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Forge weld flux


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Thomas,
I didn't address silica because it is nearly non-existent in wood ash. The highest concentrations listed in the attached document are 0.24% by weight of products burned to 600C. Some species did not even contain Si. Wood ash is primarily calcium and potassium compounds. In fact, rereading potash (Na2CO3) was not found according to the linked document, Sodium was less than .06% in most analyzed wood ashes.

Admittedly I only found one set of chemical analysis.

Potash was referenced elsewhere when I was looking, but I did start on Wikipedia.

I did not look for rice ash compounds.

Quartz sand is silica sand. Different names for the same stuff.

Phil


And yet that was the primary source for potash for soap making for centuries, and is where the name "potash" (pot ash) comes from. More research needed.

edit: a little research shows potash refers generally to potassium salts. Potassium and sodium salts act very similarly.
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Do you REALLY want to breath in HOT WD40??????? Not I thank you!!! I'm not an arteest blacksmith,but I've forge welded a zillion bar shoes(that's a kind of horseshoe for you Farrier Haters) with 20 Mule Team Borax.Cheap. Works great. Why look for another wheel to invent? During my apprenticeship in Kansas we used white sand from the Kaw River.Also cheap and works......

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Well, considering that I have nobody to teach me, I'm going to try to find the easiest way to weld. If that just so happens that I use WD40 and it works, great. If not, I'll try borax. My BIG problem is that I don't know of anyone in the Antigo/central Wisconsin area that I can ask for help.

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WD40 is just a bunch of petroleum distillates. Not a bigger deal than burning a little kerosene, AFAIK. I've heard of using it in a nearly sealed can to exclude oxygen for forge welding. Creates a reducing atmosphere in the can to prevent oxidation. The steel has to be very clean, though. WD40 isn't going to dissolve oxides like borax will. I've never heard of using it as a flux in an open forge, without a can.

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I just watched a demo from a blacksmith and farrier (Ray Mager) who took classes from Francis Whitaker he said that Francis did not use flux when forge welding. He the then welded two pieces of 14 gauge sheet metal together. Then 2 bars of 1/2"x3/4" steel. The reasoning for not using flux was borax is not metal and could leave a layer of impurities between the area to be welded. It was a great weld he ground into the welded area and the bond was complete. He said you get it up to heat trun off the air flow wait a few seconds then take the metal out of the fire and hammer.

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WD40 is just a bunch of petroleum distillates. Not a bigger deal than burning a little kerosene, AFAIK.
The main ingredient is indeed kerosene. :lol: I looked up the MSDS. Then I looked up some of the CAS numbers listed.

http://www.wd40.com/files/pdf/msds-wd494716385.pdf

http://www.cdc.gov/niosh/ipcsneng/neng1379.html

I can't help but wonder if the "proprietery surfactant" has something to do with the MS's success with fluxing.


(that's a kind of horseshoe for you Farrier Haters)
I don't "hate" farriers. I just don't want to be one. A few bad apples have given them a reputation of being sour-pusses. :P
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Sorry-Wasn't really aiming that remark at anybody. It is just a reflection of my first experience at a blacksmith conference. When asked,I, in all innocence,told folks that I shoed horses for a living. I got looked at like my breath smelled like the wrong end of a cow!! In these times I figure any honest work is commendable.....
Also-sour pussed ANYTHINGS don't succeed at business very long. I spent 25 years being kind to horses and caring about my clients... There were a lot of sour pussed old guys when I was looking for somebody to apprentice with though....fifty years ago or so.....

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  • 2 weeks later...
Anhydrous borax is chemically(Na2B4O7), while Borax (the Twenty Mule Team Variety) is Na2B4O7·10H2O having ten water molecule per unit of borax.

I have access to a large amount of 'disodium octaborate tetrahydrate', which is similar to the above. The chemical formula is Na2B8O13-4H2O. Any chemist-types out there who tell me if I can asafely use this as a flux? I tried a bit, and it works very well, but not being a chemist, I want to exercize caution ...... :huh:
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I have access to a large amount of 'disodium octaborate tetrahydrate', which is similar to the above. The chemical formula is Na2B8O13-4H2O. Any chemist-types out there who tell me if I can asafely use this as a flux? I tried a bit, and it works very well, but not being a chemist, I want to exercize caution ...... :huh:


http://en.wikipedia.org/wiki/Disodium_octaborate_tetrahydrate

It is a weak answer, but I am not a chemist.

Phil
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Thanks Phil, the stuff I have is used as a micronutrient to supply Boron to plants. I really don't see why it wouldn't work as flux, I would think that when heated in a forge it should convert to the anhydrous form, just like 20 Mule Team does. I don't have much experience with various fluxes, this stuff melts and becomes very water-like in viscosity. Is that what regular borax does too? I think I will do some experimenting to see how it compares to the more standard fluxes. :blink:

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Thanks Phil, the stuff I have is used as a micronutrient to supply Boron to plants. I really don't see why it wouldn't work as flux, I would think that when heated in a forge it should convert to the anhydrous form, just like 20 Mule Team does. I don't have much experience with various fluxes, this stuff melts and becomes very water-like in viscosity. Is that what regular borax does too? I think I will do some experimenting to see how it compares to the more standard fluxes. :blink:


That is more or less what borax does. If you use 20 mule straight from the box it will foam at a high black heat, then become crusty till at a low red heat when it becomes liquid. Borax boils below the melting point of steel.

http://en.wikipedia.org/wiki/Borax

Phil
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  • 3 months later...

I know flux isn't technically a tool, but I couldn't find a better forum for this question. I haven't done any forge-welding before and I'm looking to start, but the website I use (www.blacksmithsdepot.com) has a bunch of different fluxes and I don't really know which one to use or why. Can anyone recommend a specific kind or brand that you've had success with?

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I second this. 20 Mule Team is pretty much the standard. The main ingredient of the commercial fluxes is borax. They may have a few other ingredients, like boric acid and/or iron filings. And they may use anhydrous borax, which is basically dehydrated 20 Mule Team. It has some advantages. But for most things plain old borax it just fine. And it's dirt cheap. (Literally. They dig it out of huge, open pits in the ground.)

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For a specific brand knowing WHAT COUNTRY YOU ARE IN may help.

In general I use 20 Mule Borax here in the USA and when I work with higher alloy steels I cut it with Roach-Pruf which is 98% boric acid (and much much cheaper than buying USP Boric acid at the pharmacy!)

Forge welding is something that a good afternoon with someone who knows what they are doing can save you *months* of flailing about on your own. Finding a local smith or smithing group is strongly suggested!

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Most use borax
It is very hard on the lining of a gas forge
Also if you dont wash away any residue from the weld area in humid climates the weld will bleed white for years

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I have myself used Borax laundry for many years I went to a demo and the demonstrator said when he took classes from Francis Whitaker the he did not use any flux at all. I dose work . One of the fluxed I used at a friends shop was borax and iron oxide powder it worked well. The big thing is consistent heat, clean metal and fire, tempature of the metal (heating it all the way through to the same temp) timing, and not hitting it to hard.

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I'd add a reducing atmosphere to Francis's list, especially if you're going fluxless. Flux will help prevent oxidation, and will remove any oxides that do form (up to a point). If you go without flux, atmosphere becomes even more crucial.

By the way, I don't really recommend going without flux as a beginner. It can be done, but flux makes the process somewhat more forgiving. This skill is hard enough to self-teach; there's no need to make it harder until you have a good handle on it.

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