Small wood stove out of LP tanks

[Jim Timber]

I don't fish. Too damn boring.

 

[redfin]

Do you purge the tank with any gas before cutting them?

 

[Jim Timber]

I de-valve them in batches, and then leave them upside down for what's turned out to be years at a time. You can light off the residual gas with a torch once the valve is removed. I filled my 100#er's with water, but that was mainly trying to eliminate the stink. Bigger tanks have more residual fuel load, so I'd be more cautious with a larger vessel than I am with the small ones.

The gas falls out right away, but the mercaptan stink lingers for ages. Fortunately, the plasma cutting process burns it up nicely.

 

[Jim Timber]

Well, my stack baffle is too restrictive and so is my air inlet. I can pretty much smother it by closing the door.

So when the fire dies, I'll be chopping a hole in the bottom and working on a new air delivery system/ash pan, as well as fixing the baffle restriction.

 

[7sleeper]

How much natural draft do you have? With a chimney flue as short as the one in the picture I can imagine it to be very bad. So besides opening the baffle a little it might be a idea to make the chimney a little longer to get more natural draft. As an example houses here should have ~11metres chimney height to get a good natural draft.

Another thought I had was that it might be an idea to make a ash pan located in the middle underneath. It would be easy to slide under and remove to dump out the ashes. Making a small adjustable breather hole in it would be quite easy.

Hope to see progress!

7

 

[Jim Timber]

I have the same thoughts on the ash pan. My original thinking was that I could plumb outside air into the stove and prevent smoke from stinking up the room, but I chose far too small an orifice, and the dynamics of that large of fire box aren't going to work well with a point source for oxygen. I have some ideas on how to correct it, but I haven't fleshed them out yet.

I've got high efficiency concepts stuck in my head from forced air natural gas furnaces and didn't think about how much different a wood fire would behave. This is part of what I love about tinkering - I learn a ton!

My idea about the venturi might be right. The area surrounding the baffle is 492F and the stack is down to 89F within 3" of that. It's hotter than anywhere else on the stove. Even so, I'm probably going to remove it entirely and go with a more traditional baffle design.

The stack is roughly 3' tall. It's that short because that's what I had. It's a truck tail pipe section. I do have more chunks of that piece, so I can extend it.

 

[Jim Timber]

Made a couple changes today and stuck some punky ash in to see what she does with it. So far so good.

Integrated grate and ash collection chute inside view:

This one's a video. Click on the pic to play.

 

[7sleeper]

Anything new?

7

 

[Jim Timber]

Nope, it's out on my back patio covered in snow waiting for a door handle and paint.