Uncle Levi Posted January 28, 2006 Share Posted January 28, 2006 I was looking through some old posts and I want to make sure I understand this right. A side-draft hood works better than an overhead hood-- is that right? :?: Quote Link to comment Share on other sites More sharing options...
HeavyHammer Posted January 28, 2006 Share Posted January 28, 2006 It can but it all really depends upon how well the hood is made. With the right diameter pipe and a good set of measurements then a sidedraft hood will pull the smoke and flames right up to the mouth of the hood. Heres some info on them to give you a good idea of how this all works.http://www.beautifuliron.com/chimneys.htmhttp://www.beautifuliron.com/mysteel.htm Link removed at the request of Jock at Anvilfire I use a large sidedraft hood on my coal forge and i absolutly love it. As long as there isnt any wind comeing in it sucks the smoke right off the fire.Though i must say a little bit bigger pipe would allow more smoke to exit the flue. Id say go with 10" minimum. Quote Link to comment Share on other sites More sharing options...
bruce wilcock Posted January 28, 2006 Share Posted January 28, 2006 for small to medium coal fires,up to shoemaking and jobbing size, a side draft well made takes some beating ,but big coal fires it doesnt seem to work as well coke fires need a full hood and a grit arrester hood is the best ,with big coke fires the amount of air blown in will send not just grit but coke with fire in up the hood and if there arent grit arester ledges in the flue the grit will be raining back down onto the hearth filling the shop with grit. Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 28, 2006 Share Posted January 28, 2006 My experience follows Bruce's suggestions. I use a side draft hood with a 13" diameter firepot and it works well. I have seen masonary side draft hoods in use and they work well. Both have straight stacks of 12" or so diameter. Side draft hoods have the advantage of pulling air up the hood from a small entrance way (usually 1 sq feet of opening or so) creating a lot of suction. A open hood pulls air from the entire opening (many square feet of open area) and tries to get all that air up the stack. For a big fire the additional heat helps with the draft, but the chimney needs to be sized according to the hood. Quote Link to comment Share on other sites More sharing options...
elkdoc Posted January 30, 2006 Share Posted January 30, 2006 At the suggestion of many here, I built a side-draft hood. I'll admit, I was quite hesitant. However, I wouldn't trade it for anything in the world. It really sucks up the smoke - even during startup. I just toss a few burning leaves of newspaper inside the hood and then light my fire. Over, up, and out the nasty green smoke goes. It works even better when it gets heated up. I built mine on the cheap. I have a tall, 12" diameter flue, and I used a 25 or 30 gallon drum for the hood. It sits down on my forge surface. I cut an 8" "mousehole" aperture and away I went. Quote Link to comment Share on other sites More sharing options...
metalmaster1766 Posted January 30, 2006 Share Posted January 30, 2006 any pictures of it Elkdoc? or anyone else for that matter? im in the process now of building a coal forge, gonna use the top end of a co2 tank for the fire pot, im thinking about a side-draft hood, i have a 30 gallon drum too, and a few 55 gallon drums, I was planning on a 10-12 inch diameter flue, if anyone has any pictures of a homebuilt coal forge i'd like to see them, thanks oh yeah the fire pot (tank) is about 8 inches in diameter, i havent cut it yet, gonna do that tomorrow Ron Smith Quote Link to comment Share on other sites More sharing options...
elkdoc Posted January 30, 2006 Share Posted January 30, 2006 I'll try to get some pics of it up in the next couple of days. Probably won't be in action, but you'll get thte idea. Quote Link to comment Share on other sites More sharing options...
HeavyHammer Posted January 30, 2006 Share Posted January 30, 2006 Well, my hood wasnt built on the cheap :shock: .....I decided to use 14 gauge stainless steel and have it welded professionally ( a.k.a. my dad). Works really well. My forge is just sheet steel welded together with a nice ol' Canedy Otto firepot. Heres some pictures... THe brick is for size comparison. This thing aint small.. Quote Link to comment Share on other sites More sharing options...
stryder Posted February 1, 2006 Share Posted February 1, 2006 i was a chimney sweep for 15 years, and my 2 cents are, build the chimney as tall as possible, a chimney works mechanically , on pressure.the pressure at ground level is greater than the pressure 20 feet up so you get draft. the taller the chimney the more warmed air it can hold as to increase the draft. the rule of thumb is 3 feet above the roof or 2 feet above anything within 10 feet. keep in mind that anything within 25 feet can affect the draft. it takes aminimum of 12 to 15 feet of pipe or tile to be an effective chimney. use as few offsets or elbows as possible, no more than 2 , 90 degree elbows in a run. or 4 , 45s which equals 90. the straighter the better. plenty of wind bracing tying to structure. a good cap with spark guard also keeps rain out, which when mixed with the soot in the chimney creates a mild acid which can eat out mortar joints as well as pipe. also use the right alloy of pipe if going with a stainless steel system. 304 alloy for wood, and i forget the alloy # for coal,as i never used any and didnt memorize it, will post it when i get home. also copperfield chimney supply is the place for these materials. hope this helps, and remember to keep chimney cleaned on a regular basis. Thanks, Stryder Quote Link to comment Share on other sites More sharing options...
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