whats a good material to fill motor mounts?

[busychild0]

i know everyone says to fill the mounts with a casting urathane. but i work in granite and marble fabrication and use a two part epoxy to glue steel rod in the back of the stone. it gets very hard but still has good flex to it i was thinking of doing this. but if thats not good i also use a flowing acrylic that also gets really hard. then also a polyester flowing and that ALSO flexes well and gets hard. would any of these be good to use? or should i just get some urathane

[NAiL05]

Urethane has been proving over time. You can try those other products and see if it works. But can the product take consistent flexing and how are its holding properties? If its good then I would say go ahead and try it out and get back to use bout it.

[HondaGuy1212]

^^ yup urathane