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Forge weld flux


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Reading past posts on welding rod my understanding is the flux is what makes the rods different. The rods are basically the same mild steel. So if you mix scrap ends or just pound off the flux from different graded rod what kind of flux would you end up with--even if you could get it to stick to the pieces to be welded?

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Considering what's in arc welding flux---things like Mn and Flourites---it might help jazz up a flux for high alloy steels; but the fumes will be more toxic than a borax/boric acid flux.

Try it and see! If you are real hard core you might heat it up to burn off the cellouse and then re-grind the result into a powder.

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  • 3 weeks later...

I've been part of a team running a Y1K bloomery for quite a while and black iron sand was a great ore for it. Scale is the same stuff but with some different elements in it, less Ti for one thing as rutile can hide in black sand.

Hmmm perhaps when I'm building my coal forge smithy I should put in an area for a bloomery with a massive chimney as it does work on CO.

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  • 6 months later...

So, this may be out in left field, but I really need to ask 'cause I don't know. I was walking through Walmart the other day in the laundry soap isle and noticed a box that said it was borax. Is this the same stuff that's used in forge welding or am I just totally lost? I'm not sure if it's a brand name or the actual stuff. I didn't pick up the box to read it, I was a lil pressed for time... thanks for any help..

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20 mule team has chemical water in it
I dont like it as it foams up and falls off
It feels dry but has water in it.
anhydrous does not fall off unless you dont have the bar you are applying it too hot enough
heating 20 mule team up to get rid of the water and then griding it back up only to have the humidity suck back into it is too much work for me.
But then the most anyhydrous I bought at one time was 1000#
I only had it a week as I was the front man in a group buy

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That's the stuff. As '781' mentioned it will foam and fall off but you can make welds with it. There has been literally tons of steel forged welded with the 20 mule team borax, you just have to take a little more care as to not cause the stuff to fall off your part before it has done it's job. It's really not hard. Once it has melted you are good to go...it won't fall off once melted any more than any other flux.

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When the lumps form in my 20 Mule Team, I use the lumps to make a good hand soap, Add just enough soft soap or dish soap to make a gooy paste. Put that in plastic tub with a lid. I get a gob about as big as a tablespoon and scrub really dirty greasy hands with that. Works as well or better than most anyother handcleaner.

I also use 20 Mule Team when silverbrazing jewerly and when melting gold and silver as a flux to clean the dross off.

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If you want anhydrous boarx, roast 20 mule team borax in the oven at 200 degrees for a while, that will get the moisture out of it. Then you can crush up the clumps. Only problem is anhydrous boarx starts drawing moisture out of the air as soon as it is exposed, keeping it in a tightly closed container helps.

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What I understand about fluxing.

Borax:
When using Borax, as I understand, you get two, possible three effects. One: The borax shields the iron from the oxygen in the forge, therefore preventing oxidation (scale). Two: It dissolves the scale already present, making it easy for the scale to squirt out during the first blows of a well formed scarf. Three: I've heard that borax also lowers the melting temperature of iron, therefore making it easier to reach a welding heat.

Sand:
Sand only does one thing, it acts as a flux, shielding the iron from oxidation, but does not dissolve oxidation already present.

Iron filings:
Iron filings allow one to see that the metal has reached welding heat without having to peek at the metal. The filings will start to spark first, therefore letting one know that the pieces are ready to weld, long before the pieces themselves would start to burn.

So far I'm pretty good on understanding. Where it starts to get fuzzy for me, is when we start to mix fluxes together.

First, why mix sand and borax together as a flux?

Second, why add Boric acid to the mix? I looked up Boric acid on Wikipedia and if I'm correct in my understanding, Boric acid is made from borax. If this is true, what does boric acid do, that borax doesn't and if boric acid works better then borax, why mix the two?

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NO clue where you got borax lowering the melt temp of iron.

Boric acid is added to the plain borax to make the flux more aggressive, I use it for higher alloys. I know many that prefer to use Sand, as using clean silica sand is common in many places. I don't know of any real proven reason to mix them.

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