Flux

[Jamesconn]

I have been watching alot of videos on casting and I think I'm about ready just need to finish with the money part and some use factory bought flux and I
Think i heard on this forum you can use bar of soap does it matter which kind?

[XWrench3]

i have not seen that. not for flux anyway. bar soap makes its way into bullet lube quite often though. for flux, i use parafin wax (used for canning) and saw dust. i have seen motor oil used as well. but i have not tried it.

[kbstenberg]

Jamesconn. First Off welcome to the brotherhood of the Silverstream.Wonderfull people here.
Just to get things strait. You are talking Flux that you put in your melting pot. Correct? If that is what your talking about, I suppose it could be used but it would be on the epensive side. Most everyone uses parafin products (candles, bullet lube), Sawdust, catlitter, used motor oil. Actualley the list is endless. Usually whatever is cheap an handy. Kevin

[Bret4207]

Just stir and scrape with a dry wood stick., Carbon is what you are after, getting the carbon under the surface and into the mix is the point. There is simply no easier way to do that than by stirring and scraping with a cheap hunka wood. It works- no flame, not much smoke, no money involved.

[-06]

MJ used Pine straw in his demonstration at our gathering last weekend.

[mebe007]

i too have been baffled by fluxing. ive seen videos of people throwning in a piece of candle and it flares up but how does in get mixed in if you cant stir it?

[Calamity Jake]

Any kind of flux laying on top of the melt does no fluxing, it needs to be stired!!!

[mebe007]

exactly what i thought so the guy throwing in a candle and watching it flare did absolutely nothing for his melt. so what do you do add the paraffin or saw dust and quickly stir or wait for the flare to end(but that doesn't make sense because the carbon would be gone at that point)

[dragonrider]

The parrafin itself actually does nothing for fluxing, it's the carbon left behind after it burns that does the fluxing. Sawdust is easier to use and it leaves your pot much cleaner than anything else you can use. Said sawdust MUST BE DRY to use. Put it on top of your melt and alow it to burn to ash before mixing it up.

[gunslinger20]

I have a papper shreder that puts out 1/4" wast, thats what I use. It does smoke alot untill all burned but then nothing. The carbon on top keeps oxygen from getting to the mix. This is my way of useing junk liberal mail.LOL

[GRUMPA]

Well after buying store bought flux and seeing what it does I read somewhere that some of the old timers were resourceful and used the dried sap from trees. After reading that I used pine and juniper dried sap (about the size of a pea) which is just all around here and it works just as well as the store bought stuff but sure does create a lot of smoke. But on the other hand I try and save my coin when ever I can.

[Longwood]

The parrafin itself actually does nothing for fluxing, it's the carbon left behind after it burns that does the fluxing. Sawdust is easier to use and it leaves you pot much cleaner than anything else you can use. Said sawdust MUST BE DRY to use. Put it on top of your melt and alow it to burn to ash before mixing it up.
I wonder if the ash from wood pellets would work better than the wood itself?
I wet some pellets so they would swell and separate back into sawdust then let them dry and used some for fluxing the last two casting sessions and it appears to work very well. I wonder if the ash is all that is needed, maybe using the ash is all that is necessary.
As soon as this blasted wind dies down I will give it a try.

[cbrick]

Welcome to Castboolits Jamesconn, you'll find a tremendous amount of varied experience from great folks willing to share and get you started in the right direction.

Here is some reading for you on fluxing explained much better than I could.

The simple Act of Fluxing pdf (http://www.lasc.us/Fryxell_Fluxing.pdf) By Glen E. Fryxell

And in a bit more detail, see chapter 4 on fluxing the alloy.
From Ingot To Target pdf (http://www.lasc.us/Fryxell_Book_textonly2.pdf) By Glen E. Fryxell

Read these and you will know more about flux than you thought there was to know. :D While Glen has a Phd in heavy metals he writes in a style that is both interesting and easy for us common folk to understand.

Rick

[Paulinski]

So to properly flux the mix has to be stirred with wooded stick?

What I have been doing is throwing a but of bullet lube and stirring with metal spoon - I got black tarry looking stuff popping up on the top that I just scooped out.

??

[cbrick]

Paulinski, no, you don't have to use a wood stick though many here do with reported great success. I use sawdust and stir with a stainless slotted spoon and I can also report great success. The goal is to turn the sawdust into carbon as it burns, it's the carbon that does the fluxing. Yes, it does need stirring. The bullet lube you mention will leave residue on the sides of the pot, the reason I don't use it.

