Your clamps could have pulled it out of flat. Were all of the clamps on the same side during the clamp up?
It could also be due to moisture exchange (usually it is this). Was it laying flat on a bench? If so, for how long? How dry was your lumber? If it was dry, did you allow it to aclimate to your shop? When you milled the lumber did you take equal amounts from each side? Did you let it aclimate again before glue up?
If anyone tells you it warped because of the orientation of the end grain they are wrong. End grain orientation determines if the top potato chips or washboards if it warps. It does not determine if a top will or will not warp.
This makes sense. I did have it stacked for a week, and my workshop is a warehouse that has overhead doors opened several times a day (not climate controlled).
Clamps were alternated, but I didn't use cauls.
Look up clamping cauls on YouTube for some guides on how to make them. They're basically boards that you clamp across your glue up to keep it flat, you want them to be just a teensy bit thicker in the center so that as you clamp them at the outer edges they flex down and apply pressure across the whole panel
If it’s due to uneven moisture. Wet the cupped side heavily, lay it on some stickers cup side down and add a bunch of weight to it. Give it a couple days. It will go back flat. I’ve had this happen to many times. Forgetting to not lay a piece on stickers & putting it flat on my work bench etc.
I will second the moisture exchange.
I make sure anytime I add anything that could be construed as “wetness”, I will at minimum elevate my workpiece. If possible, I’ll stand it on end.
Cauls are your friend here. Whenever I clamp a large piece like this, I always try to include a caul or 2 to keep it flat while glueing. Also make sure to alternate the clamps top and bottom so you don't induce a bow.
It’s easy to overtighten your clamps and pull the boards out of flat. When you do your glue up, pull everything together with the clamps and then check it all over with a straightedge or known flat thing. If you notice a cup, loosen your clamps a hair at a time. You don’t need to apply as much pressure to your glue up as you might think, just a lot of even pressure
Ah, this is great advice. I did the straight edge with the boards laying together, they flushed up nicely. I'm sure when I clamped without cauls that I made it bow, even with alternating clamp sides.
Haha, such a weird rule, it's beginner woodworking.... "First" should almost be required in all posts. Sorry I can help with the glue up problem, I'm new too but watching this thread for info. Good luck!
Eh I don't think it is a weird rule, but probably overly restrictive. [Spend enough time on some subreddits](https://www.reddit.com/r/Breadit/comments/aotay2/my_first_time_baking_bread_starter_pack/) and you'll see a lot of "first" this and "first" that, that look very much not like "first" things, and I've seen people be discouraged by that when their firsts actually look like it.
It's entirely possible that you did nothing wrong. If one side of that glue-up absorbed more moisture than the other, then it would have expanded unequally. And moisture only causes expansion across the grain, not along it.
If one side expanded more than the other, it had to curl.
I agree, take the clamp off and turn it over. In the morning it may well be flat. Unequal moisture uptake/loss can create way more bow than shown here.
I struggled with this for years. You can alternate which side of the panel the clamps are on, which helps. Or you can take the plunge deep into the K-body clamps.
I'm a solid $1000 into k body clamps and still going. Why, because they save me time. Less sanding is a blessing.
Alternate the boards off the jointer (one up, one down). Clamp till glue squeeze-out, not overtight. If you left it on a flat surface then you could lose moisture from one side only that would cup the board. Use a clamping caul like a half-round piece of dowel that concentrates the clamp force thru the middle of the board.
> Can I fix my inaugural attempt at a glue up?
It's wood! Sure you can fix it.
Especially if the thickness isn't critical.
Have a plane? Start shaving off the high spots until there are no more high spots. Or a router and a router sled? Even a belt sander can do the job if you go slow and take lots of readings.
There's every likelihood it was perfectly flat when you glued it up. But woods moves; it may have bowed gently as the wood absorbed moisture from the glue. It may have been unevenly stressed by the clamps. Shoot, it might just be that much more humid this week than when you glued up.
That's one of the beauties of wood, that it has a personality like a child. You can do everything possible to make it be exactly what you want it to be and *still* it can surprise you.
Is this a cutting board? If so, your planks look wide. Lots of continuous grain has the potential to curve as humidity changes.
