Fisher, Baby Bear...burning coal?

Hello, The UL plate on the back of my Fisher states that coal can be burned in it (use a grate). I would like to use coal for an over night burn when it get's down into the teens here, I was thinking of using Chestnut sized Anthracite.

Pros, Cons, Experiences? Thank you for the input.

 

WeldrDave is the resident Fisher expert. He will be by shortly.
LodgedTree burns some coal. I'm sure he has some info too.

 

Thanks for the info WD...I don't have oak in my neck of the woods...a lot of black cherry, some hard maple, some ash, and black walnut are what I have at my place. Just got the stove in this year...been a few years since I have had a stove to burn...loving the independence it has brought back to my world. If I only had oak on my old farm...lol.

 

If your stove can burn coal I would definitely try it.

The biggest thing with coal is to understand how it burns, it is opposite than wood in that it burns from the bottom up. That means it is entirely controlled by air going through the dampers UNDERNEATH the grates, in fact if there is any air going above the coal bed when burning anthracite coal, the fire will go out. For bituminous coal, you need a bit of a draft open just above the coal bed to give some air to the gasses so that they burn off.

What size coal you burn determines the heat and longevity of the fire. Obviously rice coal is for stoker boilers, but pea, nut and stove coal is for stoves. Generally the smaller the coal, the hotter the fire, but the shorter the burn time (because they plug up with ash). You can fiddle around with sizes to see what you like. I once had a coal-only gravity fed stove that said Pea Coal Only, yet I tried nut coal in it and it burned better and longer I thought. In that case Pea Coal would give me a 14 hour burn and Nut Coal would give me 18 burn times. I use stove coal on my Pot Bellied Stove and really like it because it gives me 24 hour burn times.

Coal reacts a lot slower than wood. You do not just add coal, and then it blazes away...it takes time to really ramp up to a burn, but equally slow down due to its density. The key is to get a good hot wood fire going, get a good bed of red glowing coal that are fairly deep, then add the coal a layer at a time. As that layer starts to glow and get blue flames (what I call the dancing blue ladies) add some more. A lot of people make the mistake of starting a wood fire, getting some coals going, then just dumping in a ton of coal which never catches afire. Coal is low and slow. Dry pine like pine board kindling works really good as it makes a quick, hot starter fire with coals.

And it is all the way across the firebox too. Remember my first paragraph where I said air has to come up through the grates and through the coal bed? A novice will put coal just in a hump in the middle, yet the air takes the path of least resistance and goes to the outside of the firebox and bypass the coal never getting it going. So the initial wood coals must be fairly deep (because they burn up fast), even and across the entire grate. This is why size is so important. Stove coal (about the size of a fist) is bigger so it allows more air to go up through the coal bed, and takes a lot longer for the ash to plug those big holes.

Do not be overly concerned however with your chimney thermometer however, coal is a more radiant heat and so chimney stack temperatures are a lot lower. This is not a concern if it is below 300 degrees (and it often is) because anthracite coal does not create creosote so you can not have a chimney fire. But coal does put out a fine black soot that can dry out the creosote produced if you burn firewood that does create creosote, and that can fall down and plug elbows. That is why it is not generally recommended to switch from wood to coal a lot. Not that you would want to anyway, once you get a coal fire going, they burn a long time. It is like a diesel engine that way, as long as they get fuel to burn and air, they won't go out. Add coal to the top, clean the ash out of the bottom, and they roll along. Most proud coal burners are known to boast about being "1 matchers", that is they start one fire and it goes the heating season. I am not that good yet though.

A low stack temperature does cause an issue though...draft. Because warm air being drawn up the chimney pulls air up through the coal bed, coal stoves are sensitive to draft. This can be remedied somewhat with the type of coal burned, stove coal is bigger so air moves through the coal bed better. On my pot bellied stove, this works because my outside chimney is single wall pipe and the coal smoke (unseeable) cools off a lot before it reaches the top making my stove prone to draft issues. In my case a masonry or double wall chimney pipe would be much, much better. So with coal it is all about air in, air out.

The biggest thing for now is to not let coal frustrate you, because it will. It takes getting used to coal, it takes getting to know your stove, and tricks to get the problem areas to reignite, and needing it to go NOW when coal is slow to react, but I think you will like it. Just remember coal is like a cat...hands off until it is really to be cuddled, where as wood is more like a dog where it is always ready to be messed with. Mess with coal too often and the fire goes out.

