how to: rebuild a woodstove

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Starting the job.

Thirty three years ago, in 1978, Jeanne and I bought a compact L. Lange Model 6303 wood burning stove for our apartment. It went along with us to our new house in Ira in 1984 and has been keeping us warm ever since. Last year it was showing small fissures in the seams between it’s cast iron panels and we knew it was time for a major overhaul. I tried smearing furnace cement into the cracks but that wasn’t working. To recaulk the stove it had to be taken apart.

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Taking the stove apart – piece by piece.

L.Lange, a Danish company, made their stoves from premium cast iron as is evident in their durability and engineering. Because the stove weighs over three hundred pounds I took it apart, and later, reassembled it in place. Only eight short bolts hold it together and all but two surrendered to my wrench. Those had to be drilled out.

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Almost apart.

The original caulking between the stove panels was very deteriorated and the panels pried apart easily. Now I could start cleaning them. I used a small air powered chisel but hand tools would have worked too to remove the remaining baked on caulk from the mating joint surfaces. Joint surfaces should be cleaned as close to bare metal as possible, I used a wire brush after chiseling and then sandpaper to expose the base iron. There were fifteen panels to clean and the job took me a few hours out on the lawn making noise and dust. I wore a ” nuisance” style paper dust mask because of the caustic dust.

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Rutland brand furnace cement.

To reassemble our stove I bought Rutland brand furnace cement, made right here in Rutland, Vermont, a silicon and alkali mixture which bonds metal to metal, perfect for stove repair. I used two 10oz tubes for a caulking gun, plus a half pound container in the course of the job. The caulking gun made filling the long joints on the panels easy with little mess. The contents of the bulk container spread into the wide joints between  the stove’s arched side panels with a putty knife.

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Dry fitting mark.

To make sure the assembly went right I put a series of the panels together without caulk and marked them one to the other with a fine chalk mark, then laid them out on drop cloths. That is important because the caulking compound is chemically aggressive and will permanently etch any ceramic or glass it dries on. We have ceramic tiles under the stove and I learned this the hard way. Wearing rubber gloves is recommended.09-woodstove_rebuild 3456x2304-017

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A nice tight fit.

Application is pretty simple. Wet the joint surfaces with water (I used an old paintbrush) then apply enough caulk to fill the joints when assembled. Then put the panels into place lining up the chalk marks and any bolt holes. Remove excess caulk that squeezes out of the joints to use on the next panel and smooth the work. If any caulk gets on an outside surface it has to be immediately wiped off and the area washed with warm water. Rutland’s refractory compound is permanent when it dries.

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Aligning the joint.

After more than thirty years of heating our woodstove had some slight warping which resisted reassembly at the final stage. I solved that by using two wood clamps to bring the panels into alignment and locked them in place with the last bolt. In a couple weeks, if cool weather arrives, I’ll light a small fire in the rebuilt stove to set the refractory and then it will be ready to heat our home for some more winters. In the meantime it needs a new coat of stove blacking, and that’s for a rainy day.

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Finished project.


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Day to day life in the hills of Vermont.

5 thoughts on “how to: rebuild a woodstove”

  1. Hi good evening.
    I am just in the process of doing the same thing with a stove that I picked up years ago, and never had a chance to work on. Of course I took it apart then…and lost the photo’s as well. I was wondering if you would be willing, if you still have the stove, to snap a few photos of the firebox.

    I have a sneaky feeling I may have reversed the firebox top panel…one side is ‘closed’ by a small half moon insert. This is at the rear end of the firebox for me now. Is that accurate for you, or is it at the front?

    Also, if you wouldn’t mind describing how the top inner ‘flue’ or air directer is situated that would be awesome. I really hope I don’t have to take the whole thing apart….again.

    Thanks, Fraser

    1. Sorry I didn’t get back to you Frazer, hope you fixed the problem yourself.
      Server problem had me blocked out. I had the same trouble realigning the internal baffle
      found that a small cast iron “tit” had broken off.

  2. Good evening Bob. My husband and I have just bought a Lange 6303 and despite many hours on the internet I still have no idea how to use it. It is in very good condition except for the fact that someone had tried to convert it to gas. We will try and restore it to wood using your above instructions, but still require some instructions.

    Really hoping you can help.


    Carol-Ann (South Africa)

    1. Thank you for your comment Carol-Ann. Using the stove in the manner for which it was intended is straight-forward. Assuming you have a proper flue the Lange stove will efficiently heat about 900 square feet of living space. Since the stove’s design is “air-tight” making sure that it has little or no air leakage is important. If there are holes anywhere in the firebox from the gas device make sure they are sealed after you remove it. The stove requires no grate under the wood. It does have a metal heat shield on the bottom of the firebox, if that is missing you could use a layer of sand instead or have a steel shield made. Wood ashes need to be cleaned out only when they become deep enough to hinder operation. We remove all the ashes only when laying the stove up for the summer. Good luck with your stove. Bob

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