Benjamin Hein

What's the minimum gauge for something like that side draft chimney?

That looks like a really good chimney to go with, it isn't as tall as I thought it would have to be. My biggest issue with traditional chimney is the price of pipe though, but with it only being 10' tall I may be able to afford that. On the model I was looking at, yes the motor is inside the duct. I thought it might. The walls are poured concrete.

Yeah, I know that a straight up chimney would be best, but with a duct fan, can it overcome the loss of efficiency due to the bends in the pipe? and what about the direct heat exposure on the motor if the pipe was straight up and out? I could go for a bigger duct fan, I just had my eye on one in 8" duct that had 420 CFM and was wanting to know if that would be sufficient, if not I can try to find a bigger one with more CFM

Sorry for not providing more details, I assumed there was a typical CFM requirement for this kind of thing. I currently am using a coal forge I built for being mobile, but I am wanting to build a brick hearth in the building I am going to be making into my permanent smithy. Nothing enormous, so moderate sized coal forge. The building itself is between 8 and 10 foot square. I live in the country, so no regulations. It is not attached to the main house. it's a concrete walled building, an old well house and it's about 6' at the top of the walls and 10' at the peak. I'm thinking a 2' sq. hood to 8" single wall chimney pipe. The reason I am wanting to go out the window is because it's there lol, I wasn't really wanting to cut a hole in the roof. I don't have any experience with that type of stuff. Also I didn't know if the duct fan being directly above the firepot would lower it's life span. If I went straight up there would only be about 2 or 3 feet worth of pipe before it was through the roof.

Howdy folks! First time posting here. I am currently trying to get a permanent set up for my forge and was taken back by the price of chimney pipe. I was thinking of using a duct fan and found this thread and wanted to ask here so I didn't need to make a new thread. what I'm thinking is, having a good sized hood over the forge, with 8" chimney pipe L over to a horizontal 8" duct fan, then L out a window. What kind of CFM are we talking about as being enough for something like this to work? I have my eye on an 8" duct fan with 420 CFM. Would that work? Thanks! Ben