Sunday afternoon science - Thing 1

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Poindexter

Minister of Fire
Jun 28, 2014
3,161
Fairbanks, Alaska
Went to the homestore today and brought home two of 4x6x96 S-grn Doug Fir.

Thing 2 is particularly twisty, has been on the racks at Team Orange probably a while and is easily several pounds lighter than Thing 1. Thing 2 is for later.

Thing 1, today's topic, feels about right for weight as a fresh from the mill S-grn Doug Fir 4x6. 18 inches was cut off one end twice, then a 6 " scrap cut from the middle of the plank, with the remainder of length cut into 3 pieces 18 inches long.

The six inch scrap was split roughly in half. The freshly exposed face felt damp to the touch, and with pins inserted parallel to the grain, the MC measured 21% (wet basis) at 55 degrees F.

5 pounds of kindling was prepared using a kitchen scale.

Preparing to load the cold stove, author's opinion, this wood is too wet for my stove to run good, and this is a LUDICROUS amount of kindling to deal with at every cold start. From an operational perspective (with no instrumentation to collect emissions data), this is clearly suboptimal fuel compared to softwood at 12-16% MC wet basis.

20220313_175559[1].jpg 20220313_175617[1].jpg 20220313_175639[1].jpg
 
FWIW the 2x4 among the kindling did have some fish glue on it. Fish glue is a product of naturally occuring substances, but God didn't put it on the tree, so it was planed off and no further correction for kindling weight was made.

I will now go load all this into my cold stove with one eyebrow already reaching for my hairline. 20% MC is a minimum, but it isn't optimum for anyone I know of that has run a little fuel at 16%.
 
Sounds like you read the Dirgo labs test report. Like you, I raised an eyebrow when I saw Grn doug fir. I would not test with anything above 20% internal moisture content which leads me to believe that this wood sat in the shop for a while, possibly months because it's unlikely they run out and get a fresh load of wood for every test.
 
First the full length pieces were loaded. The 5 # of kindling on the load bill does include 6 of 1x2 furring strip at 18". Then the kindling smalls, and finally the plane shavings.

20220313_182059[1].jpg 20220313_182112[1].jpg 20220313_182124[1].jpg

20220313_182059[1].jpg 20220313_182112[1].jpg 20220313_182124[1].jpg
 
Last edited:
The MC of the fuel was not, that I noticed, listed. Green Doug Fir, fresh from the mill and shipped to Alaska consistently meters 19-22% MC. I couldn't quite make out the mill marks in the picture of one of the fuel cribs used.

I am not sure how much lighter Thing 2 is, pounds lighter for sure. Right now I am going to set a match to Thing One and get dinner in the oven.
 
I used two seasons worth of kindling, or thereabouts, on one cold start and cut a solid one minute off my previous personal best cold start to clean plume time. Air intake was at wide open throttle all the way through.

T + 8 seconds - audible draft in chimney. That was super quick for me.
T +90 seconds, loading door moved to just cracked open, no visible stack plume (yes I ran out on my deck barefoot at +12dF to go look.)
T + 3 minutes, loading door latched, exhaust gas probe at 200dF. Also quick. All that kindling did get this burn off the line fairly quickly.
T +5 minutes - visible plume, 400dF exhaust gas temp
T + 9 minutes, 450dF exhaust gas temp, cat probe indicator lifted off the low stop
T +17 minutes 1100dF exhaust gas, cat probe half up inactive zone
T +20 minutes, 1200dF exhaust gas, active zone, combustor engaged
T +21 minutes, clean plume

21 minutes ET to clean plume, minus the 90 seconds at the start of the burn with no visible plume, means the smoke police, maximum, might have seen a visible plume for 19.5 minutes, a legal cold start inside the 20 minute regulation local to me.

I am at T +53 minutes now, the combustor has been engaged for 32 minutes with the air control on high, and I am not impressed. The legal fuel is burning, the cat hasn't stalled, but the probe indicator is at about 1/3 of full active and has lowered since the last of the kindling burnt out. I am not willing to turn it down, mostly because my wife is still wearing socks, but I think there is a ways to go to bake the remaining moisture out of the remaining fuel as well.

