G'day guys, im needing some help with a project of mine for a friend, he's gotten me to make up a few test sets of free diving flippers, ive pretty much copied a professional set from him, ive gotten the tapper (thin at one end thick at the other) and thickness (1mm to 2mm) correct but I still can't get near the flexability as the professional set, wondering if theres a additive or something i can mix with my infusion resin to make it more flexible as theres seems stupidly flexible, i was also thinking maybe i go away from just using 2x2 twill carbon and maybe add in some unidirectional carbon? Any help will be much appreciated 👍

Maybe the set you are copying are not full carbon, just thin skin over glass .. or all glass with black pigmented resin.

If you need them more flexible try using glass or flax fibre instead of carbon. If you 'need' it to be carbon make it thinner, or use most of your plies at +/-45 degree layup to make it less stiff.