Epoxy primers have become really popular and started competing with original self-etching primers in the car painting industry. One of the questions people often ask about these primers is whether you can paint over them. The question is whether you should use any kind of sealers over epoxy primers or you may just spray some paint, acrylic lacquer, or whatever else you choose for painting your vehicle.
And we can say the following: you can paint over the epoxy primer if the producer says it’s possible. But you will need to read the instruction or even consult with the producer to figure out more details about a special primer you use. Sometimes, epoxy primers made by different producers have various recommendations and application rules.
Here’s what we are going to talk about today:
- epoxy primers and their advantages over other traditional primers;
- things to consider when painting over epoxy primers;
- when it is not recommended to paint over the primers;
- how to prepare your primer for painting;
- what kinds of paint should you use over epoxy primers.
Let’s get started!
Epoxy primers – when should you use them?
Traditional primers aren’t that good in protecting your metal from getting rust and corrosion. Shortly after you cover the metal part with any self-etching primer, rust starts its dirty business under the coats of the primer. You should bear in mind that this will lead to hidden corrosion which means you will notice problems with your car body parts when it is too late to do something.
That’s why experts don’t recommend cars that have been repainted in garages after accidents. A car that was painted in a factory during production was immersed into a special bath filled with expensive primer. This ensured wonderful protection from rust and allowed car manufacturers to give 5 to 7 years of warranty from corrosion.
Epoxy primers are relatively new and they haven’t been used much by manufacturers. But some experts and experienced car paint specialists have started using them. These primers have quite a lot of important advantages:
- they protect bare metal much better than any other primers available on the market;
- they prevent rust and prolong the lifespan of the metal surface you cover with primers;
- two-part primers contain zinc which makes them even more efficient in the prevention of rust;
- primers are fast to dry, they form a solid coating, and are waterproof;
- you can apply the primers easily with not many rules that need to be taken into account.
When it comes to epoxy primers, you will find two types of people. The first type will recommend forgetting about all other primer types. The second type will still use old good self-etching primers and will say that all these new products aren’t worth the money. We are somewhere between – we recommend epoxy primers for those cases when you strongly need them. For example, when you are working on a project car, restoring the old or antique vehicles. But when you want to paint a door in your Chevy Spark, a simple cheap primer will be OK for that.
Paint over epoxy primer – why not?
We’ve investigated what specialists say on niche forums about painting right over epoxy primers and we’ve found many thoughts and guesses. One person recommends using another sealer over epoxy, another guy says it’s OK to paint over the primer, then some people say you will have to go through a big cycle of preparation. Why is it so complicated?
Here are the reasons:
- Epoxy primer cures really fast, but you will still have to wait at least 24 hours (better up to 5 days) before painting. Otherwise, your paint may not stick well to the car body.
- The primer cures completely after 7 days, and this is the point where you should paint right over it. If you have waited that long, better apply another sealer – just any other primer will be OK.
- If you see any defects and problems after you applied epoxy primer, painting over it will be a big mistake. Paint will not even try to fix that.
- Epoxy primers are really hard when they cure completely. Sanding them will be a challenge. But you shouldn’t start sanding before 2 or 3 days after you applied the primer.
- Some types of paint won’t be good to coat right on the primer. But unfortunately, we can’t make a list of those paint types. It all depends on the producers’ requirements and instructions.
What’s more, epoxy primers are now made by dozens of companies all over the world. It means you will find different chemical components in those primers and different requirements.
Our golden tip: always read what the producer says about the product in instruction. Once you do that, you know whether you can or can’t paint over the primer and whether you should take any other measures before.
Unobvious ways to use epoxy primers
Here, we decided to add some situations where epoxy primers can help you do the job wisely. And here’s what we’ve found:
- Working on a long-term project. You may cover the bare metal of your project car with epoxy to avoid any rust damages while you are searching for parts or for a decent paint option.
- Temporary protection for your car body. Sometimes it happens that you don’t have a chance to have your car painted after a small accident. Just clean the spot and cover it with epoxy to avoid rust issues.
- Epoxy as a final sealer before painting. This is another way big car shops use this primer type. They just put one or two coats of epoxy to seal the metal when it’s ready for painting.
- Sealing the area with some filler. If you used a filler to make the metal part smooth enough, just apply some epoxy over it. Otherwise, a simple primer will let the corrosion develop quite fast.
Some rules of painting over epoxy primers
The first and the most important rule is that everything should be done in accordance with the requirements. Just grab the can with your epoxy and read the rules of application. Remember that different producers will set different requirements for their primers.
Then, the second important rule: you have to wait until it cures, but not too long. Painting over a poorly cured epoxy will require sanding your paint off in the future and doing the job again. Painting over a fully hardened epoxy after 7 days or more will require the same – the paint won’t stick well.
The third rule – be careful with paint choice. If you used epoxy paint, you shouldn’t make any other coats. There is no adhesion, so you will need to abrade the paint before applying anything over it. If it’s the epoxy primer, no abrading is needed.
And finally, the fourth rule: use proper instruments. While primers may go in spray cans, the paint should only be sprayed with a special paint gun. If you use paint in spray cans, you will never paint your vehicle with good results.
What paint will stick to epoxy?
It’s hard to say in general – each producer will probably have a special list of paint types you can apply over epoxy primer. It’s dangerous to name any special kinds of paint here because you may use them and get bad results. Then you will blame us, and we don’t want this.
