CAT Stove.... big or small splits, does it matter?

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Bster13

Minister of Fire
Feb 24, 2012
810
CT
1st year burner (well next fall) who is having a BK Princess Insert installed today.

I started splitting wood in Nov. of 2012 and have 7+ cords now. I am very concerning about getting this 1st yr wood dried as fast as possible so I stacked some of it criss-cross for max air exposure. I am considering respliting my bigger pieces to expose the wood to even more drying. I want DRY wood for next year.

Question... with the Cat basically running low and slow, heating my house off the wood gas, does it matter if I pack my Princess with large splits (I've read large splits = long burn times) or stuff it with smaller splits (historically read, hotter burning)?

I could understand in a Non-CAT stove, split sizing mattering, but with a CAT, as long as the wood u have in there, big or small, is giving off gas, I'm good to go, right? If this is a the case, I'd really like to resplit my stuff small to improve drying. If resplitting small wouldn't give me an overnight burn time with coals leftover to relight in the morning, then I'd back off, but then my <1yr old wood would be as dry which lends to other problems (creosote, not as hot a fire).

Any advice? Thx.
 
The BK seems to be less sensitive to split size than you might expect. While it is capable of burning huge splits cleanly, it is harder to stuff the firebox with just big ones so a mix will always be helpful. I think that BK uses the ability to burn huge splits as a product "feature" so that you can spend less time splitting. I recently switched from a non-cat to the BK and when I bought the BK I had already prepared the next few years of wood supply, all split down to the 4-5 inch range for the non-cat hearthstone I had. I have been burning these smaller splits in my BK and easily getting 30 hours. Overnight burns are the least of your concern, that will be easy. I stuff 13-15 splits in the firebox each load.

All new wood since picking up the BK has been split to the 6" size, so yes, I'm going a bit bigger to speed up the processing.
 
I'm a cat stove owner, but not a BK owner. What I am about to say may be more applicable to non-BK cat stoves, as I know many of the Woodstock guys have had problems similar to me.

A lot of small splits = high surface area ratio, and so it will off-gas quicker. This leads to higher cat temps, which may or may not be a big problem for you. More importantly, when trying to run very low and slow on a stove stuffed with small splits, you may have trouble with back-puffing. The reason for this, as I understand it, is that gasses are being thrown off by the wood more quickly than they are being swept out of the firebox. When the combustable gas to air ratio reaches a critical level, the gasses ignite in the firebox (backpuff!), quickly deplete the oxygen, and the puff starves out. Slowly, fresh air enters the firebox thru the choked-down inlet, air to flammable gas starts to climb again, until you reach the critical ratio where the cycle repeats.
 
BK Insert was just installed. I feel like any stove you swing the door open quickly will puff. I just opening it slowly and no troubles.
 
I feel like any stove you swing the door open quickly will puff. I just opening it slowly and no troubles.

? Back-puffing has nothing to do with opening the door.
 
Bster, I do not think you will have any problem splitting small. When you get further ahead with the wood supply, then you can split more of it a bit larger but still keep some small ones which make filling the firebox easier.

We have a cat stove and it makes very little difference the size of the splits. What matters more is how you can fit them in. Leave lots of air space and the fire will burn hotter. In addition, we find that the bottom rear is the spot to concentrate on when trying to hold fire a long time. We tend to push most of the hot coals away from the back of the stove then place a large split or round in the bottom rear. What happens is that in the morning, there won't be much left in the front of the firebox but there will still be quite a bit left of that big piece we put in the bottom rear of the firebox. I hope this helps.
 
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There is a similar "zone" on the BK. No doubt due to the combustion air inlet geometery the center of the fuel load gets burned out first so you end up with the last coals on the far left and far right side of the fire box. My first and largest splits get shoved into each of these outside corners.
 
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Ok, sorry, I'm a newb. I thought when you open the stove door too quickly, it pulls the smoke out of the stove and goes backwards.

? Back-puffing has nothing to do with opening the door.
 
Ok, so for Backwoods's stove, the sweet spot is in the rear, East to West. Looks like for Highbeam and his BK Princess it is North to South and placing the big splits towards the outsides.

There is a similar "zone" on the BK. No doubt due to the combustion air inlet geometery the center of the fuel load gets burned out first so you end up with the last coals on the far left and far right side of the fire box. My first and largest splits get shoved into each of these outside corners.
 
