In reading the posts regarding CA v. Epoxy everyone stated that using a 30 minute epoxy to join the two wings halves was a must.

I was instructed by the guru at the my LHS that a Med gap filling CA (that he provided to me) would be more than sufficient in connecting my wings on my Sig Kadet LT-40. I followed his advice, should I be worried??

Personally I would be worried!!! Just understand I have no proof whats so ever to back up that fear.

I can tell you what I'd do since this is cheaper then a new plane

Go to the LHS and get some fiberglass cloth 1/2-1 oz and about 3-4 inches wide. also get some 30min epoxy and a couple cheap paint brushes. Now remove aileron servo and linkage from wing.
where wing halves meet measure back 1-1/2-2" on either side and remove covering. next apply light coat of epoxy to bare balsa take fiberglass cloth and wrap around wing start at underside trailing edge of wing make slits in fiberglass for torque rods to go through. apply light coat of epoxy between layers use 3-5 layers depending on weight of cloth purchased. Let dry completely sand and using dremal or xacto knife remove enough material around torque to allow ailerons to move without binding.

next use monokote trim coating to cover fiberglass joint (its adhesive backed so you won't have to iron it on)

reinstall aileron servo and linkage making sure with aileron servo in neutral position ailerons are even with trailing edge of wing.

Fortunately, I have not finished building the plan and it is still uncovered w/no electronics.

Referring you your advice about the fiberglass cloth, I installed fiberglass cloth in accordance with the instructions. I wonder if this is why he feels it will be sufficient. However, at no point was 30 minute epoxy used.

The think that gets me is that the individual who made the recommendation has built many plains, is well respected and actually has designed and mass produced his own planes.

Thanks for the advice Chrashem, I think as a precaution I will follow it.

I agree with Crashem,have never used ca to join wings was taught that was a no no,but last weekend did see wings break in half while plane was doing square loops,neat trick, bet he wished he had glassed his wing,was his first plane and he didn't do a good job joining the wings.

xavier,

I lot of "advice" people give you (including my own) is simply an opinion most likly based on what someone taught them. I learned to build when CA was new and not as widly used. (Titebond was recommend) I wasn't trying to worry you I simply like to be cautious especially if I spent a lot of times making the plane.

To be on the safe side you could just use more fiberglass to compensate for a possible weaker glue joint. Just remember don't go crazy since this will add weight.

good luck

I think you're saying that you did fiberglass the wing halves together, but you used medium CA instead of epoxy.

There is no point worrying. Just make a test joint and find out. Now is a better time than when you're 100 feet in the air. Take two pieces of balsa, butt them together. Glass them together with medium CA exactly as you did for your model. When it's dry, really try to tear it apart (be ruthless, your plane is at stake, not your reputation). If you can get the fiberglass off the balsa, then yes, you should worry. If all you can get apart is little tiny bits of balsa, then go fly without worry, and for sure don't worry about a bunch of folks on the forums!

I can tell you that if you do this test with epoxy, the fiberglass, epoxy and wood will join into an incredibly tough but flexible unit that is all but indestructable. If your CA joint is not close to this, I'd use epoxy next time.

I have built a few artf kits and the manual allways tells me to join the wings with 30 - 1 hour epoxy resin, and lucky for me the wings have never come apart even after putting them nose first into the ground.

Hi Xavier after seeing your second post about glassing the center with CA,I change my opion about your plane.I've used the same method of wrapping the center w/glass then soaking the glass w/ ca,I cover my fingers w/ wax paper and rub the ca in, gives a fast and smooth finish. I've never had any problems,other than I don't use this method anymore the reaction of that much ca on me was bad,and the ca joint isn't as flexable as epoxy,your guru is probably right,just a different method.

Everyone,

Just my 2 cents worth here.
Any CA or epoxy is stronger than the wood that it bonds if a good, thorough job is done. F/G cloth around the joint is an added plus.
I have had planes with plug in wings retained with other means than glue, and no problems there. What give this joint it's real strenghth is the wing joiner-ply/alum tube/ect.
Judges?


