Best Primer for Fiberglass Boat, Door

Best Primer for Fiberglass Boat, Door & Others – Reviews & Buying Guide

If the fiberglass surface isn’t smooth, you’ll fail to apply a long-lasting paint coat. And to even out the surface tone, you’ll have to apply primer. It will help you preventing any blotchiness or, fading. So you can easily hide the groove, furrow, or even shallow marks on the surface.

Our expectation for the best primer for fiberglass consumed a large working schedule.

And we’ve spent almost 10 days writing this helpful content for you!

So you can easily pick your best primer for painting your fiberglass items. Based on your choice, they can be applied to any fiberglass items such as – boat, door, pool, tub, deck, or even furniture of that material type.

Our list is full of the top 10 products you’ll rarely be able to find in the market. These are reliable and will surely create a strong, smooth, and consistent interface. After that, you can easily spread over the paint coat, which will adhere to the surface for a very long time.

Top ranking 5 products in a short preview table:

Image Name Our Rating Price
Krylon ColorMaster Ultra Flat White Fiberglass Primer

5 out of 5

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Rust-Oleum Automotive Filler & Sandable Primer

5 out of 5

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KILZ Adhesion High-Bonding Interior Latex Primer/Sealer

4.5 out of 5

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TUFF Coat Primer Kit for Fiberglass Painting

4.5 out of 5

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TotalBoat Topside Gray Primer for Fiberglass Coating

4 out of 5

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To read about our product selection procedure, visit the “About” page.

10 Best Primers for Fiberglass: Reviews

With a strong primer base, you can lessen the use of paint. Cause it helps you in many aspects. And the products on our list are highly committed to letting you achieve the goal successfully.

Note that our highly recommended products are starting from the top in ascending order. In that sense of view, the Krylon ColorMaster Ultra Flat Primer is best for fiberglass. (Keep on scrolling to see all the other doers that you might also pick.)

1. Krylon ColorMaster Ultra Flat White Primer for Fiberglass

KRYLON is one of the quickest drying primers out there. It dries completely within 10 minutes ONLY. Thereupon, if you’re looking for a fast-curing version, this is the best option. With an easy touch tip, it’s easy to use with great precision.

And luckily it’s a versatile product.

Besides using it on fiberglass, you can apply it on other surfaces like plastic, metal, and wood. You can use it for both indoor and outdoor painting projects. It uses the Covermax technology from Krylon to provide a smooth, uniform coat that doesn’t scratch or chip off.

This product has several other versions such as – satin, gloss, flat, etc. So that indicates you get multiple options to use. And you can easily achieve a strong, anti-shine paint finish. Moreover, it’s designed to resist fading in direct sunlight.

That’s a specific reason why we’ve listed this as the top one on our list.

And this is one of the best primers that are available for fiberglass materials!

Being an outdoor/ indoor primer, this product is resistant to many other environmental effects. That’s why it offers a strong undercoat foundation for your fiberglass painting projects. The product’s Ultraflat version is also an important element.

Since it helps acrylic paint to stick by providing some texture, the paint coat really becomes durable. This primer comes in a 12 oz. easy to apply spray-can. The only downside with this product is that you would need many spray cans to cover a large surface.

However, it’s an excellent option for priming smaller areas or items. Thanks to its affordability, versatility, and durability!

Highlighted Features

  • Versatile application
  • Ultraflat features & easy to use
  • Provides texture for paint adherence
  • Ideal for both indoor & outdoor

2. Rust-Oleum Automotive 2 In 1 Filler & Sandable Primer Spray Paint

This Rust-Oleum is another quick-drying primer. It takes only 10 minutes to dry completely. Even better, it’s a great option for fiberglass as well as metal and wood surfaces.

The most unique feature of this product is that it’s both a primer & filler. That means you can use it to fill in any unevenness and cracks on the surface. Additionally, use it as a topcoat primer for a strong base.

It has a hi-build formulation.

With that, it covers minor surface imperfections while improving topcoat appearance and adhesion. Also, it provides a strong, rust-inhibitive foundation for most automotive enamels and lacquers. Another notable feature of this product is that it sands very well.

So that indicates you can achieve an extremely smooth surface.

Just make sure you sand it properly.

It’s an ideal option for 3D printing. And you’ll get a perfectly finished outcome that you will love. But there’s one small problem with this product though. You may need many coats to cover an imperfection completely and it’s only ideal for small gaps.

However, that doesn’t mean the dew coats do not work well. It allows the paint to adhere well even after washing the surface. Thereupon, considering its performance and stability, you’ll get a better job at an affordable cost.

