Fiberglass is a long-lasting and lightweight material suitable for manufacturing boats, doors, and cars. Unfortunately, the surface of fiberglass isn’t smooth always. Sanding and applying primer is necessary to even out. Primer helps you hide notches, crushed or even shallow marks on the surface.
At the same time, the primer offers a consistent level of color and sheen while confirming a durable finish. But you will not get the expected result from a poor-quality primer. The best primer for fiberglass will enhance the quality and give a better look at the final finish.
This guide will help you find a reliable paint primer. Read the features, pros, and cons carefully to get the best-suited one.
Types of Primers are Used to Prime & Paint Fiberglass:
Different types of fiberglass primers are available in the market. Determining the right type is significantly essential to get the best result. Fiberglass primers are sticky and flat. They primarily consist of 4 elements.
Synthetic resin 20% – 30%
Solvent 60% – 80%
Additive agent 2% – 5%
Some specific Polyethylene
Each type offers distinctive features and benefits. Remember, they are ideal for specific surfaces. Let’s look at the main 4 types of fiberglass primer from the discussion below.
a) Urethane Primer:
Roughly 90% of the automotive body shops use urethane primer in the USA. These primers drying time is extremely fast, sanding is effortless, and provides an impressive build. Moreover, once they get hardened, they never go back to the liquid state.
However, these primer types are not a good performer against rust or corrosion. Furthermore, their adhesion is not that good with bare metal. These primers are suitable for repairing minor scratches or dents on the fiberglass surface.
Due to their cost-efficient feature, lacquer primers are widely used on fiberglass. They are reversible, meaning that they can return into liquid form. Also, if you use another product on top of these primers, they can react. Also, lacquer primers don’t resist rust and corrosion.
c) Self-Itch Primer:
For several years, this specific type of primer has been used, and still, many manufacturers are using it. Characteristically, these primers are the acidic type that burns into the surface of the metal, allowing it to fight corrosion and rust efficiently.
A film-build result is unavailable with self-itch primer. You can’t use them to repair scratches and dents. However, they perform well with the restoration project and new aluminum surface.
d) Epoxy Primer:
In terms of protecting against corrosion, epoxy primers are the best option. They resist moisture proficiently as well because of their excellent film build characteristics. If you decide to strip down your door, car, or boat completely, the epoxy primer would be the best one.
However, it has a drawback as well. The curing time is long compared to other primer types. As a result, sanding them is pretty challenging. The good news is that top brands are now formulating easy-to-sand and fast-drying epoxy primer.
8 Best Primer for Fiberglass Boat, Door & Car [Reviews of 2023]:
The use of paint will be less when you apply a strong primer base. We carefully selected the best primer for fiberglass boats, cars, and doors in this review section committed to helping you achieve the required goal.
The KILZ L211101 High-Bonding Interior Latex Primer forms a secure and strong bond, making it a worthwhile pick. This latex-based primer works tremendously with topcoats of oil, alkyd, or water-based. This primer will be the best solution if you face difficulties with a vital bonding skill while priming hard surfaces.
Traditional oil or water-based primer doesn’t develop a secured bond over slick surfaces. This is a unique primer that can be used on multiple surfaces like PVC, metals, glossy finishes, tile, glass, vinyl, fiberglass, etc., along with slick surfaces. More importantly, it is suitable for both interior and exterior surfaces where a secure bond is challenging.
It comes with a 1-gallon size which can cover 300 sq. ft. conveniently. The application process is so effortless with a brush, roller, or sprayer. Great coverage and optimal usage is confirmed regardless of the application item. The product dries to touch within half an hour, and after 60 minutes, you can provide another coat. Simply make sure to clean the surface thoroughly to eliminate dust, mold, chalk, etc.
Clean-up is super easy. You can easily wash your brush, roller, or sprayer using warm water. It is smooth, thick, and durable. Don’t hesitate to buy this if you have an iffy surface and want to skip/or are unable to prep.
For many people, priming a fiberglass boat is a daunting task, and it is because they use a poor-quality primer. Your priming task will never be a daunting one when you have the Rust-Oleum 207014 Marine Wood & Fiberglass Primer in hand. Above the waterline, this primer will give you the expected finish on different surfaces, including wood, metal, fiberglass, etc.
One important note is; that you can’t use it for surfaces that come into contact with constant water submersion. Apart from that, it is an ideal solution for trim tabs, aluminum boats, cars and even ceilings. Overall, it is worth the price. This paint lays extremely well and performs equivalent to more expensive paint. All you need to do is stir it very well before applying.
