De-Gluing: Is it safe?

You can tell if I have to ask this...

I've got a wing in the jig with the trailing edge box under construction and the leading edge glued to the ribs. I'm holding off on gluing the spars down until I get the trailing edge box built and can put a final careful alignment in place.

I noticed last night that a couple of the ribs are slightly askew from 90 degrees.

The right thing to do is to break the CA glue joint, move the point where the rib meets the leading edge spar and then re-glue. It's a slight adjustment, prolly less than a 16th of an inch.

The question is: If I use CA debonder and dissolve the glue joint, what risk do I have that the reglued joint is not as strong as it should be due to residual debonder?

Or: Am I ahead to use a blade and cut the rib loose from the LE spar or to debond and reglue. Or just live with a minor incorrectness in a couple of ribs?

Debonding seems more elegant and less chance to inflict damage, but I worry about it weakening the resulting joint.

Cy

You could cut it loose with a razor blade, or, if you are going to use capstrips on the ribs, just forget about it.

I might be able to cut it loose with a blade, but I'd have to be careful.

The ribs in question are the very end ribs so I'm worried than less that perfect true alignment will affect the tips.

But yeah, if it was a rib in the middle of the wing, I'd prolly just cover it with the sheeting and be done.

I might get away with that in any event.

I'm still wondering if debonding a joint means you can't glue it back again (with CA) after the debonder evaborates or whatever it does.

Cy.

I think the problem you would have with debonder is that it would evaporate before it can solvate the adhesive. I agree with you that if you manage to get it dissolved that it should evaporate and not cause any future bonding problems.

I have used debonder to loosen CA joints and then reglued with CA and have had no problems doing that. However, I make it a habit to let the debonder dry completely, then I give the area a good cleaning with lacquer thinner and then let that dry completely, then reglue.

I have no idea if the thinner cleaning process is necessary, but it seemed like a good idea to me and I have not had any bad experiences with the process.

Hope this helps.

Bill Hodges
OTS Rulz!!

Did the same thing on both tip ribs when I was building the Legacy. Don't know how it happened but didn't notice it until I started building up the wing tips. Too late to fix the ribs, the spars and sheeting were already in place. I measured the angle, set my band saw table and cut the tips to match the ribs.

I've debonded and reglued joints. It worked OK. In one case, I removed a leading edge torque tube from a flap by putting the flap in a trough of nitromethane, the debonder of choice. All rib joints came off nicely. I reinstalled the LE, covered the flap with tissue, and flew it.

Thanks, guys.

I ended up using a combination of debonding and cutting through the soft joint with a blade. The debonder was very thin and softened the CA without fully melting it, so I eased the ribs off of the LE spar with a blade.

Everything is drying now and I will clean it all up, re-align the ribs, re-glue and press on.

Cy.

A friend of mine once said that an advantage of building with Ambroid was that all it took to correct a glue joint was some acetone. He kept some in a bottle with a needle applicator.

It's an imperfect world.

I've had a similar situation a couple of times, and it was hidden in the final wing by a) the leading and trailing edge planking, and b) the capstrips (which I DID get straight). I don't think it really harmed the structure, and was invisible in the finished wing.

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"Do not wish to be anything but who you are, and try to be that perfectly." -Saint Frances De Sales