Serious warping/bending from CA glue

I have read a bit about CA glue as a finish but haven't come across this. I'm using some spalted hackberry which is pretty soft and porous for some scales. I used some of the thin (red bottle) hot stuff glue on both of the scales on the inside wall. After it dried, the scales were bent pretty harshly. I'm guessing this is from the glue setting and pulling. Can anyone offer some advice on how to fix this (presuming it can be fixed) and a possible better solution for this problem?

Attachment 131648
Attachment 131649

Cheers,
Jonah

Putting CA on the other sides would seem a logical thing to try.
Many applications where glue is used need something to balance the stresses.

Both sides is a good start. My experience has been not so good if they warp like that. Once they fully cure/dry, you might try to press them flat for a few days, but even that didn't work for me...I had to start over. Hope you can save them.

You could sand it back to bear wood, clamp the scales between two pieces of flat board or tile (I prefer the later), bring some water to boil, and pass the contraption back and forth over the steam heating the wood and letting it cool a bit. You could do this for a few minutes a day for a couple of days to see if it will help flatten them out. Then I would sand the backside w/ 50grit and attach a liner to help offset some of the stress. Those really soft porous woods when sanded thin for scales will warp from the heat of curing glue and epoxy sometimes.

As already said, be sure you treat both sides of your wood in exactly the same way. In bookbinding, you have to glue both sides of any paper or board, because it'll swell a little from the glue's moisture, then shrink as the glue dries and tightens. It's critical to make sure that all this happens equally on both sides of whatever, or your flat surface will warp in one or two or three dimensions and you'll end up with a really wanky looking book.

Thanks for the responses. I was pretty surprised when it started looking more like a pair of boomerangs instead of a set of scales. I'll try some of the suggestions and see how far I get.

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Originally Posted by roughkype

As already said, be sure you treat both sides of your wood in exactly the same way. In bookbinding, you have to glue both sides of any paper or board, because it'll swell a little from the glue's moisture, then shrink as the glue dries and tightens. It's critical to make sure that all this happens equally on both sides of whatever, or your flat surface will warp in one or two or three dimensions and you'll end up with a really wanky looking book.

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Cool, are you a bookbinder?
My mother is a master book binder specialized in restoring antiques.
It's from her that I know this. If she binds a book in leather cover, she also has to glue the insides of the cover, or the glue will pull so hard that the cover will warp like a bowl.

I gave the scales a few steam baths and had them pressed overnight with a 15 pound anvil. I'm quite surprised how much the scales flattened out. They aren't perfectly flat, but they are pretty close to it. I'm debating now if I should CA glue the other side of the scales or just soak them in polyurethane and call it a day. I don't know that the scales will be salvageable if they bend again.

Even if slightly curved,Perhaps doing a 3 pin configuration may be in order,just a thought.

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Originally Posted by pixelfixed

Even if slightly curved,Perhaps doing a 3 pin configuration may be in order,just a thought.

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A three pin set up is actually part of the original design. I'm going to do some more passes of steam/pressing the scales and see if I can get them any flatter. I'll post another picture once my phone is charged up.

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Originally Posted by Bruno

Cool, are you a bookbinder?
My mother is a master book binder specialized in restoring antiques.
It's from her that I know this. If she binds a book in leather cover, she also has to glue the insides of the cover, or the glue will pull so hard that the cover will warp like a bowl.

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Hi Bruno,

only a hobby-level bookbinder. Folks have asked me to repair old family bibles, and I wouldn't touch such valuable projects... those are for the masters like your mother.

To the original poster: do it right, use CA on the side that hasn't yet experienced it. Anything else will be a waste of all the time you have in this so far. Even with three pins, there will be unresolved, unbalanced forces in your scales that will, over time, distort them.

You've done nice work so far. Don't rush it now.

Is there a way to keep weight on the scales when the glue is setting in attempt to keep the shape? The only ways I can think of would glue the scales to the surface.

I'm not applying any pressure in the picture below and you can see there is a slight curve. When I apply pressure on where the pins will be, it the gap is almost entirely closed.

