Adhesives

Hate to keep bothering you guys with old-timer questions, but another thing is nagging me. What are your modern adhesives of choice? A local guy (a radio flyer) swears by cyanocrylate. It scares me, as you don't have time to move the pieces around if the fit is not perfect. Besides, it is a surface adhesive (non-penetrating) as I understand.
Left to my own devices I would go with slow setting two part epoxy for doublers and wing to fuselage (profile) joints. Elmer for the rest (straight balsa to balsa stuff).
Opinions? Prejudices? I suppose Ambroid is out of the question !

LF

Sig model cement is much better than Ambroid. It seems to be a different formula than 15 years ago. I sure wish some one would make DuBro super model cement again but Sig is close.

Your choices are good and will work well. Epoxy is heavy, but for the engine area and joining the wing to the fuselage, it is a good choice. It is strong and very fuel proof. The Elmer's white glue also works well for normal balsa to balsa joints. You need to use it sparingly as it, too, can get heavy. It, also, takes a bit of time to dry so that must be factored in, and, because it wets the area, care must be used in certain applications or warps can develop. It is, however, quite inexpensive and works well.

Ambroid and similar glues can, also, be used, but they never quit drying. This means they, also, can warp the structure, and an old airplane built with Ambroid will probably fall apart, for the glue joints will pull away from one another.

We like the CA type of glue and use it for most applications. The thin stuff will wick into the wood, so there is good penetration. You are right in that you don't have time to move parts, but you don't need to. You hold them together, then apply the glue. If you have a tight joint before you apply the glue, it will hold well when making balsa to balsa joints (unless you have large areas that you are laminating. Then you should use something else.) If the joints aren't quite so tight you can use the thicker, gap filling CA. With this you can apply a dab of glue to one piece to be glued and then immediately stick it to the other. The real advantage of CA glues is they dry immediately. You save time, don't have to worry about pins, etc. It is strong enough you can even glue the wing to the fuselage with CA. If there are gaps, wedge small pieces of balsa in before applying the glue. Or put a little baking soda in the gap and then apply the CA glue. The baking soda will make it kick immediately, and will, also, give you an almost cement hard filler. It is not great to sand, so you want to make sure you don't have to.

With all glues, use as little as needed. The yellow Carpenter's glue is another choice that can be used in those areas where you would use the white Elmer's glue, or, even, CA. One more caution: The CA glue can give off a smoky odor as it kicks (hardens) and some people find they are alergic to this. We have not found it to be a problem, but others will use it only in a well ventelated work area. If you do choose to use it, you might watch for this.

And the above, ladies and gentlemen, is why this is a great web site!!!

I agree completely with Leonard, except that I would always choose aliphatic ("yellow carpenter's glue") over "white glue".
It's more waterproof and sands better. I've used CyA's since the early '70's, when you had to mail order from Satellite City, and it was about $8/oz. I always avoided the "kicker". Baking soda works just fine, and you can spray a slight dusting of it on a joint with a baby's "nasal syringe" (buy a new one!). If you have a slightly loose joint, wet the joint slightly with saliva, spray some "BS" (will Leonard edit this? It stands for Baking Soda!) on it before assembly. If you need to make some small fixtures for various things, baking soda/CyA is an instant version of epoxy.
Steve

I also use baking soda to fill small gaps, but verry rarely, for the tough sanding reason, anywhere near the outside surface of the airplane.

Since heat will also "kick" the ACC (Not CYA, Larry!), I use a politically incorrect solution near the surface. I light a cigarrette and hold it near the stubborn ACC until it kicks.

Don't take up the filthy weed, though, just to have a means of kicking your ACC. I'm certain that you can probably find another source of heat that is NOT aflame.

I hold no brief for Ambroid, but I have had planes that were constructed exclusively with the stuff decades ago, and they held together just fine.

New subject; Did you get the 1/2A tanks yet? Currell

The tanks have not yet arrived.

On the subject of Ambroid, I was once given a couple of planes that were a few years old and had been glued together with the stuff. On one in particular (a Goldberg Shoestring) the belcrank let go in flight and, one by one, went through the ribs, resulting in the expected crash. On examination it was learned that the glue had continued to dry and had actually pulled away from the wood. I was almost able to disassemble the entire plane, piece by piece, into its original kitted form (with the exception of the pieces that were now more pieces.) I don't trust the stuff any more for long term holding power.

Thanks, all! I am no longer scairt of cyanoacrylate. Like the guy said, that is why this is a great forum. You sure it is OK to call it cya? In the business world, those three letters have a different meaning.

LF

>this is a great forum. You sure it is OK
>to call it cya? In the business world, those
>three letters have a different meaning.
>
I suspect the term rose from within the Civil Service or the Military, where it's even more important than elsewhere!

But we'll just grin when we use the term CYA for glue, and pretend it's a private joke!

"C.Y.A." is altogether different than CyA. Tho if you got a 'skeeter bite on your hindquarters, a smear of CyA would be a temporary fix. Steve

Don't know if anyone mentioned it, but there are a number of CYA types including one for plastic, varying thickness and such.

There are also a number of "white" glues. I've been using some stuff called "Space Age Adhesive" that's a sort of white glue but very sandable and, for a white glue, ridiculously light.

I've also been experimenting with some stuff called Quick Stick. It's a sort of white glue on a stick. Like a roll on. pencil. Stuff is ver, vry thick and work really well in tight places and seems to hold very well. It's pretty heavy, but I only use it in certain instances (can't believe I forgot to glue in that half rim in the middle of the wing).

Because of the multiple meanings of CYA many have switched to calling it CA.
George

I do something on my 1/2A birds that works, but I would like input as to whether or not you agree with it's use. I like the yellow carpenter's glue, but the setup times drive me nuts (actualy more of a short putt than a drive). What I do now is to use the yellow on the joint, then position the joint as needed and run a bead of the CA on the outside of the joint to hold parts in perfect alignment while the yellow glue cures. This has worked so far. Someone at Isky's suggested this to me last year, so many thanks to whoever it was.

Bruce W. Burns
"DoctorDeere"
MECA 4825-08
http://www.usedhawgs.com/engines

Putting a bead around the outside might be a little much. In fact, since CA wicks into the joint, if you are going that far you don't need the yellow glue. And, since the yellow glue needs air to cure, you could be sealing it off so it won't dry, or at least, will dry much more slowly. All you would need do is to tack glue in a couple of key spots--just enough to hold it. Sort of a CA pin while waiting for the yellow glue to dry. That could give you the best of all worlds--quick drying times, but an inexpensive glue medium. Just don't put a lot of anything on, or the plane will gain weight.