Rick

[Paulinski]

Thanks for the info.... :)

[dragonrider]

"I wonder if the ash from wood pellets would work better than the wood itself?"
Should work just fine,. try it and let us know.

[waksupi]

The reason to stir with a stick, it gets completely through the melt. It is impossible to stir anything sitting on the surface to overcome the specific gravity of lead, and do much good.
So, put anything you want to on top, but STIR WITH A STICK!

[Poygan]

I like a paint stir stick to work the pot and particularly the sides. They seem to be a soft wood and don't last too long. I've also used a pine stick, bark and all.

[cbrick]

Another line of thought using a wood stick to stir the pot is that as the wood chars bits of the chared wood come off in the melt, most should float to the surfce but will they all? Will this debris then go through the flow out the bottom pour or into a ladle and into your bullets?

The purpose of stirring is to bring all of the alloy up to the surface and into contact with the flux. It would be correct if you simply placed a flux on top and left it there, wouldn't do much fluxing. Regardless of what you choose to stir with the stirring should be done in a manner that brings the alloy to the surface.

Rick

[geargnasher]

The only issue you will have stirring with a stick is if you SCRAPE THE BOTTOM with it. It will slough off ash UNDER the melt and it will get trapped there, then make it's way to the spout on a bottom pour and cause it to leak, and your boolits will have ash and dross inclusions in them.

Scrape the bottom with a spoon, sides and stir with a stick, use sawdust on top and you'll be fine. When I ladle cast, I use junk boolit lube as a reducant and light it. Not much ash left that way.

It isn't just the carbon that reduces the oxides, it's really the active formation of carbon monoxide from the charring/smoldering whatever that you put on top. Its called a Reduction/oxidation reaction, where the oxides of the metal are reduced to elements while the "sacrificial reducant" is oxidized. in essence it's electron transfer between the hydrocarbons in the flux and the metal oxides on the surface of the melt.

As far as removing slag (not dross) and impurities, the sawdust and stick have special powers here, so they accomplish both chemical reduction of the oxides AND the isolation of impurities to the surface where they can be skimmed off.

Gear

[montana_charlie]

Think i heard on this forum you can use bar of soap does it matter which kind?
That would be Ivory soap because it contains stearic acid (or something close to that name). I've never done it, but I read about it.


However, after reading all of the replies you got, it really needs to be determined what job you want the 'flux' to perform.

Are you cleaning a pot of lead scrap to make some ingots ... or wanting to control the dross on top of your bullet casting alloy?

CM

[runfiverun]

you need the carbon in there for carbourization to pull the gunk out and to help the alloy.
you need an oxygen free barrier on top to allow the oxided alloy back in the melt.
thus the sawdust, stick, and parrafin fire.

[cbrick]

But Gear . . .

If you rub the bottom of the pot with a charred stick and pieces rub/flake off and get into the melt . . . I agree with that.

What happens to the end of the stick if your rubbing it on the sides of the pot? Hhmmm, nothing rubs off?

Doesn't matter what you rub a charred stick on, bottom, sides or the palm of your hand, stuff is going to rub off and be left behind.

Or so it would seem.

Rick

[mold maker]

If any carbon particles are trapped on the bottom or sides of the pot, that's where they will stay. At any time they are disturbed, the specific gravity difference will immediately bring them to the surface. Works just like ice in a glass of tea. You can push it under, but it won't stay.
As far as using ivory or any other bar soap for flux, I belive the moisture content would be an invite for a visit from the dreaded tinsel fairy.
As long as dry sawdust is so cheap, and does such a good job, I'll not use anything else.
Just be sure its not treated wood sawdust. Those fumes can be really dangerous.

[nanuk]

"I wonder if the ash from wood pellets would work better than the wood itself?"
Should work just fine,. try it and let us know.

if it is carbon you want, then perhaps you shouldn't burn to ash, only to black carbon.

by the time it burns to ash, the carbon is gone, and another chemical is left.... Lye?

[gunslinger20]

I think you have to mix the ash with H20 to get Lye

[cbrick]

If any carbon particles are trapped on the bottom or sides of the pot, that's where they will stay. At any time they are disturbed, the specific gravity difference will immediately bring them to the surface.

If so there will never be inclusions from a bottom pour, but there often is. It doesn't all float to the top.

Truth is that lead is dense enough to keep some of the gunk trapped near the bottom and the flow of lead will/can/does carry it through the bottom spout into the bullets. That's why proper stirring attempting to bring as much alloy to the surface as possibe is important.