Metamorphosed alkyd is the primary ingredient of this primer which ensures flexible coating. The durable coating withstands harsh weather efficiently. More importantly, due to the alkyd ingredients, it resists cracking, peeling, or chipping. When dried, it does not scratch off easily, and it is very sand-able. This is crazy thick and has a super high oil base that seamlessly fills small lines and cracks.
Another amazing feature is, that it works perfectly over a previously painted surface, and most interestingly, stripping off the old paint or primer is entirely unnecessary. By providing long-lasting protection, it enhances the appearance of a surface.
Creates a long-lasting coat
Withstands severe weather
Fully dries within 1 hour
Easy to apply in both indoor and outdoor
Great semi-gloss retention
Must need to paint in a well-ventilated area.
3# Rust-Oleum 260510 Automotive Sandable Primer:
The Rust-Oleum 260510 Automotive Sandable Primer is well-known for its super-fast drying feature that dries in 10 minutes only. This is great for fiberglass, wood, and metal surfaces. It is exceptional from other primers because it can be used as both primer and filler. This way, it fills unevenness, cracks, etc., and creates a strong base when you use it as a topcoat.
It covers minimal imperfections and improves the appearance of the topcoat due to its high-build formulation. The provided foundation is solid and rust-resistant for most automotive lacquers and enamels. Additionally, it makes the sanding process easy. This means it promises to give you an extremely smooth surface. However, proper sanding of the surface is necessary.
This 2-in-1 product delivers a perfectly smooth surface and puts a smile on your face. It is ideal for 3D printing. When the discussion comes about durability, no other primer can beat it. It remains on fiberglass surfaces for many days and retains its color as well. The performance of this primer won’t disappoint a troubled user.
All in all, this product is a great deal because of its sturdy coating. It provides a smooth finish and significantly helps the surface to maintain a good appearance. You will not sweat during the application process and it is easy to clean.
Fills minor imperfections
Outstanding topcoat adhesion
Creates a rust-proof foundation
Convenient tip spray-can
Offers ultimate finish
Many coats required to cover the imperfections
4# TotalBoat Marine Topside Paint Primer:
Applying TotalBoat Primer is certainly rewarding for you and your boat. The TotalBoat Marine Topside Paint Primer is designed for professional painters. This primer is well-efficient to surfaces below and above the waterline. However, don’t assume that it performs as an epoxy barrier. It is primarily formulated for priming aluminum vessels, galvanized metal.
This good-quality primer is responsible for making the painting process effortless. It will surely make your painting task easier and provide a low-sheen finish that never cracks, chips, or fades. Plus, it fights corrosion and rust, making the surface highly durable. Besides, use a roller, spray, or brush to apply this primer.
It has a less chemical smell, making it safe to use. The odor will not disturb you while applying it. Moreover, you can clean it comfortably using a mixture of warm water and mild soap. Similar to other standard boat primers, it is free from chromate and lead. Which means it is safe to use. However, you need to wear safety gear when using it.
Most customers are impressed with its coverage capacity. 1 thin coat is good enough to fill any imperfections. If a higher build is required, apply the 2nd coat. In addition, the primer dries fast compared to other primer types and is ready to sand in 60-90 minutes at 65°F.
Suitable for multi-purpose applications
Chromate-free and lead-free formula
The flexible coating won’t lift or crack over time
If you want to improve the adhesion of lacquer and enamel topcoats of different surfaces, including chrome and plastic, the Dupli-Color CP199 Clear Adhesion Promoter Primer is for you. Moreover, you can use it for both exterior and interior surfaces. It is intended to help paint stick to smooth plastic which it does very well.
This is a versatile primer since you can use it on several surfaces such as metal, wood, and fiberglass surfaces without hesitation. It protects the surface from rust and corrosion, which increases the longevity of the finish. The primer leaves a sheen look and doesn’t fade away or chip or crack over time. So, your vehicle, door, or other surfaces get durable protection.
It is excellent stuff, dries incredibly quickly and smoothly. The primer can feature an EZ Touch Fan Spray Nozzle that needs 50% less finger pressure than other paint valves. It is worth noting that the item dries super-fast, and you will be able to finish your priming task within the given timeline. However, don’t assume that being super-fast, it provides poor service. In fact, it fills imperfections quite efficiently.
The primer doesn’t have a strong odor, allowing you to handle a priming task without trouble. Besides, it flashes quickly and makes painting more effective. It always helps the paint look amazing! No chipping, peeling, or anything; just make sure you read and follow the directions.