Attachment 131733
Attachment 131734

The glue will pull the scales closer to flat (and now, possibly beyond flat to bent in the opposite direction) as it sets up. You may need to steam/flatten them again... but at least you'll have cancelled the forces acting on only the first glued side. So don't worry about holding them flat while it sets up.

That's my advice, anyway.

Oh the joys of trial and error!

Thanks again to everyone that has contributed. I'll post the finished product at some point soon (hopefully).

I'd glue the other side as well, to fix it. Because you definitely don't want them to warp over time when you're already using them.
Seal them with CA all around, and let it rest for some time.

It's too late for this now but maybe a tip for next time - apply the coating while the scales are held together with double sided tape. When that side is dry, tape again and apply the coating to the other side. I'm assuming here that the tape is strong enough the withstand the buckling - in my experience it's pretty good.

I CA glued the other side and as some of you said, it caused a mild warp in the other direction. I'll do the same steam bath/weighing down method and try to get them straight again. I also plan on giving them a light sand. There are a few spots where the CA glue grabbed my glove and left some white patches.

I'm starting to wonder if any kind of liquid, not just finishing solution, will cause untreated wood to warp. I just got done rubbing down a scale with some acetone and it caused that to warp a bit as well. Anyone have thoughts on this?

Acetone might not have done anything if there wasn't already CA on one side. But heed what quite a few of us have written: with thin wood (or paper, or binder's board), make sure that if you give one side it some treatment, you give the opposite side the exact same treatment, no matter what the glue, solvent, whatever. This will matter both in the near term and the distant future.

With scales, it's a good assumption that the inner surfaces will experience greater humidity over their lifetimes than will the outer surfaces--so it's critical to pay the same attention there as to the sides you'll be admiring.

I unpinned a set of nice but warpy horn scales once and they sprung so far apart I've never been able to flatten them again. I think that someone must have waxed the outer faces but not the inner ones, thus dooming them.

http://straightrazorpalace.com/works...tml#post720223

I hold them in place to start :) work slow, use thin aplications until the first coats have "Set" the wood

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Originally Posted by roughkype

Acetone might not have done anything if there wasn't already CA on one side. But heed what quite a few of us have written: with thin wood (or paper, or binder's board), make sure that if you give one side it some treatment, you give the opposite side the exact same treatment, no matter what the glue, solvent, whatever. This will matter both in the near term and the distant future.

With scales, it's a good assumption that the inner surfaces will experience greater humidity over their lifetimes than will the outer surfaces--so it's critical to pay the same attention there as to the sides you'll be admiring.

I unpinned a set of nice but warpy horn scales once and they sprung so far apart I've never been able to flatten them again. I think that someone must have waxed the outer faces but not the inner ones, thus dooming them.

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Originally Posted by gssixgun

http://straightrazorpalace.com/works...tml#post720223

I hold them in place to start :) work slow, use thin aplications until the first coats have "Set" the wood

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That's actually the skeleton I was using for this. Great stuff!

I probably should have clarrified. I applied some acetone on a different set of scales that I had just finished sanding. I was really surprised that they started curling as well.

When I was reading the walkthroughs on CA glue finishes, I missed the part about needing to do the whole scale in one fell swoop. It's all a learning experience.

That's interesting that acetone swelled the bare scales, I didn't know it would do that. In my experience, mineral spirits do not swell wood. The acetone may have had some water in it, too--unless it was labeled 100% acetone and had been opened recently. Left open, acetone will absorb water from the air. And, since you're in Florida, I'm guessing that there's plenty of humidity to be absorbed.

Learning experiences are the best kind. Sounds like you're having fun. Watch for posts by Hirlau; he's somewhere in Florida and has done a lot of scale work too. Fun, nice guy.

Given that acetone is used as a drying agent, I'm assuming there was moisture in the wood and the acetone forced it out/displaced it. It definitely caused a pretty good bend. I was able to get some weight on it quickly so it didn't get too misshapen, though it isn't entirely flat anymore. All of this has been a great learning experience. It's been a pain at times, but I'm learning a lot of do's and don'ts. Good stuff all around.