what does "fluxing" actually do?

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specopsjeff posted this 31 May 2010

I did as “ordered” and fluxed with parafon wax.

btu was wondering what it actually does?

I learned my lesson the first time i tried this yesterday... wow it caught fire like gasoline

I almost fell over backwards lol!

well i learned anyway and no burns.

I need to order the book on casting.

Jeff

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JetMech posted this 31 May 2010

Fluxing cleans the impurities. I think it actually breaks the surface tension of the junk allowing it to float to the top. If it ignites spontaniously, you may have the temp up a little high. Usually, I cast @ about 700-750 and I have to light it off.

Lyman's new Cast Bullet Handbook, 4th Edition is due out soon. Last time I checked, it's supposed to ship this month. It should be worth the wait, Jeff.

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redball 2 posted this 31 May 2010

What fluxing does is it takes oxygen out of the mix. anything that burns can have this effect. anything that burns is oxidizeing. 

Jim Wilcox 

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303Guy posted this 14 June 2010

What fluxing does is it takes oxygen out of the mix.It returns metal from the oxides to the mix by releasing the oxygen.

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JSH posted this 14 June 2010

I have my own thoughts on “what it does". None the less it does several things and does them at different temps. For the most part, I have found fluxing at a lower temp, between slush and fully molten, to work best for me. I used to put my flux in and it would flash pretty quick. I never really saw anything more than the dross rise. I started fluxing at a lower temp, alloy seemed to flow better. I also give the pot a stir about every 10 minutes. jeff

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303Guy posted this 14 June 2010

I'm going to keep that in mind - sounds interesting.

I do things a little differently - as I do.  I keep a layer of Kity Litter on to of my melt and I stir and flux with a dry stick.  The carbon released gets trapped over the metal within the Kitty Litter.  The Kitty litter allows for a higher melt temperature and prevents oxidation.  Nevertheless, oxidation takes place when the ladle remains are returned to the pot and also the sprew plugs.  Those get dropped onto the kitty litter and warm up and melt through, leaving a skinr of oxide.  That gets returned to the melt by fluxing from time to time.

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TRKakaCatWhisperer posted this 14 June 2010

Flux comes from the latin word meaning 'to clean'.

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cityboy posted this 14 June 2010

specopsjeff wrote: I learned my lesson the first time i tried this yesterday... wow it caught fire like gasoline

I almost fell over backwards lol!

The same thing happened to me when I started casting about 50 years ago. Scared the heck out of me. I have tried many fluxes and find that Ivory soap works about as well as any. Just take a bar and shave off some slivers. Don't just toss in big chunks. No smoke and smells pretty good.

Jim

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303Guy posted this 14 June 2010

What exactly is Ivory soap?  Does it have a brand name?  (Remember I'm from 'down under' where things are.... well.... a bit upside-down!/images/emoticons/134.gif)

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Dale53 posted this 15 June 2010

Ivory Soap is a bar soap and a product of Proctor and Gamble of Cincinnati, Ohio. It has been very popular in the U.S.A. for about 100 years.

FWIW Dale53

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FAsmus posted this 18 June 2010

303Guy:

You say: I'm going to keep that in mind - sounds interesting.

I do things a little differently - as I do.  I keep a layer of Kity Litter on to of my melt and I stir and flux with a dry stick.  The carbon released gets trapped over the metal within the Kitty Litter.  The Kitty litter allows for a higher melt temperature and prevents oxidation.  Nevertheless, oxidation takes place when the ladle remains are returned to the pot and also the sprew plugs.  Those get dropped onto the kitty litter and warm up and melt through, leaving a skinr of oxide.  That gets returned to the melt by fluxing from time to time.

Forrest:

How do you cast with all that stuff on top of the molten alloy? ~ Doesn't the litter get into your casting ladle and thus into the mold?

