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Noob advice about cupping, please . . .

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McGill

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OK, new at this and learning all the time. Please be gentle.

Got some 9" wide red pine planks for a bookcase project for the wife. Stored them in my modest shed/workshop, well ventilated and not too cold. Been in there for about a month. Looking at them today and they've started to cup a little - some more than the others. Obviously this will pose a problem.

So, what can I do to remedy the cupping? I don't have a thicknesser/planer, which would seem to be the obvious answer, I only have a carefully fettled cheapo smoothing plane and a fairly brutish hand-held electric planer. I'm confident using either on edges, or 3" or 4" wide pieces, but not too sure about using them on a 9" wide face.

What's my best option for getting them flat?

Cheers in advance. =D>
 

9fingers

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Bring the board into the house to acclimatise to the environment where the wood will be used and stack them with small spacers in between the layers so air can circulate.
Wait and see what they do.
n.b. Always do this with project wood for a week or more before starting to make sawdust.

Rip the worst offenders along the centre line (or near to) of the greatest curve. Plane the cut edges straight and true. Glue back together.

hth
Bob
 

Argus

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As Bob says, but without a planer/ thicknesser, I would alternate growth sides on alternate boards to minimise further movement when you re-assemble them.
i.e. growth rings up on the first board, growth rings down on the second, third one up and so on, but I guess that you are in for a fair bit of planing by hand.




.
 

Benchwayze

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Mac,

Whenever possible, examine the end grain of boards when you buy them.
If the grain lines form diagonal or near diagonal lines across the thickness, they are not so likely to cup.
If the centre of the tree is apparent in the end-grain, then the timber each side will be less likely to cup.

If the grain forms wide arcs across the end-grain they will be likely to cup, and will cup towards the outside of the tree. If you have to use such stock for drawers, put the 'outside' of the tree to the inside of the drawer. Then any movement will tend to close the shoulders of the joint. For this job, ideally use quarter-sawn stock, which will display the diagonal grain pattern on the ends of the boards.

Gluing boards together with alternate 'wave' patterns is good, but try to keep the lateral grain direction the same for each board. That way you can clean-up the job with a sharp plane, instead of having to resort to sanding the job to death.

Plus one for the advice to acclimatise the timber in the environment where it is to be used.

HTH :)
 

AndyT

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If your bookcase is of conventional construction, with the shelves held in housings (cross-grain shallow grooves) in the uprights, then to some extent you can force cupped boards back to being fairly straight when you assemble it. From experience, a helper makes a big difference, and you may need to nail the ends into the housings as you go to stop them from popping out straight away. (I'm assuming you don't have a lot of big sash clamps.)

Also, don't be afraid of using your smoothing plane on the face of boards - now could be the time to get some practice in!

On projects I've done in pine, boards as broad as nine inches have generally started out looking a bit wavy - I think the days of huge old growth trees were over some time ago!
 

Benchwayze

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True Andy,

Some pine I bought last week couldn't have come from a tree much wider in the bole than 15" diameter, if that!

But they are nice clean boards all the same.

So far they are still flat!

:)
 

woodbloke

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Another alternative is to produce your own laminated pine boards, which are quarter sawn...but it is a bit of a faff. Take your cupped slash sawn boards and glue them together to form solid block, say 100mm thick and use lots of cramps to pull them up. Then prep two adjacent edges to form a face side and edge. The block can then be cut (bandsaw is good here) into boards which will be almost truly quarter sawn...all that then needs to be done is to edge joint the narrow boards to obtain boards of the desired width. A faff, but it does mean that you can turn cr@ppy, bowed slash sawn pine into something approaching a decent quality, stable timber - Rob
 
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