Tip: Great source for sawdust flux

[Fathersalt]

Idea hit me last night and I followed thru today. I went to home depot and asked for some sawdust out of the filter for the plywood ripping saw. This sawdust has an incredibly fine particle size which I assume will help with the fluxing based on simple surface area. Its free and relatively infinite resource. Just wanted to share. Ohh bring a bag!

On a second note could somebody explain or refer me to a thread as to why we prefer sawdust over candle wax for fluxing? I have been using candle wax with inconsistent results. I admit I think I am just not fluxing enough. I flux once, skim and start casting. I have a reject rate of 4-10% which is too high for me to continue to tolerate.
Bullet on left is what I make the other 90+/-%. I want to be more efficient.
Im sorry the picture is sideways I cant figure out how to fix it.
Thanks
Colby


71176

[Smokepole50]

I think the idea is that the saw dust keeps the oxygen away from the suface and thus reduces oxidation, plus I would think it last longer then wax and does not catch fire as fast. The wax fluxing I believe is still needed to get your alloy mixed well and then you put the saw dust on your melt.

[Fathersalt]

I was looking thru this thread and it seems sawdust is their primary flux skipping wax altogether.
http://castboolits.gunloads.com/showthread.php?199862-Fluxing

[Alan in Vermont]

You ought to stay away from the plywood sawdust. The glues and binders in composits can be some nasty stuff when burned off, which is just what happens when you use it as flux. You can buy a bag of sawdust/shavings pet bedding for not much $$, it will likely be kiln dried so it won't introduce moisture into the pot and it won't contain toxins in the smoke.

I'm blessed in having a softwood sawmill here in town, nice, coarse pine or hemlock. Only drawback is that it is very "green", if you don't let it char thoroughly before stirring it in you can feel the tinsel fairy, rumbling around in the pot, looking for a way out.

[RickinTN]

"Flux" removes impurities. "Wax" is a reductant, not a flux. Flux will help you to remove the things from your mix that are unwanted. A reductant will reduce the things that you do want but are oxidized back into the melt. Wax will not remove the impurities you want to remove.

[lka]

What about flux paste? I have a bucket of it but I only use golf wax.

[cbrick]

Fathersalt, I believe I've given this link to you in the past.

From Ingot To Target (http://www.lasc.us/Fryxell_Book_textonly2.pdf)

Read chapter 4 on flux, it will explain why sawdust is used and wax is NOT a flux.

Rick

[Defcon-One]

A true Flux does three things:

1.) It reduces oxides back into the mix!

2.) It removes and carries away impurities!

3.) It creates a barrier against further oxidation, if left on top of the melt!

Saw dust does all three. As RickinTN says, Wax only does one (1), it reduces, so it is not a Flux!

I get my sawdust by just running some scrap pine 2X4's thru a cheap table saw or circluar saw. In ten minutes I can create and gather enough to last for months of smelting. I too worry about the glues in plywood and recommend that you avoid sawdust from plywood or treated woods. That is why I make my own!

[Fathersalt]

Alan, thanks. the tinsel fairy did indeed rumble in my pot when I began to stir tonight. I immediately backed off and let it dry a bit before continuing. Funny, when stuff like that happens I immediately freeze and become hyper aware like a big buck that caught the scent and is just waiting for the next mosquito to fart so he can react.
I will admit, I'm not too concerned with glue or binder fumes in plywood saw dust. Relatively speaking all the fumes and smoke and nasty stuff we subject ourselves to sorting and smelting and pouring just to grind out our meager projectiles. What's a little trace glue smoke to worry about. You should be around when I am smelting roofing vents covered in tar or lead flashing with a huge bead of construction adhesive all over it. Just my two cents.
Preciate the help there Rick. I will read it all again.
I got great results tonight after fluxing with saw dust. Cast about 550 bullets with 15 or so rejects. 10 of those were just to get the mold up and running.
Thanks guys. Awesome info. I learned so much as always.

[geargnasher]

Formaldehyde is a poison.

Waxes are sacrificial reducants, not fluxes. They un-oxidize oxides, but don't remove impurities.

Fluxes remove impurities that impede the flow, or "flux", of the metal so it will cast better. Sawdust and borates function as true fluxes for lead alloys. Other types are required to do the same job for other kinds of metals. Borate fluxes, such as Marvellux, also encapsulate the oxides of boolit metals which are particularly rich in tin and remove them permanently from the mix, so are not desirable unless no tin is present or you reduce all oxides before fluxing with them. Borates are also very hygroscopic and make a mess of everything.

Oxide barriers are oxide barriers, no matter whether you use bentonite, ash, or borate glass.

