Possibly the best Flux??? IDK

[xXFREEDOMisNOTfreeXx]

Hey guys, I am very new to the "Boolit" casting game so far. My Dad and I have now casted about 80Lbs of pure lead from roof flashings. Just recently we ran out of Flux wax and were complaining to ourselves about how much a stick cost from the NRA website and wondering why it cost so much. We started researching for cheaper alternatives and found from information on this website that anything from kitty litter to sawdust works great because of the fact it had carbon derivatives. This gave me an idea that I want to throw out to you guys. I use to work at a pet-store for years and we used "Activated Carbon" (which is extremely pure) to filter our fish tank water. Would it be possible to beat/pulverize these small pellets into a fine grit and add it to the smelting lead to harvest more impurities out easier? I am just an amateur at this so far but I think i am going to try this unless there is something someone knows on why it wouldn't work optimally. If the main point is to add carbon for a better end product I'd think this would work great. If anyone does try this before I do Plzzz let me know how it goes. I'll include some pictures below of what it looks like. Like I said you can get very high grade activated carbon at any pet-store or on-line at that matter. It's not to expensive either (depending on the grade and manufacturer). :Fire:

The pic below is from here: http://www.marinedepot.com/Aquarium_Pharmaceuticals_Super_Activated_Carbon_Ca rbon_Chemical_Filter_Media-Aquarium_Pharmaceuticals_API_MARS_Fishcare-AP2125-FIFMCHCM-vi.html
http://www.f3images.com/IMD/600/AP2125/AP2125_99.jpg

http://www.cameroncarbon.com/activated_carbon2.jpg

[cbrick]

Welcome to Castboolits Freedom,

Sounds fascinating, I had no idea of getting carbon like that from a pet store. It sounds like it should work well. Should and do are two different things though. Perhaps someone else will chime in here and say yes or no. If you try it please let us know. If I can get to a pet store I'll get some and try it.

Very interesting indeed. We shall see. Thanks for the idea.

Rick

[DLCTEX]

Why buy anything when a dry stick works so well? I'm sure the carbon would do nicely as that is what does the work when using a stick.

[Bret4207]

Ditto on the stick. As the stick chars and you're rubbing the sides and bottom of the pot it's putting the carbon way down deep under the surface. The longer you stir/scrape the more you add to the pot. Cheap, simple, effective and you aren't spending time trying to push the carbon under the melt.

[dragonrider]

Exactly what DLCTEX and Bret4207 said, WHY BUY ANYTHING.

[buck1]

Carbon is what steals the O2 from the oxicides and fluxes your pot. That pet store carbon may be great but most likely not better then the rest. t It would be like building a campfire with the pre fab fire logs. Carbon is all arround, any wax,oil,wood ++++. Carnuaba wax is my favorite! Little to no smoke and works well and lasts a long time.
If you want strong carbon flux I would buy cheepo charcoal

[timkelley]

I use sawdust and stir with a wooden stick.
If you want pre-made carbon go out to the BBQ and get some Charcoal Briquettes, crush them down.

[Doby45]

I also use an old well seasoned oak dowel to stir/flux my pot. Works like a champ.

[garym1a2]

I made a wax lube for pan lubing out of Lee Alox, Candle wax and toliet bowl wax. It was an aweful lube. But it makes a great flux, much better than the F.A. wax I brought.

[xXFREEDOMisNOTfreeXx]

First thanks to everyone who responded so quickly. :smile: I see where most people are saying to try the stick because it is so cost effective and that is what makes the difference in the casting game. I actually found some activated carbon last night in my storage room and will try it out on our next smelting session but the "Cost Effectiveness" of the stick or sawdust will probably seal the deal. Even though a good sized container of pure activated carbon might be a few bucks i think i will be thinking of the "long term" cost which will definitely add up sooner or later. There's nothing better than FREE.

I would like to know what kind of sticks you all are using though and how big? Is it just any old stick off a tree or do you want to use a piece of 2x4 or something more like tender wood, or does it make a difference? As for the sawdust, how much do you use? A tablespoon or more? If someone could take a picture of what they are using and post it that would be great. I know i am kind of nuking this out but again i am an amateur and rather have all the correct info from the start. Again thanks for all of your responses. It's great to be able to learn from the MASTERS! :lovebooli

[waksupi]

Most any stick will work. I generally use ram rod cut offs, as I have a lot of them around. Something about as big as you little finger is plenty. And as soon as you start stirring with the stick, you have just made yourself some activated charcoal.
A lot of us like about a half inch or less of plain kitty litter on top of the melt in our bottom pours. Keeps the lead from oxidizing, and helps maintain a steady pot temperature.

[montana_charlie]

xX,
Most any kind of stick will do...just don't use a green one fresh from the tree. The moisture in it will cause problems. I use scrap from under my table saw...some use (free) paint stirring sticks from the hardware store.

If you are fluxing a pot to clean out impurities, almost any amount of sawdust is okay, as you are just going to scoop it out, anyway. The less you waste, the better.

