ORIGINAL: Smoggyboy
As a newbie to r/c planes, and not having built one, YET.
Can somebody explain the ART OF ADHIESIVE SELECTION and AREA OF APPLICATION.
I understand that glue type is a personal choice, but as a newbie, the range of different adhiesives it's mind blowing.
There must be a genraly accepted standard for types of addhiesives required and the places on an aircraft were they need to be used.
Can you somebody explain please.
MOST applications will be as follows:
Balsa to balsa with a TIGHT FITTING JOINT and CA hinges (what typically come with ARFS and many kits) - thin CA
Balsa to Balsa with a sloppy joint OR balsa to lite ply - medium CA
Plywood to plywood - 30 minute (or longer ) epoxy
Pinned hinges (these are the plastic/nylon hinges with a pin holding the 2 halfs together) - 30 minute (or longer ) epoxy or a polyurethane glue. A tip - use a toothpick and put a thin coating of vasoline on the pin area before installing to prevent the epoxy/polyurethane glue from getting into the hinge joint.
Applying balsa sheeting - thick CA or (preferred ) Titebond wood glue or similar glue.
Firewall (typically plywood ) - 30 minute (or longer ) epoxy For strength add tri stock between the firewall and fuselage.
Landing gear mounts (the plywood mount ) - 30 minute (or longer ) epoxy For strength add tri stock between the ply mount and the fuselage.
ANY joints that will be subject to high stress (joining wings together, etc ) - 30 minute (or longer) epoxy.
Hardening screw holes in balsa or lite ply - thin CA (use sparingly and after the CA is dry rethread the screw )
Epoxy is heavy and for most applications (except as noted above) is not usually required.
Thin and medium CA is what is typically used for the majority of building. Sanding a CA joint is difficult since the balsa is substantially easier to sand than the CA. Neatness is a BIG plus when doing ANY TYPE of gluing.
If you find that you start having a stopped up nose or your eyes start watering when using CA, you most likely have a sensitivity to it. In that case switch over to a decent wood glue (yellow glue ) such as Titebond or Elmer's Carpenter glue. The drying time on these glues is usually a couple of hours so clamping/pinning of the part(s) is required.
As you may have noticed, nothing is mentioned about epoxy with less than a 30 minute work time.
Epoxy with less than a 30 minute work time is substantially weaker than a 30 minute epoxy.
Except as noted above, thick CA is almost never needed and due to the longer working time, a wood glue is frequently used for sheeting instead of thick CA.
Polyurethane glues expand quite a bit when drying. The rate of expansion is determined by the amount of moisture in the wood and the humidity. Polyurethane glue has limited but some good uses, however, it is quite expensive and once the bottle has been opened, the bottle life is about 3 months.
Hope this helps.