Polyester resin contraction

hi all colleagues

I have a question, I'm designing a small sailboat class, where the margins of tolerance in the measurement of the hull are very short, I build the molds for the hull, pergunta is whether I should take into account the contraction and make molds taking story index of contraction polyester resin (2%)

thank you very much to all greetings

 

I think your info isnt accurate - the contraction is a lot more than 2%


One notable feature of fiberglass is that the resins used are subject to contraction during the curing process. For polyester this contraction is often of the order of 5-6%, and for epoxy it can be much lower, about 2%
http://en.wikipedia.org/wiki/Fiberglass

 

I would think that as long as the same resin is used for all the boats it wouldn't matter, shrinkage is typically not the same in all directions, you would usually get more shrinkage in the long dimensions.

steve.

 

thank you very much steve I will consider

 

Contraction will be influenced by fiber content and orientation. It's complicated and transverse shrinkage can actually have a straightening effect on woven cloth that yeilds a net expansion in the plane of the weave.

http://books.google.com/books?id=aQ...&q=shrinkage of polyester resin glass&f=false