plane_crazzy Posted December 31, 2009 Share Posted December 31, 2009 I have a small garage that I am attempting to transform into my smithy. I used a few of the designs discussed here to design a side sucking hood. After designing this, I realized that the building only has a seven foot clearance between the rafters and the floor. the Rafters are far enough apart to install an overhead style hood between them and still be a safe distance apart. Are there any good designs floating around for this style hood? Anyone have any good advice on how to proceed? From what I found, the major difference between the side mounted and overhead style hoods are more of a preference thing based upon where you are. overheads being more prominent in Europe. Although there is some support for the side mounted producing a better draft is there any reason I shouldnt adopt the overhead hood design? Thanks for any help fellas Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 31, 2009 Share Posted December 31, 2009 Even with a large area and a forced fan draft I was not able to get an overhead hood to work as well as a much smaller un-fanned side draft hood. The ones I have seen that seem to work seem to rely on the forge being enclosed to keep the smoke heading toward the draft Why would you want an overhead version? Side version also has the advantage of leaving the overhead open in cause you need to put an odd shaped piece in the fire. Quote Link to comment Share on other sites More sharing options...
John Larson Posted December 31, 2009 Share Posted December 31, 2009 I agree with Thomas Powers. Just wanted to add that a tall chimney with 10" or more of diameter will help all forge hood designs. The column of rising hot air pulls along smoke and the longer the column the better when an inefficient hood is used. Hofi wouldn't use his side drafts in his school if something was better. Quote Link to comment Share on other sites More sharing options...
njanvilman Posted January 1, 2010 Share Posted January 1, 2010 When I installed a side draft hood in my shop, it was almost like magic to watch the smoke turn sideways into the hood. I have 12" pipe that goes up 14' from the forge. The top 5' are above the roof. Years ago I went to the Haystack school in Maine. They had overhead hoods that barely worked. A recent picture of the forges there showed only side draft hoods. Peters Valley smithy also only uses side draft hoods. Quote Link to comment Share on other sites More sharing options...
plane_crazzy Posted January 1, 2010 Author Share Posted January 1, 2010 I am concerned that if I use a side draft I will not have a safe clearance over the fire since its only about seven feet from the floor to the rafters. Is this concern unfounded? Quote Link to comment Share on other sites More sharing options...
Dragons lair Posted January 1, 2010 Share Posted January 1, 2010 My guild has moved to a craft center. They have a newly built smithy. We are running 5 forges 4 of them are paired back to back. Not sure of the height but thats a lot of forges in a small area. You can put a sheet steel or cement board above the fire if needed. Ken. Quote Link to comment Share on other sites More sharing options...
Bad Creek Blacksmith Posted January 1, 2010 Share Posted January 1, 2010 Your concern about height is not an issue since on side draft forges the flames also gets sucked into the smoke box. My ceiling height is 8' and I have a side draft works great with a 10" dia. flue. Quote Link to comment Share on other sites More sharing options...
kevan Posted January 1, 2010 Share Posted January 1, 2010 Your concern about height is not an issue since on side draft forges the flames also gets sucked into the smoke box. My ceiling height is 8' and I have a side draft works great with a 10" dia. flue. Have you perhaps got a picture of your set-up? Kevan Quote Link to comment Share on other sites More sharing options...
plane_crazzy Posted January 1, 2010 Author Share Posted January 1, 2010 i had considered the concrete board above the fire. is a 10" pipe pretty standard? I was planning to use 14ga sheet for the side draft, is that about right or should I lighten it up to 16ga? once again, thanks for all the help. Quote Link to comment Share on other sites More sharing options...
JNewman Posted January 1, 2010 Share Posted January 1, 2010 My original hood was an overhead hood which did not draw that well after a few years I switched to a side draft hood which drew better. I did find I got a LOT more radiant heat from the forge however, so I put a hinged steel cover over the fire hanging from the side draft hood. This cover had the added benefit of improving the draft and also was a place to store stock before it went into the fire (Pick up with tongs as it got hot). I have recently switched back to an overhead hood because I have a power hammer on both ends of the forge and the overhead hood allows me access all around the forge. The new 36" dia hood draws reasonably well with a 10" pipe. It is about 16-18" above the fire but it is easily adjusted up or down to suit what I am working on. Quote Link to comment Share on other sites More sharing options...
