matonis
06.05.2021 5:15:45
These are the most expensive of the three resin types, but well worth the cost.
See full version: Choosing the Appropriate Resin (Epoxy vs. Vinylester vs. Polyester Resins)
These are the most expensive of the three resin types, but well worth the cost.
Don't confuse the "yellowing" of epoxies over time with the slight amber initial color of most epoxies. There are only about 4 epoxies in the market that will not yellow over time. The West System 207 is the best of them all (that is the reason we sell West System's Epoxy). Even for indoor applications, UV will eventually yellow your epoxy. So if you don't plan on painting you piece/application and you want your piece to look good and last as long as possible, plan either protecting it with UV coating (such as a UV urethane), and/or use the 207 hardener. [links]
Epoxy resins are typically about three times stronger than the next strongest resin type. Epoxy adheres to Carbon Fiber, Fiberglass, and Aramid (Kevlar), very well and forms a virtually leak- proof barrier. Epoxy also adheres to older epoxy and most materials quite well. more
Polyester resins are formed by the reaction between polyols such as glycol or ethylene glycol with dibasic acids such as phthalic acid or maleic acid. These unsaturated resins are combined with other chemicals sometimes called hardeners or catalysts. This changes the molecular structure and the resulting compound cures, generating heat in the process. Methyl ethyl ketone peroxide ('MEKP') is one such 'hardening' agent.
On a broad scale of viscosity, vinyl esters are midway between polyesters and epoxy resins, before adding styrene. Thinning effects workability and strength - 'thinning' reduced strength but makes it easier to brush or spray.
If improved durability and impact resistance is important, then vinyl esters win over polyesters - and again the build can be tailored to use the vinyl esters in those areas with higher impact probability. However, these are relative and other resins or composites may be superior (and more expensive).
304, 306, 307, 308 GELCOATS ARE DESIGNED FOR USE IN A MOLD AND WILL NOT… more
Ve resin or epoxy. Which one can not long lasting and become yellowis when expose to much under sunlight?
More than 95% of all boats, truck & car bodies made of fiberglass are made primarily of E-glass, an orthothalic polyester resin and isothalic polyester gelcoat.
Ortho polyester, isothalic polyester and vinylester resins are compatible, they all have styrene (commonly known as the “fiberglass smell”) and chemically bond to one another.
The majority of all fiberglass parts are constructed using polyester resins, it's the most widely used type of resin in the composites industry. Polyester resins require a catalyst to cure or harden, typically methyl ethyl ketone peroxide (MEKP). They are naturally UV resistant, generally viewed as easy to use, fast curing, tolerant of temperature and catalyst variations, and they are less expensive than epoxy systems. Many view polyester resins as being easy to use because they have a high thixotropic index, basically they do a good job clinging to vertical surfaces so the resin won't run or drip as much when making parts and molds. They also wet-out fabrics quickly and easily and they are easy to mix. As the most common resin type in the industry, it can be difficult to narrow down a list of common uses. That said, you can expect to find polyester resins used in the marine industry, used for boat hulls and other applications, they are used for general part fabrication, automotive applications, and for low-cost molds.
For composite laminates, there are three main types of resins used in the production of both parts and molds: polyester, vinyl ester, and epoxy. At Fibre Glast, we carry a selection of each type of resin and each has its own set of benefits and drawbacks that should be considered before starting any project.
Vinyl ester resins are often considered a cross between polyester resins and epoxy resins. This is oversimplified, but it does help convey the qualities of the resin. Like polyester resins, they require MEKP as a catalyst to cure or harden. Vinyl ester falls between polyester and epoxy on price, most physical properties, and handling qualities. Vinyl ester resins actually exceed both polyester and epoxy in corrosion resistance, temperature resistance, and elongation (toughness). Because of this, they are typically used when high durability, thermal stability, and extremely high corrosion resistance are needed. These applications often include building and repairing chemical storage tanks. Increasingly the marine industry is exploiting these properties by using vinyl esters to produce and repair fiberglass boat hulls. Vinyl ester boat hulls become nearly impervious to the blistering and osmotic problems commonly encountered when polyester resins are used. here
While these positives obviously weigh in polyester's favor in many applications since it is so widely used, there are a few drawbacks which must also be considered. For one, polyester does not offer as much corrosion resistance as vinyl ester resins, or as much ultimate strength as epoxy resins. Also, thin applications of polyester resin can remain tacky when exposed to the air. We recommend adding Styrene Wax to your resin for thinner layers. The wax rises to the surface and provides a barrier to the air which allows the resin to fully cure. Note, the wax must be sanded and washed off before application of the next coat of resin or paint. If a laminate or mold is constructed using three or more layers of fiberglass reinforcement, no wax is necessary as the heat generated during the cure cycle will fully set the resin.