Cyanoacrylate (CA) and Other Adhesives
There are many different glues used in the construction of model airplanes. Probably the most popular glue in use today are cyanoacrylates, also known as CA. Other glues include those in the epoxy family, aliphatic-resin glues, and rubber-cement-style glues such as 'Shoe Goo'.
CA Glue
CA glues are more expensive than other adhesives, but a little goes a long way. When using CA, choose the right viscosity for the application. Thicker CA fills gaps and has longer curing time. Thin CA (water viscosity) can be used very sparingly to 'tack' parts in place and will also seal balsa by soaking into the grain — particularly useful when painting wooden parts.
Some CA glues come in various formulations now, including foam-safe, in thick, thin, medium, etc. I typically keep the foam-safe one around mostly so that I don't make the mistake of using the non-foam-safe CA on some part that will come in contact with EPS, EPP, or EPO foam.
ALWAYS use CA glues with plenty of ventilation. Use as little kicker (accelerator) as needed. Acetone will clean up overspill or un-stick your fingers. There are special formulas for foam — most standard CA glues 'attack' or dissolve foam such as EPS or EPP.
Are CA glues worth the extra expense? Most modelers would say yes — you can build an entire airplane in a single weekend where once it took weeks. No more clamping, weighting down wings, tons of T-pins, and waiting for joints to cure.
Epoxy
Epoxy is another family of glue used when you need a lot of strength in a joint. Epoxy cures chemically by mixing one part resin with one part catalyst. It cannot be used in high-heat situations but is impervious to almost anything after curing — ideal for motor mounts and any part that might contact raw fuel or solvents.
Other Adhesives
Aliphatic resin (yellow wood glue like Titebond) — excellent for balsa-to-balsa joints, lightweight, sandable. Shoe Goo / E6000 — flexible rubber-cement style, good for EPP foam and joining dissimilar materials. Hot melt glue — fast and decent on foam, but can be heavy if overused. White glue (PVA) — surprisingly good on EPS foam where CA glue might melt it.