The Best Undercoat Paint: Reviews For Your Paint Job

Any time you take on a painting project, it can be a big undertaking, and the undercoat paint you choose can make or break the time you invest in the project. No matter what surface is being painted, without a good undercoat, it won’t come out the way you want it to. Your home deserves the best, and the best comes from underneath.

Before deciding on what color you’d like to paint, it is vital to pick which undercoat you need to use. Remember the important thing to think about when choosing the under coat paint you’d like to use – pick something appropriate for the surfaces you’re painting, and the desired outcome of the project.

Consider the size of the surface that you’re painting and whether you want to use a spray application product or a canned product. Also consider what kind of surface you’d like to paint on top of.

Best Undercoat Paint - Comparison Guide

Image

Model

Size

Type

Price

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3M 03584 Professional Grade Rubberized Undercoating

3M 03584 Professional Grade Rubberized​

16 oz

Spray

$$

Rust-Oleum Automotive 254864

Rust-Oleum Automotive 254864

32 oz

Can

$$

POR-15 45404 Semi Gloss Black Rust Preventive Paint

POR-15 45404 Semi Gloss Black Rust Preventive Paint

1 qrt or 1 pint

Can

$$$

Rust-Oleum 248656 Automotive 15-Ounce Undercoating Spray

Rust-Oleum 248656 Automotive 15-Ounce Spray

15 oz

Spray

$

Automotive Spray-On Rubberized Undercoating Material

Automotive Spray-On Rubberized Material

1 gallon

Bottle

$$

Dynatron 544 Dyna-Pro Paintable Rubberized Undercoating Can

Dynatron 544 Dyna-Pro Paintable Rubberized Can

1 or 5 gallon

Can

$$$$

Penray 4424 Rubberized Undercoat

Penray 4424 Rubberized Undercoat

16 oz

Spray

$

TRANSTAR (4363-F) Quick Dry Rubberized Undercoating

TRANSTAR (4363-F) Quick Dry Rubberized​

17.75 oz

Spray

$

3M 08881 Undercoating

3M 08881 Undercoating

16 oz

Spray

$

Evercoat 1348 Low VOC Premium Rubberized Undercoating

Evercoat 1348 Low VOC Premium Rubberized

17.75 oz

Spray

$

Advantages and Disadvantages of Rustproofing your Vehicle

Worker Painting A Red Car In Paiting Booth Using Professional To

To make the car stand up against the wear and tear of the elements, undercoating tends to be a good idea.

This is especially true when living in areas such as Hawaii or South Dakota.

Living in close proximity to the ocean means your car is subjected to salt air. Objects that are in contact with salt water tend to become rusted faster than others. 

That’s because salt creates a reaction that begins the oxidizing process. When a car becomes dented or damage, it creates openings in the paint where rust can easily occur.

This is the same concept for people who live near a lot of snow. They will be traveling on roads where salt is used to melt ice. This salt will also cause corrosion to a vehicle and therefore should be protected. Another benefit is that the undercoating can be a sound dampener making it quieter on the road.

There are some drawbacks to consider before undercoating your vehicle. The first is the cost. Car dealerships can charge a good amount of money to apply an undercoat to a car. Another downside is the additional weight the undercoating can apply to a vehicle. This can affect a car’s fuel efficiency.


Different Types of Undercoating

When looking to apply an undercoating, you will notice several types available.

Water and Paraffin-Based

Water-based tend to be the most popular for DIY projects. They are found in automotive parts stores generally in an aerosol can. They are thin set and have fast drying times. The downside to this type is that they often need to be repeated at a later date.

The paraffin-based coating contains a wax to make it slightly stronger than a typical water-based undercoating. These are available as a spray or paint-on formulas. They should be replaced once a year.

Petroleum and Rubber-Based​​​​

A petroleum-based undercoating contains oil and will deflect road salts and debris. It also repels water better than a paraffin-based version. These formulas are generally only available through a professional provider or applied when purchasing a vehicle. You will need to replace this once per year as well.

A rubber-based coating is the second strongest available. It is designed for rough terrains due to the flexibility in the undercarriage. They are available as a spray or paint-on application. It can also be purchased as an option when buying a new vehicle.

Asphalt-Based Undercoatings​​​​

An asphalt-based undercoating is the strongest you can purchase. It is meant for all-terrain or military vehicles. It lasts the longest and is the ideal option for a vehicle that sees heavy road use.


10 Best Undercoat Paints Reviewed

Some choices are better than others and this list should help you decipher the good options for your project. To help you decide which of the number of undercoat options to choose from, I’ve compiled a list of the best under coat paint to help you get started on your paint project.


3M 03584 Professional Grade Rubberized Undercoating

This is my number 1 option to use on vehicles and other items made of similar metallic materials. The black undercoating provides a good base to paint on top of, and it provides a perfectly smooth rubberized surface on which to put the next coat of paint.

The easy spray can, may not be best for large surfaces, but it works well when patching up small areas on a vehicle. Special chemicals within this product also help prevent corrosion, so that the coat of paint you add on stays on!


Rust Oleum Automotive 254864

Rust Oleum has produced this fantastic, professional grade undercoat paint that comes in a 32-ounce can, which makes it great for larger projects! Perfect for all types of vehicles, and the unique formula prevents against rust.

The rubberized coating that this product leaves behind also has a special feature that helps to reduce sound that comes from clinking and clanking vehicles on the road.

The final benefit of this product over this is it’s quick dry quality. By drying quickly, it allows you to get that first coat on, and move on to the next within a very short amount of time. DIY quick time!