 

Excellent post. I have a box of coal to try in my Baker wood/coal stove. I was always curious about it. I plan to wait till it's really cold out and just hoped to extend burn time. Maybe that won't be the case.
Thanks for the share of info.

 

Thank you all for the good info...the problem I am having is finding a grate that will fit in the Baby Bear...I am not a welder, so it may take a while to make this work...some kind of grate will show up though.

 

Thanks Dave...Tractor Supply has one that is the right size...Amazon sells the same one...the thing is that the reviews on it are pretty bad and that is mainly from folks burning wood...I just can't see it holding up with the heat from Anthracite...I need to locate a welder around my area or see if I have anything in the barn that may work.

 

I might try the Tractor Supply grate only because you might not like burning coal. I do, but I cut my teeth on a stove that would only burn coal.

I brought a lot of information up on burning coal, but one thing I failed to mention was that dual purpose stoves seldom do well burning both fuel types; that excel at one or the other. I have a New Yorker WC-90 coal/wood stove and it does better burning coal, as does my pot bellied stove...BUT these are stoves with proper grates and shakers. I have a sneaky suspicion that a wood/coal stove without a shaker would do better burning wood.

I am in no way saying not to try burning coal in it, I just might not invest a lot up front.

One other point; fire brick can stand up to the heat of a coal fire. A lot of pot bellied stoves glow red from the heat of the coal fire inside the fire pot, so I (and others I know) line the fire pot so the coals do not lie on the cast walls and scare the wife by glowing. For whatever reason, my antique pot bellied stove must be better made because it does not glow so I do not need to do this, but always had to before. So I know from experience regarding this.

All this is your call of course, and I tend to be a minimalist and very frugal in nature.

 

Coal is a long lasting heat maker... I had 12 hr burn times. Like LodgedTree said, it takes some getting used to. You have to put in the time to learn how to control it... if you don't, you'll probably give up. I burned coal for 4 seasons in a hot air furnace. I finally stopped because I could no longer get 5 tons delivered (had to borrow a friend's 7 yard dump truck for the last year)... coal is dirtier than wood, and it stinks. Someone near us here is burning coal. Could smell it way off in the distance the other day... unmistakable.

 

I used to burn coal many years ago in a Sears & Roebuck 'Parlor' stove...still have that stove in my barn...and I like the coal a lot. I have plate steel and angle iron, the thought of drilling a bunch of hole to make the basket sounds like no fun. I want to see how burning coal will go for me in the Fisher, it might be a nice option at night for the cold snaps. Thanks guys for your input. I will get around to this project of mine....just going to take some time to build the basket.

 

Us ole coal burners are funny, at least in Maine where we are a bit more rare with so much wood about. I can drive down the road and go, "hey, someone here is burning coal". You can just smell it. Not in the house of course; but outside.

I disagree wholeheartedly about the mess, and so would my wife, I think coal is a lot cleaner than wood.

We went to burning coal when we were bringing wood into the house by the stove and she dropped a stick on her foot. "You don't do that with coal", she muttered, and have not burned wood since. That is why I call her my "Domestic Supervisor".

Up in the County they burn a lot of coal because there is a potato plant in PA, so the trucks haul potatoes down, then haul coal back. Of course up there, they need it, it is so cold.

 

Agreed, coal is much cleaner.
That comment comes from the finer fly ash that can become airborne when operators don't know how to prevent the ash from entering the house.

Also larger coal burns FASTER, not slower. The larger the pieces, the more air between them. You get the same amount of BTU per pound no matter the size. More air flow is a faster burn rate. For this reason on warmer days you use the "fines" from the bottom of the bin to slow the fire getting less air through the coal bed.

Use the smallest size that won't fall through your grate. Normally Chestnut.

Anthracite also requires a small amount of air above the fire bed to ignite coal gas given off by the fresh coal as it heats. This is the blue flame above the coal bed. Coal stoves have this secondary air source built in as a leak around the grate at front or through the slots between glass panels of European stoves. Fisher Coal Bear has an upper air intake on the upper door that is only cracked during coal use. This is required due to using up the available oxygen from primary intake coming up through fire bed. Too much secondary air slips up the chimney over fire cooling chimney and slowing draft, preventing enough air from moving through coal bed. As stated above, coal takes a LOT of air. With no door gasket you should have enough leakage for air molecules to mix with gas above fire. Always have a low spot in the fire to maintain a flame to ignite coal gas, otherwise you can get a small to medium flare up of coal gas when opening door. When it is considered a small explosion of sorts, you don't have enough secondary air. (the sulfur smell outside is due to not enough heat in coal mass or enough oxygen to burn off the gas) When burning properly with flames across the top the smell is minimal. That's why you need a glass door to learn it.

