even when I dross using bee's wax and the beeswax ignights ( using a propane turkey fryer as a heat source, and I start drossing as soon as the alloy goes from slushy to liquid mercury looks), when I use a spoon and angle it so I am not dipping into the alloy, the dross I put in a coffee can has metal in it, and that metal is harder than the alloy ingots......

[leftiye]

Bret - They do not separate as in one metal floating out, BUT they do form oxides, and the oxides do separate And those do float out. Tin being most active forms oxides at a much higher rate than antimony, and antimony separates (forms oxides) in preference to lead. Reducing (we call it fluxing on this board) changes (reduces the oxides - takes the oxygen from the oxide) oxides back into pure metal and allows them to be re-alloyed into the melt. This is only IF a carbon bearing or other flux is used that can attract the oxygen away from the tin,antimony or lead oxides. True fluxes (like Marvelux) do not do this, they only capture the dross for removal.

[Springfield]

hemiallen: you might be removing the zinc. I just did another 500 lb batch of different batches of lead form different sources. Most of the unwanted elements float to the surface(clips, pieces of steel, dirt, rocks, jackets, whatever) but sometimes I get a slushy coating on top. It could be oxides, I don't know. But I do know that if I flux well with wax or sawdust or whatever, and it is hot enough to burn, most all of the slush goes back into solution and all I am left with is ash. I pefer to keep all the metal I can and not have to dispose of it. So I flux well when doing the initial melt. I also find I don't have to flux the lead in my pots much if I do a good job initially. And the less crap I put in my pot the better it works.

[hemiallen]

Thanks

I was pretty sure I was right, ie not fluxing during the inital melt was a bad idea, hope the seller of the Linotype , or more importantly the buyers realize the alloy may not be high in Antimony anymore.

Allen

[snaggdit]

I saw a posting that stated that they had Linotype biscuts, dross'd but not fluxed.

I have always heard the proper tecniw=que when you melt any alloy for use OR to cast into biscuts you HAVE to flux to get the Tin and Antimony back in solution, then dros which is hopefully just oxides.

If you don't flux, don't you end up with a softer alloy because you remove some of the hardening alloys? Ingots look shiny, but I think not fluxing is bad???

Thanks

So I guess what the consensus is saying is this:
Exposure to air forms oxides. Flux converts oxides back to alloy. Dross is garbage and any oxides not fluxed back in.

I would add that oxides are a small part of the melt and linotype has lots of tin and antimony. As long as the garbage has been scooped off, not being fluxed is probably not that biga deal. If the price is right, go for it.

[hemiallen]

Incorrect on the LOTS OF ANTIMONY in Linotype, my friend.

Lino is about 6% antimony, 2% Tin, so removing ANY of the dros containing any silver colored metal makes the bullets softer than many linotype casters would like. This is why a lot of people want Linotype to be still in strips or typeset, because a lot of casters don't understand this and are selling inferior alloy, which may not be any better than WheelWeights . When a person adds pure lead to lynotype, knowing the constituents of the Linotype determines the mix before melting the 2 together.

Allen

[Bret4207]

Bret - They do not separate as in one metal floating out, BUT they do form oxides, and the oxides do separate And those do float out. Tin being most active forms oxides at a much higher rate than antimony, and antimony separates (forms oxides) in preference to lead. Reducing (we call it fluxing on this board) changes (reduces the oxides - takes the oxygen from the oxide) oxides back into pure metal and allows them to be re-alloyed into the melt. This is only IF a carbon bearing or other flux is used that can attract the oxygen away from the tin,antimony or lead oxides. True fluxes (like Marvelux) do not do this, they only capture the dross for removal.

We're in agreement, you just explain things a lot better than I do!:drinks:

[snaggdit]

Incorrect on the LOTS OF ANTIMONY in Linotype, my friend.

Lino is about 6% antimony, 2% Tin, so removing ANY of the dros containing any silver colored metal makes the bullets softer than many linotype casters would like. This is why a lot of people want Linotype to be still in strips or typeset, because a lot of casters don't understand this and are selling inferior alloy, which may not be any better than WheelWeights . When a person adds pure lead to lynotype, knowing the constituents of the Linotype determines the mix before melting the 2 together.

Allen

OK, I agree with that. My thoughts were that "compared to WW" lino has more tin and antimony. I have no basis for this next statement except some chem in college: I would think that the oxides formed and skimmed off (if not fluxed back in) would constitute only about 2-5% (max) of the available tin and antimony. That would make the 6% antimony now 5.7% (using 5% loss). That, to me, is minor. YMMV:)

[high standard 40]

Incorrect on the LOTS OF ANTIMONY in Linotype, my friend.

Lino is about 6% antimony, 2% Tin

Allen

Ok, I'm confused now. Rotometals sells ingots of Linotype metal and they claim 12% antimony and 4% tin. A mixture of 92-6-2 is usually listed as "hardball" alloy.

[snaggdit]

Ok, I'm confused now. Rotometals sells ingots of Linotype metal and they claim 12% antimony and 4% tin. A mixture of 92-6-2 is usually listed as "hardball" alloy.

Good catch. I wasn't thinking. I just went to lacs.us and they state linotype is 4% tin, 12% antimony, 84% lead. WW are 1/2% tin, 4% antimony, 95.25% lead, 1/4% arsenic. That is where my LOTS comment came from. In my mind I remembered it having a substantial amount more. I use foundry type to make a HV rifle alloy. That is even higher at 15% tin, 23% antimony, 62% lead. 8 or 9 to 1 WW/foundry gives me a nice alloy with about 2% tin and 6% antimony.

[leftiye]

1/2 % tin and 5% antimony alloy will heat treat to over 40(!) BHN. Thas close to wheelweight composition. Much harder than lino (BHN 22). My wheelweights are at BHN 22 twelve hours after heat treating. BHN 28 at 36 hours. BTW, they were HT'ed at 525 degrees (by a thermometer). Never seen an alloy not slump before at that temp. Also, HT'ed WW's are not brittle like lino is.