Gear

[383]

Since I'm primarily smelting Iso core alloy, which seems really clean, would the several pounds of lard I have be sufficient for fluxing? I'm not short on pine sawdust, but I wouldn't mind not having to skim it off either.

[Defcon-One]

Use the Lard for french fries! I'd flux with the pine sawdust. Clean lead means that you can use less.

[pdawg_shooter]

Formaldehyde is a poison.

Waxes are sacrificial reducants, not fluxes. They un-oxidize oxides, but don't remove impurities.

Fluxes remove impurities that impede the flow, or "flux", of the metal so it will cast better. Sawdust and borates function as true fluxes for lead alloys. Other types are required to do the same job for other kinds of metals. Borate fluxes, such as Marvellux, also encapsulate the oxides of boolit metals which are particularly rich in tin and remove them permanently from the mix, so are not desirable unless no tin is present or you reduce all oxides before fluxing with them. Borates are also very hygroscopic and make a mess of everything.

Oxide barriers are oxide barriers, no matter whether you use bentonite, ash, or borate glass.

Gear

Gear, seems like every time I read one of you post I learn something new. I have been casting since the 60s and to me flux is just flux. I have used everything from bullet lube to old engine oil. Now, sawdust is all I use. Dont really understand why or how it works but it does. Better than anything I have ever tried.

[Hardcast416taylor]

Stay away from wolmanized sawdust as well as plywoods! Make your own sawdust with a saw, hand or power, and some scrap pieces of soft pine wood. Spread a piece of plastic on the floor beneath where you are cutting up the scrap wood. When done simply brush the sawdust into a container for the next casting event.Robert

[Ole]

I've been getting my sawdust for free from Home Depot for a while now and it's a solid source. :)

[Freightman]

when you cut your firewood up into useable pieces it makes a lot of saw chips put them in a bag let dry all summer and use that. I smelted with old oil once not any more think to much of my hair, wood chips and dust is better

[gray wolf]

Sometimes I think it's impossible to reach some folks.

[PS Paul]

I had to use some alder smoker chips recently since I ran out of my usual sawdust and I was in a hurry. The chips actually worked out alright for flux, but not so good sitting on top of the melt. Made beautiful boolits though, so my smoker chips are ALWAYS handy for all the salmon I smoke. Made more sawdust since then on my bench, so back in biz!!

On the subject of Ingot to Target: a fascinating read, I've printed it out in its entirety and STILL go back and re-read lots of it in the car on my daily ferry ride to and from work. Invaluable!

[452460]

$4.00 at any Agway will get you a brick of good sawdust that would last me a year+ if only used to clean lead

[Airman Basic]

Had a thought. Got a lot of birdcage bedding crushed walnut hulls for the case cleaner vibrator. Wonder how that would work for flux?

[leeggen]

Redcedar sawdust does great, also smells good and the other half does not complain!!!!!!
add a good handful and let char then stir.
CD

[wlc]

I create all the saw dust I can ever use. Woodworking as another hobby gives me all the sawdust I need. I just have to sweep it up or clean out the shop vac.

[Lizard333]

I use the pellets from my pellet stove. A fifty pound bad would give you a lifetimes worth of sawdust. 5$

[mold maker]

Had a thought. Got a lot of birdcage bedding crushed walnut hulls for the case cleaner vibrator. Wonder how that would work for flux?

I take for granted you mean unused bird cage litter. The Walnut tumbling media works great, but maybe not so, if it is full of primer dust or polishing compounds.

[Airman Basic]

Yes, mold maker, I was referring to fresh walnut media straight from the bag with the birds on it. Unused by birds either, though that might be a new odoriferous sensation also.

[imsoooted]

coarse corncob media??? someone gave me a large bag of this. I think it was for a pet cage. way too big for the tumbler, maybe this would be effective for flux??

[Hickory]

Had a thought. Got a lot of birdcage bedding crushed walnut hulls for the case cleaner vibrator. Wonder how that would work for flux?

Walnut hulls are poison, do not use them for fluxing.
They can make you sick for a long time.
Walnuts in any form is deadly to horses and goats.

[383]

Walnut hulls are poison, do not use them for fluxing.
They can make you sick for a long time.
Walnuts in any form is deadly to horses and goats.

I assume you're referring to the smoke and not the dust?

[louism]

Is there a preferred wood species to use as a fluxing material?

[Airman Basic]

That's black walnut shells that develop a specific mold that's said to be harmful to some animals. English walnuts, the usual variety, don't have the problem. According to Google, some folks use them to smoke meat, so don't think fluxing is too dangerous.

[geargnasher]

Is there a preferred wood species to use as a fluxing material?

Sappy, yellow pine is my favorite, and having a custom cabinet shop owned by a friend within walking distance of here I have tried a lot of different things. I find the sap aids the reduction of oxides when you first put it in the melt and that speeds the fluxing process of the activated carbon that forms as the wood chars.

