Hank Rearden

Welding flux


I have come to realize there are many types of fluxes that blacksmith’s have used in forge welding over the years.  Although, much information easily found on the inter-web list borax as a flux; it is more suited as an ingredient to a flux formula.  After reading different blacksmiths accounts of what makes a good welding flux in “Practical Blacksmithing” by author M.T. Richardson, there seems to be a variety of flux formulas to match each blacksmith’s welding style. From metal filings, white sand, salt petre and pulverized glass including heating and cooling of formulas to get the flux just right. I couldn’t help but wonder if there’s a new combination to what could be used to make a successful weld.


With that being said I’ll start with the most basic formula and try a few experiments myself. Wouldn’t it be interesting if there was new flux formula someone created today that hasn’t already been tried. If I come up with something new I might just name it “Magic Weld”.   


I’ll post the formulas old and new and share any pros and cons as I go. Easier formulas first.

Source of Formulas are found on pages 102 - 105 of "Practical Blacksmithing" By M.T. Richardson The formulas below include ingredients and basic directions. I did not use the complete text. You can find the book for free on Google books if you care to read in original context.

No. 6.
One part lime
Two to Three parts river sand
By R.

No. 7.
One part copperas (iron sulfate)
Two parts salt
Four parts sand
Mix together well
By A. G. C.

No. 8.
One once of carbonate of iron (iron carbonate,  FeCO3) see how to video below
One pound of borax
Mix together
By G. W. P.

No. 3.
Two ounces of copperas
Four ounces of salt
Four pounds of white sand
Mix together

The next flux formulas require more than just mixing ingredients.

No. 1.
Ten ounce of borax
One ounce of muriate of ammonia (sal ammoniac)
Heat until spume disappears then let cool; pulverize and store in dry place
By J. C. McM

No. 4.
One part borax
One part pulverized glass
Wet with alcohol then heated to a cherry red in a crucible.
Pulverize when cool

If you have tried these fluxes or any similar formulas with success or failure please share with others.

code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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there are different types of fluxes for forge welding, it is the same for submerged arc welding. there are agglomerated flux and fused flux according to production process. there are basic and acid flux according to basicity index. there are also different types of welding fluxes for low carbon steel, stainless steel, low alloy steel, hardfacing, etc.
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Hank Rearden
Hi Charliehill, Thanks for the information. Have you used any of these products? What are your thoughts? Looks like a good resource.
code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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