Eric- Here's some starter's- The last one is a test lab if ya want to spend the bucks to answer the qestion. I personally use the Canadian boulder test. The new Zalt/Zam formulation survived. http://www.matweb.com/reference/shore-hardness.asp http://www.matweb.com/reference/tensilestrength.asp http://www.psrc.usm.edu/macrog/mech.htm http://www.plasticstechlabs.com/ Have fun "Science operates according to a law of conservation of difficulty. The simplest questions have the hardest answers; to get an easier answer, you need to ask a more complicated question." Al Warner "All Water is Zalt Water" http://www.zaltnad.com | 
Tinsel strength (PSI's),Cranks and Gliders.