jester Posted January 10, 2017 Share Posted January 10, 2017 I people of the blacksmithing type I have a random question that I couldn't find on the forums at all. (apologies if it is around - my search skills failed). Currently putting together my coke forge to be used inside my purpose build shed, however, I need to put in a chimney and hood. I have a second hand stainless steel domestic range hood (900mmx500mm) and I was wondering if that might be a good start for a hood for a coke forge? (only ever had a gas forge till now). Looks like the attached image minus the lights and filters and inbuilt fan. Any advice/comments/ridicule welcome (I am new to the concept of using ducting and hoods and chimneys and the like. Thanks in advance LJ Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 10, 2017 Share Posted January 10, 2017 Side draft hoods tend to work better. I first tried a large hood overhead; didn't work at all well, then added a fan assist still not great though I burned up a fan. Now I'm using a variant of a side draft and it works a treat! Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted January 10, 2017 Share Posted January 10, 2017 Not only a good start...pretty good finish too I would say. Pretty easy to find out if it will work. Depends on a lot of things like size of fire, height above fire, height of flue above roof ridge etc. The only thing you might be aware of it that the flue size is fairly small, you may need to do away with the chimney section and build it a bit larger. I have a stainless hood over my coke hearth. But then I have a gas furnace sitting under it on the hearth-which is rarely used. Almost always gas now. The stainless hood gets the heat up the chimney adequately, and has not deteriorated in the 20 years it has been in use. I got through two mild steel ones in the 20 years before that. Quote Link to comment Share on other sites More sharing options...
JHCC Posted January 10, 2017 Share Posted January 10, 2017 To expand on Alan's comment about the flue size, you will find a lot of recommendations here that the flue be a minimum of 10-12 inches in diameter. That's a cross-section of approximately 80-115 square inches; compare that to your existing flue and adjust the latter accordingly. Quote Link to comment Share on other sites More sharing options...
jester Posted January 16, 2017 Author Share Posted January 16, 2017 Thank you for all the replies. Much appreciated. I guess I'll start with the rangehood but try a larger flue size. Some modifications will be done. It is a pain though that I have to have the flue through the wall and not straight up through the roof... Quote Link to comment Share on other sites More sharing options...
JHCC Posted January 16, 2017 Share Posted January 16, 2017 2 hours ago, jester said: It is a pain though that I have to have the flue through the wall and not straight up through the roof... Not necessarily; you might want to forget about the commercial hood and try one of these: http://www.iforgeiron.com/topic/23197-bp1048-side-draft-chimney/ Quote Link to comment Share on other sites More sharing options...
jester Posted January 17, 2017 Author Share Posted January 17, 2017 14 hours ago, JHCC said: Not necessarily; you might want to forget about the commercial hood and try one of these: http://www.iforgeiron.com/topic/23197-bp1048-side-draft-chimney/ Ooohhh.... This looks most interesting!!! Hmmmm... Thank you sir. I only need to go through a 2 inch wall (metal sheet outside concrete sheet inside), maybe a 2 foot long horizontal draw flue to a vertical flue up to the top of the roof might work? Like the 4 degree back tilt to keep water out of the forge. Quote Link to comment Share on other sites More sharing options...
gote Posted January 17, 2017 Share Posted January 17, 2017 An alternative is something on the lines of my setup. Look in the thread "flashing around the chimney" Quote Link to comment Share on other sites More sharing options...
jester Posted January 22, 2017 Author Share Posted January 22, 2017 On 1/17/2017 at 9:11 PM, gote said: An alternative is something on the lines of my setup. Look in the thread "flashing around the chimney" Hi Gote, Thanks for the heads up. That looks like it is another option for me that would definitely work. Appreciate the help. Quote Link to comment Share on other sites More sharing options...
Millhand Posted January 22, 2017 Share Posted January 22, 2017 On 1/16/2017 at 8:52 AM, JHCC said: Not necessarily; you might want to forget about the commercial hood and try one of these: http://www.iforgeiron.com/topic/23197-bp1048-side-draft-chimney/ Oh man! I could have saved 80 bucks in elbows with that design! I want a mulligan!! Quote Link to comment Share on other sites More sharing options...
BarbarianArms Posted April 25, 2017 Share Posted April 25, 2017 I do love a good search and result. Looks like a fantastic idea to go through the wall horizontally and then up! Shame I can't use the galvanized air conditioning flues I have laying around. Shouldn't be too hard to weld up something interesting. Quote Link to comment Share on other sites More sharing options...
BarbarianArms Posted April 29, 2017 Share Posted April 29, 2017 Random question about this awesome design: http://www.iforgeiron.com/topic/23197-bp1048-side-draft-chimney/ I know galvanized metal is a MASSIVE no no for anything that is going to get hot because of vapor and potential death (which is always a bad thing)... However, with the flue section (ie: chimney part and not the 'draw body/rectangular component of the design') - could the flue/chimney be galvanized or is stainless the only way to go? Thought I would ask before I go ahead and build the wrong thing. Cheers! Quote Link to comment Share on other sites More sharing options...
wpearson Posted April 30, 2017 Share Posted April 30, 2017 could the flue/chimney be galvanized. yes Quote Link to comment Share on other sites More sharing options...
gote Posted April 30, 2017 Share Posted April 30, 2017 There is so much air from the room drawn in with the smoke that the chimney temperature never gets into the dangerous area. My own stays around 200°C The original sticker on the pipe is not even brown. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 30, 2017 Share Posted April 30, 2017 It will last a lot longer if you make it from stainless steel. Depends on how you account for your construction time. In terms of percentage of total project budget, the difference in material cost between galvanised and stainless relative to their respective longevity makes it stainless for me every time. My philosophy....If you are saving on labour costs by doing it yourself, do not stint on materials. Double the profit...Make the project better than you could otherwise afford! Alan Quote Link to comment Share on other sites More sharing options...
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