*Building and Feeding a Wood Stove Fire*
This of course applies to MY situation primarily, so it's *A Way* not *THE Way*. These tips are for cast iron stoves, not camp fires, fireplaces, fireplace inserts or wood furnaces because they are a little different in the way they burn fuel, and every stove has its own quirks.
Begin at the beginning...
I guess the first thing is to figure out your operating temp and how to measure it.
Fireplaces tend to be really over loaded because so much heat goes up the chimney. Cast iron stoves should have a suggested operating range from the manufacturer; use this before any "rules of thumb". Mine is 135C - 190C (about 275F-375F) for "optimal" and max of 250C (just shy of 500) as a "regular spike", but they recommend that you keep it below 220C. I measure mine at the exhaust pipe where it connects to the stove, mostly because it's convenient for me. I have a thermometer that sits on the stove so I'm getting constant feedback at a glance, not just when I remember to check it. Our experience here is that if it gets above 220C we HAVE to open windows because the room is too hot to be in without sweating and being generally uncomfortable.
So first "rule" figure out your optimal operating temp and how to consistently measure it.
Second thing is air flow and wood size. These two things go together much more closely in an oven than in a fireplace. If you have a high efficiency stove then you need to understand its method for catalyzing the exhaust. My stove has a good damper (air coming into the stove) adjustment so I keep the flue (the air going up the chimney) full open and adjust it from below. I have a pretty dependable draft on my chimney and really that flue handle gets way too hot to be messing with anyway. My stove also has a relatively conservative firebox (38cm deep, 34cm high, 34cm wide [divide by 2.5 for in]) as we planned to be able to take it with us, and we had space limitations in the house. This means that most of my wood needs to be in the length around 30cm to allow air movement and a little shorter even so that I can put it in sideways. I don't know how to explain the size of wood we use other than saying the "small stuff" is a little bigger than the cross sectional size of a baseball bat and the "big stuff" is about the size of a quart mason jar. Bigger than that, we end up fighting with it more than is fun. Smaller than that, we split it a couple times to make kindling :)
Since my stove is a catalyzing variety (85% efficient) we need to have a decent steady flame to re-burn the gasses. It's not "heat" it's FLAME... So as long as we are burning wood there needs to be a nice dancing flame tall enough to lick the top of the firebox, more than that is going to overheat the stove if you keep it to high. Remember that the hottest part of the flame is right at the top of it, and your gasses need to pass through the flame to be consumed. This gives you that nice invisible chimney smoke btw.
I try to keep the coals large and loose so air can move through them from below. If you get a solid layer of ash you will clog the air intake and your fire will start to stall (this isn't all bad if you are banking the last load for a slow burn through the night, but it's not helping if you're trying to get more heat out of it). Don't be afraid to drop some of the ash and coals down into your ash pan to improve the air space under the fire. Those coals in the ash pan will continue to heat the air moving up into the fire and they will keep burning in the ash pan till they are consumed. I usually alternate the directions of the wood each layer to make sure there are some air gaps. If you need more flame use the smaller stuff which will burn hotter and faster, but make sure you get some big stuff on before it burns down to much or you'll be doofing around with a lot of hot coals and some logs that just don't want to light, and no flame to get that heat going.
Dry wood is a lot easier to work with than damp/wet (obviously), we also pre-warm ours in baskets so that there is 3 days of wood inside the house drying and warming up be used. We just cycle the baskets as we use one it gets filled and put in the store room to sit on a shelf till it gets used. We also prepare whole baskets of kindling at a time which takes about 2 weeks to go through. This is a fun activity for my son (9yrs old) to do with a small camp hatchet and a mallet. We use the large Ikea bags for this, as they are just the right width for the stuff to lie in with a little space on each side. We fill them up with stuff that's about the size of 1x2 and we use this to start the fires with a classic "log house" type fire. The only addition is that we usually use 3 sticks on each layer so there is fuel in the middle as well as the sides. 3-4 layers with a fire starter at the bottom and the paper balled up tightly in between the layers. We would use the equivalent of 2 full pieces of newspaper at most torn into 4 pieces each and balled up. I do it tightly because I want them to be a wick for the fire-starter, not "quick fuel". I want a nice steady flame that spreads. On top of the "house I usually put two big pieces that are good and dry. Then small stuff on top of that as the bottom burns out from under them, this helps get the temp up a little faster.
As for the type of wood, I use birch/beech and oak cause that's what I have. Oak is always long burning and never used to start a fire, but it is good as a second layer. The softer stuff burns faster but it leaves smaller coals that start to block the airflow if you use it exclusively you have to watch that you're getting enough air from the damper. I don't use Pine; number one, I'm still gun shy about it after growing up in chimney-fire country. Second, I think that the sap will clog the catalyzing element faster. However, that's just what the fireplace people said. I really don't know if it's true. Third, it leaves a lot of ash and it has that really flammable sap in it that would mean learning the habits of a new wood. To give you an idea what we have now, at the end of a day of burning wood and coming out to some live coals in the morning, we didn't have more than a quart of ash and no pieces bigger than a gumball. This means emptying the stove less, and all the fuel is being consumed as heat and that's efficient use of fuel and money/resources.
See, nothing earth shattering, or even new. It's mostly just repackaged info that is already out there. I'm just a fire bug that gets to indulge his hobby in a productive manner :) I would imagine many of us just enjoy the heck out of sitting and poking a fire. It's just *my* way and it works for me and my stove. I imagine there is other stuff but it skips my mind right now.
I'm always looking for some more tips or tricks to getting the most out of this stove. If I ever get a piggyback from the states, I will have some thermoelectric modules so I can build a power unit to fit onto the side and really start playing with that tech.
Boceph00
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