What are you guys using for 12" chimney's?  I have a "Super Sucker" type hood that I am installing and need to come up with the chimney pipe. It will go straight up through the pole barn roof (asphalt shingle). I am a novice on this type of thing so don't assume I know anything. I'm having a tough time finding single wall 12" wood stove pipe. People look at me like I'm crazy.......

 

Any help would be appreciated. 

 

Robert

thats because most wood stoves use 6" or 8" at most for their chimneys. have you talked to your local fireplace supply store? seen what they say you'll need for the pass through?

Greetings Robert,

 

You can use double wall for the pass through and bring it right down to the sucker box.  From that point it is a easy roll flange...

 

Forge on and make beautiful things..

 

Jim  

HVAC can make it up for you.

Or you can put two pieces of smaller pipe together to make the 12 inch.

 

 

Do not build a box just so you can then think outside the same box.

 

Do not look for 12 inch chimney, but instead see what can be used instead.

Nothing wrong with using a 12 inch culvert. Bend a piece of 48 inch wide material into a box. No one ever said a chimney had to be round. Look for a old hot water tank,good pipe on the inside.

Don't know if they have them in your country; but here in the USA there are places called re-stores that sell donated construction materials for Habitat for Humanity.  I got my spiral seamed round commercial grade ductwork from them.  Got it on sale US$4 per 10' length.  Picked up a couple of stainless pieces too---way more pricey $10 for 4' and thick walled made for commercial kitchens I believe.

Thanks for the ideas. I'll keep looking. 

I made my chimney from a 10' length of tin roofing. Just rolled it like a burrito and screwed the sides together. It actually came out to 11" wide.

Since most flue type pipe is from sheet metal and they have a seam down the side,  Use 2 pc of 6 inch,  open the seam up and join into one 12 inch,  they do not make every possible size because they are pieced together to make the desired size.

One can also use the (15 gallon?) grease drums. Double wall is just an inch of cool wool between the layers ( use stainless for the inside or plan on periodic replacement). You still need a 2" stand off from the wood of your roof (none if its all steel roof) 12" pipe moves a lot of air, so the pipe is actually warm, not hot so unless something goes absolutely wrong there is a lot of fudge.
Any sheet steel will work, even cutting the side out of a 55 gallon drum and resizing it ( your truck and drive way make short work of the ribs) it is certainly easyer if your going threw the ridge line to seal up such a big hole.

Great thread. I have to get around to installing a chimney myself and am still determining the best approach when taking material availability, cost and durability into consideration. Several good ideas here.

You can also just order 12" metal duct from websites like McMaster Carr. They sell some of everything, every type of joint also. They ship items quickly and while it will be more expensive than making duct from scrap metal it will be much much faster. Its all about forging to me, I am not a sheet metal worker

Great stuff. Do you think it needs to be double walled going through the plywood roofing? Or, is it cool enough with simply adequate spacing?

I tend to be belts and suspenders. As a minimum I'd plan on double wall. Even if its a bit of 16" threw a 20" hole. You'll sleep better. Aluminum is ideal for the second skin, as it will reflect 98%+ of the radiant heat. Wood heaters in marine applications use aluminum at 2" from the heater and 1" from the cabin wall. Code might have other ideas. Another bennifit of double wall in colder climents is the stack won't cool as fast and efect draw.

If it's going to be adjacent to your house follow code to excess!

 

Me I'm at the far end of the acre from the house and the shop is steel walls, roof and frame (save for 4 telephone poles).

I didn't even go out the roof.  My walls are the hail damaged metal roof from a former co-workers house.  There was a big hole where the woodstove chimney went through it so I just stuck my pipe out that hole at a steep angle.  Works well, will "sing" when I get a good fire going.  It ends about a foot over the fire from the side and I bent a piece of sheet metal that will go down to the forge table around the firepot or can be pushed up if I need the access.

Hey guys thanks for all the tips. Thought I'd follow up and let you know what I ended up doing. I ended up using 12" spiral duct sleeving it with 14" to go through the roof. I went back to 12" before exiting the flashing. I used 4' of the 14" to make a low loss stack cap on the top. The 12" chimney and "super sucker hood" draws wonderfully, I'm really impressed. I was a little skeptical about the low loss stack cap but it works great in keeping the rain out. It does, however, let in a little snow. 

 

Thanks again,

Robert

Picts?

Hi rwolfe,  Take a look down the page at "The forge is ready".  One of the big advantages to this Uri style is that going through the wall is a lot easier than going through the roof.  No chance of rain leaking through.  I built a sort of ladder arrangement to hold it in place because I didn't want to bother with guy wires getting slack and me going up on the roof to re tighten.  Good Luck!  

 

Larry

Any chance of getting a picture of your 'ladder' set-up?

 

Thanks,

Bill

Bill,  Look at "The Forge is Ready"  thread.  Pictures 1,2, and 3 show the 'ladder'.  It's hard to see because it too is painted blue.  In picture 1, you can see it standing away from the building.  A few feet above the green box is a support attached to the building with a 12 in. clamp for the chimney and up at the top of the ladder is another 12 in. clamp.

 

Picture three shows the support for the steel box and the ladder.  Two 4x4 pressure treated posts in cement support a cross piece which holds the box.  The ladder itself is attached to the inside of the 4x4's although it's hard to see in the picture.  The top of the green steel box has a 2 in. collar over which the chimney sits and adds further support.

 

If you need another picture tell me what you'd like to see.

 

Larry

Larry,

 

Your explanation helped a lot.  I will need to do something similar in the future.

 

Thanks,

Bill

You're welcome.  You are only 50 min. away from me, come out and see it if you wish.

 

Larry

Just thought I'd post an update on what I ended up doing - I appreciated all the help. I ended up using 12 inch spiral pipe for the chimney and 14" spiral pipe to double wall it in the rafters (perhaps not needed but it made me feel better). I also used a section of 14" pipe for the low loss stack above the roofline. I attached a few pics to show what I did. The low loss stack seems to work well (the draw is great) and little rain or snow gets down to my forge. Precipitation has to fall straight down to get in. I was worried about snow but last winter even with lots of snow I did not have an issue. Anyway, thanks for the help.