Unexpected Flux Discovery

[mpkunz]

I put a couple of old ingots into the pot this afternoon and had some floaty junk, so I decided to add some flux. But I didn't have wax handy. So I got some straight 30 weight oil, no detergents. Added about 2 mL and gave it a hearty still, then scooped off the dross. FWIW, it worked beautifully. You might want to give it a try.

[zuke]

And here I was trying to get all the oil off the WW before I smelted them!

[lwknight]

If it really totally worked , there would not be any dross to skim.

[mpkunz]

Could you elaborate ?

[idahoron]

I have used motor oil in the first smelt when I was making ingots. It works ok. Ron

[lwknight]

Almost everything in the melt can be returned to solution with fluxing and violent stirring.
What most people call dross is really nothing but oxides that will flux back in.

Motor oil has long even hydrocarbon chains that are formulated to tolerate high heat and as a result will not oxidize easily. This makes it a poor flux. You need something that will readily steal the oxygen from the metal oxides like low grade wax would do.

[firefly1957]

Years ago I tried motor oil and had a problem with thick black residue I think it was 10W-40 same Residue with bacon grease. I got it out by raising the temperature above where I would normally cast. No I do not remember how high the temp. got And I was smelting range lead not casting so it is possible that it was something picked up with the lead.

[sqlbullet]

I don't user motor oil in my casting furnace, but use it liberally when refining. Usually add about 1/2 cup to a 90 lb pot along with saw dust, flame it up and stir good. All that I have left is ashes when it goes out.

I have a diesel truck though, and therefore have lots of used motor oil around. The thing take 15 quarts on an oil change.

[mpkunz]

FWIW, I'd bet the ashes are probably largely zinc oxide from the anti-oxidant in the motor oil.

[mpkunz]

Almost everything in the melt can be returned to solution with fluxing and violent stirring. What most people call dross is really nothing but oxides that will flux back in.

Motor oil has long even hydrocarbon chains that are formulated to tolerate high heat and as a result will not oxidize easily. This makes it a poor flux. You need something that will readily steal the oxygen from the metal oxides like low grade wax would do.

What does your phrase "returned to solution" mean ? Lead oxide is not soluble in molten lead. Do you mean simply redistributed and mixed in ? If so, the oil was very successful for me in that is acted to gather and coalesce the unwanted oxides at the surface and make them easy to remove.

I think the oil did what I wanted in that there was probably not enough lead capable of being reduced from the oxide to be worth the time that would have taken, and this was cleaned, over and done with in a matter of seconds.

[madsenshooter]

The oxide portion of a metal oxide, be it lead, tin, or antimony oxide, depending on whether you flux with something that contains hydrogen, or carbon, will convert to either water (in a form that quickly evaporates of course) carbon monoxide or carbon dioxide. In either case that oxide becomes free of the metal it's bound to and that metal is then free to join in your melt.

[Doby45]

When I smelt WWs the only thing I scrap off is ash and clips. There is no "dross" to scrap off. The "dross" should be mixed back into the melt. That is what lwknight was letting ya know.

[lwknight]

What does your phrase "returned to solution" mean ? Lead oxide is not soluble in molten lead. Do you mean simply redistributed and mixed in ?

I should have said " reduced back to metal"
And lead oxides can be reduced back into lead metal if you use something more volatile than motor oil.
Diesel fuel has a high cetyl rating that you can benefit from just like using acetylene or ether. Obviously we cannot use ether or acetylene for flux. Both are the only hydrocarbons that will burn at 3% concentration and with as little as 3% oxygen. They are extremely oxygen hungry. Thats why they are so dangerous.

Diesel fuel is also very oxygen hungry so it makes a great refining aid. It is too flammable to use for flux so the next best thing is wax or tallow.

[1Shirt]

I will just stay with a wood stur stick. Less work, decent results, and satisfactory results. Think I have tried just about ever flux that anyone suggested, and always came back to the wood stur stick that I get from the paint store for nothing.
1Shirt!:coffee:

[mpkunz]

So the flux is to act as a reducing agent ? Not to help gather crud and hold it together for skimming ?

[montana_charlie]

So the flux is to act as a reducing agent ? Not to help gather crud and hold it together for skimming ?
Correct.

Surely you have noticed a grey scum that builds up on clean alloy as you cast.
There is no way that any 'dirt' can magically invade the molten alloy, so that scum has to come from inside the pot. If you know the metal started out clean, then the only thing it can be is 'oxides' of the metals contained in the alloy.

That is - metal which has captured oxygen molecules through contact with the air ... and been transformed into an insoluable material which is no longer 'metal'.

The kind of 'fluxing' used to 'reduce' oxides simply steals those oxygen molecules, and replaces them with carbon molecules. That returns the oxide to the metal state ... allowing it to again become soluable in the alloy.

