How to Make a Woodburner

So, as I mentioned in my last post, one of the projects I was involved in while staying at The Floating City was building a woodburner for the van.

This is how we did it.

Ingredients

  • 1 and a half fire-extinguishers (or similar – one to make the woodburner out of and another to use for extra metal)
  • Large hinge
  • Sheet of metal
  • Piece of wood for base
  • Hot plate
  • Nuts and bolts
  • Bit of metal for the latch
  • Bit of wood for the hadle
  • Flue pipe
  • Fire brick
  • Angle-grinder, welder, spanners, screwdrivers, etc…
  • Some very cool friends who know what they’re doing
  1. Learn how to use an agle-grinder. Cut top off fire extinguisher (see pictures below).
  2. Cut door out. You need it to be fairly wide so you can get wood in easily. Buffer edges of door – both the cut piece and the hole.
  3. Cut a bigger piece of metal the same shape as the door from the spare extinguisher (or whatever you are using for spares). This should be a couple of inches wider in each direction.
  4. Learn how to weld. Weld the two cut pieces together to make one door so the wider piece covers the gap when shut.
  5. Weld the hinge into place. Make sure it’s as airtight as possible (ours ins’t completely airtight, but the gap is tiny so it works just fine.)
  6. Make a latch from something that you can find. I used a funny bit of metal (pictured below) and used a bit of a wine rack to make a little wooden handle that you can hold when the rest of it is too hot. Attach your latch with a bolt and put another in for the latch to sit behind when closed. You will need to drill holes into the metal for the bolts to go in.
  7. Cut an air hole halfway or so up the burner. This is because wood burners apparently need air from higher up than coal burners do. Coal burners require air intake from the bottom, whereas with wood it’s better from above the door. I cut the hole with a small angle-grinder blade, but it was quite tricky and hard to neaten up as the buffer wouldn’t fit. I eneded up using a combination of things, including sandpaper.
  8. Cut a piece of metal from your spare extinguisher (or whatever) that covers the hole with a bit of space all around. Again I screwed ours at the top and attached a little wooden handle from the same wine rack, although if I did it again I would make the air-intake hole a little differently. The way we did it, you can have the hole open or shut, but can’t control the flow any better than this. Fortunately it works very well anyway.
  9. Cut a square piece of metal and a square piece of wood that is bigger than the metal to form the base. Weld or screw the burner onto the base.
  10. Find a flue pipe. We went around loads of scrapyards and asked lots of people before finding one on the wall right outside the workshop that was unused and exactly perfect. It’s around 4 inches in diameter. Cut to size – ours sticks out about 15cm above the roof of the van. You also need a bit with an angle, which we found in the hangar attached to a giant tank they are going to use to build The Floating City with (see last post). Fortunately they didn’t need this bit of pipe that was sticking out. Weld together the straight bit and the bend bit (if they are not already the same thing) and weld onto burner. You will first need to cut a hole in the burner the same size as the flue pipe and stick it through. This bit is tricky and worth taking time over!
  11. After searching and asking for help on the internet we decided to make a baffle. A baffle is a piece of metal inside the burner which directs the heat up the front, under the hotplate and then up the flue at the back. Without a baffle it is likely that the heat will just travel straight up the back of the extinguisher and out of the chimney – no good if you want to cook on your burner as we do! I cut the baffle out of the spare parts extinguisher and bent it into place. I had to cut it in an oval shape. I pretty much guessed it and it worked out fine so I don’t really have any advice on that front, sorry! Buffer it up to get the paint off then weld baffle into place. A few spot welds is fine, it doesn’t have to be perfect, just as long as most of the air is being directed. It’s important to make sure the space you are creating for the air to travel past the baffle is at least as big as the flue, or you will be restricting it and you might as well put a smaller flue on, which will effect how the wood burns.
  12. Put the hotplate on top. We got one off an electric oven, so it really is a proper hotplate! For some reason I don’t have any pictures of this yet, but I’ll take some for a later post. We didn’t bother welding it as after a lot of careful buffering of the top of the burner it fits quite snug and we’re still able to access the inside of the burner in case we need to.
  13. Give it a trial run to burn off the paint and check it’s all working ok before putting it into your van / living space. Buffer the last of the paint off when it’s all cooled down.
  14. Screw into place. You now have a cosy live-in vehicle. :)

While I was finishing the burner off, Pete was cutting a hole in the van and making a chimney. The flue pipe sits inside another, wider chimney which is welded onto the van. The space between the chimneys is stuffed with rock wool (the stuff they insulate lofts with). The flue is not fixed onto the van, so it is removeable, but it doesn’t rattle around at all while the van is in motion. A shame I don’t have any photos about this, but advice can be given on request. The finished look of the van has a little hat on top, which Pete made out of the same metal sheet we used for the base. Then he bent it round into the right shape (like a stereotypical Chinaman’s hat) and welded it.

So that’s it basically. I will try to take some more pictures of the finished article and add them to this post. Check back soon if you’re interested. Also if you have any questions you can ask them in the comments and I’ll add the missing info.

Please note that neither of us had any experience in any of these things before doing this. We just had some nice friends who knew a bit, a good workshop and some internet research powers.

Total cost: €2.20 (about two pounds fifty) for the fire brick. Everything else was tatted (found).

Resources

2 thoughts on “How to Make a Woodburner

  1. Having had some time to use the little beauty I thought I could make some considered comments.
    It. Is. Great.
    It burns really well despite the comments we had from the un-believers regarding the size of the flue (pipe).
    The little hat on the pipe on top of the van also works fine and hasn’t had any problems going at speeds exceeding 140 kph.
    With good burning wood we can cook and boil water on the hob.
    Plus we get really toasty and warm when we need heat in the van, horrah!
    However IF I were to make any recommendations about possible changes I’d say first do put the air intake hole lower, if not on the door then to the side of the door. Sometimes I just keep our one closed and slightly open the door. Since all the smoke goes up the flue a lot of air gets to the fire without causing any hassles.
    Second I would put a grill on the bottom after all. Basically though the ash insulates the flame, particularly when lighting it, some of the wood when turning into hot-coal gets smothered by the ash. If there were a grill then a little poke would fix at least most of this problem.
    Oh and unrelated to the actual woodburner itSELF we have been opening both front windows of the van about a cm so as to deal with condensation. The heat rises and creates a droplets of water on the ceiling, this has then run to the front of the van, opening the windows has helped some with this.
    As you can see these recommendations are for fairly ignorable problems, so YEAH to us Jo!!!
    Good luck making yer wood-burners peeps!

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