But if you have a bottom pour pot, you might want to put a sawdust 'cover' on the molten metal...initially about 1/4 inch thick. It will keep your metal 'fluxed' more or less constantly, if it has already been cleaned well.

CM

[cbrick]

Is there no curiosity on this forum?

I think FREEDOM came up with a very interesting idea. Whether or not it would be a long term fluxing solution isn't the point. For me it's all about the education of Rick. This is something I'll try, may not continue fluxing this way but it will be an interesting experiment to see if it's better, worse, the same, easier, harder, messier, cleaner or whatever.

I'm extremely pleased with how well sawdust both cleans my alloy, reduces Sn & Sb and leaves my pots completely clean but still, here is a chance to learn something and add to the education process and at the same time please the curiosity factor.

With out the "what if" and "why not" curiousity factor we would all still be casting the same way it was done at the turn of the century . . . the last century.

Isn't there anyone here with at least a bit of curiosity or want to learn something?

Rick

[Doby45]

Weird but true, I used some very well dried grass trimmings that were left in my mower bag lastnight. Worked very well and formed a nice little 1/8" thick layer of fine powder ash on top of my pot..

[geargnasher]

Is there no curiosity on this forum?

I think FREEDOM came up with a very interesting idea. Whether or not it would be a long term fluxing solution isn't the point. For me it's all about the education of Rick. This is something I'll try, may not continue fluxing this way but it will be an interesting experiment to see if it's better, worse, the same, easier, harder, messier, cleaner or whatever.

I'm extremely pleased with how well sawdust both cleans my alloy, reduces Sn & Sb and leaves my pots completely clean but still, here is a chance to learn something and add to the education process and at the same time please the curiosity factor.

With out the "what if" and "why not" curiousity factor we would all still be casting the same way it was done at the turn of the century . . . the last century.

Isn't there anyone here with at least a bit of curiosity or want to learn something?

Rick

I was thinking the same thing, and furthermore I think Freedom has a good idea for a Reducant. I have a bunch of activated carbon myself and might just try it. The only thing I can say for sure is that a couple of years ago I thought I might cut down on the sawdust smoke some and use crushed charcoal retrieved from my fireplace. It didn't work well at all, seems the carbon just sits there, and no matter how much stirring and mashing around I did the stuff wouldn't reduce the oxide scum. The filter charcoal may be a whole different animal.

Freedom, let us know how it worked, and trust us all on the stick trick, you need to be able to scrape the sides of the pot and then rake the oxide scum into a little pile against one side of the pot so you can mash/smear it against the metal with the stick, forcing the oxides to reduce back into the melt. When you're done, the alloy should be shiny and just a small pile of fine grey ash with no metal in it is all that's left to spoon out. Or as has been said you can leave a layer of sawdust in for the whole session if you cast with a bottom pour.

Gear

[sagacious]

Copied from one of my previous posts:

I suspect it's the hydrocarbons in unburned sawdust that are facilitating the reduction. Ordinary carbon can bond/adsorb molecules, but does not have the hydrogen to supply to the reaction. Activated carbon has had all of the hydrocarbons removed.

Consider that hydrocarbons supply reactive hydrogen, and that adding hydrogen to PbO might give you this:
PbO+H2 ---> Pb+H2O
Lead oxide plus hydrogen produces pure lead and water vapor.
The excess hydrogen also likely produces acids that help form a reducing atmosphere. This explains the popularity of acid fluxes.

Using a fluxing agent such as wax is using pure hydrocarbons. The result is positive fluxing, and a black powdery residue-- probably some left-over unreactive carbon. Sawdust has hydrocarbons plus resin/rosin, and rosin is a powerful fluxing agent as it both wets and reduces lead oxide, which helps in dross separation. This is why when you put a good flux, such as sawdust or wax, on the surface of oxidized lead, the oxide will rapidly clump together and expose a mirror-bright melt surface-- sometimes even without stirring.

A few years ago I mixed up some paraffin and rosin for fluxing. The rosin makes the wax rock hard. It is about the most aggressive fluxing agent I have ever seen. For normal scrap lead, most fluxes work fine, but when fluxing lead particulates/dust or heavily oxidized lead, the wax/rosin flux is far superior, because the huge surface area of the lead dust benefits from a flux with superior wetting ability.

[zxcvbob]

Consider that hydrocarbons supply reactive hydrogen, and that adding hydrogen to PbO might give you this:
PbO+H2 ---> Pb+H2O
Lead oxide plus hydrogen produces pure lead and water vapor.
If I remember my inorganic chemistry correctly, the reaction won't go that direction. Pb++ has a lower (barely) electrode potential than H+.

The best flux that I've found is lard or Crisco. It works about like old motor oil but it doesn't flame up or stink as much. And it leaves an oily film (glycerin?) on top that lasts a long time. I have some chicken fat in the fridge; I'll try that text time. It should work exactly the same.

I also use paint stir sticks; I pick up one or two whenever I go to Home Depot.

