Proper Procedure Of Applying A Gel Coat Over Fiberglass Surface
Gelcoat is a kind of liquid that hardens to form a thick layer that is usually used to safeguard fiberglass as well as give it a shiny, smooth finish. Applying gelcoat to fiberglass is regarded as a simple process provided you have the right tools and you are able to mix your Gelcoat properly.
Step 1: Preparing The Fiberglass
- Make Sure You Have A Smooth Surface To Apply Gel Coat
First of all, you need to fill in any cracks or gouges in the fiberglass with the help of a polyester filler, marine grade. Epoxy filler, in spite of the fact that it is a great product, is not suitable when it comes to gel coating topcoats. Polyester gel coats will not chemically bond to epoxy, therefore, it is important to take care of any damage on the fiberglass first, in order to make sure that you have a smooth surface to apply the gel coat. To fill in damaged areas, sand them using coarse 36 grit sandpaper in order to get rid of any debris. Then, fill in the damaged areas with the help of the polyester filler using a plastic spreader. - Clean The Fiberglass Surface Before Applying Gel Coat
Now, clean the fiberglass surface with the help of ajax or comet and water, before you Gelcoat over it. If there is any dirt or dust on the fiberglass, then it is highly possible that it will get trapped underneath the gel coat. Go over the fiberglass using a soapy rag before wiping it down with the help of a clean rag in order to get rid of any leftover suds. - Wipe The Fiberglass Down Using Acetone
Next, wipe the fiberglass down with the help of acetone in order to get rid of grease and wax. It is particularly important if you are gel-coating old fiberglass that earlier has a coating on it. Getting rid of any grease or wax on the fiberglass will help the Gelcoat stick better to the material’s surface. After you have gone over the whole surface using a rag soaked in acetone, immediately remove it while still wet using a second dry rag.
Step 2: Applying The Gelcoat Over Fiberglass
- Methyl Ethyl Ketone Peroxide (MEKP)
Take a bucket & mix Gelcoat and methyl ethyl ketone peroxide in it. Methyl ethyl ketone peroxide (MEKP) is a catalyst that will help make Gelcoat start to harden. You need to purchase a container of MEKP individually if it doesn’t come with your gelcoat. Go through the manufacturer’s instructions on the side of the Gelcoat can in order to find out the amount of MEKP you need to mix with the Gelcoat. The amount of MEKP that you need to use is entirely dependent on the amount of gel coat you are using and what brand it is. It is important to follow the manufacturer’s instructions in order to make sure the gel coat isn’t the wrong consistency. - Add Gelcoat Color Pigments
Add Gelcoat color pigments if you are looking for your Gelcoat to be colored. If you are looking for the gel coat to be a different color than white, then it is important to add color pigments. Buy Gelcoat color pigments that match or complement the color you are looking for and go through the manufacturer’s instructions in order to mix the pigments into the gel coat. - Apply The Gel Coat Using A Brush For Small Area
Apply the gel coat with the help of a brush if you are covering a small area. To apply the gel coat using a brush, soak the brush in the Gelcoat in order to make sure that there is a liberal amount of gel coat on it. Brush the gelcoat onto the fiberglass by applying short vertical strokes. Prevent spreading the Gelcoat too thin otherwise, you will get stroke marks. You are looking for a thick, even layer of gel coat on the fiberglass. When you are done, you shouldn’t be able to see any of the fiberglasses under the gel coat. - Apply The Gel Coat Using Gel Coat Spray Gun For Large Area
Apply the gel coat with the help of a gel coat spray gun when it comes to a large fiberglass surface. A gel coat spray gun will help make it easier to get even coverage on a large fiberglass surface. To use a gel coat spray gun, you need to fill the plastic container on the gun using your gelcoat. Then, secure the cord on the gun to an air supply source, like an air compressor. Hold the spray gun nearly 1 foot (0.30 m) away from the fiberglass before spraying the gel coat onto it in short, even strokes. - Allow The First Coat To Dry
Allow the first coat of gel coat to dry for at least 4 hours and then check on it. The first coat should be retaining a slightly sticky feel when you touch it. Try pressing into the gel coat using your fingernail, if it doesn’t leave an impression, then the gel coat is dry enough. If your fingernail does leave an impression, then it is important to allow the gel coat dry for a couple more hours. - Apply Two More Coats Of Gel Coat To The Fiberglass
Apply two more coats of gel coat to the fiberglass. Three coats should be enough, however, you can apply more coats if you are not fully satisfied with the final result. Allow the second coat to dry for at least 4 hours as you did with the first coat. For the final coat, you need to add a sanding aid. A mixture of styrene as well as a gulf wax, to the gel coat and add MEKP as before. You can buy it at the same place you bought the gel coat. It is important to keep in mind that Gelcoat is air inhibited, which in turn means that it will not fully cure in the presence of oxygen. The wax migrates to the surface of the final coat before creating a barrier to allow the gel to cure.