GLUE CHOICE

I used gap filling CA with no problems. I can imagine a Polyurethane glue like Pro-bond or Gorilla Glue will work as well.

| READING SOME OF THE POSTS I SEE SOME USE GLUES OTHER THAN | EPOXY FOR JOINING THE WING. I HAVE ALWAYS HAD A BIG MESS | WHEN USING EPOXY. WHAT SAY YOU ABOUT OTHER CHOICES OR | SHOULD I STAY WITH EPOXY FOR JOINING THE WING ON MY NEW 40 | SIZE ARF. (NOT A HARD CORE BUILDER)

On the left side of your keyboard, you will find a `Caps Lock' key. Please press it once :)

Epoxy is a good bet. It's very strong. It's also a bit heavier than some other glues, but this not a place that you really want to skimp on strength.

If you're not familiar with glues, I'd suggest following the directions and using epoxy. Yes, there are other glues that would work, but they may not be as strong, or may not be strong enough unless used properly. Epoxy is pretty forgiving ...

As for the big mess, putting down wax paper (or newspaper in a pinch) can help make the cleanup much simpler.

Epoxy is the best gap filling adhesive you can use. Because of the difficult nature of clamping the wings together when gluing and how critical this joint is, epoxy is the product of choice. Use a slower set epoxy such as 30 min or more in order to let the compound to penetrate the wood fibers before it sets up. Even though 30 minute epoxy sets up in 30ish minutes, the joint will not reach maximum strength for approx 24 hours and I would wait to handle it at least overnight.

The aliphatic resign glues tend to be more brittle but can be as strong as epoxy as long as the joint is tight and has no gaps.

Also, it is not a bad idea to use fiberglass cloth and thinned epoxy or CA wrapped around the wing joint for added insurance. A split wing will ruin your day.

Finally, you need to look at the wing mounting method to determine how you approach this subject. If you use rubber bands, there is more pressure on the joint than if you use 4 wing bolts (provided that the wing fits properly in the saddle).

Jim

I have never been able to avoid the mess, but it can be made lighter by adding micro-balloons. I use the white (glass) ones, but anything that thickens the epoxy will work. The result is lighter, and doesn't run out of the joint as much.

I only add enough to thicken the epoxy "somewhat". In other places, I add them until the mix is stiff and white, but not for joining wings.

Note: When you sand glass micro-balloons, please wear a dust mask. They're cheap, and lungs are not.

-- Mike Norton

Thanks for the responses. Looks like I should stay with epoxy and I will. Now I know what that key is for.

You don't need gap filling glue for wings. You need to make sure the spars touch, you can use CA or aliphatic to glue the joint, be sure to have a good brace that covers at least one side of the spars, across the wing joint. Covering the entire rib is a waste of glue, just glue on and around the spars. I have used aliphatic glue with good success on firwalls, CA is not fuel proof so don't use that. However with a lot of use the aliphatic will crack and crase, though it didn't let go till a minor crash occured so I have gone back to epoxy for firewalls.