fluxing with kitty litter?

[EDG]

You could float almost anything inert on top of lead to act as a barrier to oxygen.
That could be a stainless plate, steel shot, or glass marbles.

One of the largest medical products foundries uses argon gas to do the same thing with their ASTM F75 cobalt chrome alloy. They have an argon drip line that provides a very small supply of argon to the top of the crucible. The alloy is melted and stirred by the current in induction coils. The argon provides a blanket of inert gas on top of the melt pretty much in the same fashion as the gas supply in a GTAW torch.

The next step up in shielding alloys is used with casting titanium.
Molten titanium is highly reactive it is melted in a vacuum furnace. To be sure the atmosphere is free of oxygen the pressure vessel is evacuated and purged with argon before pumping the chamber down to a partial pressure. Any residual gas is going to be a tiny bit of argon. The surface of titanium castings still have contaminants from the investment casting shell so the titanium has the alpha case removed by chem milling.
The titanium castings are also HIPPED which is hot isostatic processing. The castings are heated in a vacuum furnace to near the slumping temp in the presence of about 30,000 PSI argon pressure. The plastic like metal crushes any gas porosity and makes the gas diffuse back into the metal. This "heals" internal porosity defects and improves the fatigue life of castings like knee components that are load cycled all day long for years.
After hipping castings are xrayed and liquid penetrant tested. The xrays look for cracks and other internal flaws. The liquid penetrant looks for porosity that was connected to the surface of the part. HIPPING cannot heal a surface connected porosity defect since the porosity will have the same gas pressure internally and externally.
Maybe in a few decades younger guys will have better techniques to protect their alloy than those used by cats.

[dikman]

Personally, I reckon we're overthinking this whole process. A Promelt holds about 22 lbs. or so, when you're casting it needs topping up fairly regularly, so it's not as if it's sitting there for hours slowly oxidising. When I top mine up (with clean ingots/sprues) once it's melted I throw a small piece of wax on, stir it around, scoop off the gunk and start casting. Had no problems so far. The gunk, which will have some lead in it, gets thrown into the melting pot next time I melt down a batch of range scrap so any lead doesn't get wasted.

What we're doing hardly needs to be "laboratory clean".

[tankgunner59]

I use sawdust to flux my smelter, but I use paraffin for my furnace. Each works very well so I go by the old motto, if it ain't broke don't fix it.

[Dave W.]

I have used wax, saw dust, even some old dry grass on occasion. They all seemed to work fine. Never tried to use gunpowder, that just doesn't seem the best to use.

[Kraschenbirn]

+1 on what Char-Gar and Thumbcocker said. Been doing it for years without any issues. Keeps the pot clean (no pun intended) and absorbs/retains any crud that might float to the top of the melt.

Bill

[EDG]

Over thinking? Not a chance if you look at the cruddy bullets cast by most casters. Any convenient way to keep the metal clean is better than bullets loaded with inclusions and dross. Commercial methods are good because commercial companies have developed them as part if their competition for business and existence in the market place.

[Littleton Shot Maker]

long ago- told to me by a guy that had been casting and making shot for 30+ years..that was 10 years ago-
he uses the cat litter on top of his dutch oven smelter-to be the filter-
the lead goes down into the mix and the crud stays on top. clips, jackets, rocks etc etc…
he still fluxed- with parafin/beeswax mix to get the tin/lead/Ant to bond- the litter was the 'poor mans charcoal filter' for lead - the way he told it to me…
but he told me also - most folk get into a rush and over heat the lead- so he always did his smelting at just around 600f not much more….lower if he could get the alloy to melt down through the litter...

[captaint]

I used kitty litter for about a year. I felt like I had dirty boolits constantly, so I switched back to just the wax. I'm much happier now. It's much easier to keep my melt clean..

[greenjoytj]

I read about using saw dust as flux, so I tried our cat litter material. We buy the type made from ground corn cob as it is advertised as toilet flushable. It work great put smokes heavily till it chars.

[Smoke4320]

Tryed kitty litter once.. Wife got really mad when she could not find her cat.. Guess i should have removed it first

[trapper9260]

I use ground corn cobs.The same one that i use on my brass. But the unused one.It works for all I do with it.I had a farmer ground up some cobs for me years ago in his feed mill for me. I have alot to last me some time.Some times when I am smelting ,I use wood for my heat and it is low heat at first before the ashed a build up.I take the ashes and put in in the pot to flex also.Beside use the corn cobs.Since it all that is added for flux turn to ash. My alloy is clean after and put in igot after. I also flux when casting with the corn cobs.

[wjham77]

I recently tried kitty litter (Walmart special kitty natural clay) in my Lee 4 20 and I like it, I still flux with wax. I've also had issues with dirty bullets recently, I really hope it's not the litter, cause it really helps cut down on the need for fluxing. I cleaned my pot and am gonna start with different batch of lead. First without the kitty litter, then once I know I getting good bullets, I'm gonna try the litter again, and see if it makes a difference.

[Mr_Sheesh]

Clay type cat litter (Bentonite) wouldn't likely do, but the paper or cob ones would.

[gwpercle]

I have access to pencil sharpener shavings , a pinch of shavings in my casting pot with a pea sized ball of bees wax thrown on top works great . Stirred with a wooden paddle and skim off any dross. The cedar smells good too.
I never did care for the layer of clay kitty litter floating on top...just seemed to dirty up things.
Gary

[john.k]

You get a strange effect with lead where contaminants stick to the sides of the pot,even tho they are much lighter than lead.Then come to the surface when disturbed,resulting in dross on the lead surface,that will end up in a ladle cast.This is the same stuff that causes problems with pour valves.Its often fine sand.