3D printing is good for many bits of an R/C plane, but not a 450mm or longer spar. What suggestions does the group have for bonding a 3D printed rib to plywood? Something besides CA glue? Do I put small grooves in the 3D printed to hold extra ridges of glue? Thanks for your suggestions!
Epoxy would probably be best, you can use the liquid resin to attach resin pieces together, but that probably wouldn’t bond with plywood.
Use CA and an accelerator. I really like this stuff: https://www.amazon.com/Bob-Smith-Industries-BSI-151H-Accelerator/dp/B0166FFCCS/ref=pd_nav_hcs_bia_t_2?_encoding=UTF8&psc=1&refRID=B6SFT2RDM54GREJ4A2KT
It cures in seconds, and makes CA more like an acrylic additive than a glue. I use about 2 bottles a month.
Have you considered a mechanical joint? if you print with the layers aligned correctly and use techniques similar to traditional wood joining methods I would expect it to hold quite well.