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Seasoned Vs kiln dried

Homemade

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Is kiln dried worth it? Is there a moisture level that firewood can only get to naturally before it won’t go any lower by seasoning/ air drying?

I seen a video of a guy burning two wood stoves side by side and one with two year seasoned wood and the others with kiln dried. This got me wondering. Could a guy make a kiln out of an old fridge and dry a weeks worth of wood? Use the hot air ducted off the wood fired furnace to dry the wood. Obviously the hot moist air would need to be exhausted outside.

Just seeing if anybody noticed a significant difference between two.
 

Homemade

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I know in the description it says the seasoned wood is 35% moisture and the kiln dried is 20%. Is 20 low enough. Is 15 or 10% better? Is it worth it for a home time non commercial outfit?
 

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I know in the description it says the seasoned wood is 35% moisture and the kiln dried is 20%. Is 20 low enough. Is 15 or 10% better? Is it worth it for a home time non commercial outfit?

That video is a joke. He must be trying to sell kilns or kiln dried wood for much higher prices.

Seasoned wood is not 35% moisture (2 years or not). Seasoned wood, weather kiln dried or nature dried, is 20% or less. Yes, drier is better, but 20% is 20% no matter how you get there.

The only advantage to kiln dried is the time to dry and it generally looks cleaner. Is a kiln worth it for a home or non-commercial outfit? Not to me but only you can decide if it is worth it to you.
 

Ryan Browne

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I'll assume you're talking about wood for your planned Lamppa furnace, so I'll relay some info from them. They recommend burning wood with a measured moisture content between 18-28%. To me, the high end if that range seems very wet, but Dale was saying that wood that a little on the green side contains more volatile liquids that can be burned in their "gasification" furnace. I have heard similar info from the guys running high efficiency gasification fireboxes in the maple syrup industry, though those setups use high pressure forced air, so it's not exactly the same.

I mentioned that I had just finished cutting 4 cords of fresh red oak and planned to burn it for the 2020-21 heating season. He suggested burning it next winter instead, which to me sounds crazy, considering that it's oak. Also, the sticker on the front of the furnace actually says that wood should be seasoned, and then clarifies that it should be cut, split, and covered in April or May and burned that fall and winter.

So, take that for what it's worth. Sorry I haven't given you a ring yet. Haven't forgotten, just been busy.
 

Ryan Browne

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I will also say that in our conversation Dale said that the Kuuma has no problem burning pine or other softwood, but then said that he thought burning Ash was useless saying it had less BTUs than burning toilet paper. So, while the man is very helpful and knows the product very well, I would say that hopefully he's not right about everything. Personally I burn a fair amount of ash and find it to be a great firewood.
 

angelo c

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For me, kiln drying is for killing bugs and stuff for specific clients who need "bug free" wood.( Kitchens ect) there is only so much moisture "kiln drying" can eliminate as it will re-absorb moisture from the environment in short order. I think for your specific burner/flue/environment/ use/ demographic..... yes just gotta see what works best..... for you(and your budget:) )
 

Homemade

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Yes Ryan. I was planing on using it with my Lamppa. It never crossed my mind that the volatile liquid (sap) will aid combustion and count toward the moisture content. So maybe 20% is an ideal ratio. All the h2o gone, but still enough sap to burn better.
 

angelo c

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Yes Ryan. I was planing on using it with my Lamppa. It never crossed my mind that the volatile liquid (sap) will aid combustion and count toward the moisture content. So maybe 20% is an ideal ratio. All the h2o gone, but still enough sap to burn better.

I have a close friend who is an engineer and works with other engineers....one of his co-workers gave me a long dissertation once on why "green" wood burned better then "seasoned". I shrugged and refused his thought processes and math-nastics....my buddy burned "green" for a few years until he almost burned his house down from a chimney fire. Destroyed a $30k full masonary fireplace. But hey, we are adults and we get to do as we choose.
 

sixonetonoffun

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I think the green house idea would be cool. Just not fond of another structure to maintain. But if a wood shed was needed some southern faced orientation and cheap clear poly panels on the roof and siding. Some clever venting wouldn't be hard. Could speed drying I think.

The seasoned wood of yester years just ain't cutting it for some of these EPA stoves.
 

Philbert

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Kiln drying is needed to transport wood in some areas, due to invasive insects. Keeps them out of your house too.

Other reason might be to shorten lag time between cutting and burning, especially, if you have limited space to let wood season for several years.

Could become a hobby, with a greenhouse, etc. Some guys talk about making a kiln out of shipping containers, with fans to move the air.

Philbert
 

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I know in the description it says the seasoned wood is 35% moisture and the kiln dried is 20%. Is 20 low enough. Is 15 or 10% better? Is it worth it for a home time non commercial outfit?
Seasoned wood at 35%? WTF? That is NOT seasoned at 35%. Is the guy smoking crack? My seasoned wood is 20-25% moisture after one year. That's soft maple and ash. Oak and locust is still around 30% after one year. I've never seasoned for 2 years so I cannot comment on how low it will be in 2 years. Most of what I read was 15-20% in 2 years. Feom what I've read 10-15% moisture is about the best you can do without a kiln and probably on the high side of that range.

Is it worth it to kiln dry it? No! How could it be worth it when 15-20% is exactly what modern EPA stoves are calling for? Even with 20-25% I do not see any I'll effects from the moisture. I'm sure diminishing return comes into play. I cant see how kiln drying it will be worth the cost unless you have a passive solar kiln. But if it involves using electricity or burning a fuel I cant imagine it is worth the return. The only exception to that is if you are selling bundled firewood and it has to be kiln dried to kill bugs.
 