EZ Touch Fan Spray Nozzle for convenient spraying
Fast-drying clear primer
Compatible with both interior and exterior applications
Best for fiberglass, plastic, and metal surfaces
It dries to touch in 20 minutes
As it is transparent, identifying any spot can be difficult
6# Tuff Coat CP-10 Gallon Primer Kit:
“Versatility” – this word perfectly goes with the Tuff Coat CP-10 Gallon Primer Kit. How? This is a 2-component water-based epoxy primer or sealer, well-suited with high-grade finish coats. It creates an effective barrier when coated on a painted coat beforehand. Also, it offers outstanding performance when applied to damp concrete or masonry.
You might be wondering why this primer is available in 2 different cans? Well, 1 can with the resin while the other can contain hardener. Follow the 1:1 ratio, prepare the mixture of resin and hardener, then you are ready to go. Handling this primer is less harmful. It is formulated with low VOC and non-hazardous ingredients.
So a simple application project will make every priming project fun. Simply use a sprayer, roller, or brush to apply it according to your preference. The final finishing result will be excellent if you follow the right directions in preparing the mixture. You will love to know that this paint is easy to prepare and apply, just as advertised.
Once dry, you will get a nice glossy look, and it will protect different surfaces from water. Also, it doesn’t emit fumes during application.
Low odor and low VOC
Well-performer on moist surfaces
Withstands flame and water
Proper mixing is mandatory to get a beautiful final finish
7# Modern Master 275266 Front Door Paint:
Make a bold statement by using the Modern Master 275266 Front Door Paint on interior or exterior surfaces. This water-based formulated product is designed for front doors. Since durability and a long-lasting coat is necessary for front doors, it is formulated to give you long-lasting performance. It is one of the best options for fiberglass, wood, and metal surfaces.
It is available in 18 different color options, allowing you to choose any theme whatever dream you have in mind. Front doors are exposed to sun, rain, dust, dirt, etc. and the never-faded formula of this paint ensures that the vibrant look will remain the same for several years. It leaves a flawless, soft, satiny finish of a pure, pleasing shade.
This paint is straightforward to use, and it leaves a super smooth and even surface. It has such a thick consistency that you will never see run, splatter, or drip after applying. Each 1-quart container has an impressive coverage capacity, of 100 sq. ft. As a result, you can paint 1 or 2 doors without hassle. However, manufacturers recommended applying 2 coats of this paint to get superior coverage.
The colors are so vivid and give an aesthetic look to your door. With the right brush, the application process is so simple. Don’t look for other options; buy it without hesitation if you want to get an easy-to-maintain satin finish.
Water-based formula, guaranteed to last long
Never-fade technology ensures long-lasting beauty
Delivers smooth satin finish on both exterior and interior surfaces
Recoat after 60 minutes
Challenging to spread evenly due to its thick nature
8# TotalBoat Epoxy Barrier Coat System:
The TotalBoat Epoxy Barrier Coat System is a high-build epoxy primer, best for above and below the waterline. This epoxy primer preparation process is so effortless that priming will be fun for you, regardless of the project type. It will bond very well with both fiberglass and epoxy.
Due to its lead and chromate-free formula, it is corrosion-resistant, making it ideal to be used on metal surfaces. Moreover, many customers are pretty impressed with its great adhesion to different surfaces. It effectively prevents damage from water permeation. It provides the highest shield and sturdiness for your materials.
Moreover, it is excellent for repairing or preventing Gelcoat blisters, allowing the material to provide an extended service period. One of the worth mentioning features is that; it is compatible with all paint. Also, it performs efficiently with every paint type. This feature is unavailable in other primer types making it an exceptional one.
All in all, it promises to give you nice and smooth coverage every time. Unlike other primers, it is not thick and easy to work. Within 45 minutes, it dries to touch. Additionally, a small amount goes a long way.
High-build epoxy primer
Creates an effective barrier
Protects metal from Gelcoat blister
It can be used for multi-purpose applications
Excellent performance on underwater materials
Typically thinning requires
How to Prime and Paint a Fiberglass Door:
Everyone wants a future-proof door. Priming and painting will give your fiberglass door a nice and glossy look. At the same time, your door will resist dust, dirt, etc., efficiently.
Let’s look at the process of fiberglass door priming and painting.
Step-by-Step Process for Priming and Painting a Fiberglass Door:
Step 01: Eliminate Weather-stripping from the Door:
Grab a soft-bristled brush to finish this step. Also, carefully follow the manufacturer’s instructions. After completing this process, if you find any weather stripping in your fiberglass door, clean it with a dry and soft cloth. Before approaching the next step, make sure the door is thoroughly cleaned.
Step 02: Sand If Necessary:
Check the surface of your fiberglass; is it rough or weathered? Sand down the rough or weathered fiberglass with 400-grit sandpaper to make it even. This will help you prime the fiberglass effortlessly.