CM

[midnight]

Montana Charlie put it all in a nutshell with that last paragraph. Remember those oxidation & reduction reactions from chemistry class?

Bob

[mpkunz]

I think I know the chemistry. I'm trying to nail down a precise and consistent terminology. So far between this and another site I've heard the term "flux" used to mean 1) a reducing agent, 2) a coalescing agent for gathering suspended particles together, and 3) as a substance for dissolvig metal oxides to prepare metal surfaces for another proces, 4) they sell stuff at Midway that is sold as a fluxing agent (Frankfort Arsenal) which I know to be anhydrous sodium metaborate, which has absolutely no reducing capability whatsoever. And I know from the days when I welded we called the material that was intended to build an oxygen barrier layer of the new weld to protect it while molten a "flux". That's at least five different uses for the word. Related perhaps, but distinctly different.

I just want to be able to use the terms properly so I don't get corrected constantly when I use them (or misuse them) the way even the people in the industry use them. Or, is that in fact the way "flux" is used throughout metallurgy ?

[garym1a2]

I just use my homebad bullet lube, it is not that great a lube but it is an awesum flux.

[montana_charlie]

I just want to be able to use the terms properly so I don't get corrected constantly when I use them (or misuse them)
When you're in church, the word 'deliverance' might have a different connotation than if you and three other dudes are paddling two canoes through the Appalachian mountains.

So, context does matter.

But, as long as you are here ... among friends and fellow bullet casters ... there are only two ways to use 'flux'.

One is that thing you do when you are melting down a hundred pounds to turn dirty scrap into pretty ingots. There may be terms for that activity that are more correct, but nobody here will fault you for saying your were fluxing while you were smelting. (Smelting is another word we knowingly misuse, by the way.)

The other way you can use the term (among us) is to say you were fluxing your bullet alloy to keep the melt clean. We know what you needed to clean off, and we understand what you did to accomplish that.

Those who don't understand the 'reduction' thing will get informed eventually ... just like you have in this thread.

CM

[mpkunz]

Cool. Thanks. YKWIM (you knew what I meant)

[gray wolf]

Surely you have noticed a grey scum that builds up on clean alloy as you cast.
There is no way that any 'dirt' can magically invade the molten alloy, so that scum has to come from inside the pot. If you know the metal started out clean, then the only thing it can be is 'oxides' of the metals contained in the alloy.

That is - metal which has captured oxygen molecules through contact with the air ... and been transformed into an insoluable material which is no longer 'metal'.

The kind of 'fluxing' used to 'reduce' oxides simply steals those oxygen molecules, and replaces them with carbon molecules. That returns the oxide to the metal state ... allowing it to again become soluable in the alloy.

CM

Now that was so well put even I understood it.
Nice explanation

[fcvan]

after hearing of folks using sawdust an wax while fluxing i tried something odd. I spooned a little ground walnut from my tumbler. the results were good and heaven knows ground walnut isnt hard to come by.

[lwknight]

The big candles that have lost their smelly are easy to get like dirt cheap at garage sales too.

[singleshot]

Ok, so reading this thread raises a question:

What is the purpose of the Franklin Arsenal "flux"?

[lwknight]

To make Franklin Arsenal company a lot of money. I never tried it but similasr stuff works great but has a really nasty residue.

[454PB]

Ok, so reading this thread raises a question:

What is the purpose of the Franklin Arsenal "flux"?

It is similar to Marvelux, which I use for fluxing while I'm casting and have for 35 years. It is "smokeless", and since I cast indoors with no ventilation, it works very well for me. When I'm "smelting" (sorry Charlie), I use about anything that contains carbon. I don't care if it smokes and flames because I smelt outdoors with plenty of ventilation. With a pile of greasy old wheelweights, I use no flux.......the grease does the job.

I don't worry about that gray slime that forms on top with Marvelux (or the Frankford Arsenal equivalent), because I don't skim the surface of the melt. I leave the "dross" on the surface until I'm done casting or until I add more metal to the pot. The gray slime disappears within a few minutes of casting and combines with the dirt and oxides we normally see on the surface of the melt.

Anyone that uses Marvelux or the F.A. equivalent needs to read the directions carefully. It IS hygroscopic and if stirring or dipping tools are not preheated, it will sizzle and pop when it touches the hot melt and the moisture is boiled off. However, this is a good safety practice regardless of the flux used.

A lot of casters hate Marvelux, and we've had some spirited discussions about it's use before. I offered to accept any and all of the Marvelux that was disliked by those on this forum, and so far only SR Custom has responded. He sent me about a tablespoon full a few years back.

[mpkunz]

Ok, so reading this thread raises a question:

What is the purpose of the Franklin Arsenal "flux"?