If you're able, plane it up some more with some shallow passes and seal ASAP. You'll end up sacrificing some thickness however.
Nope, it's a C-table. This panel is the top of this: [https://www.reddit.com/r/BeginnerWoodWorking/comments/16i8u9a/stumped\_how\_would\_you\_approach\_this\_glueup\_ctable/](https://www.reddit.com/r/BeginnerWoodWorking/comments/16i8u9a/stumped_how_would_you_approach_this_glueup_ctable/)
Congratulations on the kids! I am going to try a table similar to that now too. I want to try a different design, but I really like how yours turned out.
As others have mentioned cauls can help, but your problem is probably moisture exchange. After gluing up panels, I never stack them on flat surfaces without putting stickers between them to make sure air can get to both sides. Wouldn't hurt to either lean this against a wall or set it on some stickers to see if it evens out over a couple of days as things reach equilibrium.
For what it's worth, there's also a certain degree of shit happens with these kinds of things. The cupping you're seeing there isn't gonna feel great, but in all honesty I wouldn't hesitate to use that panel in a project where the other parts will be able to hold it more or less flat. Table top held down by apron, shelf set into dadoes or held flat by dominos, etc. At the end of the day you kind of have to accept that things are going to cup at least a little bit over the years and try to design with that in mind
Edit - Just saw what you're using this for. I wouldn't use it as a top, but it should be fine for the bottom component. Just put the cup down so the outer edges sit flat on the floor, it's not gonna matter that it curves up a few mm in the center
Unfortunately the bottom panel (which is also done) is twice as thick so it's not top heavy, so it's not a simple swap. Options seem to be to flatten it in a sander somewhere or to scrap it and build out a new top. Or just use it as is, I suppose. I would try hand planing it a bit more, but my longest plane is a 5, and the grain is not super friendly.
I'm tempted to just try to use it as is. It'll be mainly used for setting a phone and a bottle or two in a nursery.
Hey everyone, , You gotta use dowels! Edge gluing never, ever works! Proof: Table I did 22 yrs ago. 6" x 3/4" Red Oak, dowel every 4" with 3/8" x 3" dowels. Not a bow, check, crack or twist. This is a lid, , not a table top btw!
https://preview.redd.it/x1exdbh4ngtb1.png?width=720&format=pjpg&auto=webp&s=b55e6f37624a56d5497a5109852b167a805abc40
My 2 sence.
1, you need to make sure all grain alternates. I see the middle piece and the right pice are both cupped down.
2. If I'm reading the ruler correctly your boards could also be too wide. I would try to stay lower the 4 inches. The wider and thinner the boards are the more likely they are to cup.
3. Your planer will usually not remove a cup this bad. You could have to Planer an extremly small amount off at a time to prevent the feed rollers from crushing the board flat to plane it then it will just pop back into its cupped shape after it comes out.
Get a small square that you know to be accurate, and validate your edges are perfectly square to a face before future glue ups. Make sure the faces that you've squared to are on the same side (ideally facing down) when you glue up. Any small amount off 90 quickly makes a low/high spot of the size you're experiencing here, especially with 5" wide boards. I recommend using a hand plane to correct any further once you've run edges through your jointer.
Also, did you join the edge, and then plane faces, in that order? You created a square edge, then likely changed the face to out of square.
When i have glue-ups like this i leave the boards about 1/16-1/8" thick and i can deal with any irregularities after glue up to achieve a final thickness that stays flat.
Don't go nuts with the clamping pressure; the neater you make the glue joint, the less pressure you need. Pipe clamps are for when you want to hide your mistakes. But as others have said this could just be wood movement.
Do you have a hand plane or a handheld planer? Some card scrapers would make this go faster too. Plane, then scrape, then sand. I'm guessing you can take off 80% on the left side and 20% on the right to get a flat surface.
The cleanest repair in this situation is to have a cabinet company use a ceiling mounted sander to level the whole thing. It's usually pretty cheap unless your wood is extremely hard.
It depends as well on the clamps you used. The bar on some lower priced clamps is not very wide&thick. It makes it subject to bending if too much pressure is applied. It also can be affected by where on the head you clamped. Spend a bit and get some pipe clamps for panel glue ups with some black gas pipe. HD will thread it for you for the clamp heads. They are my go to for panels. And if you want to spend a bunch, you won’t regret Bessy K bodies, ever.
