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I just edge glued two halves of a syp table top and they weren't as straight as I milled them. I clamped them together which straightened them, but I think I may have "squeezed all the glue out." I've always heard this was something to be careful of, but have never seen the outcome of doing so. This top is comprised of 16 - 1 3/8" X 3" boards of which I glued 8 at a time, then glued the two halves together. Anybody else out there ever squeezed all the glue out?
 

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I just edge glued two halves of a syp table top and they weren't as straight as I milled them. I clamped them together which straightened them, but I think I may have "squeezed all the glue out." I've always heard this was something to be careful of, but have never seen the outcome of doing so. This top is comprised of 16 - 1 3/8" X 3" boards of which I glued 8 at a time, then glued the two halves together. Anybody else out there ever squeezed all the glue out?
I have talked to people from the glue companies themselves and the do not think that it is possible to squeeze all of the glue out. Their point is that what works best is a very thin layer of glue anyway and woodworkers generally put way more than that in a joint to start with so squeezing a bunch out actually strengthens the joint.
However, you can still put too much pressure on the wood and make it do weird things, like bow or warp strictly from the excess pressure. When I do glue ups I try to make them a bit over sized so that after gluing I can make final adjustments through planing or sanding if need be and not go under size.
 

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I do segmented bowls and when I first started doing them I overclamped and while I do NOT believe I squeezed ALL the glue out, and certainly 99% of the joints held, I would on rare occasions get joint failure that I have always attributed to having squeezed TOO MUCH of the glue out.

When you have 2 very hard woods and you sand them very well, I believe it IS possible to squeeze out too much glue and get a joint failure.

On the other hand, I've seen joint failure where the wood failed and the glue didn't, so I I'm not 100% convinced.
 

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I think that I have over tightened clamps and squeezed too much glue out. For example the computer desk on which I am now working had a glue seam that has opened up. I think that over tightening caused too much of a loss of glue. I have just been lazy and not repaired this problem. In fact, I am not even sure how to go about making that repair.

George
 

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I just edge glued two halves of a syp table top and they weren't as straight as I milled them. I clamped them together which straightened them, but I think I may have "squeezed all the glue out." I've always heard this was something to be careful of, but have never seen the outcome of doing so. This top is comprised of 16 - 1 3/8" X 3" boards of which I glued 8 at a time, then glued the two halves together. Anybody else out there ever squeezed all the glue out?
Pieces of a multi piece glue up should fit without forcing their mating edges with extreme clamping pressure. There will be areas of that glue up that mate without drama, and areas that have to be brought together because of gaps and misalignment of various causes.

Wood is compressible, and under clamping pressure may take a 'compressed' state that releases after the clamps are removed. This could lead to joint failure. In the gluing procedure described in the OP, eight pieces at a time may present an alignment challenge even with cauls. The clamping effort to bring all those edges together could be too extreme. After sections are together, edge mating would tell how well those clamped sections fit to each other. Its at that time I would do whatever jointing to those edges to make for a relatively stress free fit.








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Cabinetman, I agree. I think pine at 1 3/8" is still flexible enough to glue and clamp straight. However, after 8 of them are glued into one piece they are no longer flexible enough to work without re-milling. I just need a glue with a longer working time. Thanks guys for your input.
 

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also doing a dry fit with dayum near the pressure you plan on using,will show the obvious problems ahead of time, mark the boards and joint,sand or t.s the problem,very tedious but pays off huge when your ready to to start surfacing the top as a whole peace, good luck
 

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There was an article in Fine woodworking mag a couple years ago about glue squeeze out. I think the final word was that NO, you cannot starve a joint by over clamping....
 

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i think if you apply glue to both surfaces, spread well, so that the glue "seals" the grain pores, and you show squeeze out all around, your success rate is very high. i've found joint failure stems more from running a bead of glue and clamping. the wood seems to need that absorption time before on the surface before clamping. my $0.02.
 

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Marttain

I had occasions in the cabinet shop where I had to pull glue joints apart and I found that it is very very difficult to starve a well prepared joint. A poorly prepared joint is another subject. Too little glue, a line of glue not spread out and boards that don't meet are not going to glue well.
If you run a bead of glue the length of the board and then use a spreader, a brush or your thumb to spread the glue evenly across the width of the board making sure the entire surface is "wet" you should get a good joint without worrying about clamp pressure. Clamp till a little "squeeze" shows and stop there. If there is a gap between the boards you need to resaw, plane, sand or whittle the edges until they meet.
You cannot make fine woodwork unless the wood is straight and square.
 

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Yellow glue would be hard to squeeze the glue out of, it requires very little to make a good joint. Where you need to worry is when you are using epoxy. You can put too much pressure on an epoxied joint and starve it.
 

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Yellow glue would be hard to squeeze the glue out of, it requires very little to make a good joint. Where you need to worry is when you are using epoxy. You can put too much pressure on an epoxied joint and starve it.

That's true. Epoxy needs a certain amount of thickness, even if it's a small amount. That's why it's good for joints that have gaps.








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Maybe, for those experiencing glue joint failure, a refresher study of what the jointer is for and how to properly prepare surfaces to be joined would be in order. If you are using a hand plane or hand held power planer for joining edges I would suggest that your skills be up to the task, I'm not sure mine would be and that's why I use a jointer. I would not consider edges prepared with only the table saw to be glue-ready.

When edge joining wide glue ups, I'll always (almost) run the work pieces through the jointer. Also I am careful to get the glue evenly spread and fully covered on both faces to be joined. I probably have a tendency to use more clamp pressure than most. I've never had a joint fail that was prepared in this manner using mostly Titebond or Elmers wood glue. I've never edge glued using epoxy.

The photo shows the power feeder set up on the jointer which works well if you have a lot of pieces to run and also keeps your hands away from the cutter head. I've left the blade guard on but keeping it open with a pencil to keep away from the power feeder.

Bret

Bret
 

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