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Fiorini's Flux


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I have been watching an old blacksmithing video

Featuring Artist /Master Craftsman Bill Fiorini talking about his damascus.

 

Bill mentions his flux recipe as

2 to 4 parts borax

1 part boric acid

and red or black potter's iron oxide until you like the color.

 

I am hoping that someone might be able to clarify

the function of the boric acid and the iron oxide in a flux mixture.

 

I clean all my metal before I lay up a billet and cut ,mill flat and re-stack as I go.

I use anhydrous borax and a press to weld and rarely have any failures anymore,

Everything I am doing is working fine

but I am always curious why people use the methods they use.

Thanks

Steve

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I have been watching an old blacksmithing video

Featuring Artist /Master Craftsman Bill Fiorini talking about his damascus.

 

Bill mentions his flux recipe as

2 to 4 parts borax

1 part boric acid

and red or black potter's iron oxide until you like the color.

 

I am hoping that someone might be able to clarify

the function of the boric acid and the iron oxide in a flux mixture.

 

I clean all my metal before I lay up a billet and cut ,mill flat and re-stack as I go.

I use anhydrous borax and a press to weld and rarely have any failures anymore,

Everything I am doing is working fine

but I am always curious why people use the methods they use.

Thanks

Steve

 

The boric acid will work as a cleaning agent. Borax has boric acid in it but he obviously wanted a more acidic mix. I would guess that the iron oxide would be for an additional oxygen barrier. (The old smith that taught me to weld added silica sand to his flux for the same reason.)

 

Gary

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"Composition For Welding Cast Steel

 

Borax, 10 parts; sal' ammoniac, 1 part. Grind or pound them roughly together; fuse them in a metal pot over a clear fire, continuing the heat until all spume has disappeared from the surface. When the liquid is clear, pour the composition out to cool and concrete, and grind to a fine powder; then it is ready for use.

 

To use this composition, the steel to be welded should be raised to a bright yellow heat; then dip it in the welding powder, and again raise it to a like heat as before; it is then ready to be submitted to the hammer."

 

-The English And American Mechanic | by B. Frank Van Cleve 1874

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I've been using the 4 parts anhydrous borax/1 part boric acid recipe that I got from Bill for 15 years. It's cheap and works great.

You can buy the borax by the sack at a ceramics supply and the boric acid as "Roach Powder" in big cans. Read the label on the can to make sure you're getting boric acid.

Bill didn't mention the iron oxide to me.

Hank

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Thanks Guys,

I have great luck with anhydrous borax.

It doesn't foam at a low heat,penetrates well and completely covers the billet like honey.

I always make sure my mating surfaces are as clean as I can realistically get them.

I will file the boric acid ,iron oxide additions in my mind in case I ever need more flux cleaning properties.

Thanks

Steve

Edited by bronzetools
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If it adds confidence to your welding ability...then use it.

 

I had this discussion with Bill long ago. HIs original background in jewelry was where the boric acid comes from. It's a common flux additive. I do not fault his reasoning for using it, and I have in the past as well just so I would know for myself. Borax is not a dangerous compound by itself. The addition of boric acid (in which industry uses arsenicals to produce) has a reputation for being a carcinogen. The combination of both increases the health risks of the operator.

 

Bill did use iron oxides to color his clays for coating blades when producing hamon. That came from his studies in Japan.

 

As a thought problem: What happens to a compound at welding temperatures? What will you be left with when that boric acid reaches temperature and reacts with all the other chemicals in the forge environment/atmosphere? Does that provide any advantage or disadvantage when compared to anhydrous borax? Will it function as an acidic compound at temperature?

 

If I might: On Friday evening there will be a memorial service for Bill at the University of Wisconsin from 4-6 PM. The weekend we will be toasting his memory at Tunnel Mill in Minnesota. If you can't be there...send a thought in that direction on his behalf. Bill was one of the originals of our craft and deserves much more credit for his influences on us all.

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