The art market is flooded with different types of casting resins. Each bears a different set of properties and is therefore suited for specific applications. There are a lot of possibilities in store and deciding which resin is suitable for a task requires a clear understanding of its purpose and effects.
The main types of resins used in artworks are:
Polyester resin: This is also known as fiberglass resin as this resin is used as a binder in fiberglass products. It comes as a viscous, honey like liquid and is a contact product which does not require any pressure to cure. The resin cures within hours to give a very hard finish. It can be sanded and polished to yield a clear and shiny surface.
Polyester resin is easy to use and emerges as the cheapest of all resins. However, the resin products are not UV resistant and can break easily when dropped. Moreover, the resin itself emits a noxious odor that is dangerous to health. Using a respirator is always advisable.
Epoxy resin: This is an all purpose resin that costs more than its polyester counterpart and can take several days to cure completely. However, it gives a clear finish and a sealer spray will give a nice glossy finish. It is safe and a respirator is not required. It is still advisable to wear gloves and operate in a well-ventilated area.
Polyurethane resin: The most popular and widely used resin is the polyurethane version. It is available in both opaque and water clear versions. But it proves heavier on the pocket, especially the clear varieties.
The leading benefit is that polyurethane resins set pretty quickly, some within a matter of minutes. It is commonly used for making toys and figurines. Polyurethane resins have proved suitable for cold casting and even mold making variations are available. The cast is quite durable and will not break easily. However, the only drawback is that the resin is sensitive to moisture and fails to cure properly in humid environments or even in molds that contain water.
Silicone resin: Not many people may be aware that resin comes in a silicone variation as well that again cures within hours. However, it yields a rubbery finish which is more suitable for making molds for casting other resins. These molds have a long shelf life and can be used again and again.
In sum, when it comes to deciding which resin to use, keep in mind that polyurethanes are best suited for most applications as they cure within minutes, are durable and can be buffed to a shine as well. However, you need to steer clear of the same polyurethanes when working in humid areas.
Polyester resin products turn out hard and can be sanded to get a glossy finish, but they may yellow with age. Epoxy resin is suitable but cannot be buffed and needs an additional layer of resin to get a good finish.
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