If you got one of these stoves and aren't getting the BTUs you want with 20% fuel, try fuel at 16%. The stove will wake up.
 
The MC is listed on the EPA report for certifying the 30.2 boxes, 23.76% bry basis ~ 19.2% wet basis.
 
So, they tested with wood of poor quality.
How much do you think this matters for the clean plume timing if they would have used 16 pct fuel?
 
So, they tested with wood of poor quality.
How much do you think this matters for the clean plume timing if they would have used 16 pct fuel?
I got nothing. In the EPA certification tests I have looked at, the more kg/hr the stove is burning, the higher the emissions are. Doesn't matter who made the stove, cat/ noncat, doesn't matter. More fuel burned in whatever for time, higher emissions to go with. Makes perfect sense. If you burn one kilogram per hour you will have a relative low grams per hour in the stack plume. If you are ripping ten kilos per hour, there is going to be more grams of crud coming out of the stack per hour.

I am not burning 22 pounds per hour, even at -50dF outdoor ambient, but I am burning dry wood and I am burning (compared to the average here) a relative lot of it. I do know, to keep my house at the same temp, switching from EPA non cat to EPA cat stove, I am burning 7-8 cords per year instead of 10-11 and wishing I had 12 cords seasoned. At some point, someone with a spare synapse that isn't flapping in the breeze needs to look at how many grams per winter heating season instead of how many grams per hour I am producing. I don't really care how many grams I make on a cold start in early October when my next cold start is going to be October next year.

I have seen a few references that dry wood can give off more grams in the stack plume per unit time, but I haven't yet seen a good peer reviewed article in a reputable journal with numbers and somebody's reputation on the line. If you find one, please share a link.
 
  • Like
Reactions: MissMac
Sounds like you read the Dirgo labs test report. Like you, I raised an eyebrow when I saw Grn doug fir.
S-Green Doug Fir is a readily available product, at least on the west coast, and usually I find 19-20-20-20-20 % MC when I stick a piece over and over. It is technically legal cordwood, shop average for me buying 4x_ and 6x_ mill stamped S-Grn is 19.8%MC wet basis. Thing One was an outlier at 21%.

I do find DFir seasons slower than the colonial era (east coast) rule of thumb one year per inch of thickness. The chop on my leg vise started out as 16/4 DFir that I know is five years old, but is still moving seasonally.

I talked to BKVP about this subject, gosh, years ago. My Ashford 30 was installed in May 2014. Any road, Chris said (once upon a time) nationwide USA, folks are doing good to get there splits down to 20%, so the stove makers design for that and the EPA has to deal with it. Local to me EMC (Equilibrium Moisture Content) is 11%, but we have to top cover. Local we can hit 8-9% in late June if we are split and stacked in Mid March, but it starts raining here on July 5, so cord wood is either top covered and still dry, or a moldy mess, come September.
 
Please tell me about the plane you used!
#6 Bailey. I think it is a type 11. Sorry, I am not a type number snob. We have a bazillion type 13s floating around up here thanks to FDR fixing the price of gold - too low for local miners to make a living. I recall type 13 was 1931 to 1933, but that is the only one I am reasonably sure of. A bunch of gold miners up here put down their picks and tried their hand at wood working to feed themselves, judging by what I see on rust hunts.

Any road, pre type 13, I found it loaded with manure at a really good price because it was FOS and the 'not desirable' #6 size. I used a hoof pick to get most of the manure (horse I think) out, and waited for my wife to leave town for a weekend to get busy with naval jelly. New iron in PMV11 from Lee Valley honed to 4k diamond at 30 degrees secondary with a Lie-Nielson guide on DMT stones, I was able to save the factory chip breaker. I set it up as a panel plane.

Whoever the previous owner was, his wife or kids hated him. She might have hated the horse too. Happy to take it to PM if you have follow up questions. I have, at last count, 10 Bailey type planes under my bench, nine of those legit vintage Stanley Bailey's. I am hooked on PMV11 and not buying anymore A2 irons if I can help it. I look at O1 as basic, PMV11 as an upgrade when I can afford it and only buy A2 when I have too.

