Protecting your metal against corrosion is essential. However, sometimes you may have to deal with rust due to changes in weather or accumulation of moisture. There are lots of products that claim to do away with rust, but some of them are fake and won’t help with rust.
When looking for the best primers for rusted metal, you need to find a product that is durable, simple to clean, provides a nice finish for painting, toxicity levels, and the amount you need. All these factors will help you find a primer that fits your needs.
Read on to learn more about the work of primers, our top picks, and how to choose the best products.
Everything You Should Know About Rusted Metal Primers
Here’s everything you should know about metal primers and their uses.
What Is a Metal Primer?
A metal primer is a product that is painted or sprayed onto metal to prevent corrosion and rusting. Apart from helping to prevent rust, a primer creates an excellent surface when you need to paint on the metal. Primers are made of acids and chemicals that penetrate within the rusty metal.
Reasons to Use a Metal Primer
Metals like steel and iron are prone to rust due to the oxidation process. Oxidation happens when a chemical reaction on the ironic or metallic surface of an unprimed metal surface gets into contact with atmospheric moisture like haze, rainfall, humidity, and mist.
The result is some orange-red discoloration formed from oxide compounds, which is also known as rust. The oxidation weakens the metal, which leads to the metal parts’ failure, which is why some metals end up in pieces. Some of the reasons you should consider using a primer include:
A primer bonds with the rust to prevent the rust from occurring on the main metal. You can use the primer to clean rusty pieces or use it to reverse or prevent rusting.
When using a primer, it’s critical to first remove a bit of rust through wire brushing, cleaning, wiring, or degreasing. You can use any chemical treatment or solvent before priming and painting the surface.
The cleaning process also gets rid of oils and other dirt specks from metal surfaces. A solvent with trisodium phosphate would work wonders if the metal had loose paint, dirt, or rust. After this, you can apply a rust-proof primer and paint the metal.
Prolonging Paint on Metal Surfaces
Priming any metal before painting helps to prolong their lifespan. You cannot skip this step during a metal painting project as you could end up dealing with rust over time. Using a primer adds a protective element that fights rust and improves the surface when you need to paint the metal.
Primers Help With Surface Concealment
Primers are not only meant to prevent rust and ensure that paint adheres to metal surfaces, but they can also be used to cover up issues with the base surfaces. A primer has a filling element, soothing that makes it a perfect concealer for metal defects.
Adding a primer helps provide extra protection from atmospheric moisture and weathering, and it also offers paint enhancement. Note that primers can adhere to light and heavy metals, but the effect of the primer largely depends on the metal surface porosity.
Top 8 Best Primers for Rusted Metal (2020)
1. Corroseal Water-Based Rust Converter Metal Primer
If you are looking for an easy to use metal primer solution, you should check out Corroseal Water-Based Rust Converter Metal Primer. Available in 32 oz, 1 quart, 1 gallon, and 5 gallons, this metal primer prevents new rust without further treatment.
One aspect that makes Corroseal stand out is its viscosity, which is thick and doesn’t come off easily. Its performance, compared to other metal primers, makes it an excellent product.
Previous users noted that even with a single application, one could easily see the results. You’ll find that with other primers, you may need at least two applications, especially when handling heavily corroded metal.
Another unique aspect is its water-based formula, something that makes it safe to use. The company guarantees that the product is non-corrosive and non-flammable. The rust converter is easy to clean up with soap and water.
A small quantity covers a huge surface area. For example, you can use toenails wet to cover 250 square feet per gallon of coverage. Its versatility also means you can use it in industrial, marine, or automotive applications.
On the downside, the Corroseal metal primer only works best for medium rusted metal; it won’t work well with shingled metal. That’s because its thickness doesn’t allow it to fit into tiny space between the flaky rust.
Some users also found out that you need sanding before applying the primer if you’re looking to achieve the best results. This is a disadvantage because some primers do not need any prep work. Corroseal is also a bit pricey compared to other primers.
- Only requires a single application
- Easy to use
- Simple to clean
- Non-corrosive and non-flammable
- Needs preparation before applications
- You need sanding before applying the primer
2. Krylon K06903907 Rust Protector Primer
Krylon K06903907 Rust Protector Primer is different from your regular primers. That’s because it works like a primer and as a paint, something that makes your work simpler. When you plan to paint any metal surface, you can relax as this primer protects the area from rust and gives you that smooth finish when you need to paint the surface.
