what size stove pipe for small diy stove?

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DeeGore

Member
Feb 25, 2011
11
minnesota
Hi everybody,
I have just recently completed an 18 gauge ( I think) sheet metal stove for my camper/fish house. It is just a box with a heat baffle (the red line). It is 18L x 9W x 15T with a 7 x 7 door. I used 3" pipe because it was already in the camper. The problem is a ton of smoke comes out the door when I open it to add more wood. Is there a formula to determine what size pipe will be best? It would be a bummer to install 4" pipe only to find out I need 5". This is my first wood stove so any suggestions are appreciated.
 
1) It's kinda hard to tell from the pic, but it LOOKS like the first section of stovepipe is aluminum. If so, this is bad, the aluminum will melt if the stovepipe temps get hot enough.
2) what is that stovepipe teeing into? If it's drawing air from somewhere else, that'll cause the poor draft.
3) 3" is a bit small, 4" would be better.
 
I put the tee into the original gas furnace. I could try closing it below the tee to see if that makes a difference. I hadn't thought of that.
The elbow is aluminum. I'll be sure to avoid aluminum when I switch to bigger pipe.
Thanks for the reply.
 
DeeGore said:
I put the tee into the original gas furnace. I could try closing it below the tee to see if that makes a difference. I hadn't thought of that.
The elbow is aluminum. I'll be sure to avoid aluminum when I switch to bigger pipe.
Thanks for the reply.
Click to expand...

one unit, one chimney

the stove cant share a gas furnaces' chimney, neither one will work properly.

and the gas vent isn't rated to near enough temps to vent a wood fire.
not just the aluminum elbow, but any galvanized piping shouldn't be used.

i'd recommend a 6" flue, and add a pipe damper 12" above the flue collar
 
As important as the pipe size--how high is the top of the flue relative to the stove? If it is <8 feet, you will probably have a hard time with draft. More is better.

Be safe.
 
The new wood stove appears to be sitting on top of the trailers heater, which gives you 2-3' of flue before it goes through the roof, if you are still using the gas vent pipe and cap, that means you have a total flue height of about 3 feet.

You also have a pretty good chance of burning your trailer to the ground when the flue gets hot enough to catch the roof framing/paneling on fire, as the gas flue, as designed to go through the roof, is not designed for the high temps the wood stove will produce.
Backdraft or lack of exit of the flue gas is another scary thought... do you have a carbon monoxide detector? (they can be had for less than 20 bucks.)

Is your stove held together with wingnuts, or is that how you have it bolted down?
Looks like a good way to secure it!

Rob
 
earlll said:
Al melts at 1220*f.
The hotter the pipe the better it drafts. Maybe firing the gas to heat the pipe before reloading would help.
Click to expand...

um - don't do that. It is unsafe to have a solid fuel appliance and any other appliance on the same flue


Use 6" stove pipe and insulated chimney rated for wood-burning with a proper pass-through for the ceiling
get the flue at least 10' high
double check clearances - 36" to combustibles for non approved stoves - probably impossible in a trailer
get a CO detector
have a second way out
 
Friend, welcome. While I give you credit for inventiveness, I have to give you an F for safety. That sir, is an serious accident waiting to happen, aka a deathtrap. Whether that will be from a burn, asphyxiation, or fire is hard to say. But as installed, it's only a matter of time before there is a life-threatening failure.

From what is showing, there are serious errors and I suspect these continue right through the roof. This may just be for camping, but we would be ill-advised to recommend anything but a dedicated, complete new, 5 or 6" flue system. I'd also lower the stove to floor level for increased draft and bolt or weld on rear and side heat shields. This is not the kind of stove you want in close quarters. It also should have some sort of fresh air supply in the small quarters of a camper trailer.
 
Wow.







.
 
It is mainly for camping. The wing nuts hold it together. It's made to fold almost flat for winter hiking. I would never bring it in a house or let it burn unattended. I do have a CO2 detector and fire extinguisher in the camper.
I got rid of the tee and elbow today and ran the pipe straight up. The flue was 5' so I used the rest of the pipe I had to get it up to 7'. It made a huge difference. I could leave the door wide open with almost no smoke. It sounds like I'll have to keep the gas furnace as my main heat source, but I still plan on putting in a separate flue for my wood stove. I wish I could put it on the floor but there is just no room. Thanks for all the help.
 
Good to hear. Be safe. Aluminum and galvanized pipe are not good for wood fire. Get some black stove pipe. Also, how is this pipe exiting the camper? That is a primary area of violation and failure.
 
DeeGore said:
It is mainly for camping. The wing nuts hold it together. It's made to fold almost flat for winter hiking.
Click to expand...

I don't know about flues, but you plan to take this thing hiking?! What are you planning to do with this stove? It has to weigh a ton by hiking standards.
 
You are SEVERELY putting your life & maybe others' lives in danger by burning that contraption.
It is considered an UNLISTED "stove" & as such has to be 36" away from ALL combustibles.
Based on the dimensions you supplied, there's NO WAY that thing is safely clear of ANYTHING by 36"...
You indicate that you will NEVER leave it unattended. How about when you go out to get more wood?
Shouldn't THAT be considered at UNATTENDED?
Hope you have your will made out...
 
When I put in the new flue I will use a thimble for the roof.

I use a pulk sled in the winter to carry my heavy loads. I will use a tent that is designed to have a stove pipe pass through the wall similar to this one.
http://www.wintersnowtrails.org/SmLMSP_002.jpg

I guess I meant it won't be unattended for more than a couple minutes. I know its not exactly safe but the flashing stays cool to the touch. It's a small one room camper so I'm never more than 10 feet from the door if something went wrong.

Since the 3" pipe is working ok with the changes, should 4" pipe be fine or would you still go bigger?
 
DeeGore, when you built your camp stove were you building off of a design similiar to this Camp Chef Stove?
http://www.morefireplaces.com/Common/Product/Product.aspx?ID=242728

If so these stoves are not really designed for indoor use.
Comparing your stove to theirs your stove does offer more flexibility due to you be able to take it apart with wing nuts and easily carry it.
But, still it is a little to dangerous to bring inside any closed structure especially one that has little room for error.
 
I think its pretty cool. I've got a Tipi that allows me to have a fire inside, just open the smoke flaps and you're good. That's an open fire, so I would think this is even safer (depending on how hot you allow it to get). He's not talking about running a daycare with it, but I'm wondering if there's another egress. If a fire starts you're going to have to jump through the hoop!
 
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