Edge gluing bowed lumber

[Darren Vass]

HiFolks. Sure could use some advice or be pointed to a previous thread with the same info.

I just purchased 1 x 6 milled solid birch boards from a local mill. They seemed relatively flat when I loaded them into the car and took them home. I've since laid them flat in pairs on the carpeted basement floor. I live in Wisconsin where the wind chill tonight is 38 below.

I've noticed up to a 1/8" bowing on a few of the boards. The boards are 1 x 6 x 4'. The mill told me that the edges were ready for edge gluing S4S or something like that. The edeges and faces do feel very smooth.

Can I edge glue the boards with the slight bowing. The bow occurs gradually along the length of the wood so the if laid on one side of the face, either two ends would be up or two ends would be down and the middle in the opposite direction.

Will alternating the growth ring patterns of the boards take out the bow and flatten out the final piece?

I'm gluing three pieces together to form a 16.5" x 4' larger board.

Thanks,

Darren

[Joe Chritz]

Wood will do what it will do.

Alternating the rings possibly could help offset some seasonal movement but I wouldn't count on it.

Depending on your design sometime a bow like that can be taken out when the top is fastened down. Clips hold it flat but still allow it to expand, or it is fastened into a dado in the center and is held flat but can expand both directions.

Joe

[Brian Jarnell]

I would say that you need to be lucky to expect bought boards to end up perfect.
Helps to have some kit if making things out of wood.

[Darren Vass]

80466

80467

Above are pics of the loudspeaker I am trying to build. The board on the floor is one of the birch 1x6x4' pieces. You can see the bow I'm talking about. I have it sitting concave on my basement floor to see if it will take in any moisture and possibly flatten.

Anyway, say if it stays as in the picture, could I still edge glue three pieces to form the needed 16 inch width for the speaker side panel. As you can see the panel eventually gets cut down quite abit to form the shape with only a small portion of the lower panel being full width. It is then held in place to the black boxes with some dry wall screws.

Thanks for your help.

Darren

[keith ouellette]

If the board is only bowed it won't be that big of a problem. You can force the board into position and it will stay in place as its clamped.

The problem is it may be twisted also. It would be pretty hard to align a twisted board.

[Sam Yerardi]

Darren,

Wood whether it is dry or not, will try to reach equilibrium with whatever environment it is placed in. For example, if you have a board dried to 5% and you take it into a room where the humidity is high (actually no matter what it is), it will start bring in moisture from its environment. Finishes, etc. slow the process but nothing short of putting the board in a perfectly dry vacuum will stop the moisture exchange. If the board has been dried, and it has now moved, it may have (I say may have) moved all it will move in that environment once it reaches equilibrium. If that's the case, then you could cut the boards accordingly and glue them together and they will probably stabilize. But as was pointed out in an earlier posting, wood will do what it wants to do. When you consider that the ancients split stone by driving in wooden wedges and then applying water to the wedges, you can appreciate the power of wood movement due to moisture.

[John Karas]

If the board is only bowed it won't be that big of a problem. You can force the board into position and it will stay in place as its clamped.

The problem is it may be twisted also. It would be pretty hard to align a twisted board.


Is there many different clamping systems in the market but this system is by far the best i do use this system & never look back. .

www.frontlineengineering.com.au (http://www.frontlineengineering.com.au)

[Brian Jarnell]

Is there many different clamping systems in the market but this system is by far the best i do use this system & never look back. .

www.frontlineengineering.com.au (http://www.frontlineengineering.com.au)

Ah yes,are they Australian?,I have seen there here,expensive but good.

Darren could join it up,then find a friendly joiner to put job through big sander.
I have done that with table tops.

[Tom Veatch]

...I've noticed up to a 1/8" bowing on a few of the boards. The boards are 1 x 6 x 4'.
...Will alternating the growth ring patterns of the boards take out the bow and flatten out the final piece?
...

As Keith said, 1/8" bow in a 4' board shouldn't be a problem. That's actually a pretty small curvature and should be easy to take out in the clamp up.

Your question about alternating the ring pattern implies that you're not concerned about matching up grain patterns. With that in mind, what I would do in your situation is edge glue them such that the concavity alternates, e.g. first board concave up, next board concave down, etc. That way, the internal stresses in the assembly will tend to balance each other.

[John Karas]

Ah yes,are they Australian?,I have seen there here,expensive but good.

Darren could join it up,then find a friendly joiner to put job through big sander.
I have done that with table tops.


Hi Brian yes are Australian.

Brian how do you know have you see them in U.S? is available there? if they are how much are selling for is nice to know how much are selling in U.S if is the same i think it worth a look you be surprised with the quality & how good they are.i got 4 of those clamps & never look back.


John

[Ron Dunn]

You must be more rich than me, John ... the small size was quoted to me this week at $300-something EACH (ie, not per-pair).

[Mikail Khan]

Try using cauls to get the edges lined up perfectly during glue up. I don't have a wide jointer so i have this problem all the time.

http://www.newwoodworker.com/cauls.html

Mikail

[Jules Dominguez]

Un-cured boards tend to "cup" (that is, bow across the grain) in an arc opposite the arc of the growth rings. The purpose of alternating the direction of the growth rings in adjacent boards is to minimize the total cup in a finished panel. The idea is that if the rings are alternated and the individual boards cup, it would produce a washboard effect, but less total cup of the finished panel.
Assuming the wood is cured and then planed flat before assembly, further cupping shouldn't occur, and I think most woodworkers consider it more important to match the grain of the boards for appearance than to worry about cupping which shouldn't occur anyway.
The direction of the growth rings doesn't have anything to do with bowing, which occurs in the long direction of the board.

[John Karas]

You must be more rich than me, John ... the small size was quoted to me this week at $300-something EACH (ie, not per-pair).

Hi Ron where have you seen this clamps who is selling them? is nice to know to compare prices I know is a bit expensive but is only one off investment & when you use them you never use anything else.makes them a good buy.When you said $300-something each is US Dollars? or Australian dollars?




John