I don't expect the activated charcoal to work all that well, but you never know, hopefully Freedom will get back to us with a report.

[Bob.]

Carbon is what steals the O2 from the oxicides and fluxes your pot. That pet store carbon may be great but most likely not better then the rest. t It would be like building a campfire with the pre fab fire logs. Carbon is all arround, any wax,oil,wood ++++. Carnuaba wax is my favorite! Little to no smoke and works well and lasts a long time.
If you want strong carbon flux I would buy cheepo charcoal


I think Carnuaba wax is my favorite also.

Bob.

[xXFREEDOMisNOTfreeXx]

Yes, i will definitely give feedback after I try the experiment. I'm going to take some pictures too. I think that there has been some great feedback from all the posts. A lot of stuff I didn't even think of too. I would say the only way it work is to have the carbon ground into a dust form. I was also thinking of maybe making a mixture of melted wax and activated carbon dust just for the fun of it.

I am interested in what "zxcvbob" said about the chicken lard. Do you mean actual fat off a chicken in its solid state or could you use the "Grease" fat that you get after you drain hamburger meat? Or would either work? To me it would seem like it would start a grease fire...LOL.

(1) Like this:
http://penandfork.files.wordpress.com/2009/07/bacon-grease.jpg?w=500&h=333

OR (2) Like this:
http://tastyniblets.com/images/2010/050410_pork_lard.jpg

[RP]

The best sticks to stir my pot with are mast produced and then they just give them away two sizes I know of. I tell you were you can get your very own FREE sticks perfect to stir lead with since they were design to do just that stir. Go to LOWES around the middle of the store most of time is the paint department just ask for stir sticks and they just give them to you. For big pots ask for the ones for 5 gals buckets.

[zxcvbob]

The rendered fat (like bacon grease.) The skin and fat you have pictured in the frying pan still has too much moisture and might bring the wrath of the tinsel fairy. It also won't melt quickly enough.

Basically, any triglycerides should work.

[leftiye]

Just like crushed charcoal, activated crbon would probly make an excellent oxygen barrier if left floating on top of the melt.

[geargnasher]

Copied from one of my previous posts:

I suspect it's the hydrocarbons in unburned sawdust that are facilitating the reduction. Ordinary carbon can bond/adsorb molecules, but does not have the hydrogen to supply to the reaction. Activated carbon has had all of the hydrocarbons removed.

Consider that hydrocarbons supply reactive hydrogen, and that adding hydrogen to PbO might give you this:
PbO+H2 ---> Pb+H2O
Lead oxide plus hydrogen produces pure lead and water vapor.
The excess hydrogen also likely produces acids that help form a reducing atmosphere. This explains the popularity of acid fluxes.

Using a fluxing agent such as wax is using pure hydrocarbons. The result is positive fluxing, and a black powdery residue-- probably some left-over unreactive carbon. Sawdust has hydrocarbons plus resin/rosin, and rosin is a powerful fluxing agent as it both wets and reduces lead oxide, which helps in dross separation. This is why when you put a good flux, such as sawdust or wax, on the surface of oxidized lead, the oxide will rapidly clump together and expose a mirror-bright melt surface-- sometimes even without stirring.

A few years ago I mixed up some paraffin and rosin for fluxing. The rosin makes the wax rock hard. It is about the most aggressive fluxing agent I have ever seen. For normal scrap lead, most fluxes work fine, but when fluxing lead particulates/dust or heavily oxidized lead, the wax/rosin flux is far superior, because the huge surface area of the lead dust benefits from a flux with superior wetting ability.

I'm to tired to go pull out the Atkins & Beran to check that reaction, or the reduction recactions of tin/antimony oxides either for that matter, but I'll settle for your explanation about the hydrogen. Hyrocarbons are complex molecules that really love to grab up O2 and spit out CO2, CO, NoX, and H2O.

The best flux I've ever used was a combination of sappy juniper knots and boolit lube, but I like my Western Cedar shaper chips or planer shavings better, plus the mosquitoes/moths/wife stay away from me when I use it! I always stir/scrape/fiddle with the melt using a dry maple rick about 3/8"x3/4".

I figured the charcoal carbon I tried was "exhausted" by burning off whatever goodies it had to contribute to the reduction, so there must be more to reducing PbO (or is it PbO2?) than just donating carbon to the reaction. In the presence of pure carbon there seems to be no reaction of the oxides.

Gear

[alamogunr]

Sometime back when I had done very little actual casting and had only cleaned up a couple of buckets of WW, I ran across something on Ebay that was described as "lead flux". I bid on it and won the auction. When it came, it seemed to be nothing more than crushed charcoal, albeit very finely crushed. It was almost a powder. There was a label on the jar that identified it as flux. I used it but decided that the mess was not worth looking for any more. Live and learn.