Gear

[el34]

Crushed walnut shells- interesting idea.
I've been very impressed with sawdust, also learned about in Ingot to Target. When smelting it seems to return almost of the floating dross back to the melt. Then I float it in the casting pot as an oxygen barrier. As I recall it was that sawdust became charcoal which was what did the magic, so I'm contemplating pounding up a small bag of charcoal (without built-in lighter fluid!) and trying that.

[RoyEllis]

Gear is spot-on with the formaldehyde warning, and that's what makes Lowe's & Home Depot sawdust a bad idea. They cut alot of particle board to size for customers & the majority of it is LOADED with formaldehyde based glues (learned that yrs ago, safety meeting @ previous job).
Search yellow pages for custom cabinet shops, they almost never use cheap crud like particle board & most will happily give ya a big sack of sawdust.

[Oreo]

Crushed walnut shells- interesting idea.
I've been very impressed with sawdust, also learned about in Ingot to Target. When smelting it seems to return almost of the floating dross back to the melt. Then I float it in the casting pot as an oxygen barrier. As I recall it was that sawdust became charcoal which was what did the magic, so I'm contemplating pounding up a small bag of charcoal (without built-in lighter fluid!) and trying that.

Its not the activated carbon that does it. Its the starches and other compounds in the wood. Carbon makes an excellent reductant and oxygen barrier but its not a flux.

[el34]

Thanks Oreo. Now you've got me thinkin' about trying some spaghetti.

[Smokepole50]

So, do you stir in the DRY saw dust right away or is it necessary to allow it to char first before you stir it in the melt? Once you have your carbonized saw dust mixed in and now floating on the top of your melt, do you add some additional saw dust to complete the oxygen barrier or is one application good enough? How can you tell when all the impurities are removed from your range scrap alloy?

I am a beekeeper and have a sustance called propolis which I scrap from my bee hives when cleaning. It is some type of tree sap, wax and God only knows what else. It seems to act as a very good oxide reducing agent and even carbonizes on the surface of the alloy.

[fredj338]

I create all the saw dust I can ever use. Woodworking as another hobby gives me all the sawdust I need. I just have to sweep it up or clean out the shop vac.

Me too. I would shun plywood or MDF because of the glues used. No telling what breathing such fumes could give you. One small wood working project yields enough flux mat'l for years. You only need a tbs or 2 for 30-40# of alloy. Stir it in right as you add it. Keep stirring until it's basically burned up, skim, pour into ingots. When I am casting, I only use clean ingots & then just stirring w/ a wooden stick is enough fluxing.

[kendwell]

Thanks, Gearnasher: Built a set of stairs and handrails last year, all very old Hard Yellow pine, much FULL of resin. Burned up couple of 55 gal bbls of the chips!

Have numerous scraps, so will cut up with fine table saw blade for the sawdust, recovering in the dust collection system.

COWW, 60# from here, enroute next week. Also 30# of linotype. 268645 mold ready, still need top punch # for this mold.

NOE 312299 DC just arrived, now need to mike the Finn 39 mint 1970 (#2). and the 1942 Husky 38 swede.

Incidently, the swede has threaded bbl, threads being protected with the Swiss Products K-31 muzzle break/de-resonator.

Also going to pull bullets from PPU 6.5 swede, and new powder too, and the 7.62x54, replacing bullets with Sierra Match

Missed by 10 minutes a few hundred rounds of Wolf Gold...Wonder if on the import ban list?

[cajun shooter]

When you go to one of the large stores like Lowe's or Home Depot for your sawdust you are indeed taking a huge chance of becoming very sick or even in respiratory arrest. They cut all types of wood and any of the treated wood is very dangerous to burn and breathe the fumes. It can kill you.
The best woods that I've found to use are the fruit trees or spruce or the woods from the North western states. I've also found that shavings work much better for fluxing as they last longer and give off a wonderful scent for the work bench area.
I have found the shavings from stores in the areas that have a lot of horse owners as they use it for the stalls.( I went through tons of this when I was a horse owner) Find where the wood is milled rather than cut for shavings.

[RobsTV]

I use the pellets from my pellet stove. A fifty pound bad would give you a lifetimes worth of sawdust. 5$

Thanks, that seems like one of the cheapest and easiest routes to take for good wood.

Have been using Lowes sawdust from their wood cutter and after reading this thread, will stop using that stuff and switch to the pellets.

[bikerbeans]

My wife has a couple of horses and buys pine shavings in fairly large compressed plastic bales. She doesn't seem to notice the two or three handfulls I steal every month. FWIW, a bale of these shavings is about $5.