This is why I don't use a wood stick to stir. Don't get me wrong, if you do and your happy with your results you are certainly doing it right for you, simply explaining why I don't use a wood stick.

The density comparison of iced tea and molten lead isn't the correct analogy.

Rick

[montana_charlie]

Truth is that lead is dense enough to keep some of the gunk trapped near the bottom and the flow of lead will/can/does carry it through the bottom spout into the bullets.
I'm not a bottom pour caster, but I played one, once.
I don't believe your theory. Lead is so dense, anything lighter will rise to the top if it isn't actually stuck to the pot's surface.

I think the 'inclusions' that bottom spouts exhibit occur this way ...

You open the spout and molten leads runs through.
When you close the spout, the seal is up at the surface of the pot's bottom ... not down in the lower part of the spout.
So, there is an empty 'tube' with the end of the metering rod in the middle, and some semi-solid lead coating some of those surfaces, perhaps even bridging between the spout wall and the rod tip.

That lead oxidizes while you are dropping the last bullet(s), and that oxide (with some partially remelted lead ?) is washed down into the mould when you make the next pour.

The same oxides and semi-solid lead form on ladles and dippers, but you can knock them clean before filling and pouring.

I believe that's why ladles are more reliable at casting perfect bullets than bottom spouts.

CM

[CZShadow]

I'm not a bottom pour caster... I believe that's why ladles are more reliable at casting perfect bullets than bottom spouts...
CM

And I was about to order me an electric, BP melter... I'll try my second casting session this weekend and see if the laddle is all I need, I'll put a hold on that idea now.
Thanks for the experiences.

Rod

[ColColt]

Everybody to their own cup of tea but I started with a bottom pour Lyman Model 61(still have it) in 1972 and retired it recently in favor of a Lee Pro-20. No ladle for me...too slow. Others who have mastered it may do great but for me it's slow as molasses in winter. I stir with a stick but, when I want to scrape the bottom I don't use it-just in case.

[mebe007]

Welcome to Castboolits Jamesconn, you'll find a tremendous amount of varied experience from great folks willing to share and get you started in the right direction.

Here is some reading for you on fluxing explained much better than I could.

The simple Act of Fluxing pdf (http://www.lasc.us/Fryxell_Fluxing.pdf) By Glen E. Fryxell

And in a bit more detail, see chapter 4 on fluxing the alloy.
From Ingot To Target pdf (http://www.lasc.us/Fryxell_Book_textonly2.pdf) By Glen E. Fryxell

Read these and you will know more about flux than you thought there was to know. :D While Glen has a Phd in heavy metals he writes in a style that is both interesting and easy for us common folk to understand.

Rick

I actually printed that book the other week and hole punched it and have it in a binder. Have. Been slowly reading

[geargnasher]

But Gear . . .

If you rub the bottom of the pot with a charred stick and pieces rub/flake off and get into the melt . . . I agree with that.

What happens to the end of the stick if your rubbing it on the sides of the pot? Hhmmm, nothing rubs off?

Doesn't matter what you rub a charred stick on, bottom, sides or the palm of your hand, stuff is going to rub off and be left behind.

Or so it would seem. Yes, Rick, it rubs off on the sides, too, but it is easy enough to scrape the dust off and usher it to the surface with a spoon, not so much when it's trapped under the melt..

Rick


If any carbon particles are trapped on the bottom or sides of the pot, that's where they will stay. At any time they are disturbed, the specific gravity difference will immediately bring them to the surface. Not entirely a true statement, thus the rub...Works just like ice in a glass of tea. You can push it under, but it won't stay. Due to variances in surface tension between the ash and the alloy, the ash will get actually stuck in the surface of the alloy at the bottom of the pot, and it is very difficult to get it ALL moved to the edges and up the sides. Ash WILL NOT just float up through the molten lead.
As far as using ivory or any other bar soap for flux, I belive the moisture content would be an invite for a visit from the dreaded tinsel fairy. It floats. Don't push it under. No problem.
As long as dry sawdust is so cheap, and does such a good job, I'll not use anything else.
Just be sure its not treated wood sawdust. Those fumes can be really dangerous.