As far as burning coal in your Baby Bear; You can mix some Bituminous with wood, (very common where they were made in New Zealand for Australia) or build your own fire pot. Holes in a plate are not easily cleaned, as ash builds up under coal, you need to move the grate with a rocking motion or grinding motion to break up ash so it drops through grate. In the morning you can have an inch or two of ash under the coal preventing it from getting air. ONLY poke from the bottom, never from the top of a coal fire.
Building your own grate needs to seal against the sides and be high enough ABOVE the air intake so ALL incoming air must go through the grate and through the coal, not AROUND it. You will get enough leakage between the door and grate edge at front for secondary air above the fire.

Some problems you will have are shaking the grate with door open to access the grate shaker system. Coal stoves have an ash pan door on the bottom that includes the primary air intake and allows shaking of grate keeping doors closed. This is why they get the bad rap of being dirty. You need to open the air under grate in the morning and shake just a bit SLOWLY to start air flow up through fire. Let it kick up and heat the stack, THEN shake the rest of the way so any fly ash is pushed up the chimney, not allowed leak in and settle in the house! There is a knack to shaking a grate slow and smooth to dump lots of ash, or short violet strokes to clean a fire with little ash. The wrong kind of air, coal, or shaking can form clinkers which are like a hard rock that won't burn or fit through the grate causing more problems.
As stated above, it would be difficult to learn on a wood stove without a glass door how to burn coal without coal experience.

You also need a barometric damper to keep air flow constant through the fire, you can't do that with a manual damper.

I never start a coal fire on a large bed of wood coals. Burning a load of wood makes the glass black and wastes time getting a coal fire established. I've always had good luck with paper, cardboard and SMALL kindling. It takes strong flames ripping up through the coal to ignite it easily. I always establish a coal fire in 15 minutes from lighting this way. If you put some coal on top of the small kindling when lighting, as long as flames are ripping up through the coal, add a little at a time on top until glowing and it catches fine. It won't burn with a yellow flame like wood, it only glows and the gas coming out burns blue. You have to cover every hole around fire so ALL the air moving through grate is going through coal. Any holes in the fire allow air to move through without being used fro combustion of coal. Once it is burning in a good size area, cover completely with coal to the top of basket. What you build would need a "banking plate" at the front so you can fill to first course of firebrick height. Your Baby Bear should also have the second course of brick installed which was optional, not all VI models have it.

I've converted a few stoves to burn coal including my Kitchen Queen, and the Baby Bear is very small to try. (My other coal burners have wheels ) You need room for angled liners on the sides with open slots for air, and a flat grate on the bottom. The sides make like a hopper to direct coal down to the grate.

Here are pics of the cast iron coal grate system for Fisher that you want to replicate;

Grates flipped to coal position. (Liners removed)

Same grates in wood position. (They were called "Reversible Grates", Liners removed)

Side liners that make up basket.(most of what you find in Fishers will be in this condition) You then make a pattern with wood to cast your own.

You won't have the added space for ash pan under grate like the two door Coal Bear so you will need to remove ash everyday from under grate. This is VERY important since the incoming air is what cools grates. Ash under and against them causes them to warp and melt.

This is the grate and support plate style for the model of stove you have. The rectangular holes are for the side plates that make the basket called liners.
I have all the part numbers for what you need, but not being able to order them anywhere won't do you any good. They do come up for sale on eBay from time to time, but you are up against us collectors that don't mind paying the price. You're going to find an entire coal stove cheaper than a Fisher part such as this.

It is easier to make homemade grates with slots (flat plate doesn't move) and use a "slicer knife" to clean grate. Google such European stoves such as Surdiac for that design. It makes less of a mess than shaking moveable grates with door open.

Not sure what Dave means by keeping distance to firebrick. Coal stoves use firebrick on the sides of firebox just like you would use the brick lining in the Baby Bear. My coal burning Hitzer, Gibrater, (later Glacier Bay) and cook stoves have firebrick firebox liner which lasts much longer than cast iron fire pots in antiques.

 

I agree.