Well, from what I can tell after 33+ years of casting boolits, its probably being sold because casters buy it. There is an amazing amount of superstition among casters. I've used it, and I've intentionally not used it, and I see no difference in bullet quality.

It does find extensive use in the steel industry as a flux, the way that industry uses the word flux. But that's part of what led to such a long thread - the word has a lot of different meanings depending on who's using it. In the steel industry a major application is to remove iron oxide scale from steel surfaces, which it does extremely well, but it provides not one ounce of reducing ability, and it does double duty in that it melts and forms a protective coating on the hot steel so oxygen cannot reach it when its in a crucible, or when a bead of weld is being laid down.

[Russ in WY]

Is it safe for me to assume then that using a wood flake flux that is burnt down to a ash [carbon] residue is a good way to slow down or halt the formation of oxides on the surface of the melt ??????? Russ...

[bumpo628]

The Frankford Arsenal stuff is the only flux they sell on Midway. They probably sell based on that fact alone - preying on noobs. When I started out, I bought some before I knew that you could use just about any carbon-based material.

[mpkunz]

Is it safe for me to assume then that using a wood flake flux that is burnt down to a ash [carbon] residue is a good way to slow down or halt the formation of oxides on the surface of the melt ??????? Russ...

It'll work. The addition of things which liquefy easily at low temps to mix with wood keep the whole surface coated. Best not to use powdered graphite. Some folks have tried. Graphitic carbon, ie powdered graphite, is significantly less reactive than amorphous carbon found in charred wood. And minimizing air movement across the surface of the pot helps too. Its not actually carbon per se that does the reduction of the oxides, but carbon monoxide. The reduction is gas-solid reaction that takes place at the interface of the hot surfaces. Carbon, carbon dioxide, and carbon monoxide are involved in an equilibrium which favors the formation of carbon monoxide at our temperatures. According the Ellingham Diagram lead starts reducing around 308-312 oC, giving up oxygen to the CO. The CO becomes CO2, which reacts with carbon to produce another CO, and the process continues. If air movement around the pot removes the CO, the rate of reaction will decrease.

Wood char was the original classic carbon source for metallurgy and was only replaced by coal around the turn of the last century, a fact which was ultimately was instrumental in the sinking of the Titanic because of the sulfide inclusions it left in the steel.

[nanuk]

after hearing of folks using sawdust an wax while fluxing i tried something odd. I spooned a little ground walnut from my tumbler. the results were good and heaven knows ground walnut isnt hard to come by.

Ground walnut is near impossible to find up here locally. Have to have it shipped.

sorry, just had to add that.

[lwknight]

Try the sandblasting supply for ground walnut.

[t_dickinson]

Lemme get this straight and simple (in my little mind) so I know I'm doing this right.

Place WW in pot and melt.

Remove crud and debris.

Flux. Do I skim off crud one more time here?

When the lead skins over, that is oxidization occurring so flux again and everytime is "skins" threrafter.

Am I correct? How many crayons per lb?

Great explaination in this thread. Would be a good sticky called "Flux for Dummies" for noobs like me.

[a.squibload]

I usually flux before removing anything, just in case.
If WW clips are hot enough nothing sticks to 'em anyway, so pulling them out should be fine.
Also any Zinc WWs that are floating!
(I found a few "wall anchors" floating in a batch, apparently they are not lead.)

I finally tried ash from the pellet stove (fireplace ash), not sure whether it makes a good flux,
felt like adding dirt then removing it.
Sawdust from the pellet fuel seems to flux better.
I fluxed again with toilet ring wax to make sure.
Normally flux several times when smelting WWs.

Candles, pulled boolits w/lube on 'em, etc.

[mpkunz]

OK, now I realize this is just silliness, but I did it anyhow. We had Chinese last night. Had a whole quart of yellow pork fried rice left. Yeah, you guessed what I did with some of it it this morning. It worked.

For all you fans of Lethal Weapons, does that make it Uncle Benny's ? :o)

[mold maker]

Make sure to add the rice slowly and don't stir till the rice has dried and scorched. The moisture in the rice will invite the tinsel fairy, and she won't ignore the invite.

[mpkunz]

Actually that wasn't too bad. I stirred it in and it caused agitation of the melt, but not anything so bad that it was dangerous.

[Sensai]

Flied lice flux! Solly, couldn't resist:mrgreen:

[a.squibload]

Your neighbors will think you're just cookin' supper...

[Longwood]

Just this morning, I was wondering how well rice hulls or cotton seed meal would work. Sounds like rice may work also. Glad to see that pellets for a pellet stove will work. If they get wet, they puff up into stuff that won't work in the stoves but I bet it would work well for flux after drying. Sure is cheap and there is no way it could be as bad as the clay litter. I still wonder if I used the wrong stuff and should have used the type made from corn cobs which I did not know about until I came here.
BTW
I hear wood pellets makes good cat litter plus it smells better than most after the cats use it.

