Fluxing With Sawdust

[BrentD]

Navyvet1959,
I am having a heck of a time posting for some reason, but, lots of people, including myself, travel oround the nation every year to shoot long range (1000 yd) . Though I mostly shoot silhouette, Creedmoor shooting is great fun (lots moreso than typing on this darn cell phone). It is probably the finest example of cast bullet shooting with either muzzle loaders or cartridge rifles, and many people do it with bullets cast using beeswax or similar stuff for flux.

I too do not like using sawdust for flux. Tried it and got spattered with lead. I do not doubt it can be made to work, but that hardly means that beeswax will not. I also still use some flux that I bought from Walt at NEI some years ago. Works great, no danger of lead spatter (or worse). I think Walt knew what he was about. To each his own, but do not sell beeswax and the other nondust stuff short.

Now let's see if this will post right this time.

[geargnasher]

Beeswax etc. does not any ability whatsoever to act as a true FLUX by removing undesirable metallic contaminants. Those can only be removed by adsorption via activated carbon or other adsorbers such as molten borate glass.

Beeswax etc. are sacrificial reducants, which revert oxidized metals to their elemental state through electron transfer. That's all they do, and are capable of doing, PERIOD.

It's simple chemistry, not mumbo-jumbo. If you wanna argue with that, go tell it to a post, 'cause I'm not listening.

Gear

[cbrick]

It is probably the finest example of cast bullet shooting with either muzzle loaders or cartridge rifles, and many people do it with bullets cast using beeswax or similar stuff for flux.

I too do not like using sawdust for flux. Tried it and got spattered with lead. I do not doubt it can be made to work, but that hardly means that beeswax will not. I also still use some flux that I bought from Walt at NEI some years ago. Works great, no danger of lead spatter (or worse). I think Walt knew what he was about. To each his own, but do not sell beeswax and the other nondust stuff short.

Now let's see if this will post right this time.

I tried calling the dog poop in my back yard rose bushes so I wouldn't have to pick it. Didn't work, it's still dog poop. Folks can call wax flux or rose bushes or dog poop but it won't work, it won't be any of those things.

I've used nothing but sawdust for many years and not single pop or splatter or as some claim, dirty alloy & bullets. I guess if someone tried to force wet sawdust under the surface of the melt you would get both the tinsel fairy and dirty bullets but that's very much the wrong way to use it.

Go to post #68 and click on the link, the whole thing is explained in very easy to understand language. Bottom line is that wax is not flux, wax cannot flux simply because it is not flux. Wax is a good reductant but so is sawdust plus sawdust is also a flux.

Rick

[BrentD]

Gears,
I like chemistry, but as some have said earlier in this thread, you need to keep an open mind

What works is what works. Beeswax works plain and simple. Why does that bother you?

Oh well, I will keep using wax and winning matches.

I think that is really all anyone is saying. What is so bad about that?

[BrentD]

Rick, was it not you that said something about keeping an open mind? Why the anger?

Did you call up old Walt Melander (I hope I got that name right) and yell at him for marketing what he called flux and which works extremely well for that purpose?

Lots of anger here in you sawdusters.

[cbrick]

Anger? Really?

What Walt sold as flux is flux, same as Marvalux, a true flux but in no way a reductant, it removes everything.

What you amazingly take as anger isn't even remotely close. And no it's not even intended to open a closed mind. It is however for others that read these posts that actually do want to learn something.

Rick

[BrentD]

Rick, you sure read angry to me. Seems to be alot of personal esteem at stake for some of you. Why are you so angry that some folks flux with wax? If it works for them, why does that bother you?

After all, in just a few moments whether you start with with wax or whatever its all just carbon.

Anyway some of us do fine with wax. And we do not have a lot of anger management issues either.

[LeRoy.Beans]

Anger? Really?

What Walt sold as flux is flux, same as Marvalux, a true flux but in no way a reductant, it removes everything.