John
W.TN

[sagacious]

If I remember my inorganic chemistry correctly, the reaction won't go that direction. Pb++ has a lower (barely) electrode potential than H+.
...
Ya may have to brush up on IO chem! ;)
http://www.ucc.ie/academic/chem/dolchem/html/elem/elem001.html

Reducing Properties
When hydrogen is passed over many heated metallic oxides (e.g. copper oxide, iron oxide, or lead oxide), they are reduced to the metals.

CuO + H2 ==> Cu + H2O

[sagacious]

...
In the presence of pure carbon there seems to be no reaction of the oxides.

Gear
Generally speaking, that is also my experience.

[jsizemore]

Sagacious, you mentioned using resin/rosin as a fluxing agent. Are you refering to pitch from pine on conifers?

[sagacious]

Sagacious, you mentioned using resin/rosin as a fluxing agent. Are you refering to pitch from pine on conifers?
Yes, correct. It's a very aggressive fluxing agent.

[rhead]

Sawdust will become activated charcoal for a few minutes when in contact with molten lead. Just before it starts being ashes. The sawdust is free. Can the activated charcoal source beat that price that I pay for sawdust? My wife will make me sweep it up anyway.

Activated charcoal has the advantaged of being able to absorb more of a polar substance per unit weight than regular charcoal. It would have no advantage over regular charcoal (made in place from sawdust) or mant other carbon sources.

[82nd airborne]

There is a huge aluminum casting plant here that uses salt for a flux. I doubt it would work on lead but I may try.

[XWrench3]

i am a double dipper i guess. i use both parafin wax (fairly cheap, especially when you buy it for a quarter at yards sales) and then sawdust. the sawdust is even cheaper than the yard sale wax, because my father-in-law is a carpenter. he gives e a 5 gallon bucket anytime i want it.

[WHITETAIL]

FREEDOMisNOTfree, Welcome to the forum!:drinks:

[Elkins45]

If it's the hydrogen doing the work then cheap trans fat shortening ought to be the best flux of all, since it's enhanced with the good stuff by being partially hydrogenated. My experience bears that out.

When I smelted down 400 pounds of EXTREMELY dirty wheel weights back in the spring I found that flinging a spoonful of cheap Great Value shortening into the pot would make a layer of oily liquid flux that performed great and that wouldn't flame up. It hung around for a long time as a liquid layer on top of the melt and, best of all, it smelled a little like fried chicken!

[excess650]

Years ago I tried Marvelux and liked the fact that it didn't smoke or smell much. What I hated was that it built up a crud layer around the inside of my pot and absorbed moisture!

It sounds like most of you are bottom pour guys, so are having success with the sawdust and kitty litter. The layer you have on top is keeping the heat in and oxygen out, which is good. I'm a ladle caster, so having that layer on top isn't good for me.

I've used beeswax, parafin, candles, and have settled on flaked carnauba wax. Beeswax and carnauba wax both have higher ignition temperatures than candles or parafin. What I really like about the carnauba wax is that it seems to keep the inisde of my pot clean, and encapsulates the dross. There is no powdery residue in my pot or in my dross can.

When I'm outside smelting WW or recovered range lead I will try Crisco and sawdust.

[canyon-ghost]

I'd agree with Sagacious, using parafin wax works extremely well, however, when you light it up to reduce the smoke you find that it's very flammable! Parafin will produce FLAMES about a foot high. I bought 10# of pure parafin from a candle shop and poured it into ingots (little Lyman mold). Mostly, I just cut off a chunk, about 1/3 of an ingot and drop atop wheelweights.
Before finding a large amount, I used Gulf Canning Wax, from the grocery store or about any household candle from the convenience store. It's just not difficult to find.
The rosin is an interesting idea, I have pine trees! Most of my fluxing is for ladle casting so, I am just concerned with the top surface and stirring the rest. Carnuba might work better but, that's what my bullet press lube is, Carnuba Red.
Thanks for the interesting thread, newbie questions are great.

Ron

[cbrick]

There is a huge aluminum casting plant here that uses salt for a flux. I doubt it would work on lead but I may try.

Salt? Not me, no way, not my pots, not a chance!

Salt + steel = rust. Nope, not in my pots it couldn't possibly work well enough to get me to add salt to my pots. [smilie=b:

Yesterday while out & about I stopped at a pet store and bought some filter carbon. Had I read some of these posts since my last post I may not have bought it, kinda sounds like it may not work well but I have it now so I'll try it. Won't be a waste if I can learn something from it.

It was more expensive than I thought it would be so it won't be an permanent fluxing technique but as an experiment it should be interesting.

Rick

[xXFREEDOMisNOTfreeXx]

WOW, I am astonished at all of the great feedback that this post has gotten. Thanks to everyone for your input. I have learned way more than I expected too in the last two days. Again THANKS.

I still haven't had time to try any of these techniques although I am gathering as much of the assorted materials that everyone has mentioned and I will try them all.[smilie=w:

[Cord]

For years I used bullet lube for fluxing, both smelting and casting.

