Home Forums Reloading Bullet Casting Fluxing?

All, I am a very novice bullet caster, despite having cast functional bullets for both muzzleloaders and handguns for the last 40 years on and off, I know little about the technical details.

I started by making muzzleloader projectiles and fishing jigs using plumber's lead as a kid...easy enough. For pistol bullets, I have simply melted wheel weights, skimmed off the metal clips and associated trash and then proceeded to cast bullets. These bullets were then lubed with liquid Alox and worked well enough for my needs.

My primary source of lead is wheel weights, which I've collected over the years and have several hundred pounds of. I have read about fluxing and have access both to lots of beeswax and sawdust, but I don't understand the process. I have read about it on the cast bullet association forum which further shed insight into how little I know about casting.

Any simplified instructions would be welcome. Thank you.

Not unlike anything else associated with making your own ammo, there's lots of voodoo associated with this. Some of it is backed up with science, some of it is just plain BS that people have bought into.

As far as I'm concerned, fluxing simply breaks the bond (surface tension) between the alloy melt and anything else in the pot that isn't lead alloy, and allows you to remove it from the surface, and that includes non lead contaminants and any oxidation that occurs while the alloy is above it's melting point.

As far as all the voodoo you'll get on this subject, I suggest people study up on the science behind it all.

I like wax fluxes and stirring the pot with a wood stick. I use cheap Walmart tea light candles for smelting, and I mix those 50:50 with raw brown beeswax for casting. I only ladle cast so I flux fairly often to keep the pot fresh.

Fluxing is also something I have wondered about myself. I want to get into casting . I got a friend that has casted for years but, he and myself are busy a lot and it's hard to get together to learn the basics. Thanks

Fluxing also reduces the tin and antimony oxides and turns them back into metal that goes back into the melt. When melting wheel weights for the first time there is usually enough oil and junk that burns off fluxing while they melt. But when everything is melted throw a pea sized piece of beeswax and some sawdust on top and stir it up good. The beeswax will probably ignite and you might have to add a few pieces. Then you will see silver melted metal with some black ash like crud on top. Scoop off the crud.

With a clean ingot or if you are adding linotype when it is first melted you might see some silver oatmeal like stuff floating on top. Do not scoop this off. It is the expensive tin and antimony that hardens the lead. Add some beeswax and stir and it should melt back into the pot. Then scoop off the black ash crud.

For smelting dirty lead I use wax and sawdust but for clean ingots I only use beeswax. Paraffin wax and cheap candles also work.

And watch your temperature when melting wheel weights and don't let it get much over 700 degrees. Many wheel weights are made of zinc that melts at a higher temperature (look it up) and if they melt it will contaminate your lead. If you have a wheel weight that doesn't want to melt take it out.

Beeswax for me. When it starts to smoke like crazy I throw a match to it and stir until the fire's out, then skim the dross with a serving spoon I liberated from my ex-wife's silverware drawer when I left. Repeat as necessary during the casting session.

I tried Marvelux once and quit it after it made a black mess of things.

I use dry wood dust mostly & wax some. I normally flux well before pouring ignots & seldom while casting bullets.

I generally use paraffin, lube or beeswax. Paraffin seems to disappear pretty quick once lit.

Marvelux works well but retains moisture and stays there until every last bit is removed, so it has a pitfall.

Fresh pine pitch or rosin make a great flux.

My main concentration when fluxing is when making ingots.
Anything in a bottom pour should just have storage dust on it and just need those removed once fluid; no tin or antimony loss occurs at the first eutectic state.
It is said constant fluxing while casting makes bullets of greater variance.

Under what exact circumstances would that be?

In my practices the exact opposite is true if pot temp, mold temp, and casting cadence are kept constant. I only ladle cast and not fluxing two or four times through a 20 lb pot is a fantastic way to get an excessive number of weight rejects due to oxidation inclusions. I say 2 or 4 times but it's as required when I have to dig through dross and dross starts to hang from the ladle. The softer alloys i use tend to dross up a little faster so I tend to stay ahead of it. I don't know if that qualifies as "constant" or not, but it's a few more than once. I'm generally not unhappy at all with my pass/fail ratio. Fluxing does raise the melt temp slightly and I could see someone casting big right after a flux and back to small again once it cools back down, if they're not paying attention to what they're doing. Which I think is probably the root of all evil voodoo associated with bullet casting.

And there's the voodoo.......

This, is purely for the benefit of the OP, and not to argue with the voodoo witch doctors.

The melting point of lead oxide is 1630 degrees F.

The melting point of tin oxide is 2966 degrees F.

Non of the processes to remove antimony from lead involve anything on a bullet caster's bench, nor is it even possible to separate antimony from lead with the equipment and processes we use. Once antimony is in solution, it stays there, there is no separation under normal casting processes. "Oatmeal" means you're just not up to temp yet for that particular alloy. Yeah, you can skim that off and lose some hardness, but the smart caster knows it's not up to temp yet and he's watching his lead thermometer.

