Glue up 099 question: how to keep two pieces from bending or cupping up in middle?

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Forum topic by nicole72 posted 10-16-2011 12:40 AM 1100 views 0 times favorited 8 replies Add to Favorites Watch
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23 posts in 1838 days

10-16-2011 12:40 AM

Topic tags/keywords: question

Hi y’all, I am new to the forum and have a question regarding how you glue up two pieces of wood without having them bend or cup in the middle? I have been making cutting boards for gifts and got the whole glue up a bunch of strips at one time thing down, but in trying something new with end grain boards I was supposed to glue up eight strips at a time and then glue the three pieces together…..well I am using pipe clamps and bar clamps and cannot figure out how to put even two together let alone all three without them bending up in the middle once they are tightened…..any advice, constructive criticism or comments welcome! Thank you! Nicole

-- Nicole

8 replies so far

View MsDebbieP's profile


18615 posts in 3579 days

#1 posted 10-16-2011 12:41 AM

someone will have the quick answer for you .. but in the meantime, check out the LumberJocks’ End Grain Cutting Board Class by DeGoose

-- ~ Debbie, Canada (

View lilredweldingrod's profile


2495 posts in 2525 days

#2 posted 10-16-2011 01:10 AM

Nicole, I had a similar problem and I covered my clamp bars with duct tape to prevent glue cleanup later. I clamped the one side just snug with the boards touching the taped areas, I then put the same number of clamps on the other side and snugged them up with the boards just touching the taped areas, too. I then used cauls to be sure every thing stayed flat as I tightened the clamps the rest of the way.

I have found that pipe clamps and the smaller F style clamps will bow and that will automatically pull every thing out of whack. I have since bought quality clamps with substantial bars that bow very little if at all. I hope this helps. If not please get back to us and I’m sure someone with more experience than me will wade in on your problem.

Also if you over clamp the wood, it just forces the glue out and the joint becomes weak.

Best wishes, Rand

View Sawkerf's profile


1730 posts in 2487 days

#3 posted 10-16-2011 02:52 AM

A couple of suggestions -

1. Make sure that your pieces are square. If they aren’t, they will try to slide as you tighten the clamps.
2. Don’t overdo the clamping pressure. Tighten them just enough to get some squeezeout, then stop.

-- Adversity doesn't build reveals it.

View ShaneA's profile


6417 posts in 2017 days

#4 posted 10-16-2011 03:33 AM

Cauls clamped in about 3 places along the top of the board, then your usual clamping process along the sides. As mentioned, not too tight.

View yrob's profile


340 posts in 3071 days

#5 posted 10-16-2011 04:11 AM

two clamps below, one clamp above, spreading the pressure with cauls. Not too much pressure. Most importantly, make sure your edges are perfectly jointed or book matched. When you check them by standing one board on another you should not be able to see any light between them.

-- Yves

View JuniorJoiner's profile


463 posts in 2859 days

#6 posted 10-16-2011 04:56 AM

use thick battens on both sides between the clamps and the workpiece. make the battens out of softwood, and ensure the battens are properly squared up. I cover my battens with packing tape so they don’t stick to the work.
apply the glue to the workpiece evenly with a brush, not just in a gob, as that can make things move.

you could use alignment dowels to help more, but the battens alone will do it.

-- Junior -Quality is never an accident-it is the reward for the effort involved.

View nicole72's profile


23 posts in 1838 days

#7 posted 10-16-2011 05:14 AM

Whhhoooohoooo! Thank you so much everybody for replying! Number one, I didn’t have the edges square from the glue up in the three sections, and then I figured out to put a 1×2 one the ends with c clamps after I used the two clamps on top and one on bottom and it doesn’t presently look bowed at all ! Now morning could be another story, as I usually learn first by what not to do! I am so thankful for everybody taking time out to reply for such a simple question and I sure hope you’re around because I am confident I am gonna have a whole lot more questions! Thanks again! Nicole

-- Nicole

View maljr1980's profile


171 posts in 1875 days

#8 posted 10-16-2011 07:27 AM

alternate clamps under/over/under your workpiece

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