Making firewood blocks

[Racerboy832]

I'm trying to maximize burning times with my PE stove. I was wondering if when I get stuff log length if they would burn longer if I cut them into 10" thick cookies. Basically just slide one in for bedtime. Anyone try this?

 

[ss~zoso~ss]

its all about surface area, the more surface area you have the quicker it will burn. So, a bunch of cookies will likely give you a quick hot fire, which would be great to warm the stove up, but for overnight burns, deff not the thing to do

 

[Nosmo]

10" Thick Cookies

If I understand you correctly you are merely cutting a 10" thick cookie off the end of a log.
If so this gives you a round piece (cookie) that is 10" thick. It just depends on the diameter of the log what the overall size of the cookie will be.

The term smaller surface area can be confusing to some folks. For instance compare a mouse to an elephant. The elephant is much larger than the mouse but the elephant has a smaller surface area in relation to its size.

In my opinion if you were to put a cookie 10" thick and 10" round which has a smaller surface area compared to 2 logs containing the same amount of wood you should get a longer burn from the cookie.

Nosmo

 

[jh35]

If I understand you correctly you are merely cutting a 10" thick cookie off the end of a log.
If so this gives you a round piece (cookie) that is 10" thick. It just depends on the diameter of the log what the overall size of the cookie will be.

The term smaller surface area can be confusing to some folks. For instance compare a mouse to an elephant. The elephant is much larger than the mouse but the elephant has a smaller surface area in relation to its size.

In my opinion if you were to put a cookie 10" thick and 10" round which has a smaller surface area compared to 2 logs containing the same amount of wood you should get a longer burn from the cookie.

Nosmo

Yes. You are looking for a smaller surface area to volume ratio for longer burning times. Using some engineering terms, just got out of class.:msp_w00t:

 

[mizzou]

I've done that sometimes and got good burn times. Can't tell you exactly how long but overnight anyway.

 

[zogger]

Heck ya nice full logs burn the longest. I leave quite a bit of the hard to split stuff intact just for all nighters. Also see :sweetgum, and what to do with it

I have a top and front loader, at night, I drop in a mambo whatever, always have coals in the morning. Thats air intake cranked closed and just getting the leaks around the door for air (old stove) I can fit a 12 inch diameter 16 inch long round or block, drops right in. I can put a longer one by a few inches, but have to drop the diameter then to make the turn and get it to lay down in there.

 

[Racerboy832]

My stove opening is rectangular. Lets say it's 16 wide and 11 inches tall and 18" deep. I happen to have a pile of 18" round logs. I cut them into 11" cookies. Then take out my handy hatchet and knock off 1" from each side. I can then slide that right in. Yes they are not perfect squares but there is no air between like if you were stacking splits. Do you think it would burn longer? It says in my manual to burn rounds at night, it doesn't specify which way round thou.

 

[rullywowr]

Exactly. Big solid logs that are almost the size of the firebox will burn longest. I like to do just that and then pad the voids with some smaller chunks, cookies, scraps, etc.

 

[Racerboy832]

Well i'll find out in the am if it worked. I just loaded a big cookie. I'll let you guys know how it goes. I'll either be warm or frozen.

 

[PEKS]

Stuff that PE box full of hard wood logs (I use hickory and hard maple)..
You will get an overnight burn and a good bed of coals..

 

[Racerboy832]

Well i woke up this am and it was 54 in the house. I checked the stove and my cookie was about half the original size and only the bottom had any glowing ash. I guess that didn't work out as expected. Back to the regular rounds.

 

[howellhandmade]

Well i woke up this am and it was 54 in the house. I checked the stove and my cookie was about half the original size and only the bottom had any glowing ash. I guess that didn't work out as expected. Back to the regular rounds.

Perhaps not fully seasoned? Damper shut too far? When I have to noodle crotches or other unsplittable sections, I often cut slabs that will just fit in my Napoleon 1100. I don't burn them until they've seasoned a couple of years, and I make sure to start with a good hot stove and not turn the air down too much. They give a good overnight burn, or at least don't stall out like it sounds like yours did.

 

[Marc]

Even if it's fully seasoned.... remember wood fire depends on radiative feedback to the fuel source, with oxygen delivery, to maintain a self sustaining reaction. Pyrolysis (the liberation of gaseous volatiles from solid fuel) is an endothermic reaction. It depends on the exothermic heat from combustion, while the comubstion relies on the endothermic pyrolysis reaction to supply gaseous fuel.

