forge welding

[EGreen]

been a while since I was last on here and I need a couple of questions answered that have never been straight in my head.

question 1 to flux your work before you weld, you use borax, right? are we talking about the soap?

2 do you use it like the flux in a can for brazing rods? preheat work put it on then heat till forge heat and hammer, or one heat

sprinkle it on then hammer?

 I will be welding the ends of some 5/16" round rod rings for cinch rings. then add a piece of 1/2 X1/8" flat iron tacked on both ends

the flat iron will be curved like a horseshoe and the ends will be tacked to the rings. thanks a bunch

[DSW]

I use simple borax, like 20 mule team borax you buy at the store. I heat the part and prep the weld area, then sprinkle with borax while it's still red, then put it in the fire to heat to weld temp, then do a light set of taps to set the weld, then reflux and reheat to weld temp and then do the actual weld.

 

 

My biggest issue at 1st was not getting the material hot enough on the welding heats as I was too afraid to burn the material. Once I realized I needed to just get it to the point it was ready to burn, and just slightly sparking, my welds improved almost immediately.

[EGreen]

ok borax from the store. got it. prep work, you mean clean an free of rust I'm guessing. these rings I wrapped around a piece of 3" pipe then saw off at an angle. do I need to keep the lap open so flux will get between the ends or does it matter. thanks

[DSW]

Surface contaminants that can be removed should be. By prep work I was thinking about scale cleaned off well, piece tapered and scarfed etc. What needs to get done depends a lot on the way you are doing the weld. If doing a fagot weld, you probably need to wire the bundle together 1st.  If it's a simple lap weld, you would taper and fold the bar so everything is in contact where it needs to be when you take the welding heat.

 

As far as flux getting in, it will wick thru capillary action thru pretty small gaps. I usually don't take my ends to really sharp points as they will usually burn if I'm not super careful. A bit of mass helps allow things to heat to the same temp without burning as easily.

 

I'm sure there are plenty of guys here with a lot more experience at this than I have. Hopefully they will chime in with some hints I'm not aware of.

[Frank Turley]

There is a Pi times the mean diameter formula. You'll want to upset and scarf the ends 180 degrees opposite each other so when bent, the faces of the scarfs will meet properly. "The heel of one scarf meets the point of the other." You upset, because while you're welding you'll lose stock in three ways: scale; sparks; hammer reduction. If the ring inside diameter is 3" and the stock is 5/16 D, the mean diameter is 3 5/16. Multiplying that times Pi, you get 10 1/2" rounded off. Then, you add one times the thickness, 5/16" to allow for upsetting and scarf making: total length for one ring, 10 13/16". This is shown in the British book, "The Blacksmith's Craft."

 

When bending, have the scarf face to the side rather than up or down. In that way, when they are lapped, they can be laid on the anvil face for the initial hammering. It's called a side scarf weld. If the other way, you get a top scarf weld setup which must be taken to the horn for welding. The side scarf is easier, because you get to go to the anvil face, then the horn, a little like welding a chain link.

 

The borax is applied at a red heat or a little above, just so long as it melts and glazes the surfaces right away. The scarfs are making contact when you flux.

[DSW]

Thanks for the formula on the rig material length Frank. I have to make a ring or two for a project for a friend next week, so I'll give it a try then. That sounds like a whole lot better than my "make one and see how it goes" approach to rings so far when I've been playing with them for practice.

[lupiphile]

Rarely would I add anything to a post on forge welding after smooth papa Turley has given his two cents, but I would like to point out that learning to forgeweld cleanly on 5/16 round is like learning to drive on an 18 wheeler. That's really little stock. It will stay at a proper welding heat for about 5 seconds. Might I suggest you make a couple of rings out of some half inch or so,  and then work your way down. Also I wouldn't saw the ends at an angle as that it will make it nearly impossible to upset a nice scarf which becomes more crucial the thinner the parent material is. Futhermore, when I had the misfortune of having to weld about 35 seperate tiny sections together ( oh, Cussedness, how I am, but a slave to you ) I got a heavy block from the scrap yard ( about 2.5 by 3.5 by 6ish) and put it right on my hearth table next to my fire so I could yank the pieces out and tack them on that little block, put them back in the fire, yank them back out and clean them up at the anvil, it worked pretty well, after a few "test" pieces. For those seperate little pieces your adding to the rings, if your dead set against arc welding them, at lest to hold them in place, I would suggest using a sticky flux, like iron mountain or something with iron fillings in it to help you get it tacked. Hope this helps some, Take care, Matt

[Frosty]

I can't add anything very substantive after Frank's post. Thank you Frank, a formula is so much better than eyeball guestimating for some things.

 

The only thing I can add is about the flux. Laundry additive Borax is just borax while Boraxo is soap and will really mess up a weld. Borax, just borax. OR use a commercial flux, more expensive but they work well. Anhydrous is a common bit of "must be" advice but while anhydrous has advantages it isn't a must, it just stops the flux from foaming as the water boils out.

 

Here's a trick that's stood me in good stead. Clean the joint as well as you can, polish and degrease if you can, I like taking a file to it just before fluxing. Flux is NOT glue, it's to keep the oxy out of the joint. Iron oxide doesn't weld all that well and can certainly keep welds from taking unless you get everything to near melting temp.

 

After cleaning the joint I just warm it a bit, Borax melts at less than 200f. the water boils out at 212f and 230f. takes care of hygroscopic moisture. (loosely bound molecular H2O) Remember the hotter the steel is the faster it oxidizes and you're fluxing to prevent oxidizing. Fluxing at around 200f. provides a coating of borax that prevents oxy from contacting the steel. Then closing the joint, bringing it to welding temp and setting the weld with light blows does it for me.

 

Frosty The Lucky.

[Norcal]

This information helps a lot!

 

 

EGreen, how did your welds turn out?

[Dodge]

So often times it happens, once a feller gets his answer, he never comes back to report one way or t'other. I hope he's ok and everything worked great rather than the opposite :huh: