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I Forge Iron

Flue and hood recommendations


MAXJEEP

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I am new to all this but have a young son who loves it.  I built a 10x10 lean to with a steal roof and a crushed limestone floor.  A neighbor gave me 8 inch double wall wood stove flue pipe, cap, flashing, and celing support.  My first question...do I cut a hole in the steal and screw  the flashing to the inside and caulk the heck out of it?  My roof is the standard pole barn steel...not flat.  It has a 3- 12 pitch.   My second question.. Do I build a side draft or a hood.  The building is not air tight.  The walls are dog ear fence and I lined the inside with left over roof steal around the forge while leaving 25-30 inches from the fire pot to the walls.  I thought of using a cut 55 gallon drumb for a hood or a 25-30 gallon drumb for a side draft stack and attaching the double wall pipe to the top,of it. Just looking for advise.  Will any of these ideas work?  

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Most recomend 12" (10" as a minimum) as to the flashing, most steel roofing suppliers have silicon roof jacks that have soft aluminum flanges, just cut the cone to the right size. 500 degrees and all is well. 

Try zipping two peices of 6" together (the seam unlatches). Usualy you won't see 500 degrees up at the roof with a 12" stack. 

Side draft is easer to work around, one of the guys has a peice of 1/2" ID heavy pipe on the table with a hole cut in the side and 12" flue pipe nested to it. 

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Welcome aboard MaxJeep, glad to have you. If you'll put your general location in the header you might be surprised how many of the Iforge gang live within visiting distance.

Check with a wood stove, fireplace or roofing supply for a proper roof flange. 8" is pretty small for a good draft and double wall is unnecessary. The smoke from a coal forge doesn't usually carry much waste heat like a heating stove exhaust.

If you do some reading in the solid fuel forge section there are a lot of posts and pictures of effective hoods and stacks. Side draft hoods actually work better than an overhead hood, it's counter intuitive but true. Don't get carried away making a BIG hood, they're less effective than smaller. A 5gl steel bucket with a stack over it works amazingly well though a little larger works better. Moderate sized hoods heat up more and the smoke is drawn faster drawing more heat.

Frosty The Lucky.

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That'll work, spiral ducting is another option. It doesn't need to be multi wall or insulated a well managed coal or charcoal fire doesn't send a lot of waste heat up the stack so it needs a larger flue to draw.

Where do you cast a shadow? You never know there may be someone on Iforge who does roofing for a living and wouldn't mind walking you through it. It's also highly beneficial getting together with an experienced smith you'll learn more in an hour than days or longer figuring it out yourself.

Frosty The Lucky.

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wow, you sound a lot like me with your set up.....10x10, sheet metal roof, crushed limestone floor, a non air tight building....and the list goes on.....

I would personally recommend making a side draft. more specifically a supper sucker. its what I use, and works well. it was easy to make, and the plans are all over the internet.

                                                                                                                                           Littleblacksmith

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