# How much does it way?



## CurtisWilliams (Mar 14, 2005)

Can anyone give me an estimate on how much a cord of wood weighs? 

Also, on a pound for pound basis, does cardboard have the same btu's as wood?

I have access to an incredibly large supply of clean used cardboard boxes. Last year I burned an estimated 1500 lbs. It isn't the most convenient source of heat, but the price is right!


----------



## Micheal (Jan 28, 2009)

A cord of wood weighs ahhhhh, depends!
Depends on type of wood it is , whether it's green or seasoned, seasoned under cover or outside in the open, how long it's been dry(ing) and a lot of other things I can't think of at the moment......


----------



## Explorer (Dec 2, 2003)

What you need to know is BTU's per pound for different woods and cardboard (there are different types also). Google will find this info for you or search this area of the forum.


----------



## CurtisWilliams (Mar 14, 2005)

Explorer said:


> What you need to know is BTU's per pound for different woods and cardboard (there are different types also). Google will find this info for you or search this area of the forum.


I had read several years ago that a pound of wood provided the same amount of btu's regardless of what type of wood it was. The moisture content was the variable. 

Meaning that a pound of pine seasoned to a moisture content of 'X' has the same btu rating as a pound of maple dried to the same moisture content. Different volumes, same btu's

It seems to follow that a pound of cardboard would give a somewhat similar amount of heat.


----------



## CurtisWilliams (Mar 14, 2005)

Just found this. Will keep researching...

"Within reason all woods have a potential BTU value of 8000 BTU's per pound. Oak, Ash, Balsa and Pine all have the same potential. I am sure there are some exotic woods that might violate this rule but for the sake of this question 8000 BTU/Pd will do nicely. The term potential is a theoretical maximum yield and, in a practical sense, can not be achieved except in the laboratory.
The key is in the weight not the species. Wood, when alive and green, has approximately 50% moisture content. Obviously, water will inhibit the conversion to heat so actual, aka possible, BTU's available to heat a home will drop according to the moisture content. When the moisture content drops to less than 20% the available BTU's will be approximately 6000 BTU's per pound. Seldom, if ever, will the average homeowner achieve greater than this as they have no control of moisture content of whatever they are burning."

I couldn't find anything about cardboard btu ratings. I did find out that a dried cord will generally weigh about 2,000 - 4,000 lbs, with a lot of variables.


----------



## TnAndy (Sep 15, 2005)

I would think, per pound, cardboard would be right up in the same range as wood.....and might even have more because of the glue, which I'd assume is a petroleum based product.

As far as burning a LOT of it, I'd have two concerns:

1. The "per pound" is going to require a LOT of fire feeding is my guesstimate. It isn't gonna have much in the way of banking ability like a good, dense hardwood. You'd have to feed the fire pretty regularly due to the low density.

2. Burning a LOT of it, the smoke off the glue might be an issue, not knowing exactly what chemicals you're burning.


----------



## Explorer (Dec 2, 2003)

Look at this chart and you will see each species of wood gives different amount of BTU's.

http://firewoodresource.com/firewood-btu-ratings/


----------



## CurtisWilliams (Mar 14, 2005)

I spot checked the btu per pound , not the btu per cord. In the chart that Explorer provided (Thank you) The range approximates the 6k-8k btu per lb that I had posted. Surprisingly the softer woods seemed to outperform the denser woods. Possibly from the more abundant resins.

The bankability of a cardboard fire is a bit of an issue. I fold my cardboard as compactly as I can, stack them 10 high and let them sit overnite with a concrete block on top. 10 average size boxes burnt in this manner will provide heat for about 1/2 hour. If I do this twice on a cold winter morning, it raises the temperature in my large, old farmhouse by 10 degrees with little chance of overfiring (another HUGE concern) I generally burn four loads daily, and on my days off a few more. As the cardboard fire dies down, it makes an excellent bed to lay kindling on to build a 'real' fire.

Toxins from heating like this are a concern. I do not know what kind of a potential health or environmental impact this may have. Much of my supply would have otherwise have gone to the landfill or to an incenerator, so I think that I may be having a minimal negative impact. At least I hope so.

I thank you for your input. It has been helpful.

Peace,
Curtis


----------



## Steve L. (Feb 23, 2004)

Well, I found this -


> _Type 0 Waste _â Trash consisting of highly combustible waste paper, wood, *cardboard cartons* and including up to 10% treated papers, plastic or rubber scraps from commercial and industrial sources. *Type 0 Waste has a heating value of 8,500 Btu per pound*, a moisture content of 10% (by weight) and an ash content of 5% (by weight).


----------



## CurtisWilliams (Mar 14, 2005)

Thank you Steve. That is just what I was looking for. It seems that all wood and cardboard has pretty much the same btu/lb rating. I LOVE free heat!


----------



## Ross (May 9, 2002)

So if one were to use a round bale straw burner to burn cardboard bundles loaded with a skidsteer or forklift, one might well get a lot of free heat. The management of such might be a pain in the butt however when you're looking at a $15,000+/year heating bill if I used oil and more with electric, it is certainly interesting. A cheap greenhouse to store the bundles is easy enough just sourcing and delivering the bundles might be tricky. Food for thought!


----------



## CurtisWilliams (Mar 14, 2005)

From my limited experience, micromanagement seems to be the key factor. I would never burn a load if cardboard while I was not there to attend to it. It is too volatile and unpredictable. I have overfired my burner within a few minutes when I allowed my self to become distracted. 

Cardboard can burn so hot and quickly that I do not recommend it to any one else, especially the inexperienced. I burn in small batches only. An uncontrolled fire can ruin (or take) your life.


----------



## farminghandyman (Mar 4, 2005)

IF some one had a simple way of compressing it into some type of log then I think one could use it,

I know there have been startups that have straw, into logs, other falter into burnable products, I do not know why car board would be any different, the problem was marketing and machinery cost, and the process,

I would think either one would have to nearly have to shred it then slurry it, and then press it, and unless there was some kind of mechanical automaton I doubt if it would be time efficient, and there may be a need to add wood pulp, (saw dust) or some thing else (coal dust), to make the more efficient briquette or pellets, or logs,

http://www.nzdl.org/gsdlmod?e=d-000...l2.2&cl=search&d=HASH579f652e2038e0635a7cab.9

http://free-ri.htnet.hr/Branko/image13s1 Nikola Tesla Solar Energy Collector Biomass Briquett.jpg
and
http://free-ri.htnet.hr/Branko/13.html#zoom11

http://clips.insidehmong.com/?w=_orNGqJ9Elk&title=hydraulic-sawdust-briquette-press

a very primitive system but has the basics,
[ame]http://www.youtube.com/watch?v=iVrKEgKckbU[/ame]

[ame]http://www.youtube.com/watch?v=4J7K219AkaY[/ame]

If one went to an oil press extrusion type strainer and then put a tub with a mixing arm to keep the hopper filled with paper slurry some thing like this picture of an experimental oil press http://www.harvestchapelmission.org/page/2-2-vegetable-oil-press









I would think a longer chamber so the pressure would build a little more, may depend on the taper in side the screen system,

then after drying of the pellets or briquette's they should burn like wood, a system with the press pictures above would make it possibly time efficient to burn,


----------



## CurtisWilliams (Mar 14, 2005)

The screw type scissor jack is EXACTLY the system that I had envisioned about a week ago. I'm going to watch these videos now. THANKS.

Peace,
Curtis


----------

