Johnnymat and Compositepro, thank you for your advice. I have now tested -05F with no significant difference and will be using solid CO2(dry ice) allowing different Q-times in the deep freeze to ensure the material has opportunity to solidify as much as possible.
I have seen reference to core...
I am new to Eng-Tips so pardon me if this is not the correct forum. I must devise a method to drill or punch 3/4" holes through 3" diameter hard rubber spheres (ShoreA durometer ~80.) Fabricating the spheres with the whole in place is not an option. I've tried drilling with hole saws at low rpm...