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Downdraft hood design


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I just picked up a model 660 buffalo further and want to make a replacement hood for it but I can't find any relevant information on how the downdraft hoods were designed, dimensions etc... If anybody has one of these forges and could get me dimensions of detailed pictures of the hood design it would be greatly appreciated.

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I have that same forge, and did about the same. I replaced the firepot setup with a rectangular firepot from Centaur Forge.

I don't know what a downdraft hood is. However the hood size should be about the same size as the forge body and 12" flue pipe is recommended. Height of pipe should be about 12'-15' and extend about 3' above the peak of the roof. 

10" flue pipe will work, but 12" is better. Two sections of cheap 6" single wall stove pipe can be joined together to make an inexpensive 12" dia flue pipe.

 

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Anvil; see that slot to the left of the firepot?  A down draft hood is a powered smoke extractor that pulls the smoke down and has an outlet duct going under the floor and out or even just out from under the forge table---you can see a bit of pipe from the original in that picture too.   Very handy if you work with stuff that you would like to be able to swing over the entire forge area.

Neatest one I've seen had a double gear box where cranking the handle ran two blowers, one into the fire and the other pulling smoke away from it. (Back in my dead broke years or I'd have it now!)

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I plan on trying to make it original as best I can anyways, the way it's set up now is the blower intake would suck from the bottom of the hood drawing smoke and fumes back through the fire it has a t just before the tuyere that would send air up into the hood but I can't figure out how that section is supposed to be constructed to function properly.

I took some pictures of how it's plumbed currently, I apologise it got pretty dark out here already.

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Sorry, but that's not how it is set up to work.

The tee shape is the twyre.air goes in the horizontal and goes up into the fire pot. The bottom leg is an ash dump. You do not suck air down thru your firepot and fire.

Also, I'm pretty sure that that firepot is not original. The original had no firepot. It had a flat bottom and a grate setting on a ring. At least that's how mine was. I removed the twyre and cut out a rectangle, then dropped in a firepot and twyre from Centaur Forge. I still have the original twyre and grate I removed. I could be wrong on your original setup. 

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This one originally had a different fire pot but it would have been the same size as the one in it now the large rectangle was clearly cast that way. And the downdraft system definitely was set up the way I have it the only part I'm unsure of us how the hood was designed as they aren't the same as a standard hood.

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I see. Pretty interesting. To be clear, all exhaust goes to the hood. Part, apparently when starting the fire goes into a section of the hood we can't see, or just a glimpse. This must be part of the, I'm guessing, cast hood. It must return thru the air input on the blower. In all honesty, I have no clue how the air returns to the twyre. On the 666 I can see how you can divert sir from before the twyre to the hood to get better draw when first starting a fire.By what the article implies, this will take the smoke that is created when first starting the fire, and recycle it back thru the twyre and up into the fire pot. Lol, basically an early catylitic converter. I've seen something like that in Weygers books. Seems pretty complex considering a smoky fire is a minimal problem when first firing up. However, I can see that it would be a very cool restoration project. 

My forge is the same dimensions as the 660, without the water tank, hood, and blower. Lol, I never knew who made my forge. Now I do! A big thanks for that.

A note. When looking at your second pics, my pan is definitely a buffalo of those dimensions, but mine has none of the built in downdraft stuff, so it's certainly not a downdraft model. And it did have a grate, not a removable firepot.

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Actually in large commercial set ups like factories where they may be MANY forges all running at the same time there would be no chimney going up from the forge but run under the floor as I mentioned.  You can see pictures of such factories and some of the more "modern" forges designed that way.

(Always annoys me when people ask "Was it had forged or made in a factory?"  as it can be and was BOTH for much of the 18th and 19th centuries!)

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