Forge weld fail

legato1

legato1

Joined
Sep 8, 2006
Messages
1,188
I was trying to forge a wrap around style hatchet from a piece of leaf spring, i bent it over, got the shape i wanted, turned the forge up super high, boraxed the steel, let it get to temp, took it out and boraxed again, then let it heat up and tried to beat it together, first tapping lightly to attempt to " set the weld" then on the next heat really going at it. thought i got a good weld, did a few more of the high heats just in case. left in forge over night to cool. came back today and tried to flatten out the spine of the blade and my so called weld came right apart. greatly disappointed i thrust it to the bottom of the annealing can full of sand never to be seen again... i dont know what i did wrong, all i accomplished was destroying my forge floor. thanks guys
 
I get that all the time too with leaf springs. I think the rust interferes with the welding, are you cleaning all the rust off first?
 
I have read that it is hard to get 5160 to weld to itself. Not saying thats what you have but it could be your problem. Maybe try a chunk of 10xx steel for the bit a piece of old file should work.

Bob
 
Well, the one thing you didn't say that you did was clean anything. My guess is that something on the surface caused the weld to fail. In addition, how hot is "super high" in your forge? What type of atmosphere were you generating inside the forge? How hot was the steel when you fluxed it?

While it's not magic, forge welding does take some preparation and attention to detail to get right. What I'd suggest for a second go is this:

  • Grind all surfaces to be welded clean.
  • Heat the center of the bar just enough to bend it into your "U" shape.
  • Just before you bend it all the way closed, wire brush the inside to remove any scale (scale will keep a weld from setting. Guaranteed.)
  • Tap your pieces into place.
  • Heat the steel to only a dull red heat. If you see any scale, you're too hot and will need to clean things again.
  • Apply flux at a dull red heat. Make sure you have the surfaces to be welded clean and pressed closely together. Flux just the outside at the outside edges of the weld until you have a glassy coating all around the weld boundary. DO NOT put flux inside before you close things up. That will just trap flux in your weld.
  • Heat to a high-orange - low-yellow heat.
  • While you're heating. Prepare your workspace. Put your hammer in a spot where you can grab it quickly on the way to welding (I leave mine on the anvil, faced a certain direction, in a certain spot). Think about what you're about to do. Run through it in your mind. Step through the motions of coming from the forge, grabbing your hammer, and striking the first setting blow. This helps to notice anything out of place or that your forgot.
  • When the flux is bubbling on the surface and the workpiece looks like a stick of melting butter. It's time to weld.
  • Move quickly from the forge to the anvil. Now is not the time to dawdle. Get your hammer ready.
  • Strike your welding blows with a medium-light weight to them. Strike rapidly working from the eye end towards the bit end of your hatchet/tomahawk. You will hear and feel if the weld takes. It's a kind of a dull "thud" rather than the normal sounds of forging.
  • Wire brush, lightly re-flux, and put back in the forge.
  • Soak at a welding heat for 5 minutes to make sure the weld is good and set.
  • Run another series of light blows to make sure you set the weld. If it feels good, move to some heavier blows to check. DO NOT work at less then a welding heat.

If you are generating a lot of scale in your forging, you may have an oxidising atmosphere in your forge. You didn't say what type of forge you're using, so I can't give you much in the way of suggestions here. One thing that should be a constant with a gas forge though is that if you have a few inches of orange flame exiting the forge, you're more than likely at a reducing fire. The reason you can tell this is that all of the gas isn't burning inside the forge (leaving extra unburnt oxygen to screw up your steel). The gas has to EXIT the forge to find oxygen to burn. This is what you want.

Also, if you fragged the floor of your forge with one attempt, you used too much flux. For reasons that I don't fully understand, everybody seems to think that more flux is better. It is not. If you have your pieces ground clean and closely fitted, the entire job of the flux is to seal oxygen out. You want only a light coating that give the workpiece a "glassy" appearance. Lots of flux will only eat your forge up and risk inclusions of flux in your weld. I've never had flux destroy one of my forges, unless I let somebody else use it...

In short, take your time in preparation, think things through, and be careful. It'll work. Trust me :)

-d
 
deker said:
Also, if you fragged the floor of your forge with one attempt, you used too much flux. For reasons that I don't fully understand, everybody seems to think that more flux is better. It is not. If you have your pieces ground clean and closely fitted, the entire job of the flux is to seal oxygen out. You want only a light coating that give the workpiece a "glassy" appearance. Lots of flux will only eat your forge up and risk inclusions of flux in your weld. I've never had flux destroy one of my forges, unless I let somebody else use it...

In short, take your time in preparation, think things through, and be careful. It'll work. Trust me :)

-d
Click to expand...


I find this to be MUCH more common using 20 Mule Team borax Vs annhydrous,

seems like 20 Mule team just gets everywhere. whereas Annhydrous isn't nearly as messy
 
thanks guys, i re did my forge floor with kitty litter, its a 2 burner propane forge with venturi style burners, and as soon as it dries im gonna give it another go, the leaf spring seemed to be new and has a black coating that i thought would burn off. i will grind it on the seccond try, i will also try to insert a bit on the second run. thanks guys. i was kinda bummed out when it didnt work, but im gonna give it another go. il post with results. thanks again
 
You must log in or register to reply here.
Back
Top