What you amazingly take as anger isn't even remotely close. And no it's not even intended to open a closed mind. It is however for others that read these posts that actually do want to learn something.

Rick

Lookin' to me like ya DON'T want others to read that they can shoot great scores with great bullets cast using lot of other stuff for flux...

I'm likin' that sugar idea just for fun...

[cbrick]

No Brent, it's exactly like I said. Other people read these threads and many of them wish to learn. I haven't the slightest anger for closed minds, a bit of pity maybe but anger? No.

Rick

[cbrick]

Lookin' to me like ya DON'T want others to read that they can shoot great scores with great bullets cast using lot of other stuff for flux...

If you keep telling yourself that over and over it will give you a warm fuzzy feeling.

Rick

[geargnasher]

No, it isn't all just carbon. The byproducts of wax combustion (which is a redox reaction) are heat, CO, CO_2, C, H₂O, and trace other stuff. The carbon form is just soot, it doesn't adsorb jack because it forms above the surface of the melt and floats off as smoke. In the presence of metallic oxides like lead, tin, antimony, silver, gold, and copper, this redox reaction involves the transfer of oxygen molecules from the metals to the carbon in the wax as the hydrocarbon chains break down. Essentially you take HC and, say SnO_2, and end up with CO₂, H₂O, and elemental Sn. The carbon dioxide and water exit stage left as vapor and your shiny tin remains behind to do it's job in your alloy.

But what if you have some calcium oxide in your alloy? Or Zinc oxide? Guess what, wax won't reduce those. Wax won't adsorb them, either, so they stay in your melt to play hoc with fill out and the flux, or "flow" (to use the English translation) of the alloy. What to do? Well, due to ionic attraction and the nature of the microscopic surface texture of charcoal, these sorts of un-reduced, contaminant oxides get sucked right up by direct exposure to charcoal bits on the surface of the melt, where they are captured long enough for us to skim it all off.

Now, what can reduce the oxides we want to keep, while quarantining the stuff we'd like to get rid of? SAWDUST! It does both things we want to do, it reduces good oxides like wax does, but it does more, it makes charcoal that will slurp up the bad stuff so when we skim, we only take out the bad and leave the good in usable form.

If you have bad stuff in your alloy, and want to get rid of it, you'll have to flux as well as reduce. Grease/wax/oil only does the reducing, not the fluxing. You can use beeswax to reduce and borax to flux if you like and it will work fine, but you have to deal with the mess of using borax. Do what you prefer, but remember that borax is far more hygroscopic than sawdust and far easier to get under your melt. It also hardens into a glaze mess when it cools, coats everything, rusts steel, and will cause one hell of a steam explosion if you have any on a spoon and submerge it in the melt. And some people think sawdust is dangerous? If you're just using wax, you're only doing half the job. If you have reagent grade alloy with no contaminants, then I suppose all you need to do is keep the oxides reduced and will have no need for any sort of flux....but for those of us who use random, contaminated lead scrap a lot from any cheap to free source we can find, we need to do the whole job to cast the best bullets.

Gear

[30Carbine]

Gear actually you are right on part of your statement but, simply putting sawdust on the melt does not make charcoal, charcoal can only be made true in the absence of oxygen.
what burning sawdust makes on our melt is ash. for charcoal to work like you think it should you need to use activated carbon or activated charcoal which is about the same thing. again can only be made in the absence of oxygen. glen was right on that you need activated carbon but you don't get that with just burning sawdust on the top of a melt.

I use sawdust on my pots just to make a oxygen free zone and to reduce the tin back in. but in the smelting pot I go a step further and add activated carbon to it. you know where I get it go to any junk yard and pull the evap cans off of old cars break them open and there you go. most junk yard will almost give them to you.

