Mike wrote:joaozinho wrote:Epoxy resin!
That is the essence of fiberglassing
Well Mike,there is substancial difference between polyester resin and epoxy resin,that's why I prefer epoxy,(juste my opinion)
Differences Between Polyester Resin and Epoxy Resin
Polyester Resin Epoxy Resin
Polyester resins contain an ester functional group that undergoes reaction with an acid to form the condensation product known as polyester resin. Epoxy resin is actually a copolymer, wherein two substances form the thermoset compound. These two compounds are the resin (epoxide) and the hardener (polyamine)
Polyester resin is a stable compound when examined in terms electrical, chemical and mechanical properties. This is the reason why it's used for making fabric, plastic PET bottles, waterproof covers, etc. The mechanical, electrical and thermal properties of epoxy raisin is much higher and it's also resistant to acidic liquids. It's for this reason that it is used for making durable covers of machines and high impact concrete covers.
The curing time of polyester resin is much lower than that of epoxy resins. Polyester is also weaker than epoxy resins as it lacks proper binding capacity. The curing time of epoxy resin is much higher than polyester resins and it has a greater binding property. This makes epoxy resin much stronger than polyester resin.
Polyester resin finds application in processes like seaming, repairing, laminating etc. They are much less durable than epoxy resins Epoxy resin is a highly durable compound that finds wide application in a plenty of purpose, especially in the marine industry. When added to aerospace materials, carbon compounds and glass materials, it strengthens their property.
Polyester has a much lower shelf life and curing time than that of epoxy resins. The shelf life ranges between 18-24 months while the curing time is between 6-8 hours. The shelf life for polyester resin is quite long that extends to 2 years. The curing time is also considerably time taking that ranges from 5 to 7 hours.
The adhesive power (100 p.s.i.), or the bonding capacity of polyester resin is very poor while it has the highest water absorption capacity. It gets bonded only with fiberglass. Epoxy resin has a high bonding capacity 2,000 p.s.i. adhesion strength and it can adhere to even pre-cured and dissimilar matter while cured epoxy resin has a poor water retention capacity.