Slow combustion burner to burn scrap cardboard possible?

Discussion in 'Designing, building, making and powering your life' started by beginnergardener, Jul 6, 2015.

  1. beginnergardener

    beginnergardener Junior Member

    Mar 23, 2013
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    South Aus
    Warm Temperate
    I have access to a large supply of used cardboard.

    It's cold this time of year, I was wondering if there was a type of internal slow combustion burner that could burn it (slowly) to heat the house?

    Is this possible? What are the options? Are there issues with cardboard?
  2. ronnon

    ronnon Junior Member

    Jul 7, 2015
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    You can control the burn rate of any combustible material by regulating the air flow to it. Cut off the oxygen and you snuff the fire. Cardboard has a lot of air space, and in my view the only way you will get a desirable effect will be to compress the card board to a much greater density. If you compressed say 2" wide strips 2-3ft long of cardboard as dense as possible, and fed them in stacks into a rocket mass stove, you could get a decent amount of heat a manageable feed rate. Its not going to work as good as feeding wood into it, but it would still efficiently burn the cardboard. I would worry about the flaming embers blowing off the top layers though. Making the stacks as thick as staples and stapling them into stacks might help with that, and would also keep your compressed strips better compressed. The staples would be easy to clean out of the rocket stove. That's a lot of prep work, but free resources are free resources.

    As for doing that scenario with regular cardboard, I don't think you could feed it fast enough to maintain a good heat source. As for other stoves, sky's the limit. I've built a lot of different ones over the years, but never a cardboard furnace. So what ever you build I'm interested to see what you come up with, good luck.
  3. S.O.P

    S.O.P Moderator

    Jul 8, 2011
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    ronnon hit on the key point with the cardboard and that's you need to compress it. There are many designs but the one most available to the western world (and are now in the third world) is the Peterson Press that centres around a bottle jack of 2T or greater.

    This is a picture of one:

    Basically, and this is very fresh in my mind as I just got off the full research stint, you soak various organic matters into the press including your cardboard, leaves, hay, grass clippings, newspaper, whatever. There will be a central tube that allows the water to be pressed out (visible in the left of the above photo) and a top and bottom plate to keep the matter within. You then use a piston (the thicker piece of PVC) to push down on the top plate and squeeze the life out of it.

    Drying the block (with central hole) takes 3-7 days and you now have a long-burning but ashy log.

    Rather than describe each link, here is what I came across on my research and each video should explain the construction of easier/different models and the theory remains the same. There are different types of press but each follow the same sort of recipes. Youtube keywords and you will get lots of video explaining or even showing the burning of the made logs in different heaters (not included in my links below).

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