Overall, this is a great product for priming your fiberglass items.

Highlighted Features

  • Sands smooth with the ultimate finish
  • Fills in minor surface defects
  • Excellent topcoat adhesion
  • Forms a rust-resistant base
  • Comfort tip spray-can

3. KILZ Adhesion High-Bonding Interior Latex Primer/Sealer

Forms a strong & secure bondKILZ Adhesion Latex Primer is our 3rd worthwhile pick. From the name you can see that it’s a latex-based product. It works with alkyd or any oil and water-based topcoats. For those struggling for a strong bonding efficiency when priming difficult surfaces, number-3 is one of the doers!

And it keeps its promises providing you with superior adhesion.

Priming your fiberglass surface with this totally worth it!

It works like your paint’s superglue, holding the two ends in a single hairline layer. This product can also be used on various other surfaces. And to mention a few of them; use it on brick, plaster, and slick surfaces. Also, you might apply this on Formica, tiles, Kynar, PVC, and glass.

Sounds like a versatile primer right?

Oh…wait, it’s a sealer also!

Whatever the type of paint you have, this lovely product will bind it onto the surface. Just make sure you let it overlay properly. And then bring your favorite paint to take an action. This can either be epoxy, lacquer, latex, or any other solvent-based paint.

The product comes in 1-gallon and 1-quart sizes. And it requires only about 30-minute to dry. Hence note that you should wait for 1 hour between coats.

The 1-gallon can is enough to cover about 300 sq. ft.

So before ordering, ask yourself about how large the project is! That will help you choose the right one among the various options we’ve listed.

For uniform coverage and optimal usage, you can apply this using a paint sprayer. However, for external applications, we think using rolls is a better option. Or, you might also use a brush that won’t even disappoint you. Be it an exterior or interior fiberglass item, it does fight against the hard-to priming surfaces.

Consequently, it’s a worthwhile primer for a fiberglass boat or deck.

But, fret not buying this primer for your fiberglass door or, shower priming. So, for both outdoor and indoor paint prep, it can neatly establish a secure bond. Just make sure (before applying), the surface is free from mold and mildew, rust, peeling paint, grease, and chalk.

What we like most about this primer is that it bonds to most surfaces. This makes it a perfect option for surfaces that don’t accept primers with the water-based formulation. Not to forget that it forms a strong and secure bong with latex- and oil-based paints.

Highlighted Features

  • Provides excellent coverage
  • Forms a strong & secure bond
  • Prevents the growth of mildew
  • Seals porous surfaces & blocks stains
  • Water-based white primer

4. Rust-Oleum Sandable Fiberglass Primer Spray Paint

This is yet another versatile product from Rust-Oleum. Unlike most primers, this product is both wet and dry sandable. That means you can comfortably use wet or, dry sandpaper. And that results in a smooth finish, giving you an even color coat.

Although the spray can is written automotive, you can use this primer on various surfaces. So, don’t hesitate to use it on fiberglass, metals, and wood surfaces.

One thing that everyone looks for in auto priming is rust resistance, right? Therefore, you must choose a product that will protect your automotive from rust because of wet surfaces. Luckily, this product has been designed with the Stop Rust oil-based formula to give you just that!

In addition to protecting your automobile from rust, this primer offers durable protection to the vehicle.

It is available in 4 different colors, including black, red, gray, and light gray. Each of these colors comes in a convenient 12 oz. spray can. The spray bottle has an all-angle spray comfort tip. This gives you flexibility when applying the primer and protects your finger from fatigue.

One spray can cover about 15 sq. feet. It’s also worth noting that this product dries super-fast and you can even recoat within 10 minutes. After it dries, you can wet sand to get a smoother, shinier paint finish. And that ensures you get superior topcoat adhesion.

Considering all those, what else do you think it lacks? Please comment on that to let us know.

Highlighted Features

  • Forms a strong rust-resistant base
  • Ideal for various surfaces
  • Dry & wet sandable
  • Comfortable spray can design
  • Oil-based Formula

5. Rust-Oleum Marine Wood and Fiberglass Primer

Do you find priming boat fiberglass a daunting job for you to handle? Well, that doesn’t have to be the case if you’ve got the right priming product by your side. So, why not consider investing in this Marine wood & fiberglass primer from Rust-Oleum?

You can use it on fiberglass, wood, and metal surfaces above the waterline.

Please note as I said it’s suitable only for surfaces that don’t get in touch with continuous water submersion. Except for that, you can use it on an aluminum boat, car, trim tabs, and even on ceilings. It’s a very wise and valuable investment.