POR-15 45404 Semi-Gloss Black Rust Preventive Paint

POR-15 makes this high-tech and high-performance rust-preventive coating that is specifically designed for applying to any rusted or seasoned metal surface. By protecting the metal from further exposure to moisture, this formula can effectively prevent future rusting.

Don’t just use this product as an undercoating to your vehicle! It can be used on most any metal surface as a protective paint against the elements. In addition, it is sold in 1-pint or 1-quart containers, so you can purchase just what you need to get the job done.


Rust-Oleum 248656 Automotive 15-Ounce Undercoating Spray

The Rust-Oleum brand does it yet again with this professional grade and paintable undercoating spray. It deadens sound and road noise as well as provides superior corrosion and moisture resistance.

This 15-ounce spray offers corrosive protection from water, salt and other chemicals. You can use it on cars, trucks, recreational vehicles and trailers for a superior protection. It dries quickly into a professional-grade rubberized material.

This low-cost spray goes on easily and would be simple enough that even a beginner could use it.


Rusfre Automotive Spray-On Rubberized Undercoating Material

This rubberized, chemically formulated material is an effective rust preventive product. The formula contains bound fibers used for creating a superior bond. This bond prevents cracking, peeling and chipping.

It can be sprayed on for an even finish or used with a brush if you prefer. It covers completely and also deadens sound. There is no asbestos in this formula.

This automotive material also seems to work well in the tailgate, doors and rockers. In fact, you can reduce it about 20-percent and help it to flow into seams for complete protection. The price for a gallon of this undercoating material is very reasonable and well worth the money.


Dynatron 544 Dyna-Pro Paintable Rubberized Undercoating Can

Backed by 3M, this Dynatron Dyna-Pro Paintable Rubberized Undercoating provides a durable barrier against the elements. It effectively protects against weather, salt spray, rust and chipping.

The fast-drying and flexible coating combines either an easy brush or spray-on application so you can do whatever is easiest. The superior sealing and corrosion resistance formula is a great option when looking to protect your vehicle from rust damage.

In addition, this is going to help deaden sounds and road noises as well. It can be purchased in 1 or 5-gallon containers so you can complete any sized job.


Penray 4424 Rubberized Undercoat

This quick-drying rubberized undercoat is waterproof and can also be painted over. It effectively protects the surface from rust, extreme weather, dust, fumes, road salt and corrosion.

When painting over this Penray formula, you won’t have to worry about bleed-through. Use this on all automotive applications including the undercarriage, wheel wells and frame. You can also expect a reduction in road noise when using this product.

This isn’t just for automotive use. It is also ideal for minor roof repairs, downspouts, gutters and works on your foundations. This product comes in an easy-to-use spray for simple application.


TRANSTAR (4363-F) Quick Dry Rubberized Undercoating

While this Transtar product isn’t overflowing in customer reviews yet, I think it will be soon. This quick-drying protective automotive coating is easy to use, even for a beginner. It will resist abrasion while preventing rust. It also is effective at sealing out dust and moisture. On top of that, it reduces road noise.

The Transtar spray is also great for other applications like recreational vehicles and trailers. I love that it is fully paintable, but I am not thrilled with the price.


3M 08881 Undercoating

This aerosol undercoat paint creates a rubberized surface on which to apply the next layer of paint. It is an excellent option when you’re concerned about potential rusting of the surface you’re painting.

This product is less suitable for the outside surface of a vehicle, but geared more towards the undercarriage of vehicles. It is also a good option if you’re repainting/recoating the fenders and bumpers of the car as well.

Once again, the spray can provides an easy-spray application for smaller surfaces and DIY projects.


Evercoat 1348 Low VOC Premium Rubberized Undercoating

The Evercoat under coat paint is a great option if your DIY project is a redo! This option works on surfaces that have already been painted. This product creates a rough, grip-able surface for you to add your next coat of paint.

It’s a great option to use on the undercarriage, bumpers and underbodies of cars or similar surfaces.

This option is described as a ‘premium’ option, because of it’s longevity. You can guarantee that you’ll only have to make this decision one time if you choose this option, because the undercoat paint is reliable, and will allow the next coat to stick firmly to the surface you’re painting.


Quick Guide - How to Apply Undercoat Paint

Follow these simple steps to quickly apply undercoat paint:

  • 1
    Clean the underbody with a degreaser.
  • 2
    Remove any rust with a grinder.
  • 3
    Sand any remaining rust. The grit should be at least 220 or larger.
  • 4
    Wipe away any remaining dust.
  • 5
    Paint and prime the underbody of the vehicle. Allow this to dry completely before moving on.
  • 6
    Apply undercoating liberally to the underbody. Any part of the car that will be exposed to the road should be covered. Allow the first coat to dry for at least an hour.
  • 7
    Apply a second coating.
  • 8
    This should be allowed to dry overnight before driving again.


If you need to remove the undercoating at any time, it is a simple process. Simply spray the undercoating with a recommended paint remover. You could use products such as paint stripper, aircraft stripper or solvents.

Sometimes, just a simple heat gun will work as well. Once the undercoating is softened, take your scraper and remove it carefully.


Conclusion

Any kind of DIY project is a big undertaking, and one you only want to do once. Whether it’s a small surface on a car, or something that seems unimportant, choosing the right under coat paint is the one of the most important parts of the process.

So that you only need to go through this process once, make sure you pick the right one. There’s no point in doing a DIY project that you’ll have to DIY once, twice, three times or four. This list I’ve compiled is an excellent guide in making this important decision.

Good luck with your project, I hope this has helped you pick out your starting point!


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