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I don't think wood can dry out anymore than the surrounding air, at least not without heat (kiln drying). But after kiln drying I'd expect it to suck up the surrounding humidity again if not used soon enough.
 

Ryan Browne

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I do think that if you could do it in a cheaply built hoop house that it could be a good selling point. I am close enough to Minneapolis/St Paul that there is a pretty good demand for firewood at a premium price.

So far I've been able to easily sell whatever excess I have just by mentioning that I'm not out to screw my customers and stating how long the wood has been drying. But I'm the future if I ever have trouble selling wood, I imagine that saying "kiln-dried and bug free" in the ad would be an easy way to separate oneself from the competition. It certainly wouldn't be that tough to toss it into a greenhouse for a couple weeks before delivery, and I imagine that I could probably tack on another 40-50 bucks a face cord.
 

Philbert

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I imagine that saying "kiln-dried and bug free" in the ad would be an easy way to separate oneself from the competition.
Check with the DNR about certifications and labeling.

Philbert

"MDA Heat Treatment Certified means the company operates a kiln that has passed a rigorous inspection and testing process and has successfully demonstrated the ability to heat their firewood to a minimum core temperature of 140˚F for 60 minutes.

MDA Kiln Dry Certified means the company operates a kiln that has passed an inspection and testing process and has successfully demonstrated the ability to heat their firewood to a specified temperature and final moisture content, dependent on the size of their firewood pieces. This certification is limited to wood that has a maximum thickness of three (3) inches, and thus is primarily used for lumber, but may also be used for firewood kindling of the appropriate size."

https://www.mda.state.mn.us/plants/pestmanagement/firewood/firewooddealers
 

Ryan Browne

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Check with the DNR about certifications and labeling.

Philbert

"MDA Heat Treatment Certified means the company operates a kiln that has passed a rigorous inspection and testing process and has successfully demonstrated the ability to heat their firewood to a minimum core temperature of 140˚F for 60 minutes.

MDA Kiln Dry Certified means the company operates a kiln that has passed an inspection and testing process and has successfully demonstrated the ability to heat their firewood to a specified temperature and final moisture content, dependent on the size of their firewood pieces. This certification is limited to wood that has a maximum thickness of three (3) inches, and thus is primarily used for lumber, but may also be used for firewood kindling of the appropriate size."

https://www.mda.state.mn.us/plants/pestmanagement/firewood/firewooddealers

Interesting, and thanks for the link. I actually don't cross into Minnesota for firewood sales. I stay within 25 miles of home; i don't want to risk spreading anything and I deliver with a 454 powered truck :). I just mentioned the cities because there's enough io a population with enough money to support selling "premium" wood. I don't ever plan on selling more than 15-20 cords a year at the most, so I doubt I'd ever seek state certification. It would be pretty cool to know how long you have to heat a stack of firewood for the pieces to meet 140 degrees. I imagine that a hoop house could get that hot on a sunny day but I'm not positive and you'd also be limited by daylight hours.
 

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I do think that if you could do it in a cheaply built hoop house that it could be a good selling point. I am close enough to Minneapolis/St Paul that there is a pretty good demand for firewood at a premium price.

So far I've been able to easily sell whatever excess I have just by mentioning that I'm not out to screw my customers and stating how long the wood has been drying. But I'm the future if I ever have trouble selling wood, I imagine that saying "kiln-dried and bug free" in the ad would be an easy way to separate oneself from the competition. It certainly wouldn't be that tough to toss it into a greenhouse for a couple weeks before delivery, and I imagine that I could probably tack on another 40-50 bucks a face cord.
I agree with what you are saying. However, a solar kiln is not the same as a traditional kiln. To kill bugs the wood has to be subjected to a certain temperature for a sustained period of time. I dont know the specifics but I do know its unachievable in a solar kiln without an additional heat source.

Edit: I see Philber has listed those specs!
 

Homemade

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I thought they just lowered the bug killing temp spec too. IIRC, I believe it was 160 degrees f for 60 min.
 

blades

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WI. DNR has a certification program for kiln dried firewood. That said, it is more on the order of bug killing than actual drying to a specific %. My notes on this subject suggest that 30 days at a sustained temp of 140-160 deg is needed to get to 15-20% moisture content on 4-6" splits and that it varies with the type of wood. Kiln dried furniture wood is taken down to apx 6-8% ( most of that is 1" thick ) when it is removed from kiln and set aside. At that point the wood will rehydrate/ stabilze to apx 12-15% (under very adverse conditions those numbers could increase).
12% and below is a bit too dry. The wood will burn like a match stick, 13-18% is about ideal in our EPA stoves. It is very easy to tell in a tube stove when the wood has too much moisture content as it takes forever to fire off the secondary's due to the cooling effect of the moisture being driven out of the wood by the heat of the fire. With experience you can somewhat tell by the flame color as whole, Dark orange is a cold fire , a bright yellow with blue tints is hot. Also you need apx 1100 degF at the tubes for the gases to ignite and enter into a sustained secondary burn. NC 30 a lazy secondary burn sustained will net apx 450 degs at the step with an IR gun, raging jet action all 4 tube blasting will net 650 on up, if you do not close off the control it will run right past 700. Sustained temps 700+ is not good for this particular stove. Any of the moisture meters will give you a general idea where you stand moisture wise provided they are properly used- most in-expensive units are pre-calibrated for furniture type woods. Item to be tested should be opened up so a freshly exposed face is used, item should be at room temperature though out ( room temp generally 60-75 degF). for our purposes the difference is in-material between types of wood. Well any way hope this is of some help.
 
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