BB

[alamogunr]

It takes longer to char down to carbon but I occasionally use the thin curly shavings produced by hand planing. The sawdust from my table saw is collected(sort of) by my shop vac. It also collects all the various "stuff" I vacuum up from the floor. Not much telling what is in that mix.

[texassako]

If you know any woodworkers, just ask for a sack full. I whipped up a full garbage bag of kiln dried planer shavings in about 1/2 hour, not to mention all the fine sawdust that came out of the table saw. No bad chemicals in there either, unlike plywood. It is an unending supply of cedar sachets for the closet and drawers as well.

[tg32-20]

I just clean out under the table saw and planer in my shop.

Most of it goes on the flower beds, but anyone in the Sacramento area that wants it is welcome to a bag.
Lately it is mostly maple but it works fine.

Tom

[Jal5]

I have been using the sawdust and chips from cutting up firewood with the chainsaw. After it dries out of course. Seems to work fine. and is a never ending supply!

[mold maker]

Last year I had 2 mature pines cut in my yard. The stumps were left about 2' high. A chainsaw artist carved a n eagle and a bear head from them. Long story short, the carving debris and the sap that flowed off them gave me a lifetime supply. Boy does it smell good while charring.

[mold maker]

Double post. Sorry

[Fathersalt]

Well after much experimentation with my fluxing procedure I seem to be back to square one.
I will stop using plywood sawdust per your recommendations, if no other reason it's not getting the job done anyhow.
Im really am stumped guys.
My tried and failed process is, reduce once with candle wax. Flux twice with sawdust. Total stir time around 2-4 mins. Then reduce last time with wax again.
Skimming after each application. This alloy dang sure seems ultra clean when I am done. I scrape on the bottom and around the walls and spout really well during the whole process. I don't consider it good unless the bottom and sides feel "slick" when scraped by the spoon. I am really frustrated.
Only idea I can come up with, is it possible some of trash ending up in my bullets may be coming off the stem of my thermometer? After all the fluxing, I stick it in the pot and it kinda sits there somewhat close the spout on my Lee Pro 20.
At this point I am ready to start dropping some money on commercial fluxes. Price would be nothing compared to the time I am losing sorting all my rejects.
Thanks

[shadowcaster]

Sounds like your smelting process is a success! My ingots come out super clean as well, but then again so do my boolits cast from a Lee Pro 4 20. I would be looking at the casting pot or tools as a possible dirty boolit culprit. Have you given the Lee pot a good cleaning? It could be left overs on your thermometer.. I have several, 2 for casting and 2 for smelting. I don't mix them. Sawdust/shavings from walmart is my go to flux, and wax as my reducing agent if I feel more is needed.
Just another thought.. How clean are your ingot molds? Maybe the molten lead is picking up rust, dirt, or debris as the ingots are being poured?

Shad

[waksupi]

Gotta do your stirring with a dry stick.

[Lizard333]

Gotta do your stirring with a dry stick.

I use the free paint sticks from the Home Depot. Can't beat the price.

[shadowcaster]

Gotta do your stirring with a dry stick.

+1 on the dry stick.... I use the large and small paint sticks from the hardware store. They're free!

Shad

[Fathersalt]

I think you may be right shad. The only thing dirty usually is the stem of my thermometer. Never bother to clean it. :dung_hits_fan::
My spoon is nasty also but I kinda disregard it. Not like its in the pot while I am casting.
Waksupi, I will try the wooden stir stik. :Bright idea:
I have resisted the wooden stir stik but it may help.
Thanks
Colby

[Fathersalt]

I'm at a loss on this guys. This an alloy I smelted and mixed up of 50/50 COWW/Pure Lead and added pure Sn to bring it to around 2%. I made it up in roughly 400lb batches and have roughly 2,000 lbs of it. The goal with the large batches was to ensure a consistent alloy all the way through.
At this point I would love nothing more than to send some of this stuff to some of you more experienced casters to see what can be figured out on it. The scope of work being- figure out how to get this alloy clean. I will say this ahead of time, this is definitely not zinc tainted alloy. I could go on and on, all I know is I don't know how to get this alloy clean. After casting my way thru approximately 3,000 lbs of alloy I thought I had fluxing down. Nope.
My theory--somehow there is Sb that has come "out of flux" from the alloy OR there is a Babbitt metal that refuses to bond to a flux making itself readily available for removal.
Would sure be open to send samples to someone with a "ray gun" that can positively confirm the alloy also.
Send me a pm and I will send a sample. Thanks for the help folks.
For now, it's time to fix my sorrows. :drinks:

[40-82 hiker]

I use the pellets from my pellet stove. A fifty pound bad would give you a lifetimes worth of sawdust. 5$

I also use wood pellets and recommend them. I reduce first with wax and then flux with the pellets. Seems to work great for me.