Size of wood splits
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Billy123 said:
Smaller splits give you faster speed of seasoning and lighter weight of split. Some will say length of burn is lessened but that is debateable.
Shawn
Jay Shelton in his Solid Fuels Encyclopedia, figure 14-5, page 217: Ten percent increase in overall efficiency of an air tight stove using 15% moisture content wood burning 6.5 pound splits vs 1.6 pound splits. Makes sense to me as bigger wood burns at a slower rate.
I am a miser. Ten percent here and ten percent there and my wood gathering effort is reduced significantly. To date, using information gained from members on this site:
Ten percent more efficient due to using the largest breadth splits that will burn;
Ten percent due to using splits as close to 22" as possible rather than the comfortable 18" in length;
Ten percent due to intentionally exposing 6' of single wall connector to the interior;
And what ever you get from running cat stoves properly.
So I figure my sweat in the wood is half what it could be if I did just a few things differently.
When in college in the sixties, the professors beat into our heads that the only reason anybody would hire such a maladjusted group of drunks was we could squeeze another percent or two of efficiency out of the processes. So to this day, I always look for a little more efficiency in everything I do. Certainly don't want to become well adjusted or sober.
I am a miser. Ten percent here and ten percent there and my wood gathering effort is reduced significantly. To date, using information gained from members on this site:
Ten percent more efficient due to using the largest breadth splits that will burn;
Ten percent due to using splits as close to 22" as possible rather than the comfortable 18" in length;
Ten percent due to intentionally exposing 6' of single wall connector to the interior;
And what ever you get from running cat stoves properly.
So I figure my sweat in the wood is half what it could be if I did just a few things differently.
When in college in the sixties, the professors beat into our heads that the only reason anybody would hire such a maladjusted group of drunks was we could squeeze another percent or two of efficiency out of the processes. So to this day, I always look for a little more efficiency in everything I do. Certainly don't want to become well adjusted or sober.
My splits are 16- 18 inches and no bigger than what my wife can pick up with one hand, as she is the one who feeds the stove the most since I work fairly long hours and travel frequently. I've heard no more than six inches as a rule - this helps with seasoning.
She and I both prefer a MIX of split sizes. It's nice to have some smaller thin ones for getting it going in the morning from the coal bed. When I split by hand - I tend to make bigger splits. Something about machinery, when I use a rented hydraulic splitter - I tend to make smaller splits..... it's just more fun! If I have some oak I'd like to use, I split it almost board like to aid in the seasoning. I do split the oak smaller - as it takes longer to let go of it's moisture.
She and I both prefer a MIX of split sizes. It's nice to have some smaller thin ones for getting it going in the morning from the coal bed. When I split by hand - I tend to make bigger splits. Something about machinery, when I use a rented hydraulic splitter - I tend to make smaller splits..... it's just more fun! If I have some oak I'd like to use, I split it almost board like to aid in the seasoning. I do split the oak smaller - as it takes longer to let go of it's moisture.
I like to have a variety of split sizes. I shoot for an equal amount of small medium and large splits. I find larger splits burn longer, small and medium are good for faster heat and for startups. A variety also makes it easier to pack the stove full. For me a 7-8 inch thick split is what I consider large for my stove.
The really big splits we call "nite nite logs", as they are perfect for the last long on top when we dial it down and turn if for the night. Yet a variety is best.
I would like to see an experiment to see if a firebox filled with the same volume of larger splits vs smaller splits burns any longer. The perception is - bigger splits burn longer, but as long as you are packing in the same volume - you should get the same output? Shouldn't it? Maybe it's just a visual perception.
I would like to see an experiment to see if a firebox filled with the same volume of larger splits vs smaller splits burns any longer. The perception is - bigger splits burn longer, but as long as you are packing in the same volume - you should get the same output? Shouldn't it? Maybe it's just a visual perception.
My thoughts are simple. The harder woods like oak I split smaller in order to get use out of it in 2 years or less. Most of the remaining hardwood I split to normal size for one year of drying time. I will also split down the larger splits for startup fires, maybe 1/3 of a cord.
