When you begin to compare the many forms and variations of epoxies, glues, and resins available today, the results may leave you scratching your head. One question often leads to another. The chemistry behind epoxy and the varying formulas of glue has come quite a long way over the years, and can be a bit intricate. So what is the difference between each product?
Here is a simple question that we often encounter from DIY folks who find the need to make product choices:
“What is the difference between your PC- Epoxy products and the polyester resins found online or in hardware stores?”
Epoxies and resins are adhesives commonly used in home, automobile, aircraft, and boat building repairs. They are also gaining ground as go-to DIY craft and jewelry materials. But, there are several key differences between epoxies and resins.
Key differences between epoxies and resins
1. Bonding Strength
Epoxy is known for its higher bonding capabilities overall. An epoxy’s relative strength can hold up to 2,000 lbs. per square inch, while a polyester resin can hold less than 500 lbs. per square inch.
2. Resistance to Wear
Epoxy is more resistant to wearing, cracking and peeling, and corrosion or damage from chemical or environmental degradation. Polyester is more fragile and useful for temporary fixes, or low-stress use.
3. Cost Comparison
Epoxy is generally more expensive than resin, due to its strength and formulation requirements. Resin is more popular for craft and jewelry making,due to its lower cost. Remember, however, that you get what you pay for.
4. Resistance to Moisture
Epoxy is very moisture resistant, and certain formulations can even be applied underwater. Polyester resin has minor resistance to moisture, is considered water-permeable, and can fracture easily.
5. Cure Time
Although cure times vary for both epoxy and resin, depending on the formulation and temperature at use, resin generally has a faster cure time. This can be good or bad, depending on the speed with which you want to finish your project. Both products can be manipulated somewhat by raising or lowering the temperature before use. Certain epoxies are also formulated for use in extreme temperatures.
Polyester is far less pleasant to work with than epoxy. Although it sets up much faster, it has the reputation for stinking badly enough to burn your nose hairs out. Make sure to use proper ventilation when applying both epoxies and resins.
7. Shelf Life
There is no doubt about it – epoxy products have a much longer shelf life than resins do. As long as it hasn’t been mixed, epoxy can sit in a garage for several years (or more) without losing its potency. Resin is much more fragile over time.