Planked Oak

[Kev]

Hi all,

Not posted for a long time but had a question. Have been offered by a forester friend of mine some oak. It is basically a big tree that was blown down in the recent storms. Now it obviously needs cutting and planking but wondered if anyone had any advice about lengths and thickness of planks that are best asked for at the saw mill.

I appreciate that there is an element of choice about this but assume the thickness will affect the seasoning time but any thoughts would be great. As I am not sure what I will use it for yet have no real view on the matter.

Also is it best to stack it outside (under shelter of course) rather than inside (unheated garage) where I guess there is a concern that it dries out to quickly. Whats the optimum MC you are aiming at?

 

[jasonB]

I'd go for a mix of 2" & 1" boards which should cover most uses.

Store it outside out of the sun as it needs a good flow of air but cover just the top to keep rain off.

Jason

 

[milkman]

I'm told that a good clump of nettles and patience is the thing fot this : )

 

[eoinsgaff]

Jasons advice on the thickness options sounds good to me.

You need to leave it outside initially to get the moisture down to a manageable level. It could be anything from 40 - 70% MC when planked depending on how long the tree is down.

When stacked well, stickered and with a good circulation of air, 1 year per inch is a rule of thumb to get down to a moisture content in the high teens. These parameters are seldom all perfect so I find it a good idea to add a season (a year or so) to the rule of thumb.

Once your at this level you could consider bringing it indoors to bring the moisture to desired levels - 7 to 11% depending on what part of the world you live in.

Its also a good idea to give consideration to the types of grain pattern you need before planking - flat sawn, rift sawn, quarter sawn etc.

Eoin

 

[Kev]

Thanks for the useful advice.

Good point about the cuts. Was thinking to quarter saw one and rip the other assuming I go for 8' long planks. Now all I've got to do is get it to the saw mill! Should be fun.

 

[big soft moose]

Thanks for the useful advice.

Good point about the cuts. Was thinking to quarter saw one and rip the other assuming I go for 8' long planks. Now all I've got to do is get it to the saw mill! Should be fun.

might make more sense to get a wood mizer team to plank it on site.

 

[MikeG.]

Dont forget to cut it allowing for shrinkage as it seasons.......ie, perhaps cut to, say, 32mm if you want the board to finish at 25. Personally, I always have asked for the odd bit of 4 inch stuff as well, for table legs, but obviously that depends on how much of a hurry you are in.

Mike

 

[eoinsgaff]

Quarter sawing is a nice thought but impractical in a DIY situation. Difficult even with a wood mizer. Quarter sawing is also very wasteful.

As an enthusiast rather than a professional I have found that plain sawing is enough. Over all its more economical, easier and excluding the waste, about a fifth of the plain sawn boards end up quarter sawn and more fairly close. You also may need rift sawn timber for legs and flat sawn boards for panels.

Don't forget to weight the planks down very well when drying. I have some wood on a concrete slab onto which I have secured concrete tie bars keep the planks squeezed tight. A dead weight will do of course.

And paint the end grain. Oil paint - or similar - and lots of it. Seal it up well so the moisture is only lost through long grain. You might even paint the end grain the day you cut the tree, before planking.

Mike, good call on the thickness as well. I have learned that lesson the hard way.

Eoin

 

[wills-mill]

Quarter sawing's fine on a Wood Mizer. With the hydraulics to manipulate the log it's much easier than on a big traditional vertical bandsaw like a Stenner. Still very wasteful. You tend to end up with large odd shape chunks of wood that won't yield sensible timber, but good quartersawn is worth it.

Lots of things affect drying-
Board type- through and through slower than square edged
Thickness- the obvious one
Stack siting- windy hilltop or down in a damp sheltered wood?
Height off ground- ideally at least 6 to 9in off the ground for good airflow, or you will end up with much damper timber at the bottom of the stack, however long you wait.
Stick size- the spacing batten size is pretty critical.... 1/2in batten will allow very little airflow through the stack so is good to very slowly dry your precious bits, but you will get more blue stain on pine, spalting and gunk on Beech and sycamore, probably more likely to get worm infestation. On the other hand 1in batten will dry stable woods very quickly but will probably give you lots of checks and faults in Oak. 3/4in is a good all rounder.

An open sided stack with a good lid on it is ideal. Even better is shading from direct sunlight, which can be really vicious. We're getting some good results with breathable (Tyvek type) roofing fabrics on timber stacks, it's not as sweaty and horrible as using plastics tarps or as inconvenient as sheets of tin.

I'll see if I can find some pics.

W

Edit: yup, additional thickness in the sawn board is great. 1 1/4in, 1 3/4in and 2 1/4in boards have enough spare to address shrinkage, a little warping and also the machining.
For lengths and widths- have a look at what lengths are available at the tree itself allowing for use in finished projects plus an allowance (8in or so?) for wastage and wonky chainsaw crosscuts, if in doubt leave it as long as possible. Think of your transport and handling, there's no point milling 16ft long 2in boards if you're going to have to do 28 back breaking trips with one board at a time wobbling on a roof rack. Also have a think about the capacities of the machines you have access to and their siting- again those 16ft boards might be awkward to get into the shed!

 

[Ross K]

THe driest you'll get from air drying is 18-20% MC* Kiln drying is the only way to get 2" boards down to 10 or so.

*I just bought some ten-year air dried (in purpose built barn) 2" oak which is 20% MC right to its middle but another ten years would leave it the same, according to sawmillers I've spoken to.