Jetts

.....I think that the thin C A "wicks" into the wood. I think it makes very strong joints IF the pieces fit together very well. I think the medium and thick C A's work well if the pieces don't fit together perfectly enough to use the thin C A. But I don't think that the medium or thick C A 's "wick" into the wood very much, and thus the joint is not as strong. I would describe them as "second choice" to the thin C A....................I prefer to use epoxy to actually join wing halves. It provides the time necessary to make measurements and confirm that the two panels are properly aligned..............There is a new glue, (new to me anyway) called gorilla glue. It looks like Ambroid. It is at the hardware store. It was developed in Europe in the furniture industry. This is what I like about it: 1) non-toxic , 2) completely sandable, 3) expands as it dries, very handy when sheeting wings as a tiny fillet is formed around every rib at the point the sheeting is attached, and 4) supposedly has the strength of epoxy..........Having said all of that, I still use tried and true epoxy at the center section..............Another glue that I like is Pica's Gluit. This is a white glue that looks like Elmers glue. It is perfect for butt joining sheets together to form wing skins. Why? Because it is slightly flexible and sands well, ( no little ridges running down your wing). Another glue that I like is the RC560 glue. It is generally sold in the hobby shops for mounting canopies. However the label on the bottle suggest other uses. It is simply wonderful for mounting any plastic details to your plane. It remains slightly flexible and thus shock resistant. A little goes a long way, so buy the smallest bottle.............Oh, about the Gorilla glue, once open, the shelf life is only about six months. Again, get the smallest bottle.

There's nothing wrong with using CA to join wings. It's just a time factor thing. With CA you get ONE CHANCE to get it right. If the wing is already together using CA, and it's straight, GO FLYING!

Hi kingwoodbarney, gorilla glue or polyurethane the big name,if not clamped or secured the wood will be pushed apart when the glue sets up because it expands,also on the container it states use in well-ventilated area do not contact skin, may result in acute or delayed damage to the lungs,mine bottle is around two or three years old,after each usage,I stick a screw in the end then turn bottle upside down to seal itself,it still works great.

One thing that has not been mentioned in any of the posts thus far, and it is my number one reason for using epoxies in high stress areas -

CA is a fantastic adhesive in the right place. Its major drawback is (for me anyhoos) is that seems to go brittle very quickly in strong sunlight and heat. I am not talking minutes here, but certainly a matter of months.

Epoxy does yellow in uv exposure, but it seems (opinion and observation warning) that it loses less strength than does the ca.

So, if I were looking at a joint that is exposed to light, and heat, then I would prefer to use an epoxy. Does that answer the question on the wing join?

no,don't think there is going to be any sunlit in the joint,would take more heat than the sun to effect the wing glue joint ,ca is by nature more brittle than,epoxy or wood glue there fore has less shear strength,thats what I've been taught,but at times I've been wrong.

.........back when I used to use Epoxy to apply FG clothe to the center section of wings, I would always put the wing outside in the sun for several hours. I don't know if al epoxy needs U V light to cpmpletely cure, but some patch kits that I have used on canoes state that is necessary.

Thanks everyone for all of your posts. I've learned some new things.

Thanks again.

Gorilla glue, also available from Titebond, and others, is polyurethane glue. Not really as strong as epoxy, but very strong, and yes it expands quite a bit. It will also make your hands, or any other skin it touches black, so it's a good idea to wear surgical gloves, or the like. Don't forget to read the directions though, as many have poor results from not dampening one surface with water first- especially on foam, or hard woods. As for shelf life, make sure to squeeze out all extra air before closing it and hang the bottle upside down. The Titebond bottle has a hole at the bottom for this purpose.




Jetts

I always use epoxy to join the wing halves, but have used both epoxy and CA for fiberglassing the joint. I think the epoxy for joining is a good idea because it will fill small gaps where the wing isn't perfectly flush with its mate better than CA. Also the CA tends to be more brittle, but I'm not sure that's really a factor in a good joint. As previously mentioned, the epoxy gives you several shots at perfect alignment, too. I would imagine if the mating surfaces are perfectly true, either would do just fine. But always glass!