panel glue up ?

[Brian Runau]

Last time I glued up a couple pieces for some tall drawer faces @ 10" I have some cupping across the face. I am sure the faces were flat and edges were 90 before glue up. I cut it down to @ 7-1/2 and then had enough thickness left to joint a face flat, but could to much pressure on the clamps cause this?

Thanks.

Brian

[Mitch schiffer]

I'm not sure about the clamping pressure but if all the clamps were on one side I could see that possibly happening. I have had similar issues when I didn't let wood acclimate to my shop environment prior to surfacing. You can also alternate the growth rings to help prevent cuping.

[Ron Citerone]

Did you glue it up thicker than your finished size then plane to finished size?

Also, Alternating the faces that ride on the jointer fence can equalize even the slightest error in fence squareness.

If you had to clamp it really tight to get it to pull tight I would think that could cause it to cup.

Cupping from drying would look different than a gle edge angle problem.

[Ron Citerone]

Did you glue it up thicker than your finished size then plane to finished size?

Also, Alternating the faces that ride on the jointer fence can equalize even the slightest error in fence squareness.

If you had to clamp it really tight to get it to pull tight I would think that could cause it to cup.

Cupping from drying would look different than a gllue edge angle problem.

[Brian Runau]

I'm not sure about the clamping pressure but if all the clamps were on one side I could see that possibly happening. I have had similar issues when I didn't let wood acclimate to my shop environment prior to surfacing. You can also alternate the growth rings to help prevent cuping.

Wood was acclimated and it rested between steps. Bessey clamps, alternate orientation every other one?

[Brian Runau]

Did you glue it up thicker than your finished size then plane to finished size?

Also, Alternating the faces that ride on the jointer fence can equalize even the slightest error in fence squareness.

If you had to clamp it really tight to get it to pull tight I would think that could cause it to cup.

Cupping from drying would look different than a gle edge angle problem.

Yes thicker at glue up rejoined and planed to final after. Didn't seem that tight, but maybe...thanks brian

[Mel Fulks]

Did you glue it up thicker than your finished size then plane to finished size?

Also, Alternating the faces that ride on the jointer fence can equalize even the slightest error in fence squareness.

If you had to clamp it really tight to get it to pull tight I would think that could cause it to cup.

Cupping from drying would look different than a gle edge angle problem.

YEP, and when you are planing take more wood off the side that has the “ hill” in the middle. Lot of times you can immediately see the
other side move too. For critical stuff some will do ‘face and plane” leaving material thick, then stop and lean the pieces against something and let them
sit over night. But most of time ….there is NO time. Never put a panel on a surface ,while the other side is open to the air, Unless you are
trying to “fix” cupped piece. Alternating the
faces on jointer ,and marking them make for flat panels, too many spend time squaring a jointer face that is gonna immediately flop to its favorite angle.

[Mitch schiffer]

Wood was acclimated and it rested between steps. Bessey clamps, alternate orientation every other one?

Even with parallel clamps i still alternate every other clamp from top and bottom. I also try to alternate the direction the end grain radius for lack of a better term (think smile up smile down when looking at the end grain)

[Brian Runau]

YEP, and when you are planing take more wood off the side that has the “ hill” in the middle. Lot of times you can immediately see the
other side move too. For critical stuff some will do ‘face and plane” leaving material thick, then stop and lean the pieces against something and let them
sit over night. But most of time ….there is NO time. Never put a panel on a surface ,while the other side is open to the air, Unless you are
trying to “fix” cupped piece. Alternating the
faces on jointer ,and marking them make for flat panels, too many spend time squaring a jointer face that is gonna immediately flop to its favorite angle.

I don't like lay them flat, I do use spacers so air can circulate, and they sit overnight after face jointing and light plane pass, then next day flatten again and then plane. Thanks brian

[Jim Dwight]

That isn't a big glueup. I am surprised at the result. Are you sure the edges were at right angles to the faces? That could cause cupping. The wood drying out after glueup could too. I do not alternate growth rings, I orient the boards for appearance, and I often make much wider glueups. My two most recent projects are a couple coffee tables with cherry tops that are over 20 inches wide. Three boards in one and four in the other. Wood was planned to final thickness before glueup with cutting to final size and sanding the only remaining steps before finish. No problem with either. These are just my most recent projects, I did a 10 foot long dining table the same way last year. A large chest of drawers was also completed last year. No issues with any of these either.

I almost never use my jointer to prepare the edge of boards for glueup. For shorter ones, I just rip them on the table saw. For longer ones or if I'm having an issue, I use my track saw. It does a great job of giving me straight edges at right angle to the face. I know this is not traditional but it works for me.

[Brian Runau]

That isn't a big glueup. I am surprised at the result. Are you sure the edges were at right angles to the faces? That could cause cupping. The wood drying out after glueup could too. I do not alternate growth rings, I orient the boards for appearance, and I often make much wider glueups. My two most recent projects are a couple coffee tables with cherry tops that are over 20 inches wide. Three boards in one and four in the other. Wood was planned to final thickness before glueup with cutting to final size and sanding the only remaining steps before finish. No problem with either. These are just my most recent projects, I did a 10 foot long dining table the same way last year. A large chest of drawers was also completed last year. No issues with any of these either.

I almost never use my jointer to prepare the edge of boards for glueup. For shorter ones, I just rip them on the table saw. For longer ones or if I'm having an issue, I use my track saw. It does a great job of giving me straight edges at right angle to the face. I know this is not traditional but it works for me.

These are drawer faces for a dresser @ 7.25 x 39. Thanks brian

[William Hodge]

What was the moisture content of the wood, and what is the humidity level in the shop?

[Ron Selzer]

Wood was acclimated and it rested between steps. Bessey clamps, alternate orientation every other one?

yes, really easy to end up with a cup if you don't alternate
Ron

[Kevin Jenness]

It's hard to know from your description whether the problem is inaccurate joints, clamping technique or change in moisture content. A dry run in clamps using a straightedge would tell you a lot. If you are using a jointer, alternate the consecutive faces against the fence, otherwise ensure that the edges are consistently at 90*. You can throw off an accurately cut joint with unbalanced clamping - setting a straightedge across the glued assembly will help avoid that, as will alternating clamps on either face. If the surfaces between the joints are cupping (curving across the grain) it is from moisture loss or uptake so you need to allow the stock more time to acclimate or make the humidity in the shop more consistent. That sort of cupping is not caused by clamps.

[Tom Bender]

Too much clamping pressure could have caused some crush in the joint, messing up your careful edge prep.

[Jim Becker]

Too much pressure and not using cauls to keep it flat can sometimes cause that issue.

[Brian Runau]

Finished milling the pieces for the top and glue up is complete. Better this time in terms of flatness across the piece. Paid more attention to clamp pressure and used two clamps in the opposite orientation. thanks for the all the suggestions. Brian

471854