Ben_C Posted February 14, 2008 Share Posted February 14, 2008 Question about what material to use for a forge chimney. I have recently completed my new blacksmithing shop all I need to add is the forge chimney and I am stuck. Im planning on do something like this I Forge Iron*-* BP0394 Side Draft Forge. No my question is what to use for the bigger pipe that goes up through the ceiling and where to get it. None of the hardwares stores near me seems to have pipe larger than 10 inch and even if they did im not certain what I should get. Quote Link to comment Share on other sites More sharing options...
Walking Dog Posted February 14, 2008 Share Posted February 14, 2008 Ben, I found my 12-inch at a larger plumbing-heating contractor supply house (in Toledo), so it's out there. I wouldn't want to go smaller on the pipe, either. In another case where I wanted a short piece of 14 inch, I used two 7-inch pieces from Home Depot. It worked fine, just less convenient to have to put them together. Quote Link to comment Share on other sites More sharing options...
Neal L Posted February 14, 2008 Share Posted February 14, 2008 I use this design for my side draft hood.Steel s-draft drawing I didn't build the stand, mine is mounted to the forge and braced from the back wall of my shop. This thing really draws the smoke out and isn't complicated to build. I have a 12 inch galvanized chimney Ipicked up at a heating and air supply house. Quote Link to comment Share on other sites More sharing options...
rthibeau Posted February 14, 2008 Share Posted February 14, 2008 I got my chimney from a store that sells woodstoves and such. 10" diameter SS double walled made for woodstoves and they had all the parts and pieces for mounting, etc, but I needed only the chimney to go through the roof. The whole thing sits in place by its own weight. Any hardware store should be able to order what you need if they don't have it in stock. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 15, 2008 Share Posted February 15, 2008 If you can't find 10" you can put two pieces of 5" together. Frosty Quote Link to comment Share on other sites More sharing options...
yesteryearforge Posted February 15, 2008 Share Posted February 15, 2008 I rolled my 12 " out of 16 gauge sheet metal Mike Tanner Quote Link to comment Share on other sites More sharing options...
dablacksmith Posted February 15, 2008 Share Posted February 15, 2008 ide check your scrapyard i priced the double walled ss stuff for woodstoves ane it was out of my buget but scrownging at the local scrap/salvage yard i found a double wall pipe with all the stuff i needed . ( i think it was used for industrial furnace or similar) it was aluminum but shouldnt matter as there isnt as much heat as a wood stove produces and the hot part is the lower end anyway ... Good luck! Quote Link to comment Share on other sites More sharing options...
Ben_C Posted February 24, 2008 Author Share Posted February 24, 2008 Ok so i got two pieces of 7 inch stove pipe linked together for the chimney now I just need a way to mount it. I am planing on using the method of having a ten inch pipe com off the forge an feed into the chimney so that only a few inches of the chimney extened into the structure. Now I am not sure how to instal/support it any thoughts? Quote Link to comment Share on other sites More sharing options...
jimbob Posted February 25, 2008 Share Posted February 25, 2008 use a colvert- the steel pipe they put under your driveway...12-14 inch 10 to 12 feet long or longer Quote Link to comment Share on other sites More sharing options...
Glenn Posted February 25, 2008 Share Posted February 25, 2008 Why not look at the inside of a water tank? It is fairly thick and about 5 feet long. Diameters I have found are 14 inch to 18 inch. As to support, just build a stand to rest the bottom section upon. Quote Link to comment Share on other sites More sharing options...
nett Posted February 25, 2008 Share Posted February 25, 2008 Why not look at the inside of a water tank? It is fairly thick and about 5 feet long. Diameters I have found are 14 inch to 18 inch. As to support, just build a stand to rest the bottom section upon. Assuming you're talking water heater tanks, those tanks have nice 3/4 inch nipples welded into the top and might be incorporated into 3/4 inch pipe support struts if you simple turn the heater upside-down, leaving the top, now the bottom, on. I believe it would work real well for a side draft exhaust. Just an idea. Quote Link to comment Share on other sites More sharing options...
philip in china Posted February 25, 2008 Share Posted February 25, 2008 Somewhere there are some pics of Uri Hofi's chimney set up in Germany. It is braethtakingly simple and has increased my aready profound respect for that man. He uses stainless because it outlasts everything else. Quote Link to comment Share on other sites More sharing options...
Hofi Posted February 25, 2008 Share Posted February 25, 2008 The Set Up Is Not !!!!!!!!! In Germany It Is In My Smithy And School In Israel. Some Of My Students In Germany Did The Same But Not Those In The Photo's Hofi Quote Link to comment Share on other sites More sharing options...
Don A Posted February 25, 2008 Share Posted February 25, 2008 Mr Hofi, That is a great design. Any idea what the height and diameter of the round pipes are? Thank you, Don Quote Link to comment Share on other sites More sharing options...