Some time ago, I changed to cheap cooking oil, it works great, is clean
and produces a very bright shiny melt and a high surface tension. Smells
like French Fries, but if I can smell it I move upwind. I still use oil for
outdoor smelting of larger quantities of lead and for mixing alloys.

However, it did eventually build up residue in my bottom pour melter
and required an occasional thorough cleaning, so after lurking on the forum
here for awhile, I tried sawdust, and now use only sawdust for casting.

I have tried several species, and settled on Southern Yellow Pine. I found a
2 x 4 of mostly heartwood with a huge sap line in it and this piece is so heavy
and dense it resembles White Oak.

I just put it on my Makita chop saw and feed it to the blade to make sawdust,
and empty the dust bag into a coffee can. The slightly sticky dust is a honey
yellow color and very resinous. It essentially costs nothing but the time to make it.

I spoon some on, stir it in with a Lee ladle and scrape the sides with a
cedar shim or paint stick, spread more in an even layer and let it smoke,
then light it off and let it burn to ash.

The resulting crust of gray ash keeps air off the melt and lasts until I need to
add more metal, then I flux again.

IMHO, Sagacious is quite correct about the resin as an aggressive fluxing agent.
.

[montana_charlie]

I was also thinking of maybe making a mixture of melted wax and activated carbon dust just for the fun of it.
If the mixture works, you won't know if it was the charcoal or the wax that did the job...unless you also try them separately.
CM

[cbrick]

Some time ago, I changed to cheap cooking oil, it works great, is clean
and produces a very bright shiny melt and a high surface tension.

Confused :veryconfu. Not sure what you mean by high surface tension.

Rick

[sagacious]

If it's the hydrogen doing the work then cheap trans fat shortening ought to be the best flux of all, since it's enhanced with the good stuff by being partially hydrogenated. My experience bears that out.

When I smelted down 400 pounds of EXTREMELY dirty wheel weights back in the spring I found that flinging a spoonful of cheap Great Value shortening into the pot would make a layer of oily liquid flux that performed great and that wouldn't flame up. It hung around for a long time as a liquid layer on top of the melt and, best of all, it smelled a little like fried chicken!
Eeeeeeeeexactly. Many hydrogenated oils have high heat stability. This is also why many hydrogenated oils (such as crisco and palm 'wax') work extremely well as bullet lubes.

[sagacious]

I'd agree with Sagacious, using parafin wax works extremely well, however, when you light it up to reduce the smoke you find that it's very flammable! Parafin will produce FLAMES about a foot high.
...
Thanks for the interesting thread, newbie questions are great.

Ron
This is quite correct. Be sure to take all precautions to avoid risk of spreading fire when fluxing with anything flammable. Keeping a fire extinguisher handy is a good safety practice anyt ime one is working with heat or flames.

Many people light the paraffin fluxing smoke so they have direct control over when the flames begin, to avoid an unexpected flash-up, and to reduce the amount of smoke. Note that the reducing atmosphere produced by the flames assists in the fluxing process. Good luck!

[Cord]

Re: Surface tension....

I’m guessing that Sagacious could explain it better than I can,
but immediately after fluxing the melt is bright and tight around
the edges, showing a rounded edge called a meniscus which is
only there when surface tension is high.

Oxidation relaxes this surface tension, like a wetting agent.
.

[sagacious]

Confused :veryconfu. Not sure what you mean by high surface tension.

Rick
After fluxing, when the melt surface is super mirror-bright, the lead has a high surface tension. When it is covered with oxide, the surface tension is considerably lower. The highest fluidity, best pouring, and fill-out occurs when the melt has high surface tension. High-hydrogen fluxes-- among others-- quickly produce a melt with very high surface tension. Good luck.

[sagacious]

Re: Surface tension....

I’m guessing that Sagacious could explain it better than I can,
but immediately after fluxing the melt is bright and tight around
the edges, showing a rounded edge called a meniscus which is
only there when surface tension is high.

Oxidation relaxes this surface tension, like a wetting agent.
.
You posted while I was typing my reply! :) You are exactly correct on all points.

[cbrick]

:veryconfu Still confused, must not have had enough coffee yet today.

Silly me, I thought tin was added to reduce surface tension so the mold would fill out better, not flux to increase surface tension.

Rick

[cbrick]

Yep, not enough coffee, just re-read the posts and yes, that's correct. Without the coffee it was reversing in my head and the meaning turned out backwards.

Two pots simply isn't enough to keep a clear head I guess.

Rick

[sagacious]

This is another one of those times when the exact terminology makes a difference.

Surface tension is highest when the the molecules of the bulk material are exposed and reactive at the surface without yet being chemically combined with another compound. This state is reached when the lead surface is totally unoxidized, and diminishes as the layer of oxidation increases. High surface tension is also what causes the dross to bunch up when rosin is added to the melt. High surface tension should not be confused with increased viscosity.