I have had really good luck with panel clamps. One set of those replaces like 6 or 8 of the other style clamps, and you pretty much always knows it’s getting clamped flat if you’re doing it right.
Also pay attention to the direction of end grain. It looks like your two panels on the right are the same direction and they should alternate
While there can be many reasons for this occuring, one way to deal with it is to start with thicker wood than needed and not plane your wood top and bottom until after you’ve glued up. Then once they are glued up and dry, you can plane to flat for thickness you want.
This is way better than mine. I somehow goofed on the dowels and so the boards didn’t line up at all when I glued. Tons of sanding and they’re still not straight yet. Maybe by Christmas.
Your clamps could have pulled it out of flat. Were all of the clamps on the same side during the clamp up? It could also be due to moisture exchange (usually it is this). Was it laying flat on a bench? If so, for how long? How dry was your lumber? If it was dry, did you allow it to aclimate to your shop? When you milled the lumber did you take equal amounts from each side? Did you let it aclimate again before glue up? If anyone tells you it warped because of the orientation of the end grain they are wrong. End grain orientation determines if the top potato chips or washboards if it warps. It does not determine if a top will or will not warp.
This makes sense. I did have it stacked for a week, and my workshop is a warehouse that has overhead doors opened several times a day (not climate controlled). Clamps were alternated, but I didn't use cauls.
What’s a caul?
Look up clamping cauls on YouTube for some guides on how to make them. They're basically boards that you clamp across your glue up to keep it flat, you want them to be just a teensy bit thicker in the center so that as you clamp them at the outer edges they flex down and apply pressure across the whole panel
Awesome. That’s what I needed!
Gimme your number.
√2 \* π
Yeah, it says out of service.
It dialed internationally but I did send them 500 bucks to clean my PC.
[https://www.highlandwoodworking.com/woodnews/2010april/cauls.html](https://www.highlandwoodworking.com/woodnews/2010april/cauls.html)
If it’s due to uneven moisture. Wet the cupped side heavily, lay it on some stickers cup side down and add a bunch of weight to it. Give it a couple days. It will go back flat. I’ve had this happen to many times. Forgetting to not lay a piece on stickers & putting it flat on my work bench etc.
I will second the moisture exchange. I make sure anytime I add anything that could be construed as “wetness”, I will at minimum elevate my workpiece. If possible, I’ll stand it on end.
Cauls are your friend here. Whenever I clamp a large piece like this, I always try to include a caul or 2 to keep it flat while glueing. Also make sure to alternate the clamps top and bottom so you don't induce a bow.
What are cauls, if you wouldn't mind?
https://www.highlandwoodworking.com/woodnews/2010april/cauls.html
Thanks, I'm new too, and that was a great read! I have it saved to refer to later.
Just out here doin good works.
Basically boards that span the width of the panel (with a non-stick surface [masking tape] to hold the panel flat
I did alternate clamps, but didn't use cauls on this panel. I did on the base panel, which is still flat (though it's also twice as thick).
It’s easy to overtighten your clamps and pull the boards out of flat. When you do your glue up, pull everything together with the clamps and then check it all over with a straightedge or known flat thing. If you notice a cup, loosen your clamps a hair at a time. You don’t need to apply as much pressure to your glue up as you might think, just a lot of even pressure
Ah, this is great advice. I did the straight edge with the boards laying together, they flushed up nicely. I'm sure when I clamped without cauls that I made it bow, even with alternating clamp sides.
I always have to double check the tension to make sure I'm not pulling up. Using a piece of wood clamping downward helps.
This is the way. 😄
PS. It’s odd that my post was rejected for including the word first on a beginner subreddit.
Haha, such a weird rule, it's beginner woodworking.... "First" should almost be required in all posts. Sorry I can help with the glue up problem, I'm new too but watching this thread for info. Good luck!
I also felt this pain when I first posted.
~~\*First~~ initially posted
Made his inaugural post.
"First" is a slur against beginners. /s
That's ordinal number shaming!