[mpkunz]

Just this morning, I was wondering how well rice hulls or cotton seed meal would work. Sounds like rice may work also. Glad to see that pellets for a pellet stove will work. If they get wet, they puff up into stuff that won't work in the stoves but I bet it would work well for flux after drying. Sure is cheap and there is no way it could be as bad as the clay litter. I still wonder if I used the wrong stuff and should have used the type made from corn cobs which I did not know about until I came here.
BTW
I hear wood pellets makes good cat litter plus it smells better than most after the cats use it.

Rice hulls are high in silicon content and will produce a fluffy silicon dioxide ash. If you follow the treatment with some of the borate flux, it will produce crude borosilicate glass. :o)

[jim147]

While on the topic of strange flux, I have about 200# of soybean seed sitting around. Sounds like it should work.

I'll have to give it a try next time.

jim

[Longwood]

Rice hulls are high in silicon content and will produce a fluffy silicon dioxide ash. If you follow the treatment with some of the borate flux, it will produce crude borosilicate glass. :o)
That's nice.
Or is it????
I have no idea what borosilicate glass is but with a big 25 cent word like that, it must be either good or deadly.
Just makin fun,,,,, can you please explain?
I put about a cup of wood pellets in a pan and added a little water and now I have about 5 cups of sawdust drying in the sun. The way I see it, a 40 lb bag should make about a pick up truck full. Way cheaper than the pet bedding I bought recently.
The bag says hardwood but that could mean just about anything these days. I will give it a try in a day or two.

[mpkunz]

Cheap glass, low melting point, easy for artsy people to work with. Which means I'm not arsty, because I can't make anything out of glass without it breaking.

[Longwood]

I tried some of the wood pellets that I first wet so they would swell up then dried in the sun.
Seems to be working great and it looks like a cheap and easy way for those of us who use pellet stoves and don't have sawdust.

[madsenshooter]

Borsilicate glass=inclusions in yer boolits. Sometime ago that Buck Beaver fellow on ebay sent me a sample of his flux. I tried it, it was pretty inert, just sat there on top. I told him to add a little citric acid, it'll bubble, boil and smoke and people will swear by it. He did, and they are.

[mpkunz]

Borsilicate glass=inclusions in yer boolits.

Really only an issue if you don't skim it off, don't cast from the bottom, etc. Never once found it mixed with the lead, always on the surface. One really annoying thing about it however is that it sticks to the sides of the pot.

[a.squibload]

I hear wood pellets makes good cat litter plus it smells better than most after the cats use it.

Yep, works good. Friend used it in the horse barn, had to wet it first to puff up,
otherwise it was like little bearings, bad traction.
I wondered about grinding it up, will try your method. Should dry completely
on top of the melt.

Jim147: I'm no soybean expert but do the seeds have a bit of moisture in 'em?
I'm thinking like popcorn in the melting pot!

[Longwood]

Jim147: I'm no soybean expert but do the seeds have a bit of moisture in 'em?
I'm thinking like popcorn in the melting pot!

Yah but it sure might take some of the boredom out of casting. :shock:

[Longwood]

[QUOTE=a.squibload;1248277]Yep, works good. Friend used it in the horse barn, had to wet it first to puff up,
otherwise it was like little bearings, bad traction.
I wondered about grinding it up, will try your method. Should dry completely
on top of the melt.


I dried it in the sun first. I had it on top of the pellet stove for a while but it swelled so bad it was overflowing the pot. I used it again this morning and it not only works well but using it is like casting over the camp fire.


My ex wife was always bugging me about wanting one of those fancy bathrooms with a view, so I built her an outhouse without a door. :veryconfu

[madsenshooter]

Really only an issue if you don't skim it off, don't cast from the bottom, etc. Never once found it mixed with the lead, always on the surface. One really annoying thing about it however is that it sticks to the sides of the pot.

When I first started, I used to stir it in. Wondered why my boolits looked like they had little clear looking things in them. Now I'm sure some fellow will chime in and say they stir Marvelux in and it doesn't cause them any problems. Good for them, but I don't use it anymore. I like these more creative ideas! Hemp seed anyone?

[Whistler]

I'm all with Mr. Fryxell on this one: SAWDUST!

I've always been using expensive commercial fluxing agents from Midway when casting, but this weekend I tried some sawdust. The difference was amazing! No dross to skim away, just the clips and dirt from the WW. Leaving the charred sawdust as a cover on the melt gave a good protection and my boolits have never looked so fine!

Smells nice too...