At reasonable temps, tin reduces the thickness and strength of the lead oxide layer, and thus decreases the 'skin effect.' The skin effect is an immediate impediment to good cavity fill-out. Surface tenion and skin effect are terms and melt-conditions that are commonly interchanged in the bullet-casting literature, since most such books are not intended for a chemistry-based audience, and intend to convey a practical working knowledge. What is often meant by 'reduces surface tension' is actually: 'reduces skin effect.' Good luck.

(edit: Rick, I saw your post as I typed this, but figured I'd leave it up in case it helped some folks understand the thread better. Regards, and have a great morning!)

[montana_charlie]

When I smelted down 400 pounds of EXTREMELY dirty wheel weights back in the spring I found that flinging a spoonful of cheap Great Value shortening into the pot would make a layer of oily liquid flux that performed great
It performed great? What did it do?

This thread has been (almost) exclusively about that kind of 'fluxing' that reduces oxides back into the clean alloy you are casting bullets from.

The kind of 'fluxing' employed for removing dirt and contaminants and blending assorted metals into a homogenous whole - the sort of 'fluxing used when 'smelting - hasn't been part of the discussion.

So, what does a layer of oily liquid do for the smelting process?

CM

[zxcvbob]

It performed great? What did it do?

This thread has been (almost) exclusively about that kind of 'fluxing' that reduces oxides back into the clean alloy you are casting bullets from.

The kind of 'fluxing' employed for removing dirt and contaminants and blending assorted metals into a homogenous whole - the sort of 'fluxing used when 'smelting - hasn't been part of the discussion.

So, what does a layer of oily liquid do for the smelting process?

CM
It does both; first it increases the fluidity so the melt releases its dirt and crud, then as it starts to blacken it reduces oxides back to metal. Then you can scoop it out remaining dirt and ash easier because it's wet.

[jsizemore]

For years I used bullet lube for fluxing, both smelting and casting.

Some time ago, I changed to cheap cooking oil, it works great, is clean
and produces a very bright shiny melt and a high surface tension. Smells
like French Fries, but if I can smell it I move upwind. I still use oil for
outdoor smelting of larger quantities of lead and for mixing alloys.

However, it did eventually build up residue in my bottom pour melter
and required an occasional thorough cleaning, so after lurking on the forum
here for awhile, I tried sawdust, and now use only sawdust for casting.

I have tried several species, and settled on Southern Yellow Pine. I found a
2 x 4 of mostly heartwood with a huge sap line in it and this piece is so heavy
and dense it resembles White Oak.

I just put it on my Makita chop saw and feed it to the blade to make sawdust,
and empty the dust bag into a coffee can. The slightly sticky dust is a honey
yellow color and very resinous. It essentially costs nothing but the time to make it.

I spoon some on, stir it in with a Lee ladle and scrape the sides with a
cedar shim or paint stick, spread more in an even layer and let it smoke,
then light it off and let it burn to ash.

The resulting crust of gray ash keeps air off the melt and lasts until I need to
add more metal, then I flux again.

IMHO, Sagacious is quite correct about the resin as an aggressive fluxing agent.
.

I do much the same but I split the high resin wood into sticks to stir my pot and scrape the sides and bottom. So far no rust on any steel parts. I leave the ash from the fluxing on top of the melt to cut down on oxidation along with maintaining a lower casting temp. I mostly use heartpine scraps that have too much resin to accept a finish without a lot of extra steps. Good stuff.

[geargnasher]

It performed great? What did it do?

This thread has been (almost) exclusively about that kind of 'fluxing' that reduces oxides back into the clean alloy you are casting bullets from.

The kind of 'fluxing' employed for removing dirt and contaminants and blending assorted metals into a homogenous whole - the sort of 'fluxing used when 'smelting - hasn't been part of the discussion.

So, what does a layer of oily liquid do for the smelting process?

CM

MC, heat and agitation is what blends the assorted metals into a homogenous whole, not chemicals. As long as a sacrificial reducant is added to the mix and it is stirred thoroughly, the oxidized metals will return to their elemental state and blend with the mix. Any "cleaning" effect is due to bringing the alloy to beyond full liquidus state and stirring to allow contaminants to gravity-segregate to the top.

You can add whatever "flux potion" you like, but I doubt there is anything a good heating, reducing, and agitation followed by skimming won't take care of.

Gear

[rhead]

If the mixture works, you won't know if it was the charcoal or the wax that did the job...unless you also try them separately.
CM

If the mixture works do you really care which one did the major portion of the job? Either will do an adequate job alone.

[rhead]

Confused :veryconfu. Not sure what you mean by high surface tension.

Rick

Surface tension is the resistance of a liquid to take on irregular shapes. Arsenic is added to lead to increase the surface tension when making shot to get the round shape instead of the irregular shapes.
When casting bullets a high surface tension is a bad thing. It will give a poor fill out. Tin will reduce the surface tension of lead.

[cbrick]

Thanks rhead, I understand all that perfectly, I've written several articles explaining that very thing. My post was to the poster that (it seemed but I took it in the wrong context) wrote that it was a good thing.

