Boraxo Fluxing

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  • Last Post 08 March 2021
billglaze posted this 26 February 2015

Some kind person on this list mentioned usibg Boraxo for a fluxing medium.I picked some up at the local grocery, and used some on the melt I'm presently working.I wound up with a pot of dtuff that highly resembled Styrofoam pellets that used to be spreyed onto ceilings in the 1960's.Did I use too much?  More to the point:  How do the successful folks apply the stuff to get the desired results?Color me puzzled. Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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billglaze posted this 26 February 2015

Please pardon the poor proof-reading on the associated posting.  Let myself get too hurried!Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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TRKakaCatWhisperer posted this 26 February 2015

Bill -

When I flux to render the rough stuff - WW and other scrap - I just sprinkle a couple of table spoons full from my hand into the 6 qt stainless pot (on top of the turkey fryer outside).  Stir, skim, repeat.

Clumps?  Too much.  won't hurt.  Using a wooden 1x1 to stir with helps too.

Inside, where I cast, I use a salt shaker.  (Obviously well marked)  Again, stirring with wood helps.

(I use 20 mule team borax - it works well.  Crud mixes some with the borax and forms a light fluffy dark gray powder.)

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onondaga posted this 26 February 2015

http://castbulletassoc.org/view_user.php?id=5098>billglaze

Borax does not work for a flux unless you get it hot enough to melt and flow over the surface of the metal in the pot. That stops oxygen from reaching the surface of the melt. It takes a lot of heat to turn Borax into a melted glass like flux.

I have many years experience using Borax as a flux for melting and casting Gold and Gold alloys. It works fine in that application as the melt and cast  temperatures are substantially  higher than lead alloys for casting bullets.

I use pine sawdust for flux with bullet alloys. There is no particular advantage to using Borax for a flux when casting bullets. The heat needed to use Borax for a flux in a bullet alloy leaves any Tin in the alloy subject to rapid oxidation upon exposure to air.

Your report indicates you did not get the Borax hot enough to melt, flow over the surface of the melt and act as a oxygen barrier.

Gary

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TRKakaCatWhisperer posted this 26 February 2015

You may be technically right in that it doesn't melt to a liquid. But the fine powder does fluff up, melts enought to bond together in large or small clumps and/or thin sheets - and that does cover the surface. It's cheap and it works as described.

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nimrod posted this 26 February 2015

I agree with TRK I just let it cook into the Styrofoam looking stuff and then break that up and stir down into the melt grind it around on the sides of the pot as much as possible and it'll turn in to a grey powder that cleans the lead very well and smells rather nice too! Works for me!!

RB

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billglaze posted this 26 February 2015

After some of my usual scientific “messin' 'round” I quickly came to the conclusion that I had overdosed the Lyman bottom-pour furnace.  I kept skimming off the resulting “Styrofoam pellets” and got a manageable coating over the surface of the melt.The melt has remained amazingly dross-free; wherever I make an opening with my stirrer, it shows bright and clean.  Then, it rapidly closes up again, apparently (or possibly) keeping air from contacting the surface.I just now finished turning out about +/- 200 great looking 311299 bullets.I'm going to keep playing with it, but as of now, I'm a pretty happy camper.Only problem on the horizon:  I usually cast until the furnace is virtually empty; I'm wondering if any of the residual pellets are going to give me a problem when I get to the bottom?  Just wonderin'. Bill 

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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pb2au posted this 27 February 2015

 I noticed that you are using a bottom pour melting pot...do you think this would work with a pot that you use a dipper from the top? Or would the dipper become coated with the borax glaze and transfer that to the mould?  I don't want to get anything in the mould that would foul-up the bullet.

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nimrod posted this 27 February 2015

I'm a dipper and no problem it cooks into a powder and I grind that up and smash around stir and stir it then becomes finer and gets very dirty looking just push it off to the side and dip away. If you get too much powder skim some off the top.

RB

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billglaze posted this 14 March 2015

So far, the residue appears to stay floating on the surface, very, very lightly. So, while while it's been years since I've used a dipper, my guess (and I'm absolutely guessing here based only on personal observation) is that the Boraxo would stay on the surface inside the ladle, and wouldn't become a factor. I would think that the characteristics of the Boraxo would prevent any entry into the mould, given the dipper had a sufficient amount of lead in it to over-fill the cavity. Best guess, here. Bill

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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TRKakaCatWhisperer posted this 14 March 2015

My guess is the same.

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Bongo Boy posted this 24 March 2015

It seems reasonable to me that, because the Boraxo product contains soap and because most soap I know about contains at least some wax-like product, with sufficient Boraxo on the melt you may be getting some wax melting and surviving on the surface. This might also explain the clumping seen--with the soap component of the product providing an place for debris to collect together--along with the actual borax itself which I'd expect would remain in powder form unless you're running your pot well above 1,300F.

No one mentioned smoke--are you not seeing any? Or much?

So far I've only used sawdust from under the table saw--but that's real tough in the garage where the ceiling is significantly higher than the top of the garage door and smoke tends to stay there unless I've really got a good breeze outside. With a bedroom above the garage, fluxing isn't something I do too often.

