help with large glue up

[gardnesd]

I'm going to glue up my lvl workbench top over the next couple of days. Will glue in 3 seperate sections, re-plane, add biscuits and glue all 3 together. I want to have as little flattening to do once the top is totally glued. I have a bunch of bessey k clamps. Can I use a caul? HOw do i make a caul? where does it go?

My wife is allowing me to do the section glue ups on the large granite countertop in the kitchen. I'm assuming this is dead flat???

How do I glue these pieces up as flat as possible??

[Vic]

I made my cauls using the bandsaw and jointer just using eight foot 2x6s. Hardwood cauls would be better, but these do the trick. I made four. You just want the high point at the center. I found the center, then measured 1/4 down on each end and drew a line from the center to the ends. I cut to that line on the bandsaw, then cleaned up the cut on the jointer. I think I'm gonna go back and make the taper more severe, as I'm not sure this much puts enough force in the center.

[Guest Trace]

Gluing on the granite is NOT a great idea. The granite is very flat, certainly flat enough for the glue up. But, having been in the business of Marble and Granite fabrication, I would caution you to at least do the following: 1. put a really heavy coat of stone sealer for granite on the top, 2. place a layer or two of waxed paper, laped half way, 90 degrees to the length of the boards you are gluing. The glue, if it gets into the crevices and voids, will be very difficult to remove. Good luck.

[gardnesd]

Thanks Trace. After reading your post I may nix the idea altogether. However that leaves me in a serious bind. I do not have an flat surface for a glue up. The old saying, "you need a workbench to make a workbench"??? Is the garage floor flat enough???

Gluing on the granite is NOT a great idea. The granite is very flat, certainly flat enough for the glue up. But, having been in the business of Marble and Granite fabrication, I would caution you to at least do the following: 1. put a really heavy coat of stone sealer for granite on the top, 2. place a layer or two of waxed paper, laped half way, 90 degrees to the length of the boards you are gluing. The glue, if it gets into the crevices and voids, will be very difficult to remove. Good luck.

[gardnesd]

BTW, how would I go about getting a large scrap of granite???

Thanks Trace. After reading your post I may nix the idea altogether. However that leaves me in a serious bind. I do not have an flat surface for a glue up. The old saying, "you need a workbench to make a workbench"??? Is the garage floor flat enough???

[Beechwood Chip]

The way I see it, there are two kinds of cauls.

There are straight cauls which are used for lining up pieces being glued (and to keep clamps from marring softer woods), and there are are cambered cauls which are used to put pressure all along the length of the caul.

What I'd do in your case is to make some flat cauls by jointing some 2x4s so that they have flat edges. They need to be long enough to span the width or your table , with some overhang on both sides. You need enough of them to put two (top and bottom) every 18". Cover the jointed edge with packing table or wax paper to keep glue from sticking.

Use the cauls to keep the panels in alignment during glue-up. Use clamps between the top and bottom cauls, but don't put enough pressure to bend the cauls. This is assuming that the individual pieces are already true so you don't need to bend them into alignment.

[Guest Mahoganus]

Thanks Trace. After reading your post I may nix the idea altogether. However that leaves me in a serious bind. I do not have an flat surface for a glue up. The old saying, "you need a workbench to make a workbench"??? Is the garage floor flat enough???

Yeah the garage floor is flat enough,, thats what I used.

[Onboard]

Yeah the garage floor is flat enough,, thats what I used.

Mahoganus, is that a Bridgeport mill in the background?

[NYHump]

Mahoganus, is that a Bridgeport mill in the background?

[Guest Mahoganus]

Mahoganus, is that a Bridgeport mill in the background?

Yes Sir My new wood working machine.

[Guest Mahoganus]

Mahoganus, is that a Bridgeport mill in the background?

LOL, That's what I was going to ask.........

Looks like another machinist in the group!

BTW, Great looking bench.....

Welcome

Thank You! Yes indeed a machinist I am.

[gardnesd]

Don't have a jointer. I do have a jointer plane.

[PaulMarcel]

If you have concerns about your garage floor being flat enough, check it with a 4' straight edge and winding sticks (any two pieces of sock can work for make-shift winding sticks). Mine is also pretty flat, in the middle, but near the edges, there's a lot of disparity.

[Lawrence Brown]

Yes Sir My new wood working machine.

Dang. I miss having access to a bridgeport. My little Grizzly combo just doesn't cut it for a lot of things

[Lawrence Brown]

And like Paul-Marcel says, check your floor with straightedges and so on. Most garage floors are not level either by design (for drainage), or just because they weren't designed as reference surfaces, so very little attention was given to them. They will be overall sort-of flat, but there may be dips and bumps and so on.

If you're floor isn't flat, you can always do like I do sometimes and make a temporary glue-up surface on top of it. Take some known flat boards (joint them or whatever) and lay them down where you need to support your glue-up. For the bench you might just be able to get by with one on each end. Add more if necessary. Have them go across the glue joint, which I'm assuming would be the short way on the bench. Now you can put blocks or shims under the ends of the support boards and level them. Make sure they are parallel in all directions and don't forget to put wax paper or something on them so they don't stick to your bench top. Finally, be careful not to knock them over when you're putting the piece down (Get help with that). I've done that, and it's annoying to have to re-level everything right in the middle of a glue-up.