Core in a mould ?

The shear modulus of a balsa 100 kg/m3 is around 110 N/mm2. PET (Airex T92) will give you a shear modulus of 21 N/mm2.

 

Manufacturers. (edit: Thank you, Coen)

For moulds stifness is what counts, more than impact resistance (people working your tool with a sledgehammer should be ehhmm, eliminated).


But as I stated: All types of stiffening is better than no stiffening at all.

 

Sorry, I didn't see / forgot that it was concerning the mold. I thought it was about the hull. Sorry for that.

For the mold, go with balsa.

Cheers

 

Never will use wood , but see post #9

 

I have built a lot of first rate molds and chose to use first rate material every time,Yes balsa will work but why use a second rate core in block form of varying density.

 

Point is some of the testing methods do not work on the resilient cores. Once again, when they do what you pay the big money for the test will indicate that movement as failure and mark that as a absolute value.