Resin. Polyester or polyurethane?

[HotRodaSaurus]

Ok I am bit of a casting virgin but what is the difference and what are the advantages of each resin. I have asked this on other sites but not had a really clear answer though I believe casters such as Modelhaus used polyurethane.

Help me please as I have lots of polyester resin and thought it may be some use but........?

Cheers, John

[jas1957]

Polyurethane is what resin model parts are made from.  

[mr moto]

Having worked with polyester resin in boat building and polyurethane resin in modeling, I say that you want to use the polyurethane. That's the standard resin that is sold commercially for the hobby by Smooth-On, Alumilite and others. I've never been tempted to use polyester for models (except certain polyester based putties) and it has even been largely replaced by epoxy for boat building.

[Bob Ellis]

Early 80s resin kits used polyester and were very brittle.