Does anyone have hands on experience doing resin infusion of carbon fiber with a balsa end grain core. In my research on the methods, I find statements of vendors that indicate balsa end grain can be fabricated as a core between carbon fiber this way but at this time, actual evidence or instructions by someone experienced doing this still eludes me. Does anyone know anyone what has done it (successfully), or is it mere hyperbole by the vendors of the balsa core material? FYI, I have written to one notable vendor with no response. I have also done a patent search and with one notable exception there are no patents that shed light on the process of sealing the end grain. The referenced patent simply says But how to seal it and with what to seal it? And how much weight is added to the balsa when it is sealed? Is this all a secret?
Looking for replies with experience.... no theories or conjecture, please.


A Lifelong Learner

This is what I am telling you the whole time. When little sandwich composite things crash, they are not getting damaged because the pressure strength or the shear strength of the core material is surpassed. Raising that numbers doesn't make this any better. The key would be to increase the failure free energy absorption propertys of the whole structure. In fact the balsa version would be heavier than the foam version, therefore carrying more momentum when crashing. Your 100g quasi isothropic skin will never hold the forces to cause shear failure within the core. This is even more true for 3 dimensional shapes. Extreme core strength is either needed for high punctual pressure on the surface like bolt trough applications, or high shear forces in beam like structure. But as my example with bow limbs demonstrates, foams can endure even the highest tensions carbon fibre can come up with.
why do you think foams are like they are? The people who invented them did choose the density and strengh compromise the way they did for reasons.

I understand that the optimum skin/core design would strike a balance between the shear strength of the core and the tensile strength of the skin. I will have to do some in-use destructive testing to actually know if the design will work for the strength and stiffness that my UAV will need. I will very likely build more than one sample with balsa and similar samples with foam materials. My unique design will work best with higher stiffness and less flexibility and this is rather different than many other current UAV designs that make their frames from tubes which hold the motors.


A Lifelong Learner