HOW WOOD BURNS & WHY SEASONING IS SO IMPORTANT

bestchainsaw

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A log burning in your fireplace or your wood stove seems pretty straightforward, it burns. But the process of how wood burns is more complex than you’d think and how you prepare your logs prior to burning can make all the difference when it comes to igniting quickly, throwing heat, and burning clean.
Here’s what happens when a log is thrown into a fire:
 

bestchainsaw

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2. Once Dry, Things Start to Heat Up - Once your log is fully dried, heat up resumes. “The cellulose and lignin structure of wood breaks down at high temperatures (400 to 800F) and boils-off much like the water did. Instead of steam, however, we get smoke - a cornucopia of volatile organic compounds (VOCs) and particulates.” On top of that, we start to see charcoal.
 

bestchainsaw

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3. Ending With Combustion - “‘Primary Combustion’ is the burning of solid material directly. In wood combustion this is the burning of the charcoal or embers. ‘Secondary Combustion’ is the burning of gas fuels which produces the flames of a fire.”
 

bestchainsaw

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Based on the core process of how wood burns, it’s pretty clear that it all starts with the level of moisture found in the log, and thus, solidifies the importance of good wood seasoning. However, what you may not know is that aside from taking longer to burn, unseasoned or poorly seasoned wood also:
 

Luffydog

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Wood doesn't burn it decomposes.
 

deminin

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I've been using an outdoor Bryan wood furnace for the past 15 years. I have 40 acres of heavy forest, so there is no shortage of dead/damaged trees throughout the year. I chainsaw/split about 8 or 9 cords every year, and take both dead and damaged live trees. I burn mostly the dried out(seasoned) wood, but in the, evening before bedtime, I toss in 3 or 4 pieces is fairly green wood. That keeps the fire going during the night, and then, the next morning I still have a bed of good coals to quickly bring the fire back to life. The "green" wood does build up a small amount of creosote in the furnace/chimney, so every couple of weeks I run the furnace for a couple of hours with the ash door open a bit, and that creates a very hot fire, which quickly burns off any excess creosote. We have a total electric house, and I figure I save between $1000 and $1500 a year on the electric bill, this way....plus, I get all the good physical exercise of wrestling thousands of pounds of wood every year. I've probably got about $6,000 invested in the furnace, log splitter, and 2 Stihl chainsaws...but, I've saved 3 or 4 times that amount on the electric bill, over the years.
 

066

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we have had a wood burning heater over many years in different houses to heat the home but havn't thought much about the combustion process until recently when i constructed a outdoor oven (pizza oven) & have experimented with different types of wood to find heat differences & long burn times, all of the above statements are very true, with my job of working on chainsaws & test cutting wood, repairing wood spliters has come in handy for getting wood over the years, i would just like to add how dry wood is imperative - dry wood burns easier, hotter, cleaner with a moisture content below 25%.
12 - 15% moisture content is best giving the best chance of the highest combustion temperatures. fresh cut, unseasoned wood has around 60% moisture content.
how do i know if my wood is dry enough? - first of all, dry wood may have radial cracks & be darker at the ends, feel lighter in weight & the bark may peel off fairly easy.
wet wood will feel heavier, be harder to light, if it does light will sizzle or hiss out of the ends & smoke more than it heats.
these are a few more dryness tests you can do:
bang two pieces together - if they are dry they will make a sort of "clink" sound
tapping the wood with a coin or keys should give a short resonant sort of ring
if you put a small piece on to glowing embers, the top & sides should ignite in less than a minute
 

bertsmobile1

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IF you are going to make a post like this please GET YOUR FACTS RIGHT
ONLY GASES CAN BURN
Which used to be taught in science class to 12 year olds.

If you are going to pilfer stuff to post on here in order to gain access for spamming please pinch it from a science web page & not face book.
 

bertsmobile1

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Wood doesn't burn it decomposes.

Quite right.
the heat causes the wood to decompose by a process called pyrolysis.
The by products of PRIMARY Pyrolysis are hydrocarbon gasses and those gasses are what burn.
The burning of those gasses generates heat and the heat powers the pyrolysis.

Charcoal is what is left after all of the hydrogen has been driven off.

My bestchainsaw apparently has a plot of land that is 20 to 50 acres and yet owns no mower.
So most likely he is a spammer
 

Darryl G

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I never add seasoning to my wood. What's the point if you're burning it, not eating it?
 
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