OK, I am old, I was there when Vern Estes was a boy, well not quite that old, but old enough. So please show some kindness to this old rocketeer.
What is CA? Some kinda glue? Like Super Glue? What is Thin, Medium, Thick?
Does it work with paper and balsa?
Is it stronger than Epoxy?
TIA
Andrew The Old Guy From Texas
No stupid questions here...
Yes, CA is a type of glue, SUPER GLUE. You can get it in various viscosities, ultra-thin, thin, medium, thick, gel, etc. If you've ever used "Crazy Glue" or "Super Glue" around the house, you're probably pretty familiar with it, as CA (cyano-acrylate) is the active ingredient. It was originally developed as a 'wound closing' glue to seal wounds, IIRC. You can get REALLY GOOD CA glue at most hobby shops, in various 'house brands' and most glue mfg's make their own version, like "Hot Stuff", etc. I use the "thin" in the pink bottle and "medium" in the yellow bottle from Hobby Lobby, as it's MUCH more affordable than the stuff at the local hobby shop (LHS).
CA is good for some things, and not for others. Most of the CA I use is the thin pink bottle stuff, because I soak it into balsa fins, nosecones, and transitions to harden them. Thin CA will soak right into balsa wood, and hardens within a few seconds or so, turning the balsa wood into something more akin to a 'composite' material, making the balsa a lot tougher and more ding resistant than it is naturally. Be aware, though, to do this outside and stand upwind, because CA gives off some strong fumes that will make you tear up badly if you don't. Not a big deal, but don't try it indoors... it's about like chopping up a whole bag of onions! Also, the CA tends to 'raise' whatever balsa dust and loose wood fibers are on the surface, and harden them into a 'grit' that you'll have to sand off, but it's not difficult to do, and the balsa fins are MUCH stronger and more ding resistant, so I recommend it. Also, I wouldn't apply it to the shoulders of the nosecones or transitions, because it does SLIGHTLY increase the diameter, making them a tighter fit in the tubes. I'd also leave the fin root edges undone, so the wood glue can penetrate the balsa and give the fins a better bond to the tube.
CA is good for SOME stuff building rockets, but not ALL, by a longshot! A lot of folks use CA to glue their fins on, but I certainly wouldn't recommend it. CA has VERY GOOD strength in TENSION-- remember the guy hanging by the hardhat glued to the beam in the TV commercials?? BUT, CA has poor strength in SHEAR forces, the kind that fins are typically subjected to when the tip hits the ground first during recovery. CA tends to be more brittle than most other glues, and only gets MORE brittle with age, so the older your rocket is, the more likely CA glue is to shear off... For fins, motor mounts, and shock cords, I'd recommend white or yellow wood glue, as they remain a bit more 'flexible' when cured than CA, and will 'give a little' when the fin hits the ground rather than just popping like CA can. Not that wood glue is bulletproof, but it's just better than CA in those conditions.
Also, don't get CA anywhere near your shock cord or parachute lines, as it does bad things to them...
For gluing details on scalers and stuff, it's pretty good. As a general rocket construction adhesive, I recommend against it.
Epoxy is essentially two part plastic-- resin and hardener, and when combined chemically react to form plastic. Good for some stuff, and generally the adhesive of choice in high MPR and HPR, but not so much for LPR. Some folks use it for fillets and stuff like that, but it's heavy and kinda overkill. I recommend Titebond Moulding and Trim glue, sold in the hardware stores by the Titebond and Elmer's yellow wood glues. It's thickened sort of white glue that will not run, goes on very smooth, easily contoured with a wet fingertip, and cleans up with soapy water. Unlike standard white or yellow glue fillets, it stays put, won't run to one end of the fillet or the other, or run down the side or end of the tube like regular white or yellow glue will sometimes do, and it makes GORGEOUS fillets-- every bit as good as epoxy fillets, which require you to wear gloves to do, since epoxy shouldn't get on your bare skin, because over time you'll become allergic to it. Also you don't waste as much as you do with epoxy. The fillets dry clear and hard enough to sand, but a bit flexible like white glue (not like concrete like epoxy tends to harden up as it cures).
One good thing about CA is that you can get "kickers" that will harden it almost instantly. CA cures by reacting with moisture in the air and materials, and kicker greatly accelerates the process. Be careful with CA though, because you can EASILY glue yourself to the rocket, glue your fingers together, etc. CA can get rather warm as it cures, too, so be careful of that.
Hope this helps! OL JR
