Who uses cauls for glue ups? Necessary?

[Alan Tolchinsky]

Hi All,

Sometimes I have trouble keeping a panel flat when clamping. I've used cauls but find them hard to clamp up and awkward in use. Do you find using them necessary and do you have any suggestions to make using them easier? Alan in Md.

[Donnie Raines]

I have used cauls...but not always(in fact..rarely). My thinking is that if you took the time to mill the lumber properly, your edges of your top-to-be are flush and you do not over tighten the clamps(and allow air flow around the boards while cureing) your in buisness.

I do, however, use cauls for the goofy glue ups that require even clamp pressure and there is simply not enough surface area to get clamps alone on them. I use cauls for small lamination projects, too.

Time and place for everything I guess.

[Steve Clardy]

I just use clamps on bottom and top. If it starts to bow from the bottom clamps, I put clamps topside also.
Steve

[Chris Padilla]

Depends on the situation as you might surmise, Alan! :)

I had to glue some wide edge-banding on a thick shelf once and the edge was an arc. I simply used the leftover piece I had cut the arc from as a caul to apply even pressure all along the arc. Worked like a charm.

People often like to alternate their clamps above and below the tabletop (for example) but if you have good square clamps like Besseys AND your edges are clean 90s, I don't find it necessary.

Sometimes if I need to clamp deep into a board that is impossible to reach with ordinary clamps, I'll make a caul that is tapered to the middle of the caul from both ends. As an example and an exaggeration, think of a roofline where two roofs meet...they come to a point and then taper of. The caul would be that shape but with just slight tapers. When you clamp with this caul, it will put more pressure at the point (peak of the roofline if you will) than at the ends. Of course, the caul is upside-down from the roofline example.

So, it depends! :)

[Hal Flynt]

I made some cauls out of red oak that I use when I don't have enough clamps. I hand planed the ends to create a slight (1/16") crown in the middle so that when I clamp on the ends the middle gets pressure too.

I too find that it's sometimes easier to use cauls to keep edge joints from squirming as the clamps are tightened than not using them.

To make it easier, try having the cauls longer than the work and using spring clips or those one handed clamps on each end to position the cauls where you want them and hold them in place while you put the clamps in place.

[Alan Turner]

If I am edge gluing up a panel or table top, here is what I do. I have some nice, straight mahogany, that is 1/4" wider than the distance form the bench to the bar of my Bessy's. About 2" I suppose. I use packing tape on the edges so the glue does not stick. Set 2 of them on the bench, put the panels to be glued on top of them, crosswise, and then slide the bessy's under them, at 12" increments. I usually have the panel or table top overwide, so don't use cauls as such as the edges will be trimmed anyway. The boards keep the bending bar of the bessy from deflecting the wood panel upward. I have 4 more of these boards as well, and sometimes, if the panels are sliding around a bit from the glue and not wanting to stay even, esp. on 1/4" drawer bottom stock, for example, then I will put one on top, one on bottom, and clamp at the seams, to hold them together during glue up. They are taped also. Pretty quick and easy. These guys live in the rafters above my bench, and are used often. One pair is also my winding sticks.
Alan

[Alan Tolchinsky]

Thanks guys. I'm going to start using cauls more on my bigger glue ups. I do alternate board faces on my jointer to compensate for it not being perfectly square. The ideas presented here have been a great help. Since I'm milling a lot of 5/4 and 4/4 red oak, I will have plenty left over for cauls. Now back to the basement to work on the oak stairs. I'm getting there. Thanks again. Alan in Md.