JNewman Posted January 1, 2010 Share Posted January 1, 2010 I would use at least the 14 guage for a side draft. I built mine out of 12 and did not regret it. Quote Link to comment Share on other sites More sharing options...
plane_crazzy Posted January 16, 2010 Author Share Posted January 16, 2010 as I am finishing designs for this hood I am running into a quandary. Do most smoke pipes use triple wall lining as they pass through the wood of the roof or do they use another system for heat insulation? A friend suggested using single wall and then blocking around around the pipe, but that does not seem very feasible to me. Any suggestions? thanks. Quote Link to comment Share on other sites More sharing options...
Bad Creek Blacksmith Posted January 16, 2010 Share Posted January 16, 2010 as I am finishing designs for this hood I am running into a quandary. Do most smoke pipes use triple wall lining as they pass through the wood of the roof or do they use another system for heat insulation? A friend suggested using single wall and then blocking around around the pipe, but that does not seem very feasible to me. Any suggestions? thanks. I framed a 2'x2' rough opening and had a sheet metal box made about 10" deep, this covers the ceiling joist and hangs below the drywall by about 2"s. We have our meeting today but this afternoon I'll try to get some pictures posted. I used 10" duct for my flue (single wall) so far no problems, I inspect it twice a year. Quote Link to comment Share on other sites More sharing options...
plane_crazzy Posted January 16, 2010 Author Share Posted January 16, 2010 my insurance company is requiring me to have the building inspected by the fire department prior to using it. will that system pass that type of inspection? Quote Link to comment Share on other sites More sharing options...
HWHII Posted January 16, 2010 Share Posted January 16, 2010 I built my side draft forge from plans from the Blacksmiths Journel. There are plans also in Jerry Hoffman's book " Shop Drawings For Blacksmiths ". It works extremly well I have a section of 10"x 10" long gal. spiral pipe for a chimney and I get excellent draw with it. Quote Link to comment Share on other sites More sharing options...
HWHII Posted January 16, 2010 Share Posted January 16, 2010 Correction 10 inch x 1o feet of Gal. spiral pipe for a chimmney. Quote Link to comment Share on other sites More sharing options...
HWHII Posted January 16, 2010 Share Posted January 16, 2010 I have a photo posted under solid fuel forges. The thread is Bottom or Side blast Quote Link to comment Share on other sites More sharing options...
Bad Creek Blacksmith Posted January 16, 2010 Share Posted January 16, 2010 my insurance company is requiring me to have the building inspected by the fire department prior to using it. will that system pass that type of inspection? I had to have my forge inspected by the fire department also, it passed. One thing people don't realize the chimney only gets super hot when you are cranking on the blower and cools the farther it goes up the chimney. The box I built for between the joist doesn't even get hot and the chimney touches the box. Now I'm going out to take pictures to post. Quote Link to comment Share on other sites More sharing options...
Bad Creek Blacksmith Posted January 16, 2010 Share Posted January 16, 2010 These are the pictures of my forge. Where the chimney comes through the roof I made the opening big enough that the flashing would cover about 2" all the way around it. I also used sheet metal along the rafters with a 1" air space to keep any heat away from them. There is no pictures of this I didn't feel like crawling in the attic. If you don't understand what I'm explaining I'll get my son to crawl up there. Quote Link to comment Share on other sites More sharing options...
kevan Posted January 18, 2010 Share Posted January 18, 2010 These are the pictures of my forge. Where the chimney comes through the roof I made the opening big enough that the flashing would cover about 2" all the way around it. I also used sheet metal along the rafters with a 1" air space to keep any heat away from them. There is no pictures of this I didn't feel like crawling in the attic. If you don't understand what I'm explaining I'll get my son to crawl up there. BCB, Thanks for the pics. They are a tad large and one has difficulty seeing the perspective, plus I would like to see a bit more of your shop which looks most interesting. It is possible that somehow I can resize your pictures? I am a bit of a computer fossil. Kevan Quote Link to comment Share on other sites More sharing options...
Dragons lair Posted January 19, 2010 Share Posted January 19, 2010 my insurance company is requiring me to have the building inspected by the fire department prior to using it. will that system pass that type of inspection? If ya need it inspected don't ask here ask your inspector. Differant locations differant rules. Ken Quote Link to comment Share on other sites More sharing options...
billp Posted January 20, 2010 Share Posted January 20, 2010 I glad you started this, I have a side draft I built but have only used it outside and it worked great to spite the wind. Now I'm building a smithy and was thinking of building a hood out of the outside body of an old close dryer I tore apart of the sheet metal. Now from all this information posted here I'm starting to think about trying my side draft first. Might use the dryer body to build a second hood mounted to the wall for a portable forge I have, but still in the planing stage. This has been of a great help to me. BillP Quote Link to comment Share on other sites More sharing options...
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