I'm thinking with equal volume the large splits will burn longer due to decreased surface area exposed to the fire. Kinda like how a tray of ice cubes will freeze faster than the same volume of water in a single larger containerbasswidow said:
I've questioned the size of my wood too, seeing all these big splits of wood. But after my first half year of running my stove. I figured out that with my small 16" entrance space and limited inside dimensions. A quantity of small chunks burn better than a few bigger chunks in my experience. So for this year, I got a lot more small chunks to go with. But I also watch the shape and configuration of the wood itself. I created a lot of square chunks for overnight burns, out of the center of the rounds.
basswidow said:
I'm going to post up some results later when winter really kicks in with my stove.
I'm very curious in the above statement... ^^
I believe because of BK's T-stat, small splits and large splits should all produce the same burn time.
In a conventional stove I would assume small splits would burn much faster because of surface area. (kind of like how a heat sink works, more surface area to dissipate the heat)
A little OT, but I'm also going to do the difference between pallet wood and cord wood.
BK's tests show 30 hours of burn time loaded with soft cordwood.
It lists the max capacity of 40lbs of Softwood. (that's less than 2lbs of wood an hour burned, which must be incredibly low BTU output)
If the above statement is possible as BK says it is...
With the 2.75cu/ft firebox I should be able to cram in over 110lbs of pallet hardwood... depending on how much air space I want to leave.
Since the T-stat will regulate air flow... and smoldering is perfectly fine for a cat stove (thats all it does, really)... I'm very curious to see the burn time.
But then again I'm also skeptical of 30 hours on soft wood as they claim.
jatoxico
Minister of Fire
If just feeding a 1950's fireplace, a mix of sizes would be best. If feeding a woodstove (other than a Blaze King), I'd go for as many large splits as you can get from a round. There are inevitably lotsa smaller sticks leftover from making fatties out of a round and if you find too few skinnies, ya can always split fatties down later but if too many small sticks, you can't glue ' em back together for nite nite logs. So for a fireplace it doesn't matter. For a stove alot of big rounds.
Just re-read this and I hope it makes sense.
Just re-read this and I hope it makes sense.
Take it to the gutter... 
JimboM said:
Dr. Jay has been one of my woodburning heroes for years now, so if he says so I tend to believe him. I like the charts in his books. They go a long way toward reducing some very complicated phenomena into some easy to understand generalized concepts that can be applied to various individual circumstances.
In my own experience, big splits packed loosely burn much slower than small splits packed tightly. I feel the once the fire is big enough, the largest splits that will fit into the stove will give the most overall efficiency.
FWIW that's why I don't believe in oversizing stoves for the few extremely cold days that you will need some extra horsepower. Yes, you can build a small fire in a big box, but it will not be the most efficient fire. A high-output fire with big splits has been shown in research labs to be the most efficient fire in non-cat stoves. Burning at less than peak efficiency for most of the year just so you can keep the oil burner off 100% of the time is a "penny wise, pound foolish" philosophy to me.
jatoxico
Minister of Fire
I like a decent mix of sizes . . . but what I have tended to find in the past few years of burning is that if I split on the small to medium size I can pack the woodstove more . . . and the wood seems to catch and then "settle" down into its cruising temps faster without much change in the burn time. As a result, I don't worry too much about making a lot of "overnight" sized wood.
Like FFJ, I like various sizes so I can fill the stove as full as possible for long burns yet have some space for fire between the splits.
I have mostly birch & it has to be split to dry well, anything over 4" +/- I split it.
Experiment with some larger splits & see how your set up burns it, you can always make the larger ones smaller if needed.
A good mix of sizes gives you some versatility.
I have mostly birch & it has to be split to dry well, anything over 4" +/- I split it.
Experiment with some larger splits & see how your set up burns it, you can always make the larger ones smaller if needed.
A good mix of sizes gives you some versatility.
Depends on your stove. For me I burn as big as possible. Big ones are 6x8 x 22. less work splitting, better burn times. When the stove is red hot with a bed of coals almost any size splits have no issue burning. I keep different size splits segregated in the week size burn stack outside the door. That makes it easy to find just the right size split for any fire condition.
In an ideal world, conifers get split larger than hardwoods. Oak gets split small, pine as big as will fit. Inevitably, a range of sizes results from hand-splitting scrounged wood.
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