Should I use waxed or unwaxed gelcoat?

Many times I have customers ask me when buying gelcoat, “Should I use waxed or unwaxed gelcoat?” Like most things in the boating world, the answer simply depends on what you are using the product for. In this article we will discuss some common uses for both waxed and unwaxed gelcoat so that you can determine which product is best for your application.

Let’s start with understanding what the wax does in the first place. Wax is an additive that is added to the gelcoat to assist in the curing process. In certain applications, wax is a necessary product needed to get the gelcoat to cure properly. Let’s talk about a few of those applications. The most common one would be using gelcoat to finish off a repair done to a boat. When preparing your repair for the finishing stages of gelcoat it is important to determine if you will be spraying the gelcoat or rolling it on. Both application methods have their place but for this article we’re going to assume we are spraying the gelcoat. Understanding how wax works is very important. During the curing process the wax in the gelcoat will rise to the surface and create a small film on top of the gelcoat. This film creates a barrier between the gelcoat and the outside air. Without this barrier the gelcoat would remain tacky. If you were to roll to gelcoat the concept of the wax would remain the same.

Now let’s talk about some uses for unwaxed gelcoat. A common use of unwaxed gelcoat would be when laying up a mold for a new boat or fiberglass part. When working out of a mold the first part of the layup process would be the application of the gelcoat. As we learned in the previous paragraph, the gelcoat needs a barrier to completely cure. In this process, though, we will be laying fiberglass and resin on top of the gelcoat. In this insists the fiberglass would act as the barrier between the gelcoat and the outside air. So wax for this application is not only not necessary but could cause a serious problem, because the wax would rise to the surface and not allow the fiberglass to adhere to the gelcoat. Another use for unwaxed gelcoat also would be for finishing a repair. Wait a minute though, we’ve already determined that waxed gelcoat is needed for finishing a repair! Let me explain. As we learned wax creates a barrier for the gelcoat to cure. But if you are spraying multiple layers of gelcoat, which normally is necessary for proper coverage when spraying gelcoat, it is not necessary for all layers of gelcoat to be waxed. It is only necessary to use wax with the last layer of gelcoat. For instance if you were spraying 4 coats of gelcoat on a repair, then the first 3 layers of gelcoat you would use unwaxed gelcoat and for the 4th layer you would use waxed gelcoat. By using this method you will not only save yourself time but you will also see a savings in material.

So as we can see there are benefits to both waxed and unwaxed gelcoats. The most important question to ask yourself before deciding which gelcoat to use is, “What will I be using it for?” I hope this article was helpful. If you have any question or concerns feel free to contact us at support@promarinesupplies.com

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