JB Weld is not the best choice for R/C repairs unless you snapped a piece off the engine or other metal component. Too heavy and it does not penetrate the wood so you'd end up using lots.

I use Titebond II for wood to wood. 30 Minute epoxy for firewall or major structural splices (spars & fuselage longerons).

What exactly are you repairing? Foam or plastic needs different cements than balsa. Wood in the tank area is probably already fuel-proofed and so wood glues don't work so weel unless enough bare wood is exposed.

The best investment would be some triangular balsa stock in assorted sizes. Titebond this in beside cracked formers and sheets for repairs.