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Forum topic by skidiot posted 781 days ago 1268 views 0 times favorited 22 replies Add to Favorites Watch
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skidiot

50 posts in 2242 days


781 days ago

Topic tags/keywords: question

I am trying to make a solid wood table top. It is made of six 5” wide boards. I did two, 3 board glue ups. these went together with no problems. The boards were all jointed perfectly, I didnt have to use any clamp pressure to get them to come together. I then tried to put the two 3 board units together. They seem to now have a convex bow in all 4 edges. I have tried to rejoint them with no success. There is no way to pull the bow out of a 15” wide piece of white oak. What have I done wrong, and is there a way to fix it. I hate wood working.

-- skidiot northern illinois


22 replies so far

View patron's profile (online now)

patron

12955 posts in 1938 days


#1 posted 781 days ago

lay a longer straight ply or solid wood up against the fence
(it needs to be parallel )
and move the whole thing over and rip the boards one side

if there is a concave in the other side
it will still ride true after the saw fence

then after both wider assemblies are straight on one side
take off the secondary fence
and rip them regular
with your new straight edge against the saw fence

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View waho6o9's profile

waho6o9

4744 posts in 1174 days


#2 posted 781 days ago

Maybe, alternate your pieces like this if you haven’t already done so, if I understand your situation correctly.

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patron

12955 posts in 1938 days


#3 posted 781 days ago

this is an exaggerated version of what i mean

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View PurpLev's profile

PurpLev

8476 posts in 2246 days


#4 posted 781 days ago

when you clamped the boards together – were all the clamps on the same side of the glue up? or did you alternate one clamp above, one clamp below ?

if all clamps are above (or all are below) then you can introduce a pulling action towards one direction which can trigger a bow in the final panel. you should alternate clamps.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Gerald Thompson's profile

Gerald Thompson

340 posts in 832 days


#5 posted 781 days ago

I use clamping cauls on all panel glue ups. They are easy to make and save a lot of time and frustration.
Googel Mike Henderson and look @ his pictorial.

-- Jerry

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skidiot

50 posts in 2242 days


#6 posted 781 days ago

Is it possible that the water in the glue made the middle of the boards swell up slightly creating the bowing? I am going to let them sit for a while and see what happens.

-- skidiot northern illinois

View waho6o9's profile

waho6o9

4744 posts in 1174 days


#7 posted 781 days ago

Maybe post a picture of your panel skidiot.

View Lee Barker's profile

Lee Barker

2163 posts in 1447 days


#8 posted 781 days ago

The original post is not real clear to me.

The procedure Patron so vividly shows is to remove hook.

You said “bow on all four edges.” Could you clarify that?

We’ll find out if cauls or opposing clamps have anything to do with the solution.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

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Howie

2656 posts in 1520 days


#9 posted 781 days ago

I would be highly suspicious of a high moisture content in the wood.
If it is hook like Lee says, then Patrons fix is the ticket I would think. These two guys know what they are talking about.

-- Life is good.

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skidiot

50 posts in 2242 days


#10 posted 781 days ago

Its actually the opposite of what Patron showed. The long edges are bowed out.

-- skidiot northern illinois

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Howie

2656 posts in 1520 days


#11 posted 781 days ago

Guess I’m like Lee,I’m not following when you say “long edges”.

-- Life is good.

View A Slice of Wood Workshop's profile

A Slice of Wood Workshop

886 posts in 1770 days


#12 posted 781 days ago

So it is leaning towards more a a circular shape?

-- Tim- http://www.asliceofwoodworkshop.com; Twitter-@asliceofwood; Facebook-http://www.facebook.com/asliceofwood

View patron's profile (online now)

patron

12955 posts in 1938 days


#13 posted 780 days ago

then fix a board to one edge
(with double tape or brads)
and run it thru the saw

sorry for the mis-read
in the middle of the night
thought i had read concave

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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skidiot

50 posts in 2242 days


#14 posted 780 days ago

Right. Its not very much about 1/16th but enough to make a visible gap.

-- skidiot northern illinois

View Lee Barker's profile

Lee Barker

2163 posts in 1447 days


#15 posted 780 days ago

So when you put the two pieces together, the edges you want to join, they touch at the center but are gapped at the ends.

The fix is to joint both edges straight. You say you tried that with “no success.” This suggests a jointer setup problem, yet the boards jointed fine individually.

Overclamping the first set of glueups didn’t happen.

Moisture is not a logical culprit.

It is a mystery. But solvable.

What actually happens when you attempt to joint them? How long is your jointer bed? How long are the glueups?

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

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