flux question....

[rondog]

Could I use my old walnut and corncob brass polishing media for fluxing, prior to pouring ingots? I've got quite a bit that I was just going to toss out. Started out as just clean media, only has NuFinish added to some of it. I don't have any of that colored commercial media the gun shops sell that has rouge and whatnot in it.

[Bill*]

Someone with a better memory might jump in and remember exactly, but I believe I read in a recent post that walnut gives off a bad thing when burnt?

[sagacious]

Old tumbling media is not something I'd use to flux clean lead while casting, as old media will almost surely contain some grit from fired brass picked up off the ground. But if you're melting down dirty scrap, then you could give it a try. You'll know immediatly if it works or not.

[Bret4207]

If you insist on using something that produces scads of smoke and smell for flux and still requires you to use another item to stir and scrape, then go for it. Or, you can simplify things and just stir and scrape with a dry stick of some sort- way less smoke, no flame and it gets the carbon into the mix for fluxing as you stir and scrape.

[WHITETAIL]

I would not use it.
Why would you add more
dirt and junk to your mix?

[rondog]

This is why I'm asking. I've never done this yet, and don't really understand the concept of fluxing to begin with. Seems like ANYTHING that you put into a pot of molten lead is going to burn, smoke and stink. I've read about you guys using sawdust, candles, crayons, wax toilet seals, paint stirring sticks, beeswax, and God knows what else. I've read that "any carbon based substance will do".

Guess I'm kinda dense, but I'm still unclear on the reason for scooping off all the clips, zinc and other junk the best you can, and then throwing more foreign stuff in the lead to stir it around and watch it burn. It "removes the impurities", but how? Tossing in wax, sawdust, wood sticks, etc. and burning it to ash "cleans" the lead? Yet corncob and walnut, also "carbon-based organic substances" aren't good? I don't get it.

[Cactus Farmer]

Go to your friendly butcher and get some scrap fat,cut it up into 1 inch cubes and toss a couple on the top of a melt. The fat rendering out does a great job and smells pretty good too. Finish off with a scrape from a slotted spoon to the remove the trash. Voila, clean ready to pour metal.
I smelt it all out then remelt to alloy my bullet metal. More consistant metal is consistant with good shooting and repeatable results. Hardware scales are handy for weighing out the raw ingots and tin/hardening mix. Then throw it all in the pot for a second melt. Minor fluxing needed the second time. Make sure to mark the ingots as to their make up. I thought I'm remember too,but was proven wrong. I stamp mine with BIG number and letter dies to identify the metal.
No suprizes is good!

[Bret4207]

This is why I'm asking. I've never done this yet, and don't really understand the concept of fluxing to begin with. Seems like ANYTHING that you put into a pot of molten lead is going to burn, smoke and stink. I've read about you guys using sawdust, candles, crayons, wax toilet seals, paint stirring sticks, beeswax, and God knows what else. I've read that "any carbon based substance will do".

Guess I'm kinda dense, but I'm still unclear on the reason for scooping off all the clips, zinc and other junk the best you can, and then throwing more foreign stuff in the lead to stir it around and watch it burn. It "removes the impurities", but how? Tossing in wax, sawdust, wood sticks, etc. and burning it to ash "cleans" the lead? Yet corncob and walnut, also "carbon-based organic substances" aren't good? I don't get it.

I can't tell you exactly how it works, but it does. When you flux, in the sense we're doing it, you're using the carbon to "release" the tension on the oxides and stuff so that the bad goop floats to the top and the good goop remixes with the alloy. You have to scrape the sides and bottom to get the c rap loose, and you ahve to stir ti to free the "floaties". Using a dry stick you will get some smoke, but no where near what you will with oils or waxes and no fire either. Just trust me and try it.

[XWrench3]

the best thing that i have found so far is sawdust. it is CHEAP, redily available, and gives off a nice smell while using it. furthermore, it leaves a nice "crust" over the melt to help keep oxygen from getting to the mix. of course, i admit to having only tried half of a dozen things for flux. but i like this so well that unless someone tells me straight out that there is something that is 200% better, i will not be looking for a replacement.

[troy_mclure]

best thing i have found is a wood dowel rod.

leaves very little residue, but fluxes even the oxidation in good.

iv used paper too. works fine, but it leaves alot of ash.

i had to use wax(candles) when alloying antimony to tin as the wood just wasn't doing it.

the lard/fat was just too messy for me, lots of black goop stuck to my smelting pot.

[Randall]

I use hamburger grease for smelting,a touch of hamburger grease and some sawdust for casting.

[Hardcast416taylor]

If you are looking for a use of the dirty media, you might try doing what I did. I was making up a bunch of new sand bags and wondered what else I could use besides sand. I filled the bags 3/4 full then hand sewn them up. Since I don`1t leave my bags out in all kinds of weather these work great and are lighter than sand bags.Robert

[shooter75126]

I can't tell you exactly HOW it works, but I can tell you what it's supposed to do. When using a flux, I'm looking for it to do several things. One is to clean all the dirt and other gunk out of the lead. Any carbon based substance will suffice for this process. You also want to do most of this during the smelting process so you will have as clean a casting alloy as possible. The other thing I'm looking for it to do is keep the alloy from oxidizing while casting. Again, anything like wax, lube, or sawdust will work if you keep a good layer on top of the melt and keep air from getting to the lead. The other thing, and the one I just learned about, is to reduce any oxidation back into the alloy. According to Glen Fryxell, sawdust is best for this application. It will actually turn the oxidized junk back into liquid, then you stir it back into the alloy and scrape off all the leftovers.

To answer your other question, I don't know how well the corn cob or walnut media would work. I don't know what the additive in your media will do to the alloy. I can't see it hurting, other than you're adding a bunch of extra junk from cleaning your brass, which just adds more stuff to flux out of the alloy. I don't know if this would be counter productive or not. Also, I don't know if any unburned gunpowder from the media would flare up or not. Probably doesn't make a difference with the gunpowder, just a thought. Hope this helps. I'm no expert, so if anyone sees something that I've gotten wrong, please feel free to correct me.

[sagacious]

I'm still unclear on the reason for scooping off all the clips, zinc and other junk the best you can, and then throwing more foreign stuff in the lead to stir it around and watch it burn. It "removes the impurities", but how? Tossing in wax, etc. ... "cleans" the lead?

Rondog,
You are correct-- simply watching the flux burn off does not help. Question: Why put rosin in perfectly good solder? Answer: Because rosin is a fluxing agent, and it damatically helps when soldering/joining/alloying metals. A good flux will assist you while preparing/alloying/cleaning your melt for casting like a good flux will help your soldering.

Flux before scooping off all the clips! The flux helps separate the crud/dirt/clips from the lead, so you can scoop off the clips without losing lead.

It's critical to understand how to properly flux the melt. The answers to your other questions about fluxing can be found here:
http://www.lasc.us/FryxellFluxing.htm

Hope this helps, best of luck.