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onondaga posted this 24 March 2015

http://castbulletassoc.org/view_user.php?id=3348>Bongo Boy

 Go to Walmart, 20 Mule Team® Borax is 100% natural, and 99.5% pure.

It is a laundry additive and very pure with only 1/2 of 1% room for any impurity.

Verify the product description at the product homepage:

 http://www.20muleteamlaundry.com/about/what-is-borax/

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onondaga posted this 24 March 2015

http://castbulletassoc.org/view_user.php?id=3348>Bongo Boy

Consider a change in your casting equipment layout. If you don't have a window in your garage, consider adding a window and putting your pot under the window and using an exhaust fan in the window.

I do this in my apartment kitchen and wouldn't consider casting indoor if I had no window and fan. I have COPD and very low tolerance for any stinky smoke. My kitchen window:

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nimrod posted this 24 March 2015

No smoke actually smells good, well almost at least not at all offensive.

RB

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Bongo Boy posted this 25 March 2015

Thanks for the suggestions. I actually don't have any need/interest in Boraxo--I was just curious about how much smoke it produced as a guage of how much carnauba or other wax might be in the soap component.

As for casting layout, definitely need a change there for sure. My pot sits on a short stand that holds the burner (propane), and I sit on a short folding chair. It's a setup that's got to go, and a moveable, floor-standing cabinet setup is what I have in mind.

Spouse says “Build the shed first.", and she's right about that.

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mtgrs737 posted this 08 July 2015

When I am casting I like to Stearic Acid as a flux. I bought a bunch of it off ebay from a candle making firm. It is a granular product that is easy to use and clean. It behaves much like candle wax, you only need a pinch. For smelting I use candle wax I get from huge 3 - 4 in diameter by 12” tall candles that folks sell at their garage sale for a dollar for 2 or 3 of them. I also have hardwood sawdust but have not use it yet as the candle wax works well.

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max503 posted this 10 December 2020

In reference to my other thread about the range scrap, I was thinking about trying borax as a flux.  Volume wise, I get about 1 part lead to 3-4 parts dross from every pot I process.  If the borax doesn't work as a flux I guess we could wash clothes with it.  The backstop lead I'm processing is heavily contaminated with bowling pin fragments and dirt and whatever else.

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rhbrink posted this 10 December 2020

I generally just use the borax for fluxing melted alloys in the house. For a chunk of stuff like you have I much prefer to melt that outside and use plenty of wax, old bullet lube, I have lots of lube that I have made or had some wild idea to improve an existing lube that didn't work, makes for good flux or boot dubbing. Also wood shavings and really surprising old motor oil works great just be sure to do that outdoors as it get real smokey. Cook it a lot and flux often to get all the junk out of it. 

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BigMan54 posted this 10 December 2020

I tried this a few years ago on my old 20lb RCBS. Pot was at 700degrees. 

One teaspoon, FOOFFF !!!! 

Cleaned it all up and went back to sawdust.

Long time Caster/Reloader, Getting back into it after almost 10yrs. Life Member NRA 40+yrs, Life S.A.S.S. #375. Does this mean a description of me as a fumble-fingered knuckle-draggin' baboon. I also drool in my sleep. I firmly believe that true happiness is a warm gun. Did I mention how much I HATE auto-correct on this blasted tablet.

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LarryW posted this 11 December 2020

Tried it once, didn't much care for it. My favorite is Cedar or Ash sawdust after I found a supply

Of straight from the tree sawdust. 

A day late & a dollar short, story of my life ???

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max503 posted this 11 December 2020

I tried this a few years ago on my old 20lb RCBS. Pot was at 700degrees. 

One teaspoon, FOOFFF !!!! 

Cleaned it all up and went back to sawdust.

 

This just makes me want to try it more.applause

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Coydog posted this 06 March 2021

The only way I use borax is as a preservative for bird or animal skins. For flux I use ground up corn cobs. It works for me . 

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Duane Mellenbruch posted this 06 March 2021

When using the 20 Mule Team product, sprinkle lightly on the surface.  Yes, it will puff up and then crush the residue against the side of the pot and skim the remaining dust.  As some find, more is not better. 

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TRKakaCatWhisperer posted this 08 March 2021

I have used it for several decades.

Several recommendations:

when rendering WW and other dirty lead, the fastest way to get a clean batch is to melt/flux/stir and THEN pour carefully into another pot.  When a fluid changes directions it doesn't carry particles.  The crud comes to the surface and LOTS gets left in the original pot.

When fluxing the refined metal I use a salt shaker with borax.  light sprinkle on top AND stir with a piece of WOOD.  the carbon from the wood bonds to crud, the vapors from the wood brings the junk to the top.

Scrape the sides to check for crud bonding to the inside of the pot.  If you stir occasionally with wood it won't happen.  Watch out for high moisture content in the wood.  Paint stirring sticks are good.

Use what works.  Ignore the folks that have failed.  That gives you a variety of things that work!

 

 

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