if it is carbon you want, then perhaps you shouldn't burn to ash, only to black carbon. Here's the chemistry, Nanuk, and therin is why we burn it to ash: First, we have combustion (in this case the "oxidation" part of the reduction/oxidation, or REDOX reaction), take for example wood pulp which is basically a hydrocarbon like C2H4, add some oxygen, and react them completely to get (1)C2H4+(3)O2-->(2)H2O+(2)CO2, or carbon dioxide and water. But if we starve it of O2 by having our sawdust down in a melting pot where it can't get a draft, you get something like (1)C2H4+(2)O2-->(2)H2O+(2)CO (carbon monoxide) or more likely a mix of byproducts like --->(1)H2O+(1)C+(1)CO+(1)CH2 (methylene gas). After that, the reduction part of the reaction takes place between PbO2, SnO2, and SbO2 and the C and CO, leaving elemental Pb, Sn, and Sb and having the byproducts of water (vapour), methylene (gas), carbon dioxide (gas), and probably a smattering of other partially reacted components in various states. If you don't let the carbon (and the even MORE reactive carbon monoxide) suck up electrons from the oxidized metals, they won't reduce into their elemental form, which is the whole point of "reducing" the oxides in the melt.

by the time it burns to ash, the carbon is gone, and another chemical is left.... Lye? Ashes. Don't forget the most important thing, when the carbon is gone, it's because it reacted with our metallic oxides and turned them from dross to metal again!!!


If so there will never be inclusions from a bottom pour, but there often is. It doesn't all float to the top. So true! :mrgreen:

Truth is that lead is dense enough to keep some of the gunk trapped near the bottom and the flow of lead will/can/does carry it through the bottom spout into the bullets. That's why proper stirring attempting to bring as much alloy to the surface as possibe is important. And, like I mentioned already, NOT PUTTING THE JUNK IN THE BOTTOM IN THE FIRST PLACE.

This is why I don't use a wood stick to stir. Don't get me wrong, if you do and your happy with your results you are certainly doing it right for you, simply explaining why I don't use a wood stick.

The density comparison of iced tea and molten lead isn't the correct analogy. I didn't think so, either.

Rick


Sometimes there are other factors besides just SG that control what does what in our pots. There are convection currents in a typical pot, simply due to the fact that heat rises. The surface tension of lead is a buggar, the whole reason we add tin sometimes to help fillout.

Gear

[Longwood]

"I wonder if the ash from wood pellets would work better than the wood itself?"
Should work just fine,. try it and let us know.
Well,,,, I tried the puffed up pellets again this morning along with some paraffin and it worked just fine. Then I tried some of the ash from the pellet stove and all I can say is, "Don't bother". I got all sorts of junk in the bullets until I fluxed again with paraffin and the puffed pellets which cleaned it all up.

[cbrick]

I don't believe your theory. Lead is so dense, anything lighter will rise to the top if it isn't actually stuck to the pot's surface. CM

Lead is so dense that it can and does hold some of the gunk near the bottom. That's why it takes so much proper stirring to get it to the top. If you are correct why bother stirring at all? After all . . . everything you don't want in there will simply float to the top and whalla, clean alloy.

You may have a minor point on oxidation in the spout, however, oxidation is not black dirt looking spots on bullets as I'm sure most of us have seen a time or two. It's doubtful many of us actually stir long enough and properly enough to get all of the impurities to the top. That's why I choose not to use a wood stirring stick, why add even more stuff down there?

Rick

[cbrick]

This is actually a great thread. Lot's of theories and ideas coming out and getting bounced around.

Rick

[Longwood]

[QUOTE=Longwood;1249242 Then I tried some of the ash from the pellet stove and all I can say is, "Don't bother". I got all sorts of junk in the bullets until I fluxed again with paraffin and the puffed pellets which cleaned it all up.[/QUOTE]

At first, I thought Whoopee! No smoke at all. How nice is that? Not so nice it turns out.
I now suspect that the smoke, and not the carbon is what is doing the job.
BTW
After trying the ash, then going back to the pellet dust, it took a lot of working at it to scrape the crud from the side of the pot, using a spoon with a flat side and end. I would scrape the sides and bottom but when I went back around the pot, more stuff would be stuck to the sides and bottom.

[cbrick]

I now suspect that the smoke, and not the carbon is what is doing the job.

:coffee: No, it's the carbon.

Rick

[Longwood]

:coffee: No, it's the carbon.

Rick
Then why did the ashes not work? Is the carbon depleted?

Never mind, I went back and read a bit.

[Longwood]

:coffee: No, it's the carbon.

Rick

Is smoke carbon?

[Jamesconn]

Again with the flux. My mother sells wickless candles and after the wax loses it's scent i have asked her to pour it in little ice cube tray and I plan on fluxing it in the melting pot not the lead dispenser and i plan on using a 12 qt Dutch oven or larger as I plan on getting a keel or two what would the life of the Dutch oven be if I use it frequently or to melt large quantities and what I am trying to say if i use wax to flux compared to sawdust will it shorten the life of the pot if so by how much?

