Question about forge welding flux: did I waste money on the fancy stuff?

I spent $60 on a bag of that anhydrous borax that's supposedly better than the standard 20 Mule Team stuff for forge welding. After a dozen billets I can't really tell a difference in how clean the welds are or how much scale forms. Has anyone else tested both and seen a real improvement or is it just marketing?

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2 Comments

taraj113mo ago

Get rid of the anhydrous borax and go back to the 20 Mule Team. The whole advantage of the fancy stuff is that it doesn't foam up as much when it hits hot steel, but that barely matters if you're just doing basic welding in a gas forge. I've seen guys weld damascus with plain old borax for decades just fine. The real trick isn't the flux brand, it's getting your steel clean before you even flux it. Wire brush all that scale off hot, then flux, then close the weld fast. The anhydrous stuff does have a higher melting point, so if you're working at super high temps it helps a little, but for normal forge welding you probably just paid for a fancy bag. Save the rest of that bag for when you try welding really weird stuff like wrought iron or high carbon mixes.

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terry9143mo ago

Yeah I bought a bag of that anhydrous stuff once thinking it'd be some kind of game changer. Ended up using it to dehumidify my tool cabinet after a flood.

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