On the other hand, if the surface is smooth and even, sanding is unnecessary.
Step 03: Thorough Washing of the Door:
Prepare a mixture of warm water and mild soap in a bucket. Then get a dry sponge and dip it into the mixture and start wiping the door. Start cleaning the door from the top. Clean everything that comes your way.
After cleaning the entire door from top to bottom, rinse it using a wet sponge. Make sure no soapy mixture is available on the door. Once you rinse and remove the mixture carefully, leave the door for air to dry.
Step 04: Use Painter’s Tape to Cover Hardware:
Every door comes with hardware like a doorknob, door jamb, etc. You need to cover these items with painter’s tape. If your door has window glass, cover it as well. It is because you will not be priming and painting the window and hardware.
Moreover, if you decide to prime and paint the door keeping it attached to the frame, then get old newspaper and cover the door underneath. A dry rag or old clothes can also be helpful if you don’t have an old newspaper.
Step 05: Properly Stir the Primer:
Remember to ensure well ventilation when stirring the primer. Open the door and windows so that enough air can pass through the room. It would be best if you decide to prime in an open space.
Step 06: Start Applying Primer from the Edges of the Door:
Wear hand gloves and grab a synthetic brush to accomplish the job. Pour some primer into a paint tray and gently dip the brush. Then start applying the best primer for fiberglass door from the four edges of the door.
Now, you might be wondering, what if I use a spray gun or paint sprayer?
Well, you can use it, but the required precision will not be achievable. Also, spray guns or paint sprayers are notorious for the primer that they waste. Moreover, to achieve a smooth finish using a paint sprayer, you need to be a professional.
So, stick with the synthetic paintbrush.
Step 07: Apply Primer to the Door’s Exterior Part:
If your fiberglass door has a wood-grain finish, you should follow the faux-grain pattern when applying primer on the door’s exterior. Avoid applying too much primer since the detail of the door will be ruined if you do so. Then leave the prime for 2-3 hours to dry.
Step 08: Paint Applying:
Once the primer is fully dried, the paint needs to be applied. Remember to apply a thin coat of paint initially. The first coat would be as much even and light as possible.
Before applying the next coat, the first coat needs to be thoroughly dried. Most of the time, a 2nd coat of paint is necessary to get the expected finish. A couple of coats might be necessary, don’t hesitate to apply 2 or 3 coats if required.
Step 09: Apply Interior Side of the Door:
When applying primer and paint to the interior side of the door, follow the above steps carefully. Remember to dry the door properly once primed and painted.
Question: Do you need to prime fiberglass before painting?
Answer: Some fiberglass doors, cars, etc., are rough and uneven. This type of fiberglass needs to be sanded down and primed before painting. You should apply 2 or 3 coats of primer for roughed or weathered fiberglass.
Question: How do you prep fiberglass for primer?
Answer: Use 400-grit paper to sand down rough fiberglass. Then thoroughly wash the surface with a soapy water mixture. Next, use a soft and dry cloth to wipe down the water and ensure sundry or air-dry.
Question: Can you use epoxy primer on fiberglass?
Answer: Epoxy primer provides extra protection on bare fiberglass. Moreover, it makes the primer moisture-proof and blister-resistant. However, you need to remember that epoxy primer is ideal for bard fiberglass.
Question: What is the Difference between using latex or oil-based primers?
Answer: If you need to seal nail heads or cover knots of bare fiberglass, the oil-based primer will deliver the best result compared to latex-based primers. Oil-based primers penetrate imperfections meticulously, making them ideal for use on weathered fiberglass.
Can you use any primer on fiberglass?
No, it’s essential to use a primer specifically designed for fiberglass surfaces to ensure proper adhesion and durability. Epoxy or polyester-based primers are commonly used for fiberglass. Moreover, Epoxy-based paint is the best choice for fiberglass surfaces due to its excellent adhesion, durability, and resistance to moisture and UV rays.
Although fiberglass is a durable, long-lasting, and low-maintenance material, priming is necessary to enhance the appeal of your fiberglass door, car, or boat. But a nice and glossy finish will not come unless you choose the best primer for the fiberglass.
While selecting a primer, make sure it meets your requirements. Quick drying time, easy to apply, safe to use, low VOC, etc., are some of the key features of a good quality primer. So, choose wisely as you are investing valuable time, effort, and money. The primer needs to be worth the price.
Hi, I am Rogers Weber, the man behind Solvesonic. I am a mechanical engineer. I use many kinds of tools almost every day at my workplace. I love to write about tools, painting, home improvement, and DIYs. I enjoy helping people to solve their problems through my website. => Follow me on Twitter