Hofi Posted February 25, 2008 Share Posted February 25, 2008 Hello Don The Ss Pipes Are 12'' Id The Squer Tonel Is 13''x13'' 4 Degrees Dowen To Prevent The Rain Water To Flow Into The Fire . The Hight Of The Chimney Is 10' Hofi Quote Link to comment Share on other sites More sharing options...
Rick Barter Posted February 26, 2008 Share Posted February 26, 2008 Uri, Is the chimney supported by the straps or by the square tunnel or both? Quote Link to comment Share on other sites More sharing options...
Hofi Posted February 26, 2008 Share Posted February 26, 2008 Rick Dowen On The Tunnel There Is A 2'' High Coller That The Chimney Tube Is Seatting On . And With A Coller Band Holding The Chimney With Straps Bolted To The Wall One Can See It Very Clearly On The Foto Hofi Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 26, 2008 Share Posted February 26, 2008 When I said put two pieces of 5" stove pipe together to make a 10" piece, I didn't mean USE two 5" pieces. I meant snap the two pieces together along their locking seams to form a 10" diameter piece of pipe. You can make odd sizes as well, a piece each of 8" and 6" will make a 14" diameter piece and so on. Sorry for the confusion Mr. Hofi, I should've checked what I wrote before replying. Frosty Quote Link to comment Share on other sites More sharing options...
Ben_C Posted February 28, 2008 Author Share Posted February 28, 2008 Thank you for your sugestions all. I will look into something like what you use in your shop it looks like a really good idea! Quote Link to comment Share on other sites More sharing options...
Dave Leppo Posted February 29, 2008 Share Posted February 29, 2008 My flu is similar to Maestro Hofi's, but I just ran the 12"dia pipe thru the wall via an elbow, and into the forge. I didn’t know if it would work because I didn’t see any others like that at the time. It does work, but probably not as good as Hofi’s, because I suspect his square tunnel provides a chamber for the gases to expand before being drawn up the chimney. Quote Link to comment Share on other sites More sharing options...
brucegodlesky Posted February 29, 2008 Share Posted February 29, 2008 Hey Ben, did you and I speak at the Queen Cutlery show last summer? Quote Link to comment Share on other sites More sharing options...
Glenn Posted February 29, 2008 Share Posted February 29, 2008 I suspect his square tunnel provides a chamber for the gases to expand before being drawn up the chimney.Why would it be important to expand the gases before entering the chimney? Quote Link to comment Share on other sites More sharing options...
dablacksmith Posted February 29, 2008 Share Posted February 29, 2008 It would create a draw like a carburetor in a car by speeding up the airflow thru the tighter spot and opening up into a larger chamber . Also the taller your chimney is the better your draw will generally be.Hope this helps Quote Link to comment Share on other sites More sharing options...
Hofi Posted February 29, 2008 Share Posted February 29, 2008 There Are Some Reasons For The ''squer Tunnel'' 1 If The Tunnel Is Round The ''suction'' Of The Smoke Is Done Only In The Center And Not All The Smoke Is Been Sucked In. 2 The Tunnel Is Cut In An Angel That The Upper Part Is Almost Above The Center Of The Fire And That Increases The Suction. 3 The Tunnel Is Welded To The Coke And Tyre Steel Table In A Way That There Is Balance Between The Two Sections From Both Sides Of The Wall And There Is No Need To Fasten It Strong Or Heavy. 4 Because The Cross Cut Of The Tunnel Is A Bit Bigger Then The Chimney The Air And Smoke Slows Down And The Ash Is Falling Down On The Bottom Of The Tunnel And Every 3-4 Years I Open The Rear Cover And Clean By This Almost No Ash Is Going Into The Environment 5 The Upper Part Of The Chimney Is Used To Put A Small Gas Forge For Pree Heating One Can Not Do It With A Round Tube 6 The Connection Between The Pipe And The Chimney Is Very Simple And Stable No Need For Special Elbows Or Arrangements 7 From The Architectural Design It Is Nice And Very Impotent For Me Hofi Quote Link to comment Share on other sites More sharing options...
Glenn Posted February 29, 2008 Share Posted February 29, 2008 Unlike a car engine where it is drawn through a small venturi then into a larger volume manifold, Hofi has a 13 x 13 tunnel is 169 sq inches to 12 inches id or 113 sq inches. That is 67% reduction in volume. An expansion chamber in the chimney close to the fire, such as a side draft hood where the smoke is drawn in, allowed to expand, then exits out a opening equal to or about the same size as the entrance, would seem to slow the smoke down. The only advantage I can see is to drop out any heavy particulate matter at the expense of slowing the draft. Quote Link to comment Share on other sites More sharing options...
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