forge welding

Does anybody have some hints for forge welding. I am still getting inconsistent results. I am welding 1/4 x 2 mild steel flat bar in a small
coal forge and am getting satisfactory results a little better than half the time.(passes the peel apart in the vise test). Any help is appreciated .
Maxx
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Maybe it is the coal. I often have to use thermal coal, and the welds are not reliable, but when I can get metallurgical coal my weld rate improves to nearly 100%. I am not sure why, maybe it is cleanliness of the fire, or impurities, but it gives enough heat, just takes almost half again as much coal, and the coke does not conglomerate so no oven to help raise the heat. Doug

the
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hey Guy's, Once you can consistently recognize a welding heat the prime success factor usually is the fuel. Metallurgical, high BTU, Low sulfur, low ash coal really is makes a difference. A pure coke or charcoal fire makes things even easier. Whatever you are using, start with a brand new clean fire. Clear you firepot of all the dregs. keep the fire tight not hollow. With welds that really matter I would always make a few buckets of coke first and use that exclusively for my fire. Try to do all your welding first thing before the fire gets dirtied up with clinker and ash. Results will definitely improve.
Glen.
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Sounds like you're on to something with the coal. I do have access to good charcoal so I'll give that a spin. Thanks Maxx
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Maxx, real charcoal not briquettes. Briquettes are next to worthless in a forge. Pure charred wood is what we're talking about. The fire is a bit different than coal. Coal goes through the coking phase then to ash, and clinker if the coal is low grade. Charcoaled wood is nearly pure carbon and goes directly to ash. The fire will have a tendency to "hollow out" rapidly so maintenance of a tight fire is essential. The lumps should be walnut size. Mostly oak charcoal is available in the states. This works well too but there are a LOT of sparks that tend to come at you then pop in mid air. You get used to it! Japanese toolmakers prefer softer woods for forge fuel like beech and some types of conifer. It takes some getting used to but it is great to work with and makes welding a lot more fun and successful!
GG
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