Rick

[Cord]

Thank you for your kind words, gents, when someone disagrees with me it is
a test of what I think I know, and one way or another, a learning experience.

Freedom started the thread seeking a cheaper alternative to lube, and a with a
suggestion about using activated charcoal for fluxing. He has a great attitude.

After a few responses, Freedom posted:
“I would like to know what kind of sticks you all are using though and how big?
Is it just any old stick off a tree or do you want to use a piece of 2x4 or something
more like tender wood, or does it make a difference? As for the sawdust,
how much do you use? A tablespoon or more?”

So my poorly written post was meant to help answer those questions, and describe
my own transition from lube to corn oil to SYP sawdust, and how I use it, and I
certainly didn’t mean for three words, “high surface tension” to hijack the thread.

That’s another topic, and Sagacious has described it very well in scientific terms.

Yes, for me, it is a good thing.
.

[cbrick]

Thanks rhead, I understand all that perfectly, I've written several articles explaining that very thing. My post was to the poster that (it seemed) wrote that it was a good thing. That's why his post confused me. Rick

I didn't word that very well I guess, I have edited the post to better reflect what I was trying to say.

Rick

[sagacious]

...
When casting bullets a high surface tension is a bad thing. It will give a poor fill out. Tin will reduce the surface tension of lead.
This is a misapprehension, as I explained above. High surface tension does not negatively affect fillout, whereas the skin effect does. Once the lead fills the cavity, the mensicus disappears when the lead is in contact with the mold. This is easy to demonstrate, in that freshly-fluxed lead virtually always fills-out a cavity better than non-fluxed lead.

Not arguing, just saying. Cheers. :drinks:

[alamogunr]

Sawdust or just stirring with a wooden stick has been mentioned for fluxing but no mention of other dry materials. I have a big bag of very fine(20/40) corn cob blasting media that I use in the vibrator. Any reason why it wouldn't work like saw dust?

John
W.TN

[zxcvbob]

Sawdust or just stirring with a wooden stick has been mentioned for fluxing but no mention of other dry materials. I have a big bag of very fine(20/40) corn cob blasting media that I use in the vibrator. Any reason why it wouldn't work like saw dust?

John
W.TN

It does work; just like sawdust but a little slower. If I ever change the media in my tumbler, it will become lead-melting flux. Meanwhile I have a pile of sawdust under my tablesaw, and a package of old lard that smells slightly rancid so I don't cook with it.

[ulav8r]

Did my first casting about 35 years ago. Have most of a container of Marvelux left. Memory seems to be that it worked well. At that time I used a pot and dipper. Went through about 3 gallons of wheel weights, using a 214 gr. Lee 44 and a 150 gr. lee 30 mold. Have recently acquired a few more molds and some wheel weights. About a month ago I smelted about 62 pounds of WW and 24 pounds of Came lead. 2 days ago I smelted another 125 lbs of WW. On these last two smelts I used motor oil and wood shavings for flux. On the last batch I also picked up a Red Cedar limb to stir the pot. Got good clean ingots with little dross loss.

[bruce381]

I think high vs low surface tension here is backward. In my job we want LOWER surface tension so that water based cleaners will WET out on various substrates like metal.

High surface tension mean that the water based cleaners will NOT wet out effectivly on oily metal surfaces and as such they take much longer to clean the metal surface.
This is the only definition I have know about surface tension.

I would say you want a low surface tension when casting so that the lead will "wet out" and flow into all the nooks and crannies of a mold. High surface tension will cause no wetting or bad fill out.

bruce

[Rusty W]

It's a mess. Everything will be black. Seen no difference between it & sawdust. The sawdust doesn't make such a mess.

[HORNET]

Thanks, Rusty. Theory and conjecture are fine but nothing beats actual testing.

[sagacious]

I think high vs low surface tension here is backward. In my job we want LOWER surface tension so that water based cleaners will WET out on various substrates like metal.

High surface tension mean that the water based cleaners will NOT wet out effectivly on oily metal surfaces and as such they take much longer to clean the metal surface.
This is the only definition I have know about surface tension.

I would say you want a low surface tension when casting so that the lead will "wet out" and flow into all the nooks and crannies of a mold. High surface tension will cause no wetting or bad fill out.

bruce
That's a good idea, but the analogy of water (when used with a surfactant as a polar molecule) to render oily substances soluble, is not apt as compared with the non-polar, non-wetting action of lead filling a cavity. The lead just fills the cavity, and it's high density overwhelms any effect of meniscus at proper pouring temp.

"High surface tension" is a relative term. It does not mean "extreme surface tension." All it means is that the surface of the lead is... lead molecules, and not lead oxide or another lead compound. I reckon it's fairly uncontroversial that a clean lead surface hugely promotes fillout. That's what high surface tension means to casting/pouring lead. Good luck.

[Longwood]

If I remember my inorganic chemistry correctly, the reaction won't go that direction. Pb++ has a lower (barely) electrode potential than H+.