Splits, even tightly stacked, burn at their air/fuel interface and provide each other radiative feedback as the combustion generates heat to drive the pyrolysis. Similarly, if you space your kindling too far apart when lighting the stove, the reaction won't self sustain because adjacent fuel doesn't get enough radiative feedback to propogate or maintain a flame. Remember, radiative power falls off/increases with a distance squared relationship. Halve the distance to the radiative source, and you quadruple the incident flux.

If you just wedge one big split in a stove that takes up the whole firebox, the fuel/air interface is only getting radiative feedback from itself, which is also losing heat to the stove walls. Sounds like you were into a situation where you didn't have the surface area burning to provide enough radiative feedback to maintain combustion... as the ambient room air continued to draw heat away from the fire through the stove walls, the fire eventually went below its critical heat release rate for sustained reaction.

 

[BigDaddyR]

I think you have the right idea. As was said make sure it's seasoned enough.

I always get mine burning hot and good for about 15 min then damp it down. Another 10-15 and then close down the air controls on the front. Mines an old Schrader Stove.

This method usually works great. I like to use larger oak limbs from dead trees from 6-14" in depth and 16-20" long. I also fill the voids with smaller stuff and smaller dead oak pieces.

I've also made bricks out of large cookies. 10" by 5-8". When the logs are to heavy to cut on 16"'s then I cut them to 8's and split them into blocks. Just watch the Elm as its springy when split this way. Dries pretty quick though.

 

[andrethegiant70]

Even if it's fully seasoned.... remember wood fire depends on radiative feedback to the fuel source, with oxygen delivery, to maintain a self sustaining reaction. Pyrolysis (the liberation of gaseous volatiles from solid fuel) is an endothermic reaction. It depends on the exothermic heat from combustion, while the comubstion relies on the endothermic pyrolysis reaction to supply gaseous fuel.

Splits, even tightly stacked, burn at their air/fuel interface and provide each other radiative feedback as the combustion generates heat to drive the pyrolysis. Similarly, if you space your kindling too far apart when lighting the stove, the reaction won't self sustain because adjacent fuel doesn't get enough radiative feedback to propogate or maintain a flame. Remember, radiative power falls off/increases with a distance squared relationship. Halve the distance to the radiative source, and you quadruple the incident flux.

If you just wedge one big split in a stove that takes up the whole firebox, the fuel/air interface is only getting radiative feedback from itself, which is also losing heat to the stove walls. Sounds like you were into a situation where you didn't have the surface area burning to provide enough radiative feedback to maintain combustion... as the ambient room air continued to draw heat away from the fire through the stove walls, the fire eventually went below its critical heat release rate for sustained reaction.

What he said.

I know it wouldn't work in my stove.

 

[haveawoody]

Night blocks.

Easiest way to make them is when you get to the real narly twisted things stop splitting when they get to just a size they will just fit in the stove.
If they already fit the bill dont split them atall.
I usualy get enough for my needs at the splitter with quick decisions for size of my stove.
I aim for blocks of wood that all but fill the stove with maybe 1" open space around them, but any huge chunk that fits will do.
Night blocks burn a little different that a regular fire and i tend to need full air to allow them to burn all night.

Just remember you only need about 100 for an entire season.
A solid block of wood IMO will burn the longest, cookies with any air space between them might burn a long time but not as long as a night block.
A cookie stack will warp and twist in a fire creating air spaces no matter how tight you pack em.

 

[johncinco]

I never understand choking down a fire for the night. I might close my vents to half. I am going to get up to pee anyway, tossing a few more logs on isn't going to cost me that much sleep. The house stays 69-70 all night and we are not jumping around freezing all morning waiting for it to warm back up.

 

[darkbyrd]

I have bad results with only one piece of wood in the stove, whatever the size. 3 big pieces will burn hotter and longer. 1 really big piece will go out, or may as well have for the amount of good it is doing me.

 

[Mac88]

I think I understood what Marc was sayin', but I had to look up all the big words. :hmm3grin2orange:

 

[haveawoody]

darkbyrd,

Could be just an air thing for your big blocks of wood.
Seems crazy to put one giant block of wood in a stove and open the air all the way but it's a slow warm fire all night.
Takes a bit of resistance to not choke though.
Try one when you are awake one day you are around to watch it, fun to watch 1 piece of wood burn for 8hrs in the day and see what they really do when your sleeping.