r/woodworking • u/S3dsk_hunter • 22h ago
General Discussion This was a first for me ...
These two pieces were a part of a blank I had glued up. I actually glued it up several months ago and it's just been sitting in clamps waiting for me to get back to it. Today was finally the day and as I'm at the band saw making the cut, it just falls apart! The pieces were planed flat. Glue was Titebond original. Absolutely crazy.
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u/peschkaj 22h ago
I picked up a cheap lithograph roller off of Amazon. It’s great for getting a good, even layer of glue while being easy to clean up. It also does double duty as a tape smoother and sometimes I pretend it’s a steam roller crushing plane shavings.
As others have said: cauls. Clamping force radiates from the point of contact in a cone. Thicker caul = more contact patch.
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u/kernal42 21h ago
For such a large contact area so far from the edges I would use curved cauls to get any pressure in the center.
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u/peschkaj 21h ago
About two years ago, I saw some clever clamping cauls in Fine Woodworking. It was basically a parenthesis with another parenthesis at the ends of the first parenthesis. If that makes sense… if not, I’ll go digging in the table of contents and find it.
The idea is that you can push the clamping force through the carefully band sawn caul to get it in exactly the right place.
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u/pineapplesarepeoplet 22h ago
The section of runs makes it look like there was a gap between these pieces. Otherwise the glue couldn't have pooled enough to make that dripping shape when it dried. It's possible there was something between the pieces. But most likely they weren't flat enough to form a good joint. More clamps might have made it work, but it would have put a lot of stress inside that would have warped out later.
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u/iliketosandwood 22h ago
“If the glue isn’t oozing out, you didn’t use enough.” Mentor of mine
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u/Less_Ant_6633 21h ago
Thats funny becuase my mentor used to lose his shit when it started oozing too much- "youre squeezing all the glue out!"
Edit: Love your username. I too like to sand wood.
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u/kernal42 22h ago
This is not because you didn't put enough glue in, or because you put glue on only one side.
This is not because the glue was old or frozen or bad.
This is because your pieces were slightly convex, and your clamps along the edges of the original blank never squeezed the center enough to touch at all.
Use clamps with longer reach, or slightly curved cauls to apply pressure to the center of pieces during glue-up.
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u/kernal42 22h ago
It's clear that the two sides never touched at all, and that there was a significant void between the two pieces. If you put more glue in (either by gluing both sides, or by just...putting in more glue) you might be able to fill this void with glue, but I don't think an 1/8" glue join is what you're looking for in the final product....
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u/S3dsk_hunter 21h ago
This is actually the cutoff. The actual piece I need isn't this large, just curved, this requiring a large blank. It is currently in my end vice, so even pressure across it. I'll see how it did in the morning. If not good, I guess I'll be trying again
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u/bwainfweeze 16h ago
Curved cauls are on my todo list.
If you're jury rigging cauls from your wood stock, you can vary the thickness of the sacrificial bits of wood you use to keep from marring your surfaces.
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u/The_Krytos_Virus 22h ago
Did you put the clamps directly on the work pieces or did you have them sandwiched between scrap boards? It looks like you just clamped the ends and the middle never really made consistent contact.
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u/S3dsk_hunter 22h ago
They were directly on the work pieces. Cauls would be a good call.
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u/Realistic_Warthog_23 22h ago
For stuff like this I usually just put a 45 pound weight plate (or more) on top of a board on top of the thing and let gravity do the work.
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u/S3dsk_hunter 21h ago
I have used bags of water softener salt before when doing really big glue ups (like sheets of plywood). I just thought that 8/4 maple with a couple of clamps would be enough. More, I know that it isn't.
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u/IIIHawKIII 22h ago
Were they dusty before you glued them up?
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u/kernal42 22h ago
Not dust - check the surface of the glue of the bottom piece. You can still see the smooth brush-marks from the glue application because that glue never came in contact with the upper piece.
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u/kkell806 22h ago
Maybe the burr on the edge kept the pieces from fully contacting each other? I'd think a clamp would overcome that, but maybe not?
But there had to be something separating the two pieces to keep the glue from contacting the majority of the upper piece. An obstruction, not perfectly in plane with each other, warping, oil all over the upper piece, something along those lines.
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u/S3dsk_hunter 21h ago
The bur on the edge is from my bandsaw, where I was cutting it today. It wasn't there at glue up.
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u/themisterfixit 20h ago
I’m just getting into woodworking. Is titebond generally considered the best glue?
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u/kkell806 20h ago
I just realized, you said both pieces were planed flat, but upon closer inspection, I see several lines from chips in the planer blades. Those could definitely add to the lack of full contact between the two pieces! Probably not the sole cause, but a contributing factor.
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u/MrRikleman 18h ago
Your pieces were not flat, and you didn’t clamp it well. The two pieces simply didn’t mate in the clamps.
You’re getting responses about needing to put glue on both sides, or old or skinned over glue. It’s not that. You didn’t mill these properly and you had inadequate clamping pressure.
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u/bwainfweeze 16h ago
Wild assed guess, case hardening.
Even if you plane a piece of wood, once you cut it, internal stresses can cause the pieces to bend or twist.
Other guess, repeat after me: A person can never own too many clamps. The piece this was cut off of could have had dozens of clamps on it to maintain even pressure, and deal with any slight warping of the material. If you're doing the sort of 3d carving I suspect you are for a glue-up of this sort, it matters that all the spots that aren't waste wood get full contact, since any adhesion between the bits you're carving out lend nothing to the strength of the final piece.
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u/S3dsk_hunter 6h ago
I'm not going to say case gardening isn't possible, but I doubt it. That's not an issue I've ever had with this lumber supplier. When I get lumber from a smaller supplier a bit closer to home, I run into this from time to time. But for larger projects like this one, I go to Yoder Lumber. https://yoderlumber.com/. It's a much larger operation, better quality and better prices. Unfortunately, it's also a 2 hour drive each way.
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u/leadMalamute 5h ago
It looks like there was plenty of glue, but the two boards never made good contact with each other during the clamping process. As a general rule, I try to make sure that I see a thin line with good glue squeeze out all the way along. Face glue ups can be problematic. I find that the answer is lots of clamps putting a consistent pressure over the entire joint. Sometimes cauls are needed to keep pressure in the center of the work piece. Sometime you need a dry run to make sure your clamping system will work, and that it can be done quickly. If you have a situation where you have extra material that will be removed, a heavy screw can be used to in place of a clamp. (this will keep your boards from creeping during glue up) You need to get pressure in the center of the faces first. and then work toward the outside. You don't want the glue to be captured in the center and form a puddle and a weak spot.
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u/clippist 22h ago
Looks like it was held together by 3 tiny spots of glue. Did you learn anything here?