Another fantastic aspect is that you don’t have to worry about the paint surface being different from the color of the Krylon primer because there are plenty of colors available. Krylon provides over 30 colors to choose from.
You get matte, semi-gloss, and gloss finishes, making Krylon Rust Protector Primer versatile. Its quick-drying capability is another excellent aspect given that other primers require up to 24 hours to dry. That means you don’t have to worry about dust, dirt, or fingerprints interfering with the primer application. Krylon primer dries in ten minutes to a smooth and hard finish.
You’ll love how easier it is to apply this primer as it comes in a spray can. All you need is to hold the can in a horizontal position and maintain a distance of two feet from the surface. The paint doesn’t leave drip marks. It‘s a popular option as it offers consistent performance in different corrosion tests.
Although the primer best adheres to metal, you can still use it over plastic. With the 360-degree cap, you can quickly spray the primer.
Unfortunately, the primer isn’t opaque, which means you may need to apply multiple layers to hide the underlying color of the metal. Also, the instructions are not straightforward, something that can be confusing. A few users reported the 360-degree cap as missing, while others ended up with primer-soaked clothes and hands and bubble-flecked surfaces.
Overall, the Krylon Rust Protector Primer is an excellent primer with a quick dry time. Its reasonable price, durability, and being an established brand makes this worth the purchase.
- Provides a range of finish options
- Comes with over 30 colors to choose from
- Drip-free and fast drying
- Simple to apply through a spray can
- Works on metal and plastic
- Economical for tiny projects
- Offers added corrosion protection for painted ad bare surfaces
- Needs several layers of application
- Unclear instructions
- Offers light protection
- Some users encountered messy application
3. Rust-Oleum 7769502 Enamel Paint Rusty Metal Primer
Rated as one of the best protective enamel paints, Rust-Oleum Enamel Paint Rusty Metal Primer is a must-buy if you have highly rusty metal pieces. The protective enamel paint is excellent in fighting stubborn rust that other rust removers won’t take off.
The solution goes deep inside the rust layers and turns it into black enamel. One thing you’ll love about this formula is that it doesn’t peel off after applying as it forms a sturdy bond. After drying, the primer gives the metal surface a unique finish. That means you can go on to paint and coat the surface without worrying about rust.
Rust-Oleum Metal Primer offers added protection, something that makes it ideal for both indoor and outdoor setups. The primer available in a 32-ounce can is oil-based, which means you get a smooth finish and an even surface.
Dealing with a primer that requires preparation can be frustrating. Fortunately, with Rust-Oleum, you don’t have to worry about dripping as the solution is consistent. It’s easy to apply it over as the primer is not so thick.
The only disadvantage with this primer is that it doesn’t dry as quickly as you may want. You may need to wait for a few days for the primer to dry completely. Drying can take six hours or up to 48 hours, depending on air humidity and ambient temperature.
Overall, the Rusty Oleum Enamel Paint Rusty Metal Primer is a reasonably priced and unique primer that offers rust prevention with guaranteed satisfaction while working on all metal surfaces like clean, slightly rusted, or heavy metal surfaces.
- Has a consistent formulation
- Simple to apply
- Effectively handles stubborn rust stains
- Provides a smooth finish for further painting
- Take time to completely dry
4. FDC Rust Converter Ultra Professional Grade Rust Repair
Are you thinking of converting rust into an inert coating to prevent further corrosion? You’ll want to check out the FDC Rust Converter Ultra. Termed as one of the best professional-grade rust primers, the FDC primer boasts versatility as you can use it on machinery, automobiles, marine applications, railings, structures, and more.
With a gallon of this primer, you can cover up to 500 square feet of metallic surface, something that makes it efficient. Moreover, you get to save time and money. The best thing about this primer is that it prepares you for different weather conditions while offering protection against rust and corrosion.
You’ll also find it simple to apply as all you need is to stir or shake before using and use a pump sprayer, roller, or brush to apply the primer. There’s no thinning required as the primer is ready to use.
However, you should note that you need to crap off any huge rust and scale particles with a sandpaper or wire brush before applying the primer. You’ll also need to clean the surface to remove dust, dirt, and grease.
FDC Rust Converter Ultra Professional takes close to 20 minutes to dry to a dark and smooth finish. You may need to apply a second coat of the primer before applying any paint to the surface. It’s easy to clean up with soap and water after applying the primer.
