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DFogg

Forge welding

9 posts in this topic

I found this on a guy's site:

"Warning! Do NOT use borax for forge welding no matter what all the hobby smiths tell you. Borax will prevent a full weld and your tongs will separate at the weld joint if used. I know, I was one of those beginners. I had to remake nearly every pair of tongs made with borax. Never again! To use EZ-Weld, heat the iron red, coat the weld area with flux, allow a moment for the flux to heat up and stick to the welding site, then put in the fire. Heat with the weld area facing up until almost at full weld heat, rotate weld area downward and finish heat to welding heat, then take out of fire and rap against anvil to shake off excess debris (the flux will stay attached while debris falls off), then place weld joints together and forge. It is that simple...."

Has anyone else had problems with borax?  I have used borax in my attempts to weld, but I attribute my lack of success to insufficient heat.  Forge welding REALLY interests me, and I would appreciate as much info on it as possible.  I want to succeed.  Thanks.

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Trust me, borax is a fine flux, I have been using it successfully for 25 years.

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Don is right.  Borax is just fine.  

 

Look to all your other welding variables.  

 

Perhaps this other fellow just wasn't holding his tongue correctly inbetween his teeth when he was welding.   It's probably not the borax at all.   :;):

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Thanks guys, good to hear that.

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Regarding borax:  anhydrous means without water.  The 20 Mule Team storebought will function the same as anhydrous, but you have to wait for the water to boil out of the chemical as it melts onto the billet.  I'm not sure about the exact percentage but I thought it was between 20-40% water by weight.  Sometimes this means flux flying off the bar and not staying where you put it.  The anhydrous borax is just like big grains of sand that stay where you put them and simply melt into the hot surface.  There's less waste.  

 

Regarding sand:  If the fire's hot enough, the sand will turn to glass and melt, covering the welding surface of the billet and excluding oxygen.  That is the function of flux, to prevent oxygen from binding to the exposed iron and preventing the weld.  

 

What are all the other recipes for flux that folks on this list know of?  I know some folks add iron oxide to their mix.  Some folks add graphite or carbon powder to prevent decarburization at the weld.  I think it would be interesting to see what everyone else is using.  

 

Either way the melted material keeps the scale from forming and keeps the maximum amount of liquid steel present in the weld boundary until your hammer/press forces the liquid from out between the pieces and the melting iron on both sides comes into intimate contact allowing the high temperature chemical bonds to form making a relatively homogenous billet.

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What you said about the sand makes sense, but I could see problems if you got sand/glass inclusion in the weld. Seems to me it would be harder for glass, even liquid, to squirt out of the weld area, but it must have worked for someone. I have tried mixing Kasenite surface hardening compound with borax, thinking it would help with decarb, but I didn't see an improved performance in the finished blade. What did happen was the Kasenite would burn off just before welding heat, filling the forge with a bright yellow cloud. As soon as the cloud was gone and you could see the billet, it was ready.

 

If anyone needs graphite, I know of a 55 gallon drum full that the owner just wants out of his shop. That stuff seems to get everywhere.

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I've been mixing wood ash with borax, about 50/50. The ash seems to help hold carbon in and neutralizes the boric acid somewhat. One thing I don't like about borax is it eats away at the steel and forge lining. Straight wood ash is a good welding flux, which is less corrosive, but it tends to get gummy. Sometimes I weld primarily with wood ash and every now and then, take a heat with borax to "wash" the billet off. Ash can also be used in conjuction with clay slurry. This is the best for hard to weld alloys, and also in cases where decarb and shrinkage are major concerns.

 

Borax fumes are carcinogentic.

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