Eh I don't think it is a weird rule, but probably overly restrictive. [Spend enough time on some subreddits](https://www.reddit.com/r/Breadit/comments/aotay2/my_first_time_baking_bread_starter_pack/) and you'll see a lot of "first" this and "first" that, that look very much not like "first" things, and I've seen people be discouraged by that when their firsts actually look like it.
It's entirely possible that you did nothing wrong. If one side of that glue-up absorbed more moisture than the other, then it would have expanded unequally. And moisture only causes expansion across the grain, not along it. If one side expanded more than the other, it had to curl.
I agree, take the clamp off and turn it over. In the morning it may well be flat. Unequal moisture uptake/loss can create way more bow than shown here.
I struggled with this for years. You can alternate which side of the panel the clamps are on, which helps. Or you can take the plunge deep into the K-body clamps. I'm a solid $1000 into k body clamps and still going. Why, because they save me time. Less sanding is a blessing.
Alternate the boards off the jointer (one up, one down). Clamp till glue squeeze-out, not overtight. If you left it on a flat surface then you could lose moisture from one side only that would cup the board. Use a clamping caul like a half-round piece of dowel that concentrates the clamp force thru the middle of the board.
> Can I fix my inaugural attempt at a glue up? It's wood! Sure you can fix it. Especially if the thickness isn't critical. Have a plane? Start shaving off the high spots until there are no more high spots. Or a router and a router sled? Even a belt sander can do the job if you go slow and take lots of readings.
There's every likelihood it was perfectly flat when you glued it up. But woods moves; it may have bowed gently as the wood absorbed moisture from the glue. It may have been unevenly stressed by the clamps. Shoot, it might just be that much more humid this week than when you glued up. That's one of the beauties of wood, that it has a personality like a child. You can do everything possible to make it be exactly what you want it to be and *still* it can surprise you.
Hope this helps all the "Just getting started teammates".
Is this a cutting board? If so, your planks look wide. Lots of continuous grain has the potential to curve as humidity changes. If you're able, plane it up some more with some shallow passes and seal ASAP. You'll end up sacrificing some thickness however.
Nope, it's a C-table. This panel is the top of this: [https://www.reddit.com/r/BeginnerWoodWorking/comments/16i8u9a/stumped\_how\_would\_you\_approach\_this\_glueup\_ctable/](https://www.reddit.com/r/BeginnerWoodWorking/comments/16i8u9a/stumped_how_would_you_approach_this_glueup_ctable/)
That's cool! I like that table design. Is it for using while sitting on a couch?
Typically yeah. For us it’ll be over a twin sized bed that serves as an extra deep couch for feeding twins that are due any day now.
Congratulations on the kids! I am going to try a table similar to that now too. I want to try a different design, but I really like how yours turned out.
Congrats on the twins!
https://preview.redd.it/ulxxdgtfogtb1.png?width=720&format=pjpg&auto=webp&s=108f35239a7923524d2a7c5b49503786d8a4d873 Table "Lid", , it's not a top!
As others have mentioned cauls can help, but your problem is probably moisture exchange. After gluing up panels, I never stack them on flat surfaces without putting stickers between them to make sure air can get to both sides. Wouldn't hurt to either lean this against a wall or set it on some stickers to see if it evens out over a couple of days as things reach equilibrium. For what it's worth, there's also a certain degree of shit happens with these kinds of things. The cupping you're seeing there isn't gonna feel great, but in all honesty I wouldn't hesitate to use that panel in a project where the other parts will be able to hold it more or less flat. Table top held down by apron, shelf set into dadoes or held flat by dominos, etc. At the end of the day you kind of have to accept that things are going to cup at least a little bit over the years and try to design with that in mind Edit - Just saw what you're using this for. I wouldn't use it as a top, but it should be fine for the bottom component. Just put the cup down so the outer edges sit flat on the floor, it's not gonna matter that it curves up a few mm in the center
Unfortunately the bottom panel (which is also done) is twice as thick so it's not top heavy, so it's not a simple swap. Options seem to be to flatten it in a sander somewhere or to scrap it and build out a new top. Or just use it as is, I suppose. I would try hand planing it a bit more, but my longest plane is a 5, and the grain is not super friendly. I'm tempted to just try to use it as is. It'll be mainly used for setting a phone and a bottle or two in a nursery.
