Any Problem Wetting White Glue?

[Signet]

As you all know, wetting a white glue joint on wood will soften the white glue and allow the joint to be disassembled (standard white glue, not the waterproof kind). This fact has saved me a number of times.

On a section of the hull I am building, I have 1.5x4mm walnut strips laminated to 1/64" veneer, and will later be adding 0.6mm walnut to the opposite side. During gluing of the first two layers, while holding them against bulkhead sections which are to be removed later, it appeared to dry well, but when the clamps were removed, areas no longer supported/attached to the bulkheads tend to bow out. Maybe glue contraction or expansion or something, I don't know.

I know I can put a bend in wood by wetting it and clamping it in the desired position. And I know I can soften a joint with white glue, as explained above. My question is: If I dampen the strips and veneer, which are glued together with Elmer's wood glue, which will soften the glue and the wood, and clamp them in the proper position, when dry will the bond lose any or all of its strength? Or, will it stay strong, just hopefully in a more appropriate position? I hope it's just the second one, as I just tried it on my model, but I thought I'd ask anyhow.

Here is a pic of the warped areas:


After wetting the areas that appear warped (turning some of the surface white glue white again), I clamped it in the correct position, and hope that overnight it will stay in place, AND be strong enough:


I think I will make some sort if removable and temporary ties from one side of the hull to the other, in this area, so that while gluing other items (like the inside planking), it may better stay in place.

 

[Bryian]

I always use Isopropyl alcohol to soften up white wood glue.

 

[Signet]

I always use Isopropyl alcohol to soften up white wood glue.

Does that work differently than water?

After wetting down the outer surfaces in the warped areas, I clamped straight pieces of scrap to the bulkheads:

After drying overnight, the wetted and straightened areas were quite straight and seemed very strong as well.

Once inside planking is added, as long as I keep the panels in the correct location during gluing and drying, I think they will be okay.

 

[Philski]

Try your mixtures on scrap first. That way, you'll not harm the model. You can try different ratios to see what effects they each present.

 

[gk the builder]

I use ammonia to soften warped pieces first , let dry after clamping , then glue up

 

[Signet]

Thanks, everyone, for your comments.

While my fix of wetting and clamping showed the walls in the correct position the next day, left unclamped since then, they have opened up a bit since then. Not to where they were, but not as tight either. I'll probably rig some type of fixture to keep them in alignment as I add additional materials. In the meantime, I'm trying to keep clamps on them at the bulkheads, especially overnight, to try to maintain the correct position. Still no indication that it weakened the glue joints, though.

 

[Philski]

I was going to ask - were the joints clamped? You mention using clamps. I'm guess the parts need to stay clamped until FULLY dried. I've used PVA's extensively. But never diluted. When fully cured, the wood is weaker than the glue typically.

 

[Signet]

I was going to ask - were the joints clamped? You mention using clamps. I'm guess the parts need to stay clamped until FULLY dried. I've used PVA's extensively. But never diluted. When fully cured, the wood is weaker than the glue typically.

Yes, the joints were clamped. I think the difference in material thicknesses tries to bend the compound material. When clamped, it prevents it from bending, but there is still a built-in stress wanting to bend. When the clamps are removed it bends then. I'll just have to keep them clamped in place when adding other materials, vertical supports, etc., which will eventually keep it all in place. I hope.

Previously, I laminated two thin pieces of wood together, with the grain going at opposite directions, to strengthen it. In fact, this was the trucks on the 1:20 gun models I made. I put 1 pound weights on them, which held them very flat. The next day, I found that despite the weights, the difference in grain and moisture of the glue had severely warped the piece, and it was unusable. To correct this, I had to clamp new pieces using screw clamps to be sure they didn't move.

Funny things happen to wood during gluing & drying.