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Hottest burning?

Started by Sauna freak, March 07, 2021, 07:01:26 PM

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Sauna freak

Got to wondering this weekend, which burn the hottest?  Not talking about maximum btu, but most heat output per unit of time. Obviously there will variability based on size, shape and stove type. Assuming 3" split, good air dry and a high draft reburn sauna stove, what does the hive mind think?  My options are black spruce, balsam fir, jack pine, quaking aspen, tamarack, paper birch. Also some buckthorn and tag alder.  My gut says jack pine. Any thoughts?
Sauna... like spa treatment, but for men

Tacotodd

Do you have any oaks in your example for comparison? Or hickory? Definitely not Sweet Gum. Maybe some Ash.

Or does your question only pertain to your examples? If so... I don't know anything about Buckthorn, never crossed path with it.
Trying harder everyday.

brianJ

Quote from: Sauna freak on March 07, 2021, 07:01:26 PM
Got to wondering this weekend, which burn the hottest?  Not talking about maximum btu, but most heat output per unit of time. Obviously there will variability based on size, shape and stove type. Assuming 3" split, good air dry and a high draft reburn sauna stove, what does the hive mind think?  My options are black spruce, balsam fir, jack pine, quaking aspen, tamarack, paper birch. Also some buckthorn and tag alder.  My gut says jack pine. Any thoughts?
Seems you are asking not what burns hottest but what gives off the most BTU's per unit of time.      That is actually more a function of how much air you can get to the fire.

Edvantage

It all depends how often you want to feed the fire. My kids do the sauna fires and hate feeding the fire steady with the softwoodsThey love ash splits easy and burns hot. Of your choices listed I vote birch. If I remember correctly the saunas I took in Finland where mostly burning birch.

cutterboy

Of your options I only have experience with aspen and birch, both of witch burn hot in a wood stove. However, when I used to make maple syrup I wanted white pine for a hot fire in the evaporator.
To underestimate old men and old machines is the folly of youth. Frank C.

Ianab

Surface area also matters. If you want a hotter / faster burning fire, go with a dense high BTU wood, and split it smaller. 

I gave some woodworking off cuts to friend to use as kindling, and it was mostly Casuarina, iron wood is another name for it. Very hard a dense, but mostly 3/4 boards, and bone dry. Anyway it was a cold night and they loaded up the big cast iron stove with these off-cuts. About 15 mins later the flue was starting to glow a dull red, and they had to open the doors to cool the house down.  :D Being smaller pieces it burnt down fairly quickly. 

The pine and other softwoods will certainly burn hot enough, but not last very long in a hot fire. But a denser and smaller split hardwood can burn hot for longer. Buckthorn is an invasive "kill on sight" species here, so I haven't burnt it. But it's quite dense wood, high BTU etc, so it might be worth experimenting with. Especially if you use some pine or birch to get a hot fire going quickly first. 
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Corley5

Jack pine with pitchy knots burns pretty hot ;) :)
Burnt Gunpowder is the Smell Of Freedom

SwampDonkey

Tamarak burns hot fast, aspen and fir are fast and hot to. I heat the house with it and only need morning and evening fires. I get 1-1/2 cord of hard maple for the real cold nights, and place a couple sticks in with the lesser dense wood. 2900 sq feet, including basement, forced air furnace. Never been cold, in fact on sunny days, no fire during daylight, a window is usually up, all day. Solar heat from windows. ;D I usually cut 8 cords, but I burn wood 9 months to, not 2 months. ;) Plus I love killing two birds with one stone, thinning the woodlot and heating my house, $2400 stays in my pocket. I win on all fronts. ;D
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Don P

Charcoal made of any of them?

barbender

Tamarack used to be notorious among the old timers for burning stoves out, it burned so hot. That would get my vote.
Too many irons in the fire

hedgerow

Sauna Freak
Don't have the ones you listed in my area. The two that come to mind around here that has ruin a fair amount of stoves is locust and hedge {Osage Orange}. Split some hedge down to small pieces and load a stove up and things start glowing. There is not a ton of hedge in my area but I have a farm that is loaded with it and that's mostly what I burn in my Garn. 

