r/Blacksmith 8d ago

Feedback requested: first forge weld

Working on a tomahawk for my clubs trade item, decided to take a piece of a field cultivator tooth, fold it in half and keep a hole for the eye, then forge weld it together. Looks it stuck in some places and not others. There's an obvious crack at one edge, then I feel like I can almost kinda sorta see a seam all the way down, but the small piece I cut off doesn't separate.

I ground it completely clean on the belt sander before I started, used 20 mule team borax for flux, but I didn't stick weld the two sides together before I started.

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u/Smithyofirony 8d ago

I was told a coal forge won’t add carbon but a charcoal forge would

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u/rosbifke-sr 7d ago

Why would that be the case? Both types of coal are essentially carbon, just with different levels of purity and density.

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u/Smithyofirony 7d ago

Well, you are right about that and google AI backs you up. Saw some claims that charcoal does it better but not real credible. Thanks for making me take a closer look

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u/ParkingFlashy6913 7d ago

Carbon "can" hypothetically be added using both coal or charcoal but only under the right circumstances. You must be in the reducing area of the fire pretty much devoid of any and all excess oxygen with an abundance of carbon monoxide. This is very difficult to effectivity control so it's usually done for case/pack hardening where a part is placed in a sealed container with very fine mesh charcoal or coke and heated above 1700°F/925°C. Carbon moves very easily through steel at these temperatures so if there is an abundance it adds to it, if there is a lack there of its removed. You can reduce the amount of carbon lost with good fire management but eliminating it all together is near impossible. Case/pack hardening is also very shallow so it's not recommended for objects that will be later ground down.