tecnovist

Forge weld flux

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20 mule team Borax and roach-pruf---97%? Boric acid. I mainly do billets but I use the same flux when I do ornamental work. (last time I bought some I got both at the fleamarket for about US$1 to make 4 pounds of flux...)

And a class act to not dis a fellows product when the issue could be with the user! Funny how certain things will work perfectly for one smith and *not* for another. The Human factor! I have students blame the tools for their problems at times to which I will use the same tools to do a perfect example and tell them "it's not the tool"...

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I use anhydrous boarax but years ago two demonstrators I watched sumed up forge wielding this way
One had been blacksmithing for 40 or more years and he said forge welding was so easy until he started getting around other smiths who said it was so hard to do that it started to become hard for him.

The other smith Bob Patrick (forge weld Guru) said it is like olympic figure skating you cant do it once a month and expect to win gold it takes practice practice practice until it is second nature.

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Boy, you know if I opened my eyes I would have seen this thread before I posted mine. Lots of great info. Thank you all. And more than likely, the hard time welding was my fault. Just glad I went and got the borax.

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I use borax with about 5% iron filings by volume. I happened to get a 5# jar of pure iron filings (laboratory stuff) a few years ago. Works pretty well, but sometimes some of the iron sticks to the outside of the workpiece, so I have to file it off.

Some people add a little white "beach sand".

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I'm not seeing alot of alternative fluxes in this thread,
Except Jason0012 who mentioned Table salt, and Phil Krankowski who debates a number of minerals.

I am home on vacation, so I will not be able to order and use borax this following week, therefore I'm gonna try table salt.
I'm guessing it only works as a protective layer, although I tried heating the end of some 3x19mm (1/8x3/4") mild steel with a gas torch to red heat, applying Table salt, and it seemed to take some scale with it.
Will be trying to weld with it as soon as it stops snowing :angry:
The teacher at my smithing course also suggested it. -How many of you have tried?

I'm also optimistic about caustic soda, it has a higher melting point, but I'm hopeful it might be a little more aggressive with the scale. Anyone tried?
Potassium Hydroxide (caustic potash) might also be a candidate, but I don't have any. Anyone tried?

It's easy to sort fluxes by melting temperatures, but the difficulty comes by the eutectics that might occur in contact with scale, or in a mix.
By itself I'm sceptical to:

-Ground marble, melting point:
825 °C 1517F (aragonite)
1339 °C 2442F (calcite)
In the vicinity of melting points, it starts to decompose and forms CaO, which has a melting point of 2572 °C (4662 °F) -Methinks that would hinder welding, unless some eutectics aid it.
CaO would be present in wood ash as well.

-Sal ammoniac, melting point:
338°C 640F, at which it decomposes to Ammonia and HydroChloric gas. -Unless it enters a eutectic mix??

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before you start using caustic soda on a weld have a thought for your lungs.
borax is not at all good to breath, I,m betting caustic soda is a lot worse.

its not just the melting point of the flux that is important, borax has a definite top limit and a limited capacity for eating up oxygen . in a hot high heat environ it dries up (or evaporates , or oxidises...)

I wear a powered breathing mask designed for welding fumes if i am doing any forge welding with flux , its nasty stuff when used long term.

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One thing to remember too is the placebo effect. As it's possible to weld with *no* flux but using good technique I think that some "special fluxes" are really to encourage you to believe that you can weld and are not much different that the plain old borax.

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A lot of fluxes are borax, boric acid and iron filings. read some MSDS on them. They are fairly transparent about contents, but not ratios.

Phil

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Baking soda was mentioned early in this thread. I just assumed that it would decompose at relatively low temperatures like some other carbonates, thus forming caustic soda anyhow, so that using caustic soda would be the same thing, basically.
Wikipedia has shown me I was wrong, baking soda does not decompose, and boils at 1633 deg. C.
Will be trying that today.

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Okay, that didn't work.
Baking soda turned into a charred fluffy entity with a few clear droplets oozing out.
I suspect it might have to be dehydrated before use.

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Okay, that didn't work. Baking soda turned into a charred fluffy entity with a few clear droplets oozing out. I suspect it might have to be dehydrated before use.


After reading the wiki, I am not surprised. It decomposes at a pretty low temperature, even though it can melt and boil at higher temperatures.

Funky stuff, makes cake too!

Phil

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Supposed to be good for high Ni/high Cr alloy welding but it gives off fluorine gas when it's used and so is extremely toxic! Generally used in small amounts added to a standard flux like borax so as to need as little of it as possible.

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I tried forge welding with Borax but it never worked, I tried. Then started new , new side draft forge new source of coal and clean Borax. So I found out the hard way, my Borax was always left outside got filled up with soot, dust, crap it looked awful now new box of Borax in a tin covered over till I need it. Good coal with the dust screened out prior to forge welding. Now dirty steel such as chainsaw blades,crane cable, timing chains all forge weld well. Even clean steel will weld without Borax in the new Forge In fact with gates and ornamental projects no flux is ever used. This stuff is cheap and it works well.

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Anybody have any good home brew recipes for flux for forge welding... I am about to venture into  this area and at the moment just have Boraxo hand soap available to me... Been told it is workable, and also  it was mentioned the by adding salt to Borax it helps process ( but how much) ....

 

Yes I know I can order many fluxes online but that is not what I want to do at the moment....

 

So what's your favorite mix of common household items ...

 

Dale

 

 

 

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head to the nearest grocery store or drug store and find '20 mule team borax' thats probably one of the easiest to find fluxes.  plus its dirt cheap and comes in a big box :)

 

ill let people who have used other products chime in on their pro's and con's, i cant keep them all straight anymore.

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Boraxo is hand soap. Borateem is a blue laundry additive. Neither is recommended as flux. As Chinobi suggests, get 20 Mule Team Borax. For proprietary flux, I like E-Z Weld and Black Magic.

 

Sayings and Cornpone

About a flaw on your finished piece: "It won't be noticed, if you're on a trotting horse."

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Ahem.... I already have this...

 

41VA6HYfZqL._SX300_.jpg

 

Is not BORAXO and 20 Mule Team Borax not basically the same stuff?

 

"20 Mule Team Borax" is 99.5 % "sodium tetraborate"...

http://www.20muleteamlaundry.com/about/what-is-borax/

 

"Boraxo" is "sodium tetraborax decahydrate"

 

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

 

And anybody explain the difference?

 

Dale

 

This post was moved and added here from yet another thread.

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Ahem.... I already have this...
  
Dale

at least your hands will be clean....

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Good Morning,

 

This is available on the NWBA web-site www.blacksmith.org , put together by Steve McGrew

 

http://www.incandescent-iron.com/foweflre.html

 

What I have learned about forge-welding is, The Harder you Try, The Greater Chance of Disappointment.

Relax, Take your time, Don't be in a Hurry, It will stick everytime!! :) :)

 

Neil

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in the UK the borax that was once found in the supermarkets has been almost totally replaced by 'borax substitute'. I've not heard whether that stuff works or not, but being that I don't live anywhere near a place that sells it, I've not tried. Instead I just buy bags of pure borzx from ceramic supply companies. Potters use it for glazing, so its used in large quantities and is very cheap and very clean :)

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Ahem.... I already have this... Is not BORAXO and 20 Mule Team Borax not basically the same stuff?

 

boraxo is borax And SOAP,  that soap addition is going to cause trouble.  NEVER USE WIKIPEDIA AS A PRIMARY SOURCE,  anyone can and do post there, some are clueless.

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