Should I bother with a bent board?

[GarciaJ]

I glued up a 600x800 Vic Ash shelf for a glass top coffee table (WIP posted Big Stuff), but now its bowed along the width. ~ 3mm bow over the 600 mm. So I have three choices:

1. Make another board, but it seems a pity to waste the timber

2. Use the board, and let the cleats pull everything straight, but I am concerned that this may pull the other components out of shape over time, and well, I will know that the shelf is not perfect...

3. in addition to the cleats I can glue and screw 2-3 ribs in the underside of the shelf to pull the shelf straight without stressing the cleats too much. Not visible unless the table is turned upside down.

Any advice or other ideas?.

[ian]

flatten the board?

[Hermit]

^ My thoughts exactly. How thick is the board? Any leeway? I was surprised to see that machining it flat wasn't #1 on your list. (3mm isn't much to plane/thickness/drum sand out.)

[GarciaJ]

^ My thoughts exactly. How thick is the board? Any leeway? I was surprised to see that machining it flat wasn't #1 on your list. (3mm isn't much to plane/thickness/drum sand out.)

Oh I am druling over a rum sander right at the moment...A thicknesser is just a dream. My work shop is just a garden shed and I bring outthe work under the carport when I am working, so even if I could afford these machines I don't have anywher to put them.

I have a power planer and an old hand plane, but mybe not the skil to hand plane a 600x800 board.

I could ask the local timber shop to put it through a thicknesser for me, I guess

Thanks for the suggestion

[AlexS]

One side needs to be flattened, either by hand or on a jointer, before the board goes through the thicknesser, otherwise you will have a bent board with parallel bent faces.

[Hermit]

Oh I am druling over a rum sander right at the moment...A thicknesser is just a dream. My work shop is just a garden shed and I bring outthe work under the carport when I am working, so even if I could afford these machines I don't have anywher to put them.

I have a power planer and an old hand plane, but mybe not the skil to hand plane a 600x800 board.

I could ask the local timber shop to put it through a thicknesser for me, I guess

Thanks for the suggestion

Local timber shop to flatten it is a good idea.

[Hermit]

One side needs to be flattened, either by hand or on a jointer, before the board goes through the thicknesser, otherwise you will have a bent board with parallel bent faces.

G'day Alex. A job for that old hand plane, prepping for the thicknesser, or the shop could do that too. (I love my hand planes now that I'm getting the hang of using them - fast, a great finish and, best of all, quiet.)

[BobL]

I glued up a 600x800 x ??? Vic Ash shelf for a glass top coffee table (WIP posted Big Stuff), but now its bowed along the width. ~ 3mm bow over the 600 mm. So I have three choices:

Before making any decisions or comments I'd need to know the current and final/intended thickness of board.

Is it at least 3 mm thicker than it's intended final thickness then I would flatten it. If not, you cannot flatten it without making it thinner. Maybe your design can cope with a thinner board, maybe it can't.

If the board is already at the intended thickness and "thin" it can be most likely be fixed in place and straightened, if it is "thick" then this may not even be possible.

[GarciaJ]

It occurred to me that what bent the board might just unbend it! Some time ago I made some T bar clamps using 19x42x1200 pine shorts. 2 T bars and couple of bolts make a clamp. I used three of these and a few wedges to glue up the board in the first place. Cheaper and better than pipe or sash clamps, but more on that another time, the thing is that I have a means to temporarily force the board to straighten.

So I clamped the board straight, and then i wiped it with a soaked sponge. I wiped the board a few times during the coarse of a day.

To my eye, much of the 3mm bend is gone now. And I think that if I held the board slightly bent in the opposite direction to the bend and did the same, then I could straighten the board completely. I won't bother as I am pretty pleased with the result as it is.

I am keeping the board in the clamps until I am ready to sand, apply finish and assemble.

[Hermit]

It occurred to me that what bent the board might just unbend it! Some time ago I made some T bar clamps using 19x42x1200 pine shorts. 2 T bars and couple of bolts make a clamp. I used three of these and a few wedges to glue up the board in the first place. Cheaper and better than pipe or sash clamps, but more on that another time, the thing is that I have a means to temporarily force the board to straighten.

So I clamped the board straight, and then i wiped it with a soaked sponge. I wiped the board a few times during the coarse of a day.

To my eye, much of the 3mm bend is gone now. And I think that if I held the board slightly bent in the opposite direction to the bend and did the same, then I could straighten the board completely. I won't bother as I am pretty pleased with the result as it is.

I am keeping the board in the clamps until I am ready to sand, apply finish and assemble.

Well done. Is there any way that you could get steam to it? If you can steam and bend it slightly past where you want it, it'll probably settle well. Even if you're able to bend first, clamp, then steam. The other thing I thought of was flattening it out with a router, on a sled, but this is better.
(I'd still be interested to hear how thick the board is.)

[GarciaJ]

Well done. Is there any way that you could get steam to it? If you can steam and bend it slightly past where you want it, it'll probably settle well. Even if you're able to bend first, clamp, then steam. The other thing I thought of was flattening it out with a router, on a sled, but this is better.
(I'd still be interested to hear how thick the board is.)

19 mm thick. I try to use standard cuts in all my projects - less ripping and resawing that way.
In this case, the board is the bottom shelf on coffee table, so the thickness is not critical, but thinning the board is difficult for me with my tools.

s

[Twisted Tenon]

Good work. I was thinking of a more primitive solution of setting the piece over some steaming water with a couple of bricks on it. Your clamps sound a good idea, would you mind posting some pics sometime?

TT

[Robson Valley]

If the wood is "moving" in response to changing humidity and Moisture Content %, how do you know that it's finished? You might make some repair but in the middle of an on-going process. I'd make more measurements and wait a couple of months.

[GarciaJ]

Good work. I was thinking of a more primitive solution of setting the piece over some steaming water with a couple of bricks on it. Your clamps sound a good idea, would you mind posting some pics sometime?

TT

Here you go TT!

https://www.woodworkforums.com/f44/ho...8/#post1629705

[Twisted Tenon]

Thanks GarciaJ

One picture is worth a thousand words. That's a really nifty-economical way of cramping boards. I also like to find uses for scrap timbers.


TT