The best flux that I've found is lard or Crisco. It works about like old motor oil but it doesn't flame up or stink as much. And it leaves an oily film (glycerin?) on top that lasts a long time. I have some chicken fat in the fridge; I'll try that text time. It should work exactly the same.



I used to use old bacon grease for lube when taping holes. Stays solid till you need it, dip in the tap and as you are threading the hole, the tap warms the grease enough to smell like breakfast cooking. Pretty nice actually. Might work for a really good smelling flux.

If you guys want to play with pure carbon, look at lampblack which is nothing but smoke. No gritty particles to worry about getting in the batch.
LS

[lwknight]

I think all this fluxing business is overrated
The first geatest thing fluxing does when smelting , is to cause the alloy to let go of the junk like clips,jackets, and other particulates that would take a good bit of your alloy away with it otherwise when you skim the sufrace.

You can never actually get the fluxing agent into the melt. You might get it temporarily under the surface but it will be immediately spat right back out.

Fine particles of dust or carbon that may have gotten stirred into the alloy will float to the top , flux or no flux. The very fine particles will float up slowly and stop just under the surface. When we use a liquid hydrocarbon on the furface , it releases whats trapped underneath to be skimmed off. If you keep stirring , these fines will never surface and 50 gallons of your favorite flux will not bring them out.

When alloy is drained from a bottom pour , what comes out is no different when fluxed 50 times as what has never been fluxed. What is different is that you just get the fines out of the alloy so that they will not be stirred back into suspension.

Its like turbid water. Even the most turbid water will eventually precipitate the turbidity if you leave it set still long enough.

Once your alloy is actually clean because you let it sit still for a little while and fluxed the surface to release the contaminates trapped under the surface , the only thing left for flux to do is reducing the oxides back into their respective bases.

If you melt something with a lot of surface area like linotype letters or range scrap , you will have a lot of oxides that can be 99% reduced by stirring the pee waddly out of it while the flux is yet flaming. Only a little fine dust will remain on the surface.

I have tried the saw dust, oil , june bugs , chaws , wax , and all kinds of things and really only found that liquid reduces oxides the best and the dry saw dust and what not is less effective but , don't smell as bad or smoke as much.

Right or wrong thats what I think from a lot of years of metal melting and playing.

[Three44s]

Carnuba wax was mentioned as an added fluxing agent.

Would this liquid suffice?


http://www.aumauto.com/mo2.html

Or should it be a solid form?

Wood substances and bullet lube has been my mainstay fluxers since I divorced myself from Marvelux.

Right now, I've got a huge block of candle wax sitting around that cost zero ...... I think it would be a cheaper run than burning up more bullet lube.

I see the value in using wood with plenty of pitch for it's rosin value ..... pine knots run through a radial arm or table saw looks like it's in my future!

(Learn something new if you care to ...... everyday!)

A big welcome to XX........ you've sure stirred the pot! (pun intended!) ...... job well done!

Three 44s

[Wayne Smith]

Sagatious, others with a chemical background - since we are talking about fluxes and using wood products, what, if anything, is the consequence of using pressure treated wood sawdust? Introducing a few arsenic salts into the mix? Not enough to notice?

[lwknight]

The arsenic salts in treated lumber are toxic. AKA pesticidal.
Its hard to find arsenial wood anymore though.
They did away with the arsenic.
It seems that kids in school liked to chew on the jungle gym made from treated lumber.

[Bret4207]

That's why so much of your "treated" lumber these days is stamped "NOT FOR GROUND CONTACT". IOW, it's not really the treated lumber we had 25 years ago. It's SYP with green stain that helps a little.

[xXFREEDOMisNOTfreeXx]

(Learn something new if you care to ...... everyday!)

A big welcome to XX........ you've sure stirred the pot! (pun intended!) ...... job well done!


LOL, I have to say I have learned A LOT of info in the last couple weeks from this post. I am very grateful for all of the knowledge that has been poured into this thread. You guys have no idea how helpful this info is, and will be, to the other newbs who end up reading it. All the responses here have saved me so much time and aggravation.

I do have one more question on the subject of "fluxing" and that is....

When i flux with wax/sawdust/sticks etc, i noticed in my very first few fluxing runs that I was skimming off "chunky" looking dross. After fluxing a few more pots in the days to follow I was playing around with the smelt trying different things in which i added about a table spoon full of wax compared to only a small pea sized ball that i had used before. After adding more wax this time i noticed that the dross on the top of the pot was a "dust" like substance rather than the chunky grit before. Is this dust what i am looking for? My theory is that when i see the dust on the top it is more of a refined and tell-tale sign of a cleaner pot of lead due to me using more wax. Am I correct by saying this? All-in-all im kind of trying to figure out how much flux to use(wax)...

[lwknight]

I bet the chunky stuff is heavy. Generous fluxing will reduce most of it back to alloy and the dust left is just carbon.
I get the chunky stuff when smelting and just stir and smash the stuff while the pot is flaming from burning whatever. When it burns out most of the crud will have disappeared and have dust in its place.