Strength is kind of subjective. It needs to be strong enough to withstand use. It depends on what kind of use your pieces are going to be subjected to. I would never build using anything less than 5k psi strength. I normally build with Hydrostone which is 10k psi strength and it works fine for anything I use my pieces for. If I was leaving a piece in a heavy use environment, like a game shop, I would use Merlin's Magic or Excalibur because it would stand up to the heavy use much better.

Itar

image