SwampDonkey

Quote from: Don P on March 08, 2021, 07:38:09 AM
Charcoal made of any of them?
Definitely not charcoal wood. Fast hot fire, yes.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Sauna freak

Well, for next season, I will have the usual birch + slabwood of all the above species used to build the sauna + Red Pine (forgot to add that one, but it's not a normal firewood option for me), at the cabin, so I guess we shall experiment.  So far, the fastest I've gotten the home sauna to 175F was with a mix of jack pine and birch fine split.  That's usually the point where I stock the water, damp the fire a bit, and we get into our "sauna clothes."  Surprisingly, that one beat fine split Northern Red/Pin oak.  Surprisingly some sort of urban cultivar willow with twisty trunks that I took down for a friend came really close to the record.

I like to stoke it hot and fast, then put in something a little heavier and open the air a bit to build the last heat before we start, then run 'er hot and drafty while we're in there.  Lose a lot of heat when we get some sauna virgins that are in and out the door a lot.
Sauna... like spa treatment, but for men

Nathan4104

Sauna, sounds like you can't be far from me, your list of wood is what we have here!   I'd go with the Tamarack for the most heat in the time.  Jack pine likely a close second.  If your Birch is good and dry, I mean like 2-3 years under cover dry and the bark all fallen off dry, it will also be pretty hot burning. I have a wood fired pizza oven and primarily use birch in it, but use some jack pine in it at the start.  However even dry, the pine is dirty burning, lots of creosote (compared to the birch) 
I've only been told that Red Pine makes 'not great' firewood.  Not sure why, as it seems closer to jack pine than White Pine IMO.  You should do an experiment and time your stove getting to temp with different woods and let us know! 

Sauna freak

Quote from: Nathan4104 on March 08, 2021, 08:45:47 PM
Sauna, sounds like you can't be far from me, your list of wood is what we have here!   I'd go with the Tamarack for the most heat in the time.  Jack pine likely a close second.  If your Birch is good and dry, I mean like 2-3 years under cover dry and the bark all fallen off dry, it will also be pretty hot burning. I have a wood fired pizza oven and primarily use birch in it, but use some jack pine in it at the start.  However even dry, the pine is dirty burning, lots of creosote (compared to the birch)
I've only been told that Red Pine makes 'not great' firewood.  Not sure why, as it seems closer to jack pine than White Pine IMO.  You should do an experiment and time your stove getting to temp with different woods and let us know!
Yeah, we're in the same forest zone.  I'm about 25 miles as the crow flies south of the border, about 60 road miles from I-falls.
I've actually had good luck with red pine, but it is pitchy and needs a hot fire to burn cleanly.  Big chunks will make coals like hardwood.  I don't get a lot of waste RP, so don't use it often.  I'm presently removing remnant trees as they show signs of poor health and using them onsite for building projects and selling some high value specialty wood when they get a little grey and some borer holes in the sapwood.  I'm milling so close to the bark for the products I'm selling that it's really only kindling and sawdust left when I get done.
An experiment would be fun, but there are probably too many variables with materials temperature, heat loss, external temperature to control with any sort of scientific conclusion.  I'll be happy to share opinions though!  Haven't burnt much tamarack before, but have heard the old tales about melted stoves so we'll see.
Sauna... like spa treatment, but for men

barbender

I don't think it melted the stoves so much as corroded them, kinda like a hot magnum cartridge in a rifle- hard on barrels.

Red pine burns hot if it's dry, but just like most other dry softwoods it doesn't last long. Green is another matter, it has so much water in it you'll have trouble burning it even in a forced draft outdoor boiler.
Too many irons in the fire

KEC

Not sure how well you'd like buckthorn the way you're running your stove. For normal heating the house buckthorn is a real decent wood. You wouldn't want to try and put up a lot of buckthorn firewood as there is so much brush and thorns to deal with. I've cut it here with the emphasis on getting rid of it and the firewood I get is just a welcome by-product for my effort. Birds will eat the berries which stay on the trees well into winter, though some say that those berries are not as nutritious as native berries. I have shaken buckthorn trees to shake down the berries and the next day there are turkey tracks in the snow and the berries are gone.