Actually, the orange paint on the cap iron suggests my #6 is post WWII. I just took a couple pics. I have a mild preference for the earlier 'low knob' types, but I really don't care. Sharp, it has been said, solves all manner of problems. I have recently brought in a DMT stone at 8k now that I am moving into hardwoods, but 4k as my finest stone served me well getting moving with softwoods. 12" steel rule for scale.

20220318_000059[1].jpg 20220318_000119[1].jpg
 
  • Like
Reactions: charger4406
I honestly don't know about knots from an emissions perspective. I know they burn slower than straight grained wood. If they burn slower enough to reduce emissions, it might make sense to load a bunch of knots to get lower emissions and a better test score. If they burn dirty it would make sense to load as few knots as possible to beat the test.

I also knots don't dry very well. So if having wet wood, hidden knots, is less emissions I would look for those to beat the test. If having hidden knots is wet wood and higher emissions, I would look for those- and cull them- to beat the test. Either way, the testee is going to be a relative expert at reading wood grain for hidden knots. As a high volume burner, the knots go in the stove, cord after cord, year after year.

As I posted in another thread, we kinda need standardized tests for comparison purposes, but on the other hand standardized tests are useless because they don't reflect the real world. How many people do you know with awesome SAT scores who couldn't pour piss out of a boot with instructions printed on the heel? Are you getting the EPA estimated mpg right now today in the car you own and operate?

I looked at instrumenting my stack a couple years ago. The smart way to do it (as a working homeowner) is with a data logger with a serial or USB port on it, and then hang sensors on the data logger. I was looking at $3-5k in probably 2018 or so, for less than EPA grade gear. I didn't spend the money, and my wife would not be happy about me drilling a bunch of holes in the telescope and having random wires all over the living room.
 
#6 Bailey. I think it is a type 11. Sorry, I am not a type number snob. We have a bazillion type 13s floating around up here thanks to FDR fixing the price of gold - too low for local miners to make a living. I recall type 13 was 1931 to 1933, but that is the only one I am reasonably sure of. A bunch of gold miners up here put down their picks and tried their hand at wood working to feed themselves, judging by what I see on rust hunts.

Any road, pre type 13, I found it loaded with manure at a really good price because it was FOS and the 'not desirable' #6 size. I used a hoof pick to get most of the manure (horse I think) out, and waited for my wife to leave town for a weekend to get busy with naval jelly. New iron in PMV11 from Lee Valley honed to 4k diamond at 30 degrees secondary with a Lie-Nielson guide on DMT stones, I was able to save the factory chip breaker. I set it up as a panel plane.

Whoever the previous owner was, his wife or kids hated him. She might have hated the horse too. Happy to take it to PM if you have follow up questions. I have, at last count, 10 Bailey type planes under my bench, nine of those legit vintage Stanley Bailey's. I am hooked on PMV11 and not buying anymore A2 irons if I can help it. I look at O1 as basic, PMV11 as an upgrade when I can afford it and only buy A2 when I have too.

Actually, the orange paint on the cap iron suggests my #6 is post WWII. I just took a couple pics. I have a mild preference for the earlier 'low knob' types, but I really don't care. Sharp, it has been said, solves all manner of problems. I have recently brought in a DMT stone at 8k now that I am moving into hardwoods, but 4k as my finest stone served me well getting moving with softwoods. 12" steel rule for scale.

View attachment 293675 View attachment 293676


I don't remember my types either. Any woodworking I seem to do now is fixing a soffit or fascia. There isnt much need to use planes. I saw the curlies and said, oh, thats unexpected on this board!
 
I looked at instrumenting my stack a couple years ago. The smart way to do it (as a working homeowner) is with a data logger with a serial or USB port on it, and then hang sensors on the data logger. I was looking at $3-5k in probably 2018 or so, for less than EPA grade gear. I didn't spend the money, and my wife would not be happy about me drilling a bunch of holes in the telescope and having random wires all over the living room.
Out of curiosity, what type of sensors would you instrument with? What would you be trying to learn/accomplish?
 
