Using Cauls with glue up

Re: Using Cauls with glue up

John in NM

I either do C or tighten the caul clamps first, then the bar clamps, then loosen the cauls and re-snug the bars, then retighten the cauls.

Re: Using Cauls with glue up

Don Stephan

In the photo, the back clamps are off the panel, which will tend to lift the middle of the cauls off the panel.

Change your procedure

Bill Tindall, E.Tn.

1. Yellow glue has greater creep resistance. Use it.

2. In hundreds, probably thousands, of joints I have never used a caul. Not necessary.

3. I can get perfect joint alignment if I glue 2, or no more than 3, boards at a time. Clamps can be removed in 30 min at 70 degrees and less than 10% moisture content lumber. Hence, it is not an onerous task to glue up a 5 board panel one joint at a time.

4. Alternate clamps top and bottom. It would take me a minute to glue up one of your joints. Lay boards on half the clamps plus 1. Apply glue to one surface. Rub this edge against the mate. Check that the mate got mostly covered with glue. Start applying clamp pressure in the middle and work to ends while aligning joint. Modest clamp pressure at this point. When all the bottom clamps are just snug and the joint is perfect, add the top clamps staggered between the bottom clamps.

4a. Learn to apply glue so there is a hint of squeeze out. If there is optimum glue it will aid alignment. Boards will not be sliding about.

5. When all is well and the clamps are snug, tighten them to final clamp pressure alternating the clamps tightened.

Re: Using Cauls with glue up

Joe in a Cleveland suburb

I had just put a couple clamps/cauls on doing a dry run. I haven't glued up any yet.

Re: Change your procedure

E Phillip Smith

Bill's technique works. I've used it may times and consistently get good panels.

Re: Change your procedure

Barry Irby

I agree with Bill. Do it that way.

Let me add that a big part of it is in stock prep. If your boards are straight and flat with square edges, this method will be fairly easy. Or at least as easy as it gets.

Let me also admit that I have tried lots of things, including cauls. I have a set of curved cauls I made out of hardwood. I have all-thread rods in the ends and can use deep well sockets to tighten them. I also have a set of the parallel clamps that have clamps in the ends that do both jobs at the same time. I have played with both of these and they are no substitute for good stock prep.

Let me also encourage you to take the time and effort it takes to do this well. If you get the alignment nearly perfect you can get a panel nearly full thickness. If you get them misaligned by a 1/16" (terrible) you will lose about an 1/8" in leveling both sides.

Re-emphasizing glue application

Bill Tindall, E.Tn.

Too much glue makes alignment difficult. An optimum amount provides a quick tack of the joint that resists the joint skidding out of alignment as clamps are tightened. The goal is to tack the joint with the initial clamp snugging, not lubricate it with a thick layer of glue. As the clamps are tightened from center to edges the joint is coaxed into alignment with the fingers of the hand that is not tightening the clamps. You want the center alignment to stay put during this process. It won't if there is a thick layer of glue yet to be squeezed out.

I have a slotted top glue bottle (most small sizes of glue come in such a bottle). I can lay down a thin layer of glue direct from the bottle by angling the bottle tip on the board edge. I lay down two stripes for a 13/16" edge. When I rub this edge against the mate the glue smears on both surfaces for nominally +/-80% coverage. The technique is to push the edges together, then lift the front board to smear glue perpendicular to the board surface. The lifting spreads glue across the stripes I laid down and onto the surfaces where glue was not initially applied.

My son-in-lay picked up the technique in just a try or two, so it is not hard to accomplish. Once you believe edge gluing is trivial it will soon be.

Thanks all for the advice

Re: Change your procedure

Joe in a Cleveland suburb

I used this procedure last night on one of the panels and it worked out well.

On to the next panels.

Thanks.