I tried fixing with 4% PFA and sucrose 10% O/N 30% O/N. when  I put the bone in the sucrose solution, it sank immediately and did not float. When sectioning the bone detached from the oct  immedialty when it touched the slide

the best sections I had was with an unfixed and undecalcified bone, bet those sections were not good enough. I am only interested in the structure and direction of the collagen, using polscope, polarized light microscope. 

Thanks

Efrat