Finally, I have a wood stove report:
Heat has been our top priority lately. Weather turned unseasonably cold in early November. We've had many nights with temps in the low twenties, and several in the mid teens. We've been heating with a couple of unvented radiant propane burners. We've not frozen, but we've been far from comfortable. Condensation has kept everything damp. Our bed is under an uninsulated section of roof, and so it rains on us all night while we sleep. Imagine how happy my wife is about that. To add insult, we've spent a small fortune on fuel and trips to the hardware store to have 20lb bottles filled, but that's changed now.
I've had the finished stove for almost a month. It's been set up under my open shed, and I've been learning to use it. I've also made a couple of technical improvements, but I'll get to that.
The problem, as I stated in an earlier post, was installing a safe and satisfactory chimney. Dusty's photos helped my thinking immensely. I'll walk through what I did in case it may interest someone else.
After figuring out where I could put the flue and measuring clearances, I started with an 8" section cut from an old oxygen cylinder. This is great tubing: seamless, 9" OD, 1/4" wall thickness.
Then I cut a 16" circle from 1/8" steel plate:
With a hole in the middle of the plate, the combo looked like this:
The roof slopes slightly, so I measured that with a level and a sliding bevel so I could compensate when I welded my new thimble together:
The primer is Duplicolor engine paint from a rattle can.
Until this point, I had planned to use 4" insulated chimney pipe sold by Navigator Stove Works in spite of the fact that the Canadian manufacturer of this pipe told me that it is not appropriate for mobile application. This pipe has a 6" OD and would have worked fine through my 8.5" ID thimble. What changed my mind was finding a more cost effective alternative. McMaster Carr sells a similar product, but they only stock down to 6". I checked with them and found that a section of 6" insulated chimney pipe has an 8" OD. Still a good fit for my new thimble. Last week I ordered an 18" section of pipe and enough related hardware to make a chimney. Here it is:
After this stuff arrived, I modified my plans slightly for the collars to close the top and bottom of my thimble. I started by making a pair of rings from 18g cold rolled. I sized these to fit snugly over the ends of the thimble. The strips I cut are 1-1/2" wide.
Then I welded a piece of 18g to one side of each of these rings:
With the purchased pieces in hand, I decided that the bottom collar did not need a second flange on the ID. I cut a hole to fit the new pipe adaptor and tack welded the collar to the bottom of my homemade thimble. This photo shows the result, but it's upside down for the picture:
For the collar on top of the thimble, I made a second flange to fit over the OD of the insulated pipe:
Here it is with the pipe in place and then a couple shots of mockup assembly:
Here's the place where the thimble will pierce the roof shown from the inside and then the thimble in place from above after I'd drilled the 16 holes. I figured the hole spacing by measuring the circumference of the flange and dividing by 16:
Here are a few more of the process, but I seem to have failed to get a shot of the final product from the outside:
And finally, that thing we'd been longing for, making this morning's tea:
Pay no attention to the temporary mount. It will be bolted in soon.
The stove has secondary combustion from a 3/4" pipe in the top of the firebox. This pipe feeds from an opening in the rear wall. This was a problem during the test runs outside because the secondary inlet poured smoke whenever the door was open. Jason, who designed the stove, thought that extending the inlet with a down turned tube would solve the trouble. I welded a 3/4" pipe nipple to the inlet and added an elbow and six inch nipple turned down. In case this was not enough, I screwed a brass ball valve to the lower end of the nipple. Jason thought it would be a good idea to have a way to regulate the secondary draft. These mods cured the smoke trouble. The stove will still smoke some if I open the door before the box warms up, but it's not bad, and it's manageable.
Stove did great on its first night. Easily burns for 3 hours on a load, and I'm always up again by then. It is by far the best thing I've done to the bus.
Hope the rest of you are staying warm enough — or cool enough as the case may be.
Jim