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aesmith

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About aesmith

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    Aberdeenshire
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    INSCH

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  1. By the way where does anyone find air dried offered at 25% MC? Or are we assuming that most suppliers actually don't do any better than that, even though most claim sub 20%. My local place (the £50 softwood) says they aim for 15-17% but are only promising sub 20%.
  2. I wouldn't mind this lot, offered locally. But not worth £300.00, and there may be some issue getting the large section out. Firewood | in Aberdeenshire | Gumtree WWW.GUMTREE.COM Recently felled Beech tree, ideal for firewood. Buyer to collect - a few tonnes probably.
  3. Back in the real world I don't need any sort of calculation to tell me that air dried softwood at £50/cube is miles better value than kiln dried hardwood at £140. Does anyone find prices in their area sufficiently different so that kiln dried wins out? Also in the real world we have the luxury of enough storage space that I can dry stuff for at least two summers before use so even if I do need to buy in now and again it doesn't need to be ready for use.
  4. That's my mistake right there, my calculations were for M/C on dry basis, so when I said 25% I was assuming 1kg of wood plus 250g of water. Re-running on wet basis I expect my figures would pretty much match yours.
  5. Interesting, I wonder if our method was different. I calculated loss from a kg of using .. Specific heat of water from 20 deg to 100 deg Plus Latent heat of evaporation @100 deg Plus specific heat of water vapour from 100 to 300 degrees
  6. That's true and it's cracking stuff. We buy that now and again because our own supplies don't quite keep up with our use.
  7. As you say you can't comment on value without some numbers. So let's kick off with what's available locally to me, which is air dried softwood at £50/cu.m or hardwood at £90 both claimed to be sub 20% m/c. The only local supplier of kiln dried is quoting £140 for hardwood, unspecified species, unspecified m/c. Let's just compare hardwood. Obviously if both are 20% m/c then kiln dried is 55% more expensive for the same end result. Even if the kiln dried is only 15%, and the air dried is actually 25% then kiln dried is still 53% more expensive.
  8. Hi, asking here because I'm really after some layman's advice on Ash Dieback. We have a lot of Ash trees of every conceivable sort, from mature trees to regrowth from stumps to self seeded saplings. So I'd appreciate a few pointers .. (1) What is the best way for us to spot early signs? (2) If we find an affected tree, what's the best way to proceed? If it's small enough for me to handle should we immediately cut it down, and dispose of it (how?) (3) This is what triggered my post. I've been looking at a sapling that's showing no signs of the buds at it's tips opening. I know Ash is show to come into leaf but checking with binoculars I can't see any other example where the tips are not at the same stage as the rest of the tree. Is this an indication of trouble? It doesn't seem to be listed as a symptom in any information that I can find. Photo of one of the non-opening buds attached. The tree in (3) is actually unwanted, self seeded in a stupid place and I just haven't got around to removing it yet. I'm half inclined to go straight out and get rid of it. Thanks, Tony S
  9. Just for fun I did some rough calculations and assumed starting temperature for fuel is 20 Deg C, vaporisation at 100 and flue temperature 300. And calculated the losses for each kg of water to be 0.83kWh. That's actually not very much in the scheme of things. Assuming you get 5kWh per kg of dry wood, the direct loss due to water is only around 3.3% for wood at 20% m/c, or just over 4% for 25. If that was the only affect of differing water content then it looks like kiln dried at 15% m/c would give something less than 1% more usable heat than air dried at 20%.
  10. Surely 20% is 20% whether air dried or kiln dried? Or are you thinking that the kiln drying would have altered the properties of the wood as well as removing water? I expect that's possible. Some woodworkers prefer air dried, and I'll bet that kiln drying for firewood is a lot more brutal than for joinery timber.
  11. That surprises me, do you know why that is? I can't see the requirement mentioned anywhere on a quick look. When we had the Rayburn the "hearth" was actually lower than the floor. It was a concrete floor with two layers of Marley tiles glued down, so the "hearth" was made by cutting off the tiles for an area in front of the Rayburn, and painting the bare concrete with some heatproof paint. Mind you there was not Building Warrant or anything when we did this, although the stove installer was pretty knowledgeable and methodical so I think he'd have let us know if that wasn't acceptable.
  12. One cube of firewood will create the same amount of heat when it's burned whether it has 20% or 25% moisture content. The difference will be whether that extra water stops it burning properly by reducing the temperature or in other ways. Some heat will be lost turning the water into water vapour but the science of that is beyond me at the moment. It's apparently not just as simple as each kg of water using 0.6 kWh of energy to turn into vapour, the actual value depend on the temperature at which it happens. I am also not sure whether "bound" moisture when wood is below fibre saturation takes additional energy to separate it from the wood. So although I intended to do a rough calculation, I've had to admit defeat.
  13. We had a sample from Latvia. Described just as "hardwood" I think it might have been mainly Alder. With my cheap meter I read something like 13% at the outside, inside a freshly split piece it read zero, too dry for the meter to measure. It's anyone's guess what the m/c would have reached by the time it got to the end user. But it shows that drying to that extend is simply a waste of energy unless it's going to be transported and stored in sealed containers.
  14. That's very true, so stuff my dad got from a local "country superstore" looked like it needed to be stacked for a year. But larger scale suppliers aren't all blameless either. We got a load of "seasoned" wood not that long ago, and that looked like it had been left in the rain. Luckily it was only to top up our normal stocks but it was far from ready to use.
  15. Just out of interest I checked a few kiln dried suppliers, only one of these promised any actual figure lower than 20%. That one supplier offered imported Beech specified as 10-15% MC. All the others just said something like "less than 20%" or "an average moisture content below 20%". So if stove suppliers start pushing for people to use 15 or 16% it's going to mean even more wasteful kilning than's going on at the moment, and quite probably even more imports.

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