[willyflyboy]

What would be stronger to glue balsa or ply? Gorilla Glue or Good old fashion

30min epoxy.

[moo]

Both are stronger than balsa wood.
(the wood will break before the glue)
(the plywood may break before the glue)

This is why people use thin CA, it strengthens the wood near the joint.

(I prefer polyurethane glue, it can be mixed with a drop of water to make it cure faster)

[cassat]

Gorilla glue is lighter...you don't need as much as cow says mix with water and it expands.

[eajohnson]

Fine Woodworking did a study of glues a while back, and what I took away from it was that any of the above will be lousy if they are called upon to fill any sort of gap. #1 most important thing is to have a tight fit with no gaps. If you use polyurethane's expanding properties to fill a gap, the resulting joint will be weak. Both are more than strong enough in a thin layer and as a thin layer there's not as much difference in weight either.

[NorseHammer]

Less Mess is best, thin full surface spread of glue which is clamped evenly can't be beat. Its balsa that is the weak link here. CA glue has a lower "Shear" strength than the other two but is still stronger than balsa. I like the white foaming of "SUMO" glue sold by Canadian tire, it gets cut off when dry 24 to 30 hours later and then sands nicely to keep things appearing their best. It seems wasteful to mix epoxy on scraps of cardboard or whatever, but its still a great glue, its non-foaming feature is useful at times when you really don't want any mess after assembling your items. I keep all three on my building table, my current project a 35 cc powered S.P.A.D. has glue joints made with all three types. The main spar to Coroplast joint is Sumo, the area that have visible exposed joints which I dont want to run a knife blade along, such as the fin to fuse joint are epoxy and area's where I was in a hurry, such as the doubler to fuse joints were CA... There is no real right or wrong here, use what glue you have convenient and like to work with.

[Guest]

The best answer is that you really need to use only a little of the modern glues to do the job. The downside to this is that you do need to have good tight joints (little or no gap).

Poor joints will still fail and will not carry the stress loads that a good wood-to-wood joint would.

Each glue has its uses but remember that the more glue you have to use, the heavier it will weigh. Also, epoxies by themselves are heavy so the kit manufacturers recommend that they be used only where the epoxy is the best glue to the job (joining wing halves, firewall mounting and fuel-proofing) and be used sparingly and according to the instructions.

[747drvr]

Don't forget about good old water based aliphatic wood glue like Titebond . Depending what you're gluing , the Titebond doesn't slow me down . Actually compared to the polyurethane glue or 30 min epoxy , it can be quicker . No need to worry about bond srtrength for wood to wood joints . A lot cheaper too !

Marc