[Q] Should I joint cupped boards?

[Fromey]

I have two pine boards that Rob Stoakley very kindly thicknessed for me a few weeks back when I visited him. Unfortunately, in the intervening time, the boards have cupped slightly (damn, I knew I should have jointed them then and there!) Now that I'm ready to joint them into a panel (lid for my 6-board chest), using hand tools only, I'm in a quandary.

Should I flatten each board first and then square up the sides before jointing?
Should I "square" up the sides as best I can, joint the boards and then flatten the panel?

My worry about the second approach is that if I get the angle wrong on the edging, I'll end up with more flattening than should be necessary.

Thanks in advance.

 

[bugbear]

I have two pine boards that Rob Stoakley very kindly thicknessed for me a few weeks back when I visited him. Unfortunately, in the intervening time, the boards have cupped slightly (damn, I knew I should have jointed them then and there!) Now that I'm ready to joint them into a panel (lid for my 6-board chest), using hand tools only, I'm in a quandary.

Should I flatten each board first and then square up the sides before jointing?
Should I "square" up the sides as best I can, joint the boards and then flatten the panel?

My worry about the second approach is that if I get the angle wrong on the edging, I'll end up with more flattening than should be necessary.

Thanks in advance.

But that argument applies to the first approach too!

I would follow approach (2).

BugBear

 

[Racers]

What did you do with them after having them thicknessed? its either cupped by releasing the tension or moisture loss.

Pete

 

[Fromey]

The boards went on a half day excursion from my shed (where they have been sitting meditatively for about a year), to Rob's shed. Then back home where they have been stacked and stickered, waiting for time for me to get to them.

I must admit, this wood has been the Devil's own from the start (huge tear-out and movement), but show low moisture content using a moisture meter. Released tension, maybe, bit not a huge amount of wood was removed so I'm a bit surprised they have cupped noticeably in this amount of time.

Thanks BugBear. I think I'll draw a line down the centre of the boards and then try to edge them as close to perpendicular to that.

Once I get this lid finished, I intend to post pictures of the chest and a summary of the process (lessons learned).

 

[rafezetter]

I'm not expert and I've not done this myself but I saw on youtube a guy who wanted to retain the thickness as much as possible in a cupped board, so he sawed it in half length ways then rejointed it, which effectively reduced the amount of cup overall. All he needed to do was take off only the outside edges, the centre edge and a small amount from the other side.

A bit more work, but I thought I'd just add that technique as a possible solution.

I'll be interested to read your conclusions on making the chest, so pics please

 

[SpinDoctor]

+ 1 for ripping down the guts of the board to reduce the cup and then flatten. Don't joint till you have at least one flat surface on each board that will act as your reference point by which all other surfaces will be derived. Otherwise you'll be compounding the poor foundation from which you started. YMMV

 

[JimB]

I'm with Rafe too.

 

[bugbear]

Unfortunately, in the intervening time, the boards have cupped slightly (damn, I knew I should have jointed them then and there!)

If you had, you would now have an even-more-cupped jointed panel.

BugBear

 

[Fromey]

Well before I read the last few responses above I jointed the boards last night. I'll see what a mess it is tonight after work. Currently at 20mm thick, so perhaps I'm in for a 15mm thick panel. No biggy really, if it doesn't work, I may make the lid out of a different (and hopefully more stable) wood. An excuse to try out Valley Sawmills in Frome who I've just discovered on my doorstep. Thanks everyone for your feedback.

 

[J_SAMa]

I think, as far as joint making goes, it is possible to work with cupped boards. The vice or whatever holding fixture you use usually straightens them out to a reasonable extent
The real problem comes when you try to assemble them...

 

[Fromey]

The boards glued up fine. I spent about 10 minutes on each side flattening them. I'll need to clean them up tonight (hopefully they haven't moved any more). So should be sized, etc. and attached by the weekend. As an aside (largely to myself), we thicknessed a board of ash at the same time and it's been stored in the same way but has remained completely stable. I think I've developed a hatred and resentment of pine as it always seems to give me trouble (tear out, crumbly, warping, resin, loads of knots, etc.). It seems to me its only redeeming features are relative lightness and nice smell.