I do find DFir seasons slower than the colonial era (east coast) rule of thumb one year per inch of thickness.
That doesn't match what I have found. I've been burning doug fir for several years. I get it green in March and by the end of October it's reading in the 17-19% range in the core wood of a resplit 6" thick split. It stabilizes around 17% based on our average ambient moisture, even after a year of seasoning.
 
That doesn't match what I have found. I've been burning doug fir for several years. I get it green in March and by the end of October it's reading in the 17-19% range in the core wood of a resplit 6" thick split. It stabilizes around 17% based on our average ambient moisture, even after a year of seasoning.
I can't possibly explain that. I do not doubt your findings. One difference is I am working with sawmill product, usually at least 8 feet long.

My understanding, lemme open my WWPA handbook- 2017 western lumber grading rules- the S-Grn stamp indicates the lumber was surfaced in excess of 19% moisture content (dry basis) when it was surfaced.

My local EMC is 11% and DFir starting ~20% MC wet basis takes more than one year per inch of thickness to get there - local to me.I do have a little bit of DF 2x4 in my shop, two years old, 1.5" thick, not moving anymore. BRB...
 
That doesn't match what I have found.
I can't possibly explain that. I do not doubt your findings. I do have a little bit of DF 2x4 in my shop, two years old, 1.5" thick, not moving anymore. BRB...
ut oh BG. Now look what you’ve done. This has all the potential of a “can I jam pack my cat stove full of wet cardboard?” Kind of thread, lol.
 
I saw the curlies and said, oh, thats unexpected on this board!
My two remaining hobbies, are wood working and cooking. I haven't sold my scuba gear yet, but it has been hanging in the closet a long time.

The vise chop was one end of a S-Grn Dour Fir plank, currently 33 x 3 x 11 inches. It came off a plank 16/4 x 13 x 108. The other two thirds of the original plank were crosscut to 3 feet each, and then ripped on the center of the grain lines. I ended up with four legs for my next workbench, a pair of 4x7 and a pair of 4x6, each 36 inches long. They are FOHC, free of heart center cut, stickered in my shop and waiting for their turn on the dance floor.

So S-Grn when I started. When I was rip sawing the legs apart I smelled turpentine, a pretty good indicator DF is at or above 20% MC wet basis, and when I stuck my meter into the freshly exposed face I found mostly 20% with 21% indicated here and there.

Second pic shows the vise chop, the vertical piece that moves back and forth, is still shrinking. I put all those bowtie shaped pieces in while the original plank was still full thickness with parallel sides. Then I planed the surfaces flat, cut the tapers and planed the tapers flat, and you can kinda see the lower bowties are now a little proud of the previously planed flat surface.

We could speculate that @begreen 's DF splits are drying faster because they are not as long, so more water could get out the tubules, or we could speculate the kilning process on the DF I can buy has forced the tubules closed so water can't get out of longer boards. I don't know very much about industrial scale milling of kilning processes.

20220319_123209[1].jpg 20220319_123230[1].jpg
 
Out of curiosity, what type of sensors would you instrument with? What would you be trying to learn/accomplish?
I honestly don't remember. oxygen sensor was cheap. CO/CO2 sensor was cheap. logger was going to be about $1500. I think NOx and I think a particle sensor. I think it was the particle sensor that was half the price of all the system. Particle sensors for room temperature air are $60 on amazon, but sticking a particle sensor in a hot exhaust plume was $$$.

What I see on the EPA certification reports I have read is higher burn rates, more pounds of wood burner per hour, result in higher emissions from every style of stove, no matter the mfr or emissions technology. I burn a lot of pounds per hour and am probably emitting more grams than my stove did emit on the EPA test cycle. If it was a car, I would be doing burnouts at every green light, and cruising in high gear at full throttle.
 
ut oh BG. Now look what you’ve done. This has all the potential of a “can I jam pack my cat stove full of wet cardboard?” Kind of thread, lol.
Nope, I do all I can to avoid burning damp wood. Our clean flue is a testament to this. Been there done that many years ago with some damp maple.