[olafhardt]

Water is able to remove reactive components from molten metals that carbon will not. But you can't put water in the melt. You could blow superheated steam through the melt if you got it handy. But there is an easy way to put water into the melt by stirring in carbohydrates such as sugar, starch or wood. If you leave the carbohydrates lay on the top of the melt, the water is driven off by heat and carbon is left which does not attack zinc, aluminum, calcium and other reactive metals as rapidly as steam. So if you throw in some carbohydrate and shove it under the surface before it chars it will release steam into the melt where the reactive metals will snatch the oxygen off the water molecules and leave hydrogen which along with the carbon reduces the oxides of the less active metals. Thus the carbohydrates recover the lead and tin and strip out the zinc, aluminum, calcium, magnesium etc. It's basic chemistry.

[Airman Basic]

Noticed Wally World sells activated charcoal for $20 a 2 pound bottle. Use as flux? Should last a while and it's already charcoal.
http://www.walmart.com/c/bg/activate...n-buying-guide
No worries about introducing moisture to the melt, I imagine.

[bangerjim]

Fish aqurium filters use activated charcoal if you are interested in going down that path. sold almost everywhere the sell pet stuff.

[higgins]

If you have a chainsaw, you probably have oiled sawdust under the sprocket cover. I probably have my oiler set to put out more oil than some, so yours may not be as oily as mine. If you have a selection of logs or firewood, you have a choice of hardwood or softwood sawdust.

[geargnasher]

Gear actually you are right on part of your statement but, simply putting sawdust on the melt does not make charcoal, charcoal can only be made true in the absence of oxygen.
what burning sawdust makes on our melt is ash. for charcoal to work like you think it should you need to use activated carbon or activated charcoal which is about the same thing. again can only be made in the absence of oxygen. glen was right on that you need activated carbon but you don't get that with just burning sawdust on the top of a melt.

I use sawdust on my pots just to make a oxygen free zone and to reduce the tin back in. but in the smelting pot I go a step further and add activated carbon to it. you know where I get it go to any junk yard and pull the evap cans off of old cars break them open and there you go. most junk yard will almost give them to you.

True. "Activated" essentially means that the charcoal is formed under controlled conditions to maximize the surface area, it's like a sponge. But what we make on the surface of the melt at the sawdust turns black is still useful and does the job. I advocate skimming before it turns to ash for the reason you stated.

Now, how much free oxygen do you really think is present in the reducing atmosphere just off the melt's surface? I'll wager pretty close to zero if you light off the sawdust with a BBQ lighter. Charcoal aplenty is formed on top of my melt under these conditions, and it does remove some junk. After several sawdust fluxings, that abates and clean black grains are all that are left to skim.

Gear

[30Carbine]

AH I did not know you lit off the sawdust I don't remember you saying that earlier, so yea you are making basic activated charcoal that is something that needs to be pointed out to new guys that don't understand the y of the process. yes you are correct you have to light it off to get charcoal, I use to run argon over the melt from my tig but that get's real expensive real quick. now I have 2 55 gallon drums from evap cans so no worry. also yes sawdust is the best thing everyone can get a hold of that is free or near free today.
it still works the same I still don't get y everyone thinks that just using wax or oil is a flux but each his own.

[edctexas]

Just be sure that you "sawdust" flux is purely wood. Free sawdust from Lowes or Home Depot etc. has the glues from particle board and OSB. The glue is not human friendly when it is brunt.

Beewax is a great reducer. Better than parafin or candle wax. Nearly any pure wood product (animal litter, wood sawdust, etc) will be a great flux. Flux works to turn the unwanted compounds into dross. A reducer (wax and other) takes tin oxide and antimony oxide and release those two desireable metals back to the melt.

I love the smell of beeswax and cedar shavings in the casting area!

Ed C

[Cowboy_Dan]

So do light the sawdust? The only time I tried smelting so far my pet bedding spontaneousky combusted because the melt was way too hot.

Also, my pet bedding has small bits of paper in it. Is this ok or do I need to remove them?