Polyester resin is used more for fiberglass lay-up or if you’re going to finish a repair with gelcoat, as the polyester resin will bond to the gelcoat better than epoxy.
Vinyl ester resins are formulated with a base of polyester resin strengthened with epoxy molecules (a hybrid form of polyester and epoxy) and also use peroxides, such as MEKP, for hardening. These are cheaper than epoxy resins and more expensive than polyester.
Vinyl esters are more tolerant of stretching, less likely to show stress cracking and more resistant to water penetration. Vinyl ester is the choice when improved resistance to moisture is the goal (like repairing a blistered hull).
Long term water exposure (hull or water tank) or if impact resistance is important vinyl ester is usually chosen.
Epoxy resins are cured with the addition of a hardener. Unlike the polyester and vinyl ester resins, cured with a small amount of catalyst, epoxy resins usually require a lot more, often 1:1 or 2:1. A epoxy resin is the most expensive of these.
Epoxy resin has the best bonding strength as it will bond dissimilar or already cured materials for strong, reliable repair work. This is the most expensive resin but offers the most in its ability to flex, prevent delamination and ease of repair work.
If doing a repair and not overlaying with gelcoat then the epoxy will perform best as it tends to act as a stronger “glue” for the patch to the surrounding surface.
Used extensively in coating surfaces and in table tops where a clear, hard and durable coating is required. Commonly seen on bar tops and restaurant tables. Easy to use 1:1 mixing ratio of resin and hardener. Table Top Epoxy Resin is a 100% solid, two component, clear polymer coating that is mixed at a 1 to 1 ratio by volume. Each bar top epoxy resin kit contains a bottle of resin and a bottle of hardener. The product cures to a clear, high build, glass like finish that resists scratching, yellowing and will not distort with age. Items coated with it will become permanently preserved and protected for your enjoyment throughout a lifetime. The table top epoxy resin will not exhibit blushing or sweat out under high humidity conditions.