Especially, considering that it’s ideal for multipurpose applications.

The product is made using a metamorphosed alkyd that creates a flexible coating. This coating is very durable and can withstand harsh weather conditions. Moreover, advanced alkyd makes this product resist peeling, cracking, and chipping.

It has excellent UV protection and color retention. For that reason, you can apply it to small luxurious crafts like speedboats, sailboats, and fishing boats.

Sounds like a perfect one for marine fiberglass products, right?

Let us bring you some of the more amazing features!

The product sands easily providing a brilliant finish. You can also apply it over surfaces that were previously painted without stripping off the old primer or paint. It enhances the appearance of the topcoat and guarantees long-lasting protection.

Even though it’s intended for priming whatnot and boats, you can use it for various surfaces indoor and outdoor. Not to forget that it’s extremely easy to use, even for beginners. However, it’s recommended that you apply this product outdoors or in well-ventilated areas.

So, let’s give it a try!

And for your convenience, here’re the product features and specifications at a glance.

Highlighted Features

  • Forms a long-lasting coating
  • Resists harsh weather conditions
  • Creates a smooth finish
  • Great semi-gloss retention
  • Dries fully in 1 hour
  • Indoor & outdoor application
  • Covers about 100 sq. ft.

6. TUFF Coat Primer Kit for Fiberglass Painting

For a new non-skid Rubberized Deck Coating to form a great bond, this is your staff. This is something special for which it was named as priming kit. It’s a great 2-component epoxy primer that can be used on various surfaces.

You can use it on fiberglass, concrete, and wood materials.

It can also be used on other painted surfaces. And that’s a perfect sign of versatility right?

YES…! From fiberglass boats to seawalls or, docks, this is the product for you. However, when used on extremely moist surfaces, it takes longer to dry. Moreover, you should not apply it in temperatures below 40 degrees Fahrenheit.

Unlike spray cans, this product is safe to handle and less harmful.

And it’s non-hazardous with low odor and VOC.

Since it’s a proxy primer, it comes in 2 different cans, one with the resin and the other with a hardener. To use the product, mix the resin and the hardener in the ratio of 1:1. This preparation may take some time. And that’s a catch!

If you feel the mixing is an extra step, please don’t buy this. Rather consider our ready-to-use spray products at the top of the list. Hopefully, you’ll find your best match as our list contains a handful of types. However, after mixing them, the application process is extremely simple.

You can either use a brush, roller, or sprayer. Whatever you find is at your disposal, make use of them. But the only thing you have to ensure is that you mix it in the proper manner. So it can take an action accordingly for which it’s intended.

1 quart of the primer covers about 62 sq. ft., while 1 gallon can cover 250 sq. ft. Once the topcoat dries, it forms a clear and durable finish. In addition to being durable, the finish is flame-resistant and waterproof.

So till the number 6, did you get any that you might call the perfect one? Let us know in the comment below.

Highlighted Features

  • Forms a clear finish on drying
  • Works well on moist areas
  • Ideal as fiberglass primer
  • Versatile and safe product
  • Resists flame & water
  • Water-based product

7. Rust-Oleum Marine Metal White Primer

As number 5 on our list, this one is another above-waterline primer. A precise pick by our expert, that guarantees excellent coverage. You just don’t really have to look further for any other recommendation.

Either you’re priming your boat, and deck or any other fiberglass items; undoubtedly you can invest in this Marine metal primer from Rust-Oleum.

And you’ll see the results in your own eyes!

Just make sure the primer coat doesn’t sink. In other words, it’s not suitable for items that are in contact with continuous water exposure. You can easily apply it on bare metal using a soft brush. Moreover, it forms a smooth and uniform base, even when exposed to direct sunlight.

The primer has a superb adhering ability and it’s specifically designed for priming metal surfaces above the waterline. It forms a base coat that provides superior topcoat adhesion and durable finishes.

Similar to most quality primers, this product dries within 1 to 2 hours after application. It comes in a 1-quart size can, which is enough to cover about 100 sq. feet. This product is popularly known as a sandable and sturdy primer that works well in eliminating corrosion.

For that reason, it’s mainly used on lightly rusted, bare, or painted metals. Regarding the protection this primer offers, it’s simply incomparable. This allows the topcoat to dry fully, providing an even sheen and a nice look.

Because of the solid bond it forms, this product is ranked among the top primers. It flows well and it does wonder to stop your leak problems instantly since it is waterproof.

Highlighted Features

  • It’s quite sturdy & sands easily
  • Resists corrosion
  • Better topcoat adhesion
  • For priming above the waterline

8. TotalBoat Topside Gray Primer for Fiberglass Coating

Now, this is for boat lovers or, professional boat painters. And you can already guess it from the name.