- Easy to use and apply
- Reasonably priced
- It dries quickly
- Some users didn’t like the result after a few months
- Requires surface preparation
5. Permatex 81849-12PK Rust Treatment
Permatex 81849-12PK is top-rated as one of the best automotive rusty metal primers, especially for people in the automotive industry. The formulation works well with fiberglass and body filler.
The primer that comes in a can allows you to use a brush or spray the rust converter directly to the metallic surface. Its formic acid combination means you can use it for small rusty spots, but this primer won’t work for extreme rust.
On the downside, the Permatex Rust Treatment needs a certain temperature for best results.
- Effective at converting rust
- Ideal for those in the automotive industry
- Easy to use
- Doesn’t work at certain temperatures
6. TotalBoat Rust Primer Converter
Totalboat Rust Primer Converter is the best value metal rust converter in the market. It’s made from a phosphoric acid base, like most rust converters, to ensure that you cover that corroded area properly.
Nonetheless, that means you need to wear protective gear as the formulation can create a burning sensation and cause inflammation when it comes in contact with your skin. The best part of using a phosphoric acid-based rust converter is that it covers a wide surface area than any other product. You can cover up to 500 square feet of coverage with a single gallon slightly rusted metal.
Total Boat also adds a touch of versatility as you can use it as a primer for bare metal. Other acid-based primers do not work well with bare metal and often flake off or become sticky. You also get impressive performance at a reasonable price.
The product changes rust to an inert substance, meaning it stops the oxidation process before it escalates. You can use Totalboat Rust Primer on any metal surface like bikes, cars, trailers, etc.
Remember to go through the work area with a brush to get rid of loose paint or unwanted rust before using this primer. The primer is simple to use, which makes it perfect for DIYers and professionals.
On the downside, TotalBoat Rust Primer Converter takes more time to dry compared to other metal rust primers. You’ll need to leave the metal surface to completely dry for two days before applying paint or another treatment. It’s also messy and can be challenging to clean.
Overall, Total Boat primer is a good product that will help you protect, preserve, and restore metal from rust.
- Covers a huge surface area per gallon
- Works as a primer on unrusted metal
- Simple to use
- Enhances finish durability
- Requires several coats as it’s thin
- Need post-treatment cleaning
- Not biodegradable
- Stains concrete and fabric
- Requires more post-treatment cleaning
7. Rust-Oleum Spray Paint Metal Primer
Rust-Oleum is a renowned brand, and the Flat Rusty Metal Primer doesn’t disappoint. Its unique rust prevent capabilities makes it ideal for heavily rusted metal surfaces. Being an oil-based primer, you can relax and enjoy the smooth and protective finish that comes in handy when you need to further apply paint to the metallic surface.
You don’t have to worry about the primer, notwithstanding the demanding environment, harsh weather, or heavy use as the primer is durable and sturdy. Its ability to bond with the rust tightly means there’s no chance for moisture or air to sleep in during the bonding.
Once one with the primer, you get a surface that paint can adhere to effectively and smoothly. Rust-Oleum Spray Paint Metal Primer has an all-angle spray option, which is convenient.
- Comes in a twelve-ounce pressurized can to cover 20 sq.ft coverage
- Adhered to a heavily-rusted metal surface
- You can put multiple coats in intervals
- Oil-based formula to guarantee rust prevention
- Suitable for marine, automotive, and household use
- Only works for heavily rusted metal surfaces
- The nozzles can be difficult to deal with
8. Krylon K06903700 Rusty Metal Primer
Finding a fast-drying primer isn’t easy, but Krylon K06903700 Rusty Metal Primer is an excellent choice if you’re interested in something that delivers quick results. The manufacturer claims that the product delivers a rust-fighting and smooth finish. The result is a durable and effective finish.
The primer made by Sherwin-Williams, a US-based company, enhances the adhesion for paint and prolongs the durability of the paint. You can be rest assured that you won’t be dealing with a corroded metal surface as the paint not only covers the metal surface but also smoothens any uneven surface.
Another aspect that makes this metal primer popular is its quick-drying capabilities. Other primers require you to wait for up to 24 hours for the product to dry, but Krylon primer dries in ten minutes to a smooth finish. That minimizes damage from fingerprints, dust, and dirt.
Krylon Rust Protector is an oil-based rusty metal primer that prepares your metal surfaces for any weather. Its affordability and effectiveness make it one of the best primers on the market.