Good morning, Forrest

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303Guy posted this 18 June 2010

How do you cast with all that stuff on top of the molten alloy? ~ Doesn't the litter get into your casting ladle and thus into the mold? I just dip down the side of the pot.  The kitty litter is very light and if it does get into the ladle it does not get into the mold.  What it does is keep the alloy at a uniform temperature by insulating it - my pot is also insulated.  I allows me to dump the sprues plugs straight back into the pot where they sit on top and warm up until they get pushed under with a wooden stick which then is used for fluxing and stirring.  I never have to worry about skimming.  Eventually the litter gets heavy with oxides - yellow and red, depending.  This stuff is toxic and needs to be disposed of safely.  Before removal of the kitty litter, I give the pot a goodly fluxing with the stick to get all the un-oxidised metal out of the dross then let it cool.  The pot then gets tipped over and the dust and crud removed.  (Keeking upwind).  There remains a porous latticework of partial oxides.  This get returned to the melt with the addition of new kitty litter and a goodly fluxing.

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Coydog posted this 20 June 2010

I have done some lead up yesterday and I fluxing it with grouned up corn cobs that I have a famer do for me .I use it for cleaning my brass. I try it out yesterday on fluxing and it work really good for me just put enough to cover the top of the melted lead and let it start to turn black and mix and then it will catch fire and mix it again and then skim. It seem to draw the impureitys . I did have alot of cobs grouned and it is safer then wax .I had use that before . It look like the cobs a little better.Just to let you all know of something else that can work good.

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JSH posted this 20 June 2010

I tried the floor dry/kitty litter trick. I t works very well when using a bottm poor. beware you may have to turn your heat down as it keeps a LOT of it in. I used this method for a while and the cleaning of the pot is a necessary chore about every third to fifth session. Or, at least I thought it did. Any of you folks that want to try this, make sure you put the stuff on top of the pot BEFORE you turn it on. Yes it feels dry, but it will attract moisture from the air. I never had any bad mishaps, but it did get close to the point of being exciting......... jeff

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303Guy posted this 20 June 2010

It does keep the heat in!  If'n you place sawdust or something onto the metal then the Kitty Litter on top, it keeps a layer of carbon over the melt.  If you stir, the black carbon gets exposed and quickly dissappears.  That shows it's keeping oxygen away from the melt surface.  It does become contaminated with oxide and need changing from time to time.

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FAsmus posted this 22 June 2010

303Guy;

You say;

I just dip down the side of the pot..."

Forrest;

Thanks for the detailed explanation - I would have never tried that technique on my own.

My method, by comparison, is rather crude. For example I have not ever cleaned out a casting pot beyond merely scraping out the obvious junk.

I know that the cat litter's absorption of oxides make it into very dangerous stuff. Do maintain extra care in handling it at all.

My casting furnace has a wild capability for production of heat - such that I really avoid casting at all unless the outside temperature in below 40 degrees F. As you can see, this eliminates the possiblity of running into unstable temperature.

In use my alloy will gradually oxidize such that black lead oxide will accumulate on top of the metal. This is easily removed by “normal” fluxing procedures.

I flux by use of old Canola oil that the wife allows (now and then) to become rancid. I put it into an oil squirt-can and pump it onto the hot alloy as required. If I run out of this stuff I use olive oil. This method alows me to scrape off the still sticky dross and toss it into the coffee can for safe disposal in the toxic area of our local land-fill.

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Fairshake posted this 06 July 2010

What the act of fluxing does is allow the metals to blend into one and bring all the contaminants to the top of the mix.They then can be skimmed off and thrown away. I have been casting since 1970 and in the past I always used a little of the bullet lube. What you are supposed to do when it ignites is light it so that you burn off most of the fumes and keep them as a carbon in the alloy which will again make the dross come to the top to be skimmed.The flux of my choice is now purchased from a member on the Cast Boolits forum. It is a wood shaving like product that is long and not like a fine sawdust. It has the best smell while burning and if you stir your alloy all the dross comes to the top very fast.It is a cedar type of wood and he sells abox for about $20 that I have been using for over 18 months. Later

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NoDakJak posted this 15 July 2010