Unlike most primers on this list, you can apply this primer to surfaces below the waterline. However, this doesn’t mean that it’s an epoxy barrier coat. This product is mainly designed for priming galvanized metal as well as aluminum vessels.

Painting a boat should not be a difficult process. That’s why you should always choose the right primer to do the task. To make your painting task easier, you should consider giving this TotalBoat Topside Primer a try.

This product is impressive since it ensures a low sheen finish. Not to forget that it does not fade, peel or chip. Moreover, it resists corrosion and abrasion from various chemical forms. This helps it to provide maximum shield and sturdiness for your surface.

You can apply this primer directly on the surface using a brush, spray, or roller.

Another great thing about this primer is that it’s safe to use since it has less chemical smell. It doesn’t have a strong odor and you can instantly clean it with soap and water. The primer is available in 2 different colors, gray and white.

So you can choose your favorite color.

Overall, this primer provides nice & smooth coverage. Unlike most aluminum primers, it isn’t as thick and hard to work with. You can use it both above and underneath the waterline. Best of all, you can apply it on the surface as a topcoat!

Highlighted Features

  • Resists peeling, chipping & fading
  • Multi-purpose application
  • Safe to use

9. Corrosion Resistance Gray Fiberglass Epoxy Primer & Sealer

Choosing the best epoxy primer might seem like a very straightforward task, but it is not. Instead, you have to consider all your options before you make a purchase.

One thing that most experts consider when purchasing an epoxy primer is the preparation needed. Some products have to be mixed with other things before applications, but others can be used immediately. If you want an epoxy primer that is easy to prepare, this Eastwood primer is a great option.

The primer is corrosion-resistant since it’s free of chromate and lead. You’ll also love this product for its great adhesion to various materials. It enhances body fillers’ adhesion and prevents damage resulting from water permeation.

If you want to reduce this primer’s viscosity, use a thinner. This helps you to use it as a ground coat, sealer and a precoat before you apply the topcoat.

However, if you want to get the best results, don’t use this product directly. Instead, look for an epoxy catalyst, and mix with it at a 1:1 mixing ratio.

Another good thing about this product is that it’s user-friendly. And it maintains a great color hold-out that dries fast. You can use it to prime materials like; fiberglass, steel, aluminum, body fillers, and existing finishes.

Highlighted Features

  • Provide great color adhesion
  • Ideal for various surfaces
  • East to apply and dries fast

10. Krylon Automotive Filler Gray Fiberglass Primer

As a car owner, you’ll have to deal with scratches and dings from time to time. If they are not repaired, such scratches will ruin the appearance of your car. Not to mention that the surface may also weaken over time.

Luckily, with this Krylon Filler Primer, you can cover up any deep scratches on the surface in no time. It helps you to avoid expensive repair work since you can fix those scratches easily in your garage.

This product combines durable CoverMax technology and excellent Krylon color with 1-can convenience. That’s how it provides better hide without depending on fillers or shading that can wash out or muddy colors. This results in a fast-drying, durable performance.

Besides, this high-quality product is extremely easy to apply.

It comes in a 12 Oz. aerosol spray can.

And that gives you total control over the application process. So you can coat the surface uniformly. Not to forget that it features an adjustable EZ touch nozzle. It will allow you to apply in any direction to guarantee a consistent and smooth interface.

You can use this primer to fill scratches on different surfaces. That includes – fiberglass, wood, and metal. To apply this product, start by sanding down the affected part of the surface. Then feather the surface and spray the primer.

Wait for the primer to dry before applying paint over it.

Highlighted Features

  • Easy to use design
  • Effectively covers deep scratches
  • Sands easily & dries off quickly
  • Durable & improved formula

Different Types of Fiberglass Primers

There are various types of primers you can use on fiberglass. If you can’t differentiate between them, choosing the best one for you might be an issue. Basically, it’s a type of paint that is sticky and flat. It mainly consists of 4 elements:

  • Synthetic resin 20 to 30%
  • Solvent 60 to 80%
  • Additive agent 2 to 5%
  • Polyethylene (some specific)

Each type has its own benefits and features. Consequently, a single type might work best in certain circumstances and surfaces. Now, let us inform you about the 4 common different types available!

1. Urethane Primer

About 90% of auto body shops in the United States use urethane primers. They provide excellent build, sands easy, and dry fast. Also, they aren’t reversible, meaning that once they harden, they don’t go back to the liquid state.