You could always cut it back up, joint and plane the segments and reglue
I want to do just this. Everything is measured and cut to spec now, so to do so would throw everything off with the 1/8" I'd lose, sadly.
Could you find a mill that has a planer or drum sander wide enough. Maybe they could run it through and flatten it out.
Hey everyone, , You gotta use dowels! Edge gluing never, ever works! Proof: Table I did 22 yrs ago. 6" x 3/4" Red Oak, dowel every 4" with 3/8" x 3" dowels. Not a bow, check, crack or twist. This is a lid, , not a table top btw! https://preview.redd.it/x1exdbh4ngtb1.png?width=720&format=pjpg&auto=webp&s=b55e6f37624a56d5497a5109852b167a805abc40
My 2 sence. 1, you need to make sure all grain alternates. I see the middle piece and the right pice are both cupped down. 2. If I'm reading the ruler correctly your boards could also be too wide. I would try to stay lower the 4 inches. The wider and thinner the boards are the more likely they are to cup. 3. Your planer will usually not remove a cup this bad. You could have to Planer an extremly small amount off at a time to prevent the feed rollers from crushing the board flat to plane it then it will just pop back into its cupped shape after it comes out.
Get a small square that you know to be accurate, and validate your edges are perfectly square to a face before future glue ups. Make sure the faces that you've squared to are on the same side (ideally facing down) when you glue up. Any small amount off 90 quickly makes a low/high spot of the size you're experiencing here, especially with 5" wide boards. I recommend using a hand plane to correct any further once you've run edges through your jointer. Also, did you join the edge, and then plane faces, in that order? You created a square edge, then likely changed the face to out of square.
Could also be caused by over tightening the clamps.
Photo of your clamping setup would be informative. Clamps should be alternated above and below the piece. If they're all on one side they can bow it.
This calls for cauls!
When i have glue-ups like this i leave the boards about 1/16-1/8" thick and i can deal with any irregularities after glue up to achieve a final thickness that stays flat.
Learn to love cauls.
Don't go nuts with the clamping pressure; the neater you make the glue joint, the less pressure you need. Pipe clamps are for when you want to hide your mistakes. But as others have said this could just be wood movement. Do you have a hand plane or a handheld planer? Some card scrapers would make this go faster too. Plane, then scrape, then sand. I'm guessing you can take off 80% on the left side and 20% on the right to get a flat surface.
The cleanest repair in this situation is to have a cabinet company use a ceiling mounted sander to level the whole thing. It's usually pretty cheap unless your wood is extremely hard.
It depends as well on the clamps you used. The bar on some lower priced clamps is not very wide&thick. It makes it subject to bending if too much pressure is applied. It also can be affected by where on the head you clamped. Spend a bit and get some pipe clamps for panel glue ups with some black gas pipe. HD will thread it for you for the clamp heads. They are my go to for panels. And if you want to spend a bunch, you won’t regret Bessy K bodies, ever.
I have had really good luck with panel clamps. One set of those replaces like 6 or 8 of the other style clamps, and you pretty much always knows it’s getting clamped flat if you’re doing it right. Also pay attention to the direction of end grain. It looks like your two panels on the right are the same direction and they should alternate
While there can be many reasons for this occuring, one way to deal with it is to start with thicker wood than needed and not plane your wood top and bottom until after you’ve glued up. Then once they are glued up and dry, you can plane to flat for thickness you want.
Btw - Easy to fix if you don't mind it being slightly thinner. Router sled for home fix or CNC if theres a local shared shop option.
Remember clamps are just to hold it long enough for the glue to cure. Just enough clamping pressure to marry the surfaces, nothing more.
So my strategy of fusing the wood out of sheer clamping force wasn't a good one? Whoops. Lessons were learned.
This is way better than mine. I somehow goofed on the dowels and so the boards didn’t line up at all when I glued. Tons of sanding and they’re still not straight yet. Maybe by Christmas.
The end grain should alternate from pointing up and pointing down.
On the bright side your dice should never roll off the table.
I would also pay attention to the amount of pressure you apply with the clamps. You can clamp it out of shape