Panel Glue Up, what do I need to watch for?

[Bill McCarthy]

I'm making a couple of boxes to store some of my chisel sets in. I figure that this will give me some practice for making drawers latter on. I'm using left over off cuts from 2x4s, nothing fancy. I'm resawing the 2x4s to 1/2" thick, then gluing them together to make the top and bottom of the boxes.

So I can begin good habits, what do I need to pay attention to when gluing up panels? The one that I can think of, is to keep the grain all going in the same direction, so I won't have problems latter when planing. What else? Is there a general "maximum" width of each board (I'm thinking about expansion)? Along those lines, is there a suggested maximum width of a panel? Is there some kind of configuration of the boards to mitigate future cupping? What do you guys know about that I haven't even considered?

I'm not ready yet, but I do have future plans for making some kitchen cabinets.

[Jim Koepke]

Making sure your edges are square will help save a bit of time after gluing.

You may also want to make some cauls to clamp across the panels being glued so the clamps for the edge gluing do not deform your panel.

jtk

[steven c newman]

cauls.jpg
Something like this...
clamped up.jpg
Use a lot of clamps, and alternate which face they are on.

[Bill McCarthy]

cauls.jpg
Something like this...
clamped up.jpg
Use a lot of clamps, and alternate which face they are on.

Steven, is there a reason you arrange the stock vertically? I never would have considered doing that.

[Leo Graywacz]

While it's being glued up and in the clamps put a straight edge over the width of the glue up. If there's a cup it'll stay that way. Flatten it out while the glue is wet and things will be better.

[steven c newman]

One very good reason...space. Did not have the room to lay it down. One bonus....leg vise made a nice third hand. Easier to access both faces, in case I needed the cauls on either side.

[David Eisenhauer]

For me, it seems that the thinner the panel, the more it pays to ensure that the edges are truly square. If the edges are not square, the panels tend to cup or bow when clamped even though the panel appeared to be flat when not in the clamps. Cauls are important to prevent cupping or a general bowing of the entire assembled panel during clamping and I find that watching my clamp pressure also helps to prevent bowing. Clamp tight enough to get some glue squeeze and stop rather than clamp as tight as you can. I don't think there is any panel width restriction, just have to plan for panel expansion in accordance to the width of the panel. Certainly no issues with panel width in typical kitchen cabinetry. If you have not used cauls before, go ahead and try it out as there are some positioning and juggling things to figure out when using cauls while glueing/clamping and the clock is running. This is definitely a time to do the dry run before the real event.

[Robert Engel]

1. Grain direction
2. Grain matching (forget about alternating rings, etc.)
3. Edges square (joint alternating faces to create complimentary >'s and cancel any error.
4. Do not clamp too tight. A common error with thin panels.
5. Do a dry fit first!

[Pat Barry]

For me, it seems that the thinner the panel, the more it pays to ensure that the edges are truly square. If the edges are not square, the panels tend to cup or bow when clamped even though the panel appeared to be flat when not in the clamps. Cauls are important to prevent cupping or a general bowing of the entire assembled panel during clamping and I find that watching my clamp pressure also helps to prevent bowing. Clamp tight enough to get some glue squeeze and stop rather than clamp as tight as you can. I don't think there is any panel width restriction, just have to plan for panel expansion in accordance to the width of the panel. Certainly no issues with panel width in typical kitchen cabinetry. If you have not used cauls before, go ahead and try it out as there are some positioning and juggling things to figure out when using cauls while glueing/clamping and the clock is running. This is definitely a time to do the dry run before the real event.

This is counter-intuitive, at least to me right now. I would have thought it to be much more important for thicker boards to be perfectly square on edges before glue-up. This purely a geometry problem the way I see it.

[Leo Graywacz]

If you are using a jointer to square up your edges just make sure that you put one side against the fence and the other board has its side away from the fence. Then if your fence is a bit out of square the complementary angles will add up to 90 anyway. Since I've learned this trick my glue ups have been much flatter and true.

[Simon MacGowen]

1. Grain direction
2. Grain matching (forget about alternating rings, etc.)
3. Edges square (joint alternating faces to create complimentary >'s and cancel any error.
4. Do not clamp too tight. A common error with thin panels.
5. Do a dry fit first!

+1 and plus this:

Get rid of the glue squeeze=outs (with whatever method you find effective) BEFORE they are cured. Don't listen to those who tell you to scrape off the hardened glue squeeze-outs UNLESS they are tiny ones or you don't care about the underside. Or unless you want to learn the hard way.

Simon

[Leo Graywacz]

Yup, once the glue is hard on the squeeze out it's best to sand it off. Scraping it off may pull wood with it.

[Simon MacGowen]

This is counter-intuitive, at least to me right now. I would have thought it to be much more important for thicker boards to be perfectly square on edges before glue-up. This purely a geometry problem the way I see it.

I am with you on that point...but why take any risk? Start with edges that are darned square or at complementary angles so they are 90 degrees. Don't be a lousy woodworker at the stock prep. stage though I have seen many who are, while trying to be a good one after that -- with mixed results, of course.

Simon

[steven c newman]

test fit.JPG
Test fit before a glue up...the only "clamp" used..
board lock.JPG
Boards are just 3/4" pine.
glue up.JPG
Couple of clamps and a bead of Elmer's.....nothing to it....

[Pat Barry]

+1 and plus this:

Get rid of the glue squeeze=outs (with whatever method you find effective) BEFORE they are cured. Don't listen to those who tell you to scrape off the hardened glue squeeze-outs UNLESS they are tiny ones or you don't care about the underside. Or unless you want to learn the hard way.

Simon

Agreed - get it before its hard. Note - it is easier to remove squeeze out after the glue dries enough to be more of a gel / rubbery, before it gets hard. I don't like to wipe off wet glue because then you smear it into the wood and make it difficult to remove - not important if you are painting anyway, but really important if you are dyeing or staining on open pore woods.