What's wrong with useing plywood scraps to make Briquetts???

Fast4wood Posted By Fast4wood, Mar 18, 2011 at 8:45 PM

  1. Fast4wood

    Fast4wood
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    Feb 27, 2008
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    I have found a supply of plywood scraps and would like to make briquetts with the stuff, is there any reason I shouldn't???
     
  2. begreen

    begreen
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    The adhesives binding the plys.
     
  3. midwestcoast

    midwestcoast
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    There was a thread several months back where some info was posted on constituents of the adhesives... but I looked around & can't find it, sorry. I googled around a bit when that thread was going on and couldn't find any testing results on the pollutants produced from burning plywood in a woodstove. Plywood can be burned relatively safely in large commercial incinerators, but the high temps they use to cleanly burn the adhesives... are way higher than what you get in a woodstove. You're likely to get a bunch of nasty, toxic stuff coming out your chimney. I wouldn't consider doing it.
     
  4. henkmeuzelaar

    henkmeuzelaar
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    Nov 26, 2010
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    +1

    After refreshing my memory with regard to plywood adhesives, it became clear that there are currently 3 types of glues commonly used in plywood, namely phenolic glues (mostly derived from wood lignins), melamine glues (derived from proteins; think of the old bone-extract glues) and synthetic urea-formaldehyde glues. Unfortunately, the common "MR" and "WBP" class plywood designations only tell us about the resistance to waterdamage but say very little about the precise type of glue used.

    Of these three types of glue, only the phenolic glues (mostly found in expensive types of plywood and containing little or no nitrogen compounds) would be safe to burn.

    By contrast, the nitrogen-rich melamine and urea-type glues are likely to form dangerous, carcinogenic, nitrogen-containing PNAH (polynuclear aromatic hydrogen) compounds, whereas the urea-formaldehyde glues might even release some of the feared carcinogenic formaldehydes (of Katrina prefab emergency housing fame)....

    In short, unless you know exactly what type of plywood you have, I would stay well clear of burning it at home.

    Henk
     
  5. RNLA

    RNLA
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    Sep 18, 2010
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    I'll say it simple. I know it sucks but you should only burn wood, eco-bricks, or presto logs. Leave treated wood, plywood, partical board out. Sure these will burn and so will tires, styrofoam, small children! :bug: So anyhow burn clean product and help out the rest of us with our reputations as wood heat people...
     
  6. Fast4wood

    Fast4wood
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    Feb 27, 2008
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    Thanks guys I'll take your advice and use it wisely. If you have anything to add to the thread please don't hesitate to give your opinion, it's greatly appreciated. :-S
     
  7. henkmeuzelaar

    henkmeuzelaar
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    Nov 26, 2010
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    Just realized that I was writing those health warnings from my own perspective as a fireplace operator. If you happen to have a tightly closed stove or furnace I am sure you should be able to avoid harmful indoors emissions.

    Mindful Of RNLA's wise comments, however, there still is the issue of what might be going up the chimney, and thus might affect your neighbors or even draft back into your own home. The best way to keep chimney emissions down to safe levels would be to use a stove with a very efficient catalytic afterburner that has already been preheated with a small load of regular wood. This should take care of the harmful nitrogen compounds formed, e.g. when burning plywood with urea-formaldehyde type glue.

    In the case of melamine (protein-type) glues, however, chances are that there is a significant sulfur content as well, alas. This poses the potential problem of catalyst poisoning.......

    All in all, unless you know exactly what type of (unvarnished) plywood you have, it still sounds easier to stay away from burning it.

    Henk
     
  8. nate379

    nate379
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    I just burn the stuff like that outside in my burn barrel. Probably would be fine in the stove, but I don't want to risk an expensive stove just to get rid of construction scraps.
     
  9. henkmeuzelaar

    henkmeuzelaar
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    Nov 26, 2010
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    Aha, that explains it!!

    (as a simple Dutch cheese-head I always wondered what the protest sign below could possibly refer to ;) )

    Henk
     

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