SwampDonkey

Quote from: Sauna freak on March 08, 2021, 07:16:16 PM
Well, for next season, I will have the usual birch + slabwood of all the above species used to build the sauna + Red Pine (forgot to add that one, but it's not a normal firewood option for me), at the cabin, so I guess we shall experiment.  
Red pine will be similar to red maple, it's a heavy softwood. Used some 3 winters ago, burns nice and hot. Can't split the stuff by axe too easy, but neither is spruce or tamarack easy to split.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Technoid

I think oak, cherry, and maple burn the best. But I caution against burning soft woods in stoves that have full outside chimneys. Cresode build up from soft woods can cause a chimney fire. I had one this past winter. It sounds like a jet engine in your chimney. Extremely hot!! I was able to slow it down by closing off the air. Then letting it go out. Cleaning all the pipes and chimney. No more soft woods in my stove. Also keep wood dry! Wet or green firewood makes creosote.

Nathan4104

Quote from: Technoid on March 09, 2021, 06:25:18 AM
I think oak, cherry, and maple
Some of us lust for species like that on a -40 night when the wind is blowing!!!!
But rather, we are blessed with an abundance of spruce, fir and Aspen/poplar!!! 

curved-wood

In a wood,ceramic kiln, we use thin splitting of the softer wood that we have, so pine is better than oak. That is at the END of the firing where we need the strongest heat possible. We are in the 2300 degrees F range, long way above red heat, more in the white heat zone. A load in the firebox lasts only a few minutes. If we put 3'' red oak pieces, we will loose degrees, but it would have been OK at the beginning of the firing. The smaller the pieces are the best. So if TIME is the major factor, that is a way that I would experiment. It is an extreme situation and is definitely not a way to hold a fire.

Technoid

Quote from: Nathan4104 on March 09, 2021, 08:43:38 AM
Quote from: Technoid on March 09, 2021, 06:25:18 AM
I think oak, cherry, and maple
Some of us lust for species like that on a -40 night when the wind is blowing!!!!
But rather, we are blessed with an abundance of spruce, fir and Aspen/poplar!!!
Just be careful. Chimney fires will turn your smoke pipes cherry red and burn your home down. Clean the pipes every two weeks if you air down for long periods. 

Sauna freak

Very aware of chimney fire danger.  I think it's largely a problem of non-reburn stoves run with large and sometimes poorly seasoned fuel and too little air and heat.  I'm still on the lookout for buildup though, and clean regularly.  The 3 stoves in question that see a significant amount of pine fuel are very low risk.  The cabin and sauna at the cabin are both less than 10' total run from stove to rain cap.  Both modern stoves with gas-reburn devices.  I generally run them hot periodically to keep the buildup burnt off before it can get heavy.  The sauna always runs hot.

The other sauna that has been in service 2 years now has a similar modern stove and a 6' total run of flue pipe.  There is no enclosed ceiling penetration in any of the 3 stoves, and the cabin is a full class A run, so risk of secondary ignition even in the event of a flue fire is very low.  I still run the weed whips through them at least once a year though.
Sauna... like spa treatment, but for men

peakbagger

I am not advocating this for home use but about 15 years ago I got a couple of big biomass boilers approved for chipped railroad ties in the fuel mix.  The operators called it "rocket fuel" They had to make sure to blend it in with regular whole tree chips about 10 to 1 to keep the boilers in control. If they hit an unmixed clump of it the operator was in for ride to keep the boiler in control until it passed. 

curved-wood

Just a story about strong heat. My grandpa and an uncle did a contest. Who's the first one to boil 2 cups of water ? Grandpa was saying a wood fire and uncle was saying a naphtha Coleman stove. So grandpa got a dead, dry standing spruce, split into in small kindlings. . Uncle pumped the stove and here we go . Well grandpa lost, but not by much. He was surprisingly close.  Of course the contest didn't count the time for preparation. 

Sauna freak

Well I have my answer.  I think it was some sort of southern or foreign pine I'm not familiar with.  Definately not treated, but very heavy and pitchy.  Broke down a pallet from work, heavy skid, and burned a couple 4x4s in the sauna stove tonight.  They had a very turpentine like smell on the table saw.  It was like throwing in a piece of RR tie as posted above.

I wouldn't want to burn them in any flue that was subject to soot loading with a long run and 90's, or start from a cool fire where the fumes don't get a chance to burn off.  I definately wouldn't let them burn unsupervised.  Had to damp down all the air to keep the stove from going to critical mass.  A 205F sauna did hit the spot tonight though!

