tecnovist

Forge weld flux

510 posts in this topic

Hi fokes ---Wish you well---- I need to know what the Chemical name or names are for the flux's that is used in Fire Welding --and is there more than one thats used --- or any info about flux --- thanks
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Gday tecnovist,

I use Borax. you should find it with the laundary items in the supermarket.

Yes there are commercial fluxes, but generally they are expensive and contain borax as the main ingredient.

try reading this site: What is Borax?

Regards
Rusty_iron
Brisbane, Oz.

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Some smiths use clean sand. Others use sand daubers' nests and I've heard of some smiths using charcoal ash. English smiths traditionally didn't use flux; they pretty much relied on having a clean fire and not producing (or brushing off) the scale from the joint.

Common laundry borax is boraxdecahydrate which means it has 10 water molecules per every one of borax. This means when you apply it it will whizz around for a while. You can buy anhydrous borax (farrier suppliers I think, and ceramic suppliers). You can also heat a tray of hydrous borax in the oven for a couple hours to make partially anhydrous borax, or heat a tray to melting point in the forge to produce anhydrous borax.

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James Hrisoulas once posted this flux recipe:

"Flux mix is as follows:

5 parts anhydrous borax
2 parts powdered boric acid
1 part powdered iron oxide (the real STUFF NOT the concrete dyes)
1/2 part Flourspar
1/4 part sal ammoniac

This stuff sticks most anything together"

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If I'm welding mild steel together I rarely use a flux unless I'm welding say 1/16th sheet to a bit of 3/4" x 1/2" but then I'm a british smith taught by traditional smiths. Over here we've a product magi weld that's just anhydrous borax and iron powder i've got a bottle and have experimented and found it useful when trying to get the scarf tails to wash in.

I've also made the Jim Hrisoulas recipe flux and it it excellent for pattern welding steels containing crome I mainly use it on my initial welds and unknown steels. If anyone could tell me why we add iron oxide when it's what we're trying to dissolve I'd appreciate it. I also assume is in if to help it flow.

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well i could be wrong but it mat act like a wetting agent-----so to speak---- the iron oxide may be attracted to it ----

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I wonder if I could use the Iron/steel dust below my sander/grinder and mix it with my Borax...seem like I read somewhere in one of the old books I have that that is what they used to do...any one try this?

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I know someone who tried and had more inclusions, this was for damascus, I assume from the grit

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in addition to the fluxes mentioned above, I've read that lime was historically employed as a flux

(a key flux ingredient in steel manufacturing, as lime, limestone or fluorspar)

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.. wonder if I could use the Iron/steel dust below my sander/grinder and mix it with my Borax...

the problem is that isn't only iron, its also bit of your sand paper/grinder wheel. So you have to decide is that other stuff going to make good steel?

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well I guess I could use the powder fom where they turn my brake drums it wouldn't have that grit in it....I might give that a try

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Hi All i think its the iron oxide's that are used

brake drums i would not use that as it contains asbestus or is highy likey to

I think the sand paper grit MAY help as its silicon carbide and should melt

although not all grinding grit is silicon carbide

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I guess one could take a magnet and put it in a plastic bag and then pick up dust below the sander/grinder...that way you'ed only get the iron/steel dust and exclude the rest

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I collect black iron oxide when I do twisting, generally your getting quite a large area of bar fairly hot, twisting it just dumps off all the scale and the twisting jig we use is tack welded to a table which catches it all. Get snowdrifts worth of the stuff.

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I wonder if I could use the Iron/steel dust below my sander/grinder and mix it with my Borax...seem like I read somewhere in one of the old books I have that that is what they used to do...any one try this?


I have heard this is not good due to the stone grit from the grinding wheel or the sandpaper. Iron filings from using a file are good for that because it is just steel.

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Funny they melt steel in silicon carbide crucibles, I don't think SiC will melt very well in a weld!

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I collect black iron oxide when I do twisting, generally your getting quite a large area of bar fairly hot, twisting it just dumps off all the scale and the twisting jig we use is tack welded to a table which catches it all. Get snowdrifts worth of the stuff.



do you use it for welding then? thanks

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Many thanks Fellas That answers the question. Its euro 120............Duck

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you could try it on 240 if you are brave.
European systems have one leg of that 240Vac "earthed." We would call it "grounded" in America. In America, neither leg of a 240Vac supply is grounded - each leg is at 120Vac to ground.

Now, if the case of the tool is connected to the leg which would have been earthed in Europe (for safety, dont'cha know)... well... I'd hate to be reading about "roast Duck." If the case is "double insulated," then experimentation would be a lot less chancy.

Mr. Duck, Sir, I regularly touch basis with some European electrical experts. If you can share the manufacturer and model number, I could possibly get some more specific information for you.

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Any time I have wet welding rods, short rods left over from welding etc they are thrown into a metal can. As the flux is designed for welding, has anyone ever tried to use the flux from the rods as a forge welding flux?

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i havent tried it
but i think as long as they are welding rods and not brazeing rods the flux should work

only concerns i might have is the flux might be a lower temp and just burn off or react with something in the forge and make something bad for the health

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