However, these primers don’t offer great corrosion protection and rust resistance. And their adhesion to bare metals is not that good. The best time to use these primers is when you’re repairing minor dents on the fiberglass surface.

2. Lacquer Primers

These primers are still widely used because they seem very cost-effective. However, considering the dry-film-build they form, they’re the most expensive primers. Lacquer types can reverse into a liquid form. And they react when they’re top coated with another product. Moreover, they don’t provide corrosion protection and rust resistance.

3. Self-Etch Primer

This specific type has been in use for many years. And you’ll find most paint companies are still using it. It’s an acid that burns into the metal surface. So, it offers great adhesion and corrosion protection to bare metals.

Since self-etch primers don’t have a film build, they are not ideal for filling in scratches. However, they are good for a new aluminum surface and restoration.

4. Epoxy Primers

These types provide the best corrosion protection and adhesion. They also offer an excellent film build that resists moisture. If you’ve stripped down your car completely, this is the best type of primer to use.

One issue with most epoxy versions is that they take a long time to cure fully. For that, they don’t sand well. However, manufacturers are now producing fast-drying and easy-to-sand epoxy primers.

Benefits of Using Primers

1. Great Paint Adhesion

Priming before applying your final paint coat has several benefits. The main benefit is to provide proper paint adhesion to the surface. Primers also enhance the final finishing aesthetics.

2. Durable Finish

It gives a more consistent sheen level and color while ensuring a durable finish. While we’re still on the finish, a primer offers a smooth and consistent surface.

3. Enhances Surface Hiding Power

Using a primer with the same color as the topcoat offers an additional layer of the topcoat. This strengthens the paint’s hiding power over the surface.

4. Prevents Suction of the Topcoat

It also prevents suction of the topcoats into the material. Without a primer, some of the top paint coat soaks into the surface. This reduces the final film build or the thickness of the topcoat. So, a higher film build improves the appearance of the finish. Subsequently, it prevents the formation of small cracks on the surface after some time.

5. Extends Paint’s Longevity

Another benefit of using primers is that they are more affordable than topcoats. They make the final finish look better for a long time and enhance the quality of the paint works. Also, since most primers dry quickly, they guarantee a simple application process.

Oil-Based vs. Water-Based Primer

Ever wondered what’s the difference between oil-based and water-based primers? Well, the difference is simple!

1. VOCs Containment

Oil-based primers contain VOCs. They have a strong formula, meaning you only need one coat. However, because of the VOCs, you should always have a mask when applying an oil-based primer. Contrarily, water-based primers are much safer to use since they don’t contain VOCs. For that, you can either use them for outdoor or indoor applications. On the downside, they aren’t as sturdy as oil-based primers. So, you may need to apply more than 1 coat.

2. Allowed Paint Type

Oil-based primers are meant for enamel paints while water-based primers are for latex/ acrylic paints.

3. Field of Use

You can use water-based primers for ceilings and walls where preparations or new work is needed. On the other hand, oil-based primers are mainly used for metals, woodwork, doors, and windows.

4. Cleaning Process

Another notable difference between these primers is that water-based are much easier to clean. While you may need turpentine to clean up oil-based primers, you only need soapy water for water-based primers!


Choosing the right primer will add value to your effort. And it will surely improve the appearance of your painted fiberglass surface. With one of the above products, hopefully, you’ll have an affordable option to protect your fiberglass from rust and corrosion.

Feel free to let us know if you have anything to share. Also, we’d like to hear back, what product worked great for your priming job, for a satisfying result?


1. Can you use epoxy primer on fiberglass?

Answer: Of course, you can! Applying an epoxy primer on the fiberglass surface before the final paint helps the finish last longer.

2. Is oil-based primer waterproof?

Answer: Wet oil-based primer can be applied on various surfaces. Once the primer dries, it becomes water-resistant, protecting the surface from rust and corrosion.

3. What is a silicone primer?

Answer: Silicon-based primers are made up of ingredients ending in –silicone, -siloxane, -cone, -methicone, or –silicate. Some descriptions that demonstrate their benefits include; silky, waterproof, photo finish, and high definition.

4. Is oil-based primer sandable?

Answer: Yes, you can sand over oil-based primers. However, you’ve to wait for about 8 hours after application for the primer to dry fully. Also, remember to wash away the sanding dust before you apply another coat.

5. Does primer waterproof wood?

Answer: When water soaks into the wood, it causes dry rot, mildew, or warping. Luckily, applying a primer will make the wood surface waterproof and prevent it from absorbing the solvents. In addition to making the wood waterproof, it will enhance the appearance of the finish.

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