I have few larger objects I have been trying to redesign to be more structurally sound. The biggest problem I have is the overall size of the objects is much larger than your average 3D printer, and I don't intend on spending an unnecessary fortune on a new one that could print the object in one go.
So far, I've split the design into several pieces about 10 inches long. I've tried making dovetail notches to piece them together like puzzle pieces, but the object itself when pieced together tends to sag and pull itself apart with repeated handling. I've tried various glues, printing techniques, etc. and nothing quite holds together. Everything eventually breaks at the seams.
I then saw a few videos on foam R/C airplanes and their construction and had an idea. Many of those planes use carbon fiber tubes as the main wing spar. What if I took that to the next level? I could use carbon fiber tubes similarly to how you use REBAR in concrete construction.
That leads me to my concerns which I need some advice on...
1. Is this even a good idea? I'm hoping to make the printed section approximately 3-6mm (around 1/8 to 1/4inch) thick at most on it's outermost walls. I've seen some tiny rods for sale on the main website. Lets just assume the object being joined is in 3 sections... maybe 450mm-610mm (18-24 inches) and weighs around 5 pounds when fully built with all the electronics and batteries in it. I know the rods are extremely stiff but I need small ones that can resist flexing. I might attach a screenshot of an example to give an idea what I'm doing. This isn't going to be a product for selling, I'm just looking for a better solution with my builds.
2. What type of glue/epoxy should I use to seat these in their holes? I know CA (superglue) is great for most filaments like PLA and ABS, but I'm not sure if those glues will work on the rod and the filament I print with at the same time. Should I just refrain from gluing the rods in their holes and just make them captive inside when I glue the plastic seems together?
Example screenshot attached. Ignore object placement and size, it's only to give a rough idea.