[onesonek]

I use sawdust at the begining of liquidous state, to help reduce the "oatmeal" slush, followed by a light surface stir. Then push to the side, working it by rolling/grinding against the side with a round wood dowel stick, and barely forcing it under the surface to reduce the the trapped metal in it. ( think I got that tip that from Gear or Knight) What is left pretty much clings to the stick, which I tap off in a can. The original skimming pile is reduced by 10, if not more. Then finish off with a quick stir of the entire melt. But I don't stir the charred sawdust down in the melt, some of which is ash, I did that once, and had many inclusions. It seems just a simple stirring with the stick introduces enough carbon/carbon monoxide itself, without putting ash into the mix.
I found MC's point of valve oxidation interesting. I been knocking off the partially froze drip with top of the sprue, just prior to the next pour. I get better looking nose's doing that,,,found that out rather by accident. I haven't played with ladle cast enough yet to comment. Someday I have to put some time on the ladle.
I try to run a cool as pot as possible, but any dross (oxidation) is collected to the back of the pot every so often, then worked as above.

[geargnasher]

At first, I thought Whoopee! No smoke at all. How nice is that? Not so nice it turns out.
I now suspect that the smoke, and not the carbon is what is doing the job. I explained this above. Observe the chemical reactions, and you'll see that carbon monoxide, CO, is far more reactive than just plain ol' inert, elemental carbon. Carbon monoxide is present during poor combustion (smolder) conditions, like sawdust smoldering on top of your melt below the lip of the pot, and the CO wants to become CO2 really badly, so electrons easily transfer from the oxidized metals and combine with the CO, leaving elemental metals and CO2. It is also very important to realize that in a REDOX reaction, there has to be both reduction AND oxidation going on at the same time. This is by definition. If one compound is being reduced, another must necessarily be oxidized. So when you put carbon on top of your dross, it doesn't do anything because the stuff has already been reacted, and is stable at molten lead temps. Plain carbon does burn, but at much higher temps than your casting pot will provide, so you need to add something that will COMBUST, (a form of oxidation reaction), and if you oxidize the carbon monoxide to make CO2, you reduce the metal oxides to elements by freeing the extra oxygen atoms.
BTW
After trying the ash, then going back to the pellet dust, it took a lot of working at it to scrape the crud from the side of the pot, using a spoon with a flat side and end. I would scrape the sides and bottom but when I went back around the pot, more stuff would be stuck to the sides and bottom.


:coffee: No, it's the carbon. Go put some activated carbon granules on your next melt and tell us what happens.

Rick


Then why did the ashes not work? Is the carbon depleted? That's affirmed, Flight.

Never mind, I went back and read a bit.


Is smoke carbon? ....and oxygen and carbon dioxide and carbon monoxide and water vapor and lots and lots of other stuff, depending on what's being burned and how well.

The simplest way I can put this is that there is fluxing and there is the "reduction" of oxides, two different things. Glen Fryxell explained pretty well the effects of fluxing with sawdust, which actually tends to remove impurities and some elements that we commonly find as contaminants in our melts. He understands and describes "fluxing" lead alloys much better than I can. Reduction of oxides I do understand, and it is a simple chemical reaction where we add hydrocarbons and heat to oxidized metal to get oxidized hydrocarbons and elemental metal.

Hope this helps some.

Gear

PS, Rick, it's Voila!, French word. (Signed, your well-meaning and respectful personal grammar Nazi!)

[Longwood]

[QUOTE=geargnasher;1250520]The simplest way I can put this is that there is fluxing and there is the "reduction" of oxides, two different things. Glen Fryxell explained pretty well the effects of fluxing with sawdust, which actually tends to remove impurities and some elements that we commonly find as contaminants in our melts. He understands and describes "fluxing" lead alloys much better than I can. Reduction of oxides I do understand, and it is a simple chemical reaction where we add hydrocarbons and heat to oxidized metal to get oxidized hydrocarbons and elemental metal.

Hope this helps some.

Gear


Thank's Gear, you are a big help.
I did some more casting of bullets today. This time I put the pellet dust on top of the melt then as it was doing it's thing, I would push it to the side and stir the melt with a spoon that I got warm then coated it by rubbing it on a large candle. That took the paraffin deep down into the melt and it seemed to really help a lot. I can't prove it, but I got a whole lot of good bullets and very few rejects.