Curious, is most F17 construction hardwood generally plantation grown or in a Forrest?
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Curious, is most F17 construction hardwood generally plantation grown or in a Forrest?
Depends on the size you're after: mostly forest grown, but that will change as the plantation resource matures.
The issue in the plantation sourced material isnt that it cant grade to F17 (subject to species), the issue is that the logs are too small to cut the larger size boards in the first place. Australia is doing a most excellent job of decimating its own future because of well meaning decisions with little bearing in reality or science. Most plantation hardwood in Australia is exported (as either peelers or pulpers) because we dont let the things grow big enough to actually saw the products you need to build a house from them, but you can make a buck exporting them to China where they can turn them into engineered wood products and ship them back.
Its not an industry vs the greens thing or political left vs political right thing... its a lack of long term vision. When you start talking trees policy and practice needs to be long term simply because the trees themselves need time to grow, and if you want F17 boards we're talking 60 -80 years ahead. The bulk of the F17 and higher grade material in the market today is there because our grandfathers left those trees to grow when they cut across the operational areas of the 1960's. There is very little virgin forest in Australia... it's all been logged before, most of it three times or more. If we could keep the bloody woodchippers out we could be running selective harvests indefinately.
Eighty years to maturity creates a huge temptation to early felling. Add to this a lack of foresight and you have an industry hell bent on sh#*ting in it's own nest.
Another question, F17 hardwood is KD - is it dry enough to make things out of? tables etc?
Isn't that a prerequisite to be a polly, you only need to see as far as the next election.Quote:
Originally Posted by John.G
F17 IS NOT KD.Quote:
Originally Posted by qwertyu
F17 (or any other F grade) is a stress grade that relates to the strength of a piece of timber in service.
Other than that a piece must be at or below 20%MC to be assigned a stress grade it has no bearing on the moisture content of the wood itself, or its appearance, or its suitability for a given application.
KD means its been through a kiln at one point in time. When, and what the moisture content of the wood has become since then is uncertain. Mostly it hangs around the local EMC which is where you want it but there are plenty of stories of KD wood coming into a region on a truck and being too dry and swelling after a job is done, or KD being too wet and the purchaser having to wait for it to dry for cabinet type applications. A lot of woodies are paranoid about that (no, spilling water on your boards or even a shower of rain will not shift the moisture level in the timber: it took me a month in a kiln to get the water out of the middle, it takes more then getting the outside wet to run it back in there) but there are some true horrror stories out there.
Seasoned means... well nothing really. Just that its sat around long enough that it should be dry enough to be stable.
If you're going to be doing the type of woodwork where moisture levels of wood are super critical - and theres not a lot of jobs where that applies - then the best thing you can do is have a moisture meter and know how to use it when purchasing timber, or purchase timber far enough in advance that you can be sure its seasoned enough for your application.
That said mostly - in the majority of cases - if it says KD or seasoned its probably ok.
I see. I want to use it for a dining table - what moisture % should I be looking for?
Are any of these suitable?
https://www.bunnings.com.au/crommeli...meter_p0911078
https://www.carbatec.com.au/workshop...moisture-metre
Stihl Timber Concrete Wood Moisture Meter Brand New | eBay
https://www.jaycar.com.au/pocket-moi...rials/p/QP2310
I think any of those meters will do okay for you. Melbourne is usually around 10-12% EMC, obviously the closer to the ocean you get the higher the ambient humidity. Generally speaking a meter with pins will be more accurate then a pinless meter in a given price range. If you go with a pin type meter you need the pins to be replaceable - they do break off.
The thing is you need to understand how a meter works. It passes a current from one pin to the other and measures the resistance, wetter timber is a better conductor than dry timber so you get a reading of average moisture. The thing to be aware of is that different species have different degrees of electrical conductivity regardless of moisture level. Pro level meters have a species correction chart that allows for this... so you know to add 2% or subtract 1% from the dial reading to allow for this. (Temperature also causes a change in resistance so they'll have another correction chart for elevated temperatures but we'll shelve that line for a bit)
You probably arent getting that with a cheap meter but... you dont need it. Wander around the house taking readings off things of wood... kitchen cabinets, tables, floor, chairs, kids wooden toys... if they've been inside for years in the same house its pretty safe to say that they will all have the same moisture level, and the variations in readings are a species correction thing. Somewhere in there you're going to find an average... and also going to find a range thats normal, which will be average +/- a few percent. When you go timber shopping if its in that range or close to shes good to go. Wood moisture levels are constantly in flux... it doesnt matter if its a few % high or low because it'll shift there all by itself without too much issue. What you dont want to see is readings way out of your established normal range.... it might be a species thing but mostly it jsut means too wet or too dry.
the other thing you need to be aware of is that there is usually a moisture gradient across the cross section of a piece of wood, and that gets bigger as the cross section increases. Thats actually the biggest cause of wood movement in freshly made items. They have been dry on the outside but the inside was still wet. So when you buy your boards and get them home... cut one. Take a reading in the middle of the cross section well away from the end. If the mid section reading is within a couple of % of a suitable external reading you should be fine. Ideally, in KD, the core reading will be very close to the shell, or perhaps a little drier. Thats a sign that the wood has been properly dried, and the shell has taken up atmospheric moisture. It takes a lot to get the core of a piece dry obviously because the water has to get from there to the outside. Once the cells have shrunk as they lost that water it gets harder for it to take moisture back up again, both because the intracellular pores have shrunk, and because the cellulose and lignin structures have changed. Wood drying is actually a very complex process at the cellular level.
Honestly, if you want to work with hardwood and you have time the best way is always to buy decent green boards and sit on them. I got an old guy that orders a pack of 200x50 hardwood boards every year to keep him in hardwood stock for two years ahead: The old "Inch a year to dry" rule of thumb works fine in sections under 75mm thick. Green timber is cheaper then KD and he might get more KD off us through the year but ... he saves himself a few thousand on that one pack just by being patient.
Other then that the best way is to buy KD. Mostly Vic Ash is KD anyway, and being in Melbourne that shouldnt be too hard to get hold of at any hardware store. The other thing is your serious timber merchants will vary rarely have issues with timber being too wet, and they mostly will have a meter you can stick in boards you;re looking at. thats their business and its not good for them when an unhappy customer comes back complaining the timber wasn't dry and the job is now a total.
wow thanks for the detailed info. any idea where to get green boards? I would be happy with a bunch of slabs not even milled into boards (ie with the live edge)
also, with the meter - do you have to stick the prongs into the wood or just touch it? does it matter is its on the end grain side vs face when trying it at the shops (before I have a chance to cut into it and take a reading from the inside?)
Excellent posts John G.!! Both informative and thoughtful, as per usual.:2tsup::2tsup::2tsup:
Australia is not the only country that is short sighted when it comes to timber management.
Look at how China is pillaging the forests of Tibet and Mozambique. Look at how Brazil continues
to allow the decimation of its forests, despite now fairly strict laws being in place. Part of the problem
in Brazil is corruption and violence. The Malaysians don't care much for what they do and how. Everything
is simply torn down.
One day we will wake up to vast treeless plains and mountain ranges and wonder what happened.