How to Paint Fiberglass Parts

Painting Fiberglass Hood



Where precisely do you begin when painting a vehicle? Let me assure you that it is nothing like painting a wall, a house, or even a craft project. You begin by sanding the entire body, fenders, etc. with 220 grit paper. You must monitor the shine of the body’s gel coat to ensure that it is smooth, and if there are any imperfections, especially in the corners, you can build them up using Bondo. After ensuring that the surface is smooth, you can apply several thick layers of primer. The following day, sand it with 220-grit sandpaper, then, if necessary, 400-grit sandpaper. The 400 is completed wet; if this goes well, you are ready to paint. This sanding procedure could take up to two hours in total. This preparation effort is no joke.

How to Paint Fiberglass Parts

And then it’s time to spray, correct? Wrong. Before spraying the color, clean everything and then “jig” it, which means creating a system where you hang/layout/position everything to be painted. All the pieces must be painted at the same time, with the same paint, and by the same painter, or they will not match. Why is it essential to ‘jig’ the pieces? If they are painted flat, the metallic will not adhere properly, and they will be a different hue. You can attach the sections so they lay at an angle, just as they will on the vehicle, or suspend them from the ceiling, etc.


After cleaning the pieces with prep solvent and decontaminating them, you are ready to return with your basic color combination. You’ll need to work for the entire panel. Hold the gun back a bit so that the color is laid down drier, which will make the metallic shine out more in the sun. If you get too close to the rifle, it will take on the appearance of tiger stripes. Aim for a distance of about one foot.


Even if the paint is costly, it is well worth it to use a bit extra while applying the base coat to help it shine. Once the initial coat has been applied, allow it to rest for an hour and a half. Cleanse it once more. Return and begin spraying it with a clear coat; the first layer of clear will serve as a tack coat and act as an anchor. If you apply too much clear coat in the beginning, gravity will take over and it will fall to the ground. If you apply it gently, the coating or finish will have a greater “tack” or stickiness, making it easier to deal with. Go easy! It will help the subsequent clear coat(s) adhere more securely. Keep working on the clear until it has a reasonable sheen, but keep in mind that the ‘color sand and rub’ technique is what will create the truly exquisite detail. It seems strange that you would need to ‘sand’ new paint, but color sanding is required to level the surface. Using wet 800-grit paper and water, the paint’s texture can be gradually removed, the smoother the paint, the greater the shine.


Because some fiberglass components are not perfectly straight, it may be essential to prime and detail the edges. An additional reason to juggle the parts in the air: Paint guns cannot spray inverted; therefore, you will need to paint the edges from underneath. When they’re finished, you may use a paintbrush to complete the edge details; you don’t want to miss a single location!


Any underside fenders, running boards, etc. will require a protective “skin” as the last phase. If a pebble were to come up from behind the fenders and strike the paint, it may leave a scar. Attempting to adhere to things on fiberglass is quite difficult. I would suggest using POR-15 because it adheres to everything. In addition, it’s black, so it suits everything. When you’re ready to apply POR-15, you mask off the paint side of the top side of the fender, running board, etc., so that no POR-15 gets on the paint side. For application, you can use the little foam pads used for painting details on a house. The good news is that the foam pads don’t absorb much paint, so you won’t waste much of the expensive material. You will apply it with a brush, then let it sit for a couple of hours. It is sturdy, and rocks on the road will just bounce off, leaving the paint on the opposite side untouched.