I think I'll put the rest of the 4x4s in the firepit pile, and use the 4/4 donnage sparingly for fast heat.
Sauna... like spa treatment, but for men

barbender

That's known as someone near the Canadian border discovering fat lighter😁
Too many irons in the fire

Ianab

Quote from: Sauna freak on March 15, 2021, 11:29:16 PMwouldn't want to burn them in any flue that was subject to soot loading with a long run and 90's, or start from a cool fire where the fumes don't get a chance to burn off


Yeah, that's where burning softwood gets a bad reputation. Either it's not dry, or people try and damp a fire down for a longer burn time, and that leads to smoke and creosote build-up in hte flue

Let it burn hot in a good stove and it won't create excess soot. If you need less heat, don't add as much wood, so you have small but still hot fire. More work as you have to add a couple of chunks more often, but that's part of the fun of a wood fire. 

Pine is the most common tree in NZ, so it's also the most common firewood. Not the best firewood, just the most common. But if you can score wood from a big old and over mature pine it will be infused with much more resin than a young tree, and it sure burns hotter.  
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

SwampDonkey

I burn a lot of softwood here, black spruce, fir, tamarack, cedar, and a lot of aspen/balm. In my video you can see how fast I get heat. I open the ash pan door to speed up the process but close it back up once the fan kicks in. It's not a smothered fired, it has a draft on the furnace. It does a 2 stage burn. I've never been cold yet. ;D I keep on hand 1-1/2 cord of rock maple for the near zero or colder night burns. Been burning now for 6 months and have gone through 5 cords. This winter I have only burned in early morning, then in the evening. Between 10:00 and 7:00 I don't need any fire on sunny days. And there is no fire after 11:00 pm at night. I typically get 4, maybe 5 hrs out of the softer woods. I clean the stove and flu every month, but there is never any creosote, just powder soot, that might add up to a coffee cut full from the stove and 40 feet of flu. Just one of them routines to get into. ;D

I've found fat lighter in old fir seems. Hooooeeee! :)





https://youtu.be/YiV7XpYNkps
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

HemlockKing

Quote from: Sauna freak on March 07, 2021, 07:01:26 PM
Got to wondering this weekend, which burn the hottest?  Not talking about maximum btu, but most heat output per unit of time. Obviously there will variability based on size, shape and stove type. Assuming 3" split, good air dry and a high draft reburn sauna stove, what does the hive mind think?  My options are black spruce, balsam fir, jack pine, quaking aspen, tamarack, paper birch. Also some buckthorn and tag alder.  My gut says jack pine. Any thoughts?
Black spruce I would say. I recently cut up some tamarack for some firewood and boy does that wood have a nice smell to it!
A1

Sauna freak

For anyone still following this...at least in a 7x7x6,8high sauna with a Tylo Helo CK612 stove, I have my answer.

Of the woods tested, through 3 sauna sessions, finely split black spruce won the race.  Sauna was up to 175F in aprox 1 hour with similar start up conditions inside and outside.

Small, pitchy jack pine with lots of limbing scars that had healed over with pitch was a close second.

Birch was a disappointment.  Ended up adding some pine, spruce, balsam fir edging pieces to get it up to 175F, but it then held a steady temp at or above that sweet spot.  My birch was split a little larger than the others, and contained many knotty pieces.  I think with some straight grain and finer splits, it might fare better.

Did not test Red Pine, Tamarack or Balsam fir as I didn't have sufficient quantities dried out.

I've never really burned much black spruce other than some odds and ends cleared from trails or shooting lanes.  I have a lot of it and it performed amazingly well in the sauna, and also quite well in the Jotul that heats the cabin.  Burned a lot like really dry red oak in my experience.  Good hot fire with lots of air, but responded well to damping down, making and holding a nice bed of long lasting coals.  A pleasant bright white/orange burn with lots of cheery popping and snapping!  Would not recommend for an open hearth burn.  It was very easy to process (other than the limbing), which was a nice bonus.

Sauna... like spa treatment, but for men

SwampDonkey

I burn a lot of black spruce from thinning my plantation trees. Lots of heat for sure, but I love fir to. Splits as easy as white birch, one whack with the maul. Black spruce is a bear to split. ;D Bark beetles like cut spruce, so watch where you store to dry it. In your basement they will head to your windows. ;)
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Sauna freak

Interesting, I didn't find the black spruce all that hard to split.  Just need to miss the knots.  Not as easy as Balsam or clear birch, but most logs were one pop with the Fiskars.  Probably helped that the tree was sound standing dead and dry as a popcorn fart and less than 12" at the base.
Sauna... like spa treatment, but for men

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