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I Forge Iron

Gas forge & charcoal


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Well it really depends on what you are doing, how you are doing it and how you have your propane forge built and tuned.  Heat treating knives in a forge that tends to run oxidizing *YES*.  Forging blades where YOU have a tendency to leave the blade in for extended times and not work fast with the minimum heats necessary in a forge that runs oxidizing, MAYBE.  Doing regular mild steel forge work in a well tuned neutral forge NO!  (and in the first example I would use a pipe muffle with charcoal in it to make sure it's reducing.)



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I should have been more specific with my question.

I am making steel knives using spring steel. My forge is new to me and I am still not entirely comfortable with my ability to differentiate between a reducing vs. oxidizing environment. My friend's gas forge produced a lot of scale, I hope to avoid that.

Appreciate the input.

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Easy to tell if it's oxidizing---a piece scales up inside of it during heating.  I'd generally work on tuning the burner than tossing carbon in it as the exhaust flow will push the atmosphere out on a continuous basis.  The pipe muffle for heat treating a blade that is pretty close to done works well for forges that you can forge the blade in but still scale up a bit more than you would like for a almost finished blade.

Please remember "reducing" means producing carbon monoxide!

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A poorly tuned gas forge that scales in the fire needs to be tuned. However there are times you're visiting someone with one that's running lean (oxidizing) and it's unlikely they'll let you tune their burners. Tossing a piece of charcoal in will help scavenge free oxy.

The better course is to tune your burners. Post some pics of it running, include the whole burner so we can see the type and build. Then a shot in the door before it comes to heat so we can get a look at the flame. One from the side of the door so we can see what the dragon's breath looks like.

The flame will tell us what the mix ratio looks like. Showing us the whole burner will tell us what to do to tune it.

Mike's burners are a different breed of cat but yes his opinion is expert. We just do it differently is all. ;)

Frosty The Lucky.

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My answer was expert, but also flippant; so I apologize for that.

Adding charcoal won't just create a reducing atmosphere in the forge; it will create a carbonizing atmosphere, which is no big deal, unless you've gone to the expense and trouble to paint a high-emissive coating in it, in which case that nice rich carbon source will do a wonderful job if covering it up. I learned this lesson the hard way by using a propane additive that was meant to be used in an oxy-fuel flame; not air-fuel. Thereafter, I had lousy performance  for the several heats it took to completely burn that coating away (ITC-100 is too delicate to be wiped clean).


Also, all you have to do in order to know your  flame isn't oxidizing is look for any trace whatsoever of secondary flame. So long as you can see the nearest trace, than your flame is still reducing or neutral; not oxidizing.

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