Ok, sorry, I'm a newb. I thought when you open the stove door too quickly, it pulls the smoke out of the stove and goes backwards.

No problem... was there not too long ago, myself. Backpuffing is something you hope you will never have to deal with, and the result of an unhappy combination of too little chimney draw, too low a draft-control setting, and wood out-gassing too quickly for the system. Mostly only trouble for those of us running cat stoves on short chimneys.
 
I have found that split size doesn't make much difference with heat output or burn time in my Fireview. Smaller splits make it easier to stuff the smaller firebox and I can set the air to control the fire just fine. Smaller splits also make for a quicker, less smokey reload or start from cold stove. Smaller splits can also help make up for limited drying time. Most of my splits are between the size of a 2x4 and a 4x4.
 
I have found that split size doesn't make much difference with heat output or burn time in my Fireview. Smaller splits make it easier to stuff the smaller firebox and I can set the air to control the fire just fine. Smaller splits also make for a quicker, less smokey reload or start from cold stove. Smaller splits can also help make up for limited drying time. Most of my splits are between the size of a 2x4 and a 4x4.

Heh... I was splitting some big ash rounds this evening, all 22" long, and I don't think any were split under 5" x 5"! Bigger splits = longer burn time, and if you split them square-ish, it's still no problem stuffing the firebox full. It helps to have big rounds (these were 36" x 48" diameter), to get the square splits from. This is ash (dries remarkably fast) for winter 2014 / 2015, but I would be splitting smaller if for this fall.
 
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Well I think dry wood, even if small splits and lesser burn time (if that happens to be the case, maybe not), wins out here. I'm going to resplit, and resplit some more. I'm fixated on dry(er) wood. :p
 
The key is to have well dried wood in sizes that make it possible to stuff the whole firebox and to be able to control the airflow and rate of burn no matter the split size.
 
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The key is to have well dried wood in sizes that make it possible to stuff the whole firebox and to be able to control the airflow and rate of burn no matter the split size.
+1
Don't know if this will help, but I can stuff my King with dry, Pine slab wood. Some of the pieces are nice slabs, others are nothing more than 1" x 1" cut-offs. I can turn the inside of the stove into a "Tetris" looking mess, packed full. I may have to do it again in 24 hrs., but I'll have usable heat during the shoulder season for the duration of the burn. I say split what you have smaller, pack it tighter next winter, and the wood you process this summer for 14/15 you can leave in larger splits. Little less work this summer is all. It works with Pine, your Oak and Maple ought to be stellar.
 
You'll learn what works for you but to start smaller 3-4 inch splits will work fine. The BK gives you all the control you need so the smaller split loads don't run away. Honestly I could fill my stove with kindling and it wouldn't run away on me. Regardless of split size it will easily get you through the night.

I differ from Highbeam with loading the larger splits. I try to place my largest splits in the middle since my stove seems to burn from the middle out when loading N/S. You will figure out what works best for you in short order.
 
Here are a couple examples of my Princess loaded up. Talk about a sickness when you take pictures of your loaded stove. ;lol This will give you an example of the split size that I used this year. This wood was split years ago, I split larger now.(mostly due to laziness) :)
 

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When re-splitting, try to separate the would by type also; oak will take a year longer than others to season. Maple, ash and other hard woods split small and stacked loosely in an area that get lots of wind will be questionable after one year but is possible. If you have some softer woods you could burn for the first few months that would be a big advantage, that would give the hard woods a little longer.
Good luck, let us know how you like the BK.
 
Beat me to it rdust. I've been posting that link everywhere I can. hehe.
 
I think I need to stop collecting wood in my small side yard now and concentrate on restacking with your idea of separating the oak out (now that I've learned how to identify it) while splitting smaller and because I cut down a large tree branch over my stack *shakes his head*:

https://www.hearth.com/talk/threads/no-worries-i-was-going-to-restack-everything-anyway.109212

When re-splitting, try to separate the would by type also; oak will take a year longer than others to season. Maple, ash and other hard woods split small and stacked loosely in an area that get lots of wind will be questionable after one year but is possible. If you have some softer woods you could burn for the first few months that would be a big advantage, that would give the hard woods a little longer.
Good luck, let us know how you like the BK.
 
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