I had an interesting session today. I fired up the old turkey fryer and proceeded to melt weel weights. I ended up with 117 pounds of ingots but it was a struggle. I normally utilize used motor to flux this and have not had any problems other than lots of smoke and flame. A while back I was given several four gallon jugs that had contained deep fat fryer oil. I used the dregs of this oil to flux the first pot of lead. What a mess! The oil burned with a clear flame and almost no smoke and I thought GREAT! Then the residue turned into a black tar like substantce that contaminated my spoon and the wall of the pot. I added a double handfull of pine sawdust to absorb and remove this crud. The resulting melt appeared to be good. When I poured the first eight ingots however things were very different. The surface of the ingots looked a bit funky but I just shrugged my shoulders. When I dumped the ingots out of the mold they looked like large silver sponges with all the large black inclusions. Dirt, crud and a large amount of the ash from the sawdust was being held in suspension in the melt. My comments were a bit stronger than “OOPS"! It took multiple fluxing with sawdust, stirring and scraping to clean this goop out of my melt. I eventually ended up with a clean melt and a clean pot but it took about 45 minutes. I wonder how Ivory Soap would have worked at cleaning up this mess. Would have tried it but found that the Verdamnt mice had left me nothing but the wrappers. Ah Well! Neil

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Dicko posted this 21 July 2010

First lets dispel the myths.   Fluxing does not allow the tin, antimony and lead to mix properly, or prevent their separation.   Tin and antimony alloy (mix) with lead easily, and once alloyed, neither can be separated from lead except by sophisticated methods avilable to laboratories.  Fluxing has no role in that.

Fluxing cleans the alloy, but only in the respect that it separates the dirt and dross from the alloy and allows them to be skimmed off the top of the melt.  It does not get the dirt out of the alloy.  Basically, the dirt and dross float to the top being lighter than the alloy, but that requires vigorous stirring.   Dirt is what's on the lead before melting, dross is created by oxidation.  So they are different, but removal is the same so they can be regarded as the same for practical purposes.

Although the alloy has been cleaned before use, it will accumulate dross over time.  The hotter the alloy, the more dross it will accumulate.  It takes the form of a thick sludge on the top of the melt.  The sludge is particles of dirt and dross entrapped in the alloy.  If you don't mind losing some alloy you can just skim off the sludge.  

The only purpose of fluxing is only to save the alloy by separating the dross out.   There can be a lot of it in a fresh batch of alloy.   On one occasion I weighed five pounds of it from a 60 pound melt.   If it is not fluxed out, a lot of alloy can be lost if the sludge is skimmed off without fluxing.

I note your concern about flaming.  Some books say that flaming is not desirable, that it retards the effect, but I have found that it works better if it flames.  Note that you don't need fancy fluxes.   The foundries consider them too expensive for the volumes they melt, and use the dry drossing technique, which is sawdust and caustic soda.  

Here's how I do it.   I use cheap common candles as a flux.   Cut them into one inch lengths.  Drop one piece into the melt and stir it in.   Wear a welding glove to protect hand from the flames.   After a few seconds stirring it should flame.   If it doesn't, the second piece should do it.   Keep stirring as it burns.   It will burn for a few minutes.   You should end up with a pile of fine powder-like dust.   If it is more solid than powdery, it has not fully separated.   Give it another go.   Finally, skim it off.

Nothing I write is theoretical, it is all tried and tested.   I use this fluxing method for every 60 pound bulk ingot melt from raw materials, and whenever the sludge on my casting melt gets thick enough to remove.  

 

 

 

   

 

 

 

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tophet1 posted this 06 August 2010

Good to hear that Dicko,

That is exactly what i did with wax candles on my first smelt of wheel weights yesterday. Like someone said, it was a surprise to see flames leap up but so long as it isn't a bad thing.

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klw posted this 15 August 2010

I don't think I've flux once in the last 20 years. In maybe a half million bullets I've not fluxed once. If there is a downside to not fluxing I've not seen it.

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