Unfortunately, the sprayer that comes in a 12-ounce can hardly work, which means it sprays everywhere, or you may have to deal with nothing coming out of the can. You’ll need to hold the can in a horizontal position and maintain a distance of two feet from the metal surface to avoid drip marks and ensure a smooth finish.
Overall, the Krylon Rust Protector is a primer worth considering given its versatility, matte/glossy finish, and different color availability.
- Protects metal against corrosion
- Works on paint and plastic
- Comes with a wide selection of colors
- Perfect for small projects
- Provides a fast-drying resistance
- The product works as a paint and rust protector
- Can be messy to spray the primer
- Offers light protection
- Needs a rust-free clean surface
How to Choose a Rust-Proof Primer: Buyer’s Guide
Are you wondering what to consider when being a primer for rusted metal? In this detailed buyer’s guide, we take you through a list of factors to consider when shopping. Remember that the difference in formulation and methods is what differentiates a good primer from a poor quality primer.
Below are some critical considerations to make when choosing a rust-proof primer.
Determine the Purpose of Getting the Primer
Are you getting a primer for the treatment of rust or prevention of rust? You need to determine this beforehand to find a primer that works for you. Remember that manufacturers have different primers designed to meet various needs.
You’ll find that some primers are designed to handle present rust for them to be effective. This may be a problem if you are handling new metal. However, if you’re handling heavily rusted metal, you need a quality rust-primer.
Understand the Type of Surface You’ll Be Handling
Knowing the kind of surface you’ll be using the primer on is critical. You need to determine if you’ll be dealing with steel, cast iron, or a stainless steel surface. These types of surfaces are prone to rust; the only difference is in the way they rust.
For example, you need a quality primer for cast iron, but you may need some light painting and no primer for a lightly rusted steel type metal.
It’s also vital to look at the features of the metal primer. That’s because you can’t use any rust converter or primer on any rusting. A few manufacturers include oxidation related features that help with heavily rusted metal surfaces.
Know the Application Method
You need to know how the primer is to be applied. Most rust convertors are in liquid form, which means you can either brush or spray them on the metallic surface. Nevertheless, they are a few water-based primers that need you to prepare a solution. Creating a too thin solution means the primer will drip off the metal’s surface.
Consider the Time It Takes to Dry
Primers take up to 24 hours to dry thoroughly, but some products will take longer to dry. It’s essential to compare slow drying and fast-drying products and decide which works for you.
Know the Different Ways the Primer Works
You need to understand that not all primers work the same. Some are meant to handle light rust by covering and containing it, while others help remove the rust. Also, there are primers that work as rust convertors, which means they remove moisture and dust. Such primers stop the corrosion and make painting easier.
Decide if You Are Painting After
Are you planning to paint after and what type of paint job are you planning? Answering these questions will help you find a quality primer. Some metal primers cause splotches, though this is fixable with several coats of paint. You’ll find that corroded surfaces are affected by splotches, which is the reason why you need a heavy primer.
How Much Do You Need?
How much primer do you need? If you’re planning to coat a big surface, you’ll need a gallon compared to a smaller surface that will need a can of spray primer.
Determine the Primer’s Durability
A quality primer should ensure that rust doesn’t occur again. There are some formulations that provide fantastic sealing capabilities, which translates to durability. The best way to decide on a product’s durability is to go through previous user reviews and feedback. Fortunately, we’ve researched on your behalf and listed some of the durable primers you need to consider.
Remember that a durable primer will have an active response to the rust when you apply it. Always pick a primer based on the metal you are handling, which could be stainless, cast iron, or steel.
Note the Ease of Cleaning
You’ll need to clean up after applying a rust converter. It’s imperative to get a simple formula to clean if you plan on handling other activities. That will be convenient and faster.
Be Aware of the Toxicity Levels
The chances of a primer being flammable are lower if the rust converter has few toxins. Choosing a product with fewer toxins also keeps you safe as you won’t have to wear too many protective clothes. If you decide to opt for a primer with chemicals like phosphoric acid, ensure that you put it away from your skin as it causes a glow effect when in contact.
The Final Appearance
Apart from durability, quality, and effectiveness, you also need a primer that will give you that final look that you desire. You can check on precious feedback to ensure you pick a primer that will give that desired effect.
Finding the best primer for rusted metal requires research. Fortunately, we’ve done all the homework for you and ranked some of the best metal primers based on their ease of cleaning, durability, the time they take to dry, application method, among other criteria. You’ll find a primer that works for you based on your needs and budget.