Fluxing breaks the surface tension bond between lead/tin oxides and the good alloy, making it possible to remove the oxides without losing the alloy that sticks to the oxides and other contaminants. The oxides are unavoidable unless you cast in a vacuum absent of oxygen. Again, not in the normal bullet caster's world. Fluxing gets the oxides removed and reduces the amount of wasted alloy. There is no returning oxides to the melt because we are not operating at those temperatures that would accomplish it.

The formation of oxides can be reduced by reducing the amount of melt surface exposed to air. This is why a bottom pour pot is just best left alone until more alloy is added in. The oxidized surface protects the melt beneath it. Oxidation is the bane of the ladle caster though as he is constantly disturbing the melt surface and exposing fresh lead to air, causing it to oxidize. He dips and pulls, and pours and dribbles, and returns the unpoured to the pot, and then pushes the dross back to get a fresh dip for the next pour. Lots of oxidizing going on there no matter how careful he is.

If you don't believe the science then prove it wrong by weighing a clean melt, weighing a bunch of pot skimmings you know are oxides, toss it all together and flux the schit out of it. Skim off what won't melt and I'll bet very heavy odds you actually lose some of the weight of the clean melt you started with.

Geesh people.......

Thank you for the replies. I also only ladle cast and get stuff on the top of the pot that I am constantly skimming off (oxides if I understand correctly). I was under the impression that I would get less of this stuff if fluxing correctly but perhaps that is not the case. I also wanted to insure that I was not skimming off valuable tin or antimony but it sounds like once it has oxidized its lost for good.

Again I am only trying to slightly improve my relatively primitive bullet casting, mainly for 44 mag pistol at 1100 fps if that is relevant.

Thanks.

The more you skim the more the surface will oxidize, then the more you need to skim. Use the oxidation layer as protection for what's under it. Push just enough dross out of the way with your ladle to get a fresh dip. Before you dip again, tap your ladle in/on a scrap container to knock any hanging dross off and thus not introduce it back into the melt when you dip again. Keeping your ladle as hot as your melt keeps alloy from sticking to it and increasing oxidation. If I have to put my ladle down for any reason during a session I stick it down into the pot, keeping it hot and not letting it cool off. Another trick is gently "rolling" your dipper/ladle into the melt like you're getting a scoop of ice cream. That seems to reduce the amount of lead exposed to air by limiting how much you disturb the surface.

Don't know; I scrape/skim at the beginning and scrape/skim again after adding more metal. I generally don't flux beyond the ingot stage very often.

When ladle casting I use a Rowell.

Mike Venturino stated he did not flux constantly during casting due to weight variances, that's where "it is said" came from.

Hmmm, interesting.

What would be a good proof test.....Flux the pot every 10, or 20, or 30 casts? Keeping chronological track of the bullets and weigh them to see exactly what happens.

Compare them to a run of the same number of bullets with only one flux at the beginning.

That sounds similar to what Mike did to get his conclusion.

He based it on making his LRBPCR rounds, where he wouldn't even use an alloy that wasn't certified, so he was extremely fussy with those bullets.

I've never tested the concept myself, but I largely quit fluxing while making bullets after reading the article.

Fussy LRBPCR shooter only using a certified alloy.

I'd wager heavy odds his criteria +/- is a bit tighter than mine.

And that's fine I'm not shooting long range black powder cartridge at any level.

And neither is the OP from what he says...

It is not voodoo. It is basic science and the oxides don't need to melt. Waxes and sawdust create reducing conditions that will chemically reduce the oxides back to their base metal and that metal goes back into the melt instead of needlessly being skimmed off.

Glen Fryxell wrote a detailed chapter on fluxes in his book. You should read it.

So far, I have been mostly using saw dust since I have a wood shop and more than enough sawdust. Whats the difference between using sawdust and wax? I was under the impression that either does the same thing, but I am still learning. The tea candles are cheap enough and I do have bees wax on hand.

Sawdust and wax both create reducing conditions and sawdust is probably a better flux since it can also remove other metal contaminates. But sawdust also creates more ash / carbon that I don't want in my bottom pour casting pot. So I use a good bit of sawdust with wax (and cover the pot with a lid) with the dirty first smelts to get clean ingots. But once I remelt clean metal in my casting pot I just a pea sized piece of beeswax or two. That should be all you need.

Beeswax does stay in the pot longer and creates an oily surface that you can spoon off while paraffin burn off much quicker. They both work so you can decide which you prefer.

Yeah, it is voodoo.....

If you're going to stand on that hill, well, then prove it.

If it's truth, then you shouldn't have any problem adding measurable weight to a melt by adding lead/tin oxides.

Saw dust is a useless pain in the ass that just leaves more mess than benefit. If you don't want it in your bottom pour pot then why would you want it in your pot at all. I tried saw dust one time, and had to use a ton of wax to get it all back out. Not a thing at all about it I would revisit. A stout hardwood stick to stir a smelt makes sense, a bunch of saw dust stirred in and trapped throughout the melt doesn't.

Oily surface with beeswax?

Your melt is too cold.