So here we’ll only say that you have to read carefully what the producer says in its instructions about the paint types. If you don’t have this information, simply go to the producer’s website and contact the support. Usually, they answer quickly and really help with paint choice.
What to use instead of epoxy primer?
You can use two-part self-etching primers that go with a sealer or zinc to protect the metal parts from corrosion. Also, you may use a simple etching primer and then apply additionally a sealer. Another option is to go for any packaged product of a certain producer. We mean, the products that have both a primer and paint in them.
But you should avoid painting on bare metal or on cheap primer without any sealer. You will also need to sand all primers before applying paint. The primers should look good as the paint won’t repair any problems and uneven spots.
As you see, epoxy primers are really good in terms of protecting your metal parts from corrosion and rust. They are more complicated to apply because they need a few days to cure and then they are really hard to sand. But the efforts you invest in the job are worth the result. You will seal the metal very efficiently and will avoid any rust issues in the nearest 7 or 10 years.
Epoxy primers are now available by many manufacturers but you will need to read the instructions carefully. The rules and requirements may differ from one brand to another. And without looking at those requirements you are likely to waste your time and money.
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What kind of paint can I use over epoxy primer? ›
Because epoxy painted surfaces don't allow adhesion, they must be abraded before they will accept new paint. Sanding the old epoxy finish with a 120- to 220-grit sandpaper will promote adhesion. Using a power sander will ease the process. Once the epoxy has been abraded, any type of paint will bond to it.How long does epoxy primer need to dry before painting? ›
The majority of epoxy primers need 30 to 60 minutes to dry. Before painting, wipe the surface with 500-grit sandpaper if epoxy (either as a primer or sealer) has been allowed to dry for more than a week.Do I need to sand epoxy primer before painting? ›
Sand to a smooth finish. If there are runs or sags in the epoxy, begin sanding with 80-grit paper to remove the highest areas. Sand until the surface feels and looks fair. Complete sanding with the appropriate grit for the type of coating to be applied-check coating instructions.Will latex paint stick to epoxy primer? ›
Latex paints are compatible with epoxy and they do an adequate job of protecting the epoxy barrier from UV radiation. In many architectural applications, latex paint may be the most suitable coating to use. Their durability is limited.What is the best top coat for epoxy primer? ›
Acrylic polyurethane topcoat has tough film, good adhesion, full color, and moderate price. It is a commonly used topcoat in medium and high corrosive environments.What kind of paint will stick to epoxy? ›
Generally, epoxy primers and LPU paints are compatible with epoxy resin coatings and may even chemically bond. However, some of the alkyd enamels and other one part paints and varnishes may not properly dry on epoxy resin coatings.Will enamel paint stick to epoxy primer? ›
From majestic jets to plain tugboats, enamel is commonly used on surfaces that require a durable coat of paint. Available in almost any color desired, it is a topcoat and, as such, requires a primer underneath it. Enamel can not only be painted directly over epoxy paint, it requires it as an undercoat.What is the best way to sand epoxy primer? ›
Watson. Above: For wet sanding epoxy, a typical grit sequence for smoothing an already flat surface would be 80 or 100 grit, then 150 or 180 grit, and finally 220 grit. Wet sanding with waterproof sandpaper is often the best approach to sanding cured epoxy.Can epoxy primer be left unpainted? ›
I know that Epoxy Primer with the Hardner is waterproof and can be left unpainted and is an excellent rust encapsulator. It also has a nice semi to matt look to it.What is the next step after epoxy primer? ›
After first reading our Epoxy Tech Sheet mix enough SPI Epoxy Primer to spray 2-3 wet coats over the entire car. Spray one wet coat and let flash about 30 minutes then apply a second wet coat (3rd coat is optional). Let the epoxy sit overnight then apply body filler or glazing putty over the epoxy.
How many coats of epoxy primer should I use? ›
Eastwood Epoxy Primer should be applied in medium wet coats, with a 30-minute flash period between each (at 70 °F). Typically, one to two coats is enough to achieve the de- sired 1 mil. dry film thickness, though more material may be applied as needed.What is the difference between primer and epoxy primer? ›
In general, urethane primers are not as moisture tolerant as epoxy primers so the substrate must be dry prior to application. The exact limit is determined by the manufacturer. The cure time of urethane primers is often much faster than epoxy primers and have a slightly lower temperature minimum for application.Is epoxy primer enough? ›
Its bonding capacity is excellent and it produces a good surface finish. Epoxy primers not only offer excellent adhesion to metals, but also serve as a proper base for extra undercoat products and top coats (paint).Will epoxy primer stick to anything? ›
Epoxy primers have excellent adhesion properties and will stick to bare metal, paints, primers and fillers. This means you can hit an area with epoxy primer that's been sanded down to bare metal, repaired with body filler, and then feathered into the original paint.Can you use urethane paint over epoxy primer? ›
Consequently, you either need to ensure that the surface is completely free of rust before you apply a urethane primer, or you need to lay down a coat of epoxy primer or an etching primer and put the urethane over it.Can you use acrylic paint on epoxy primer? ›
Mixing paints and acrylics with epoxy is not recommended.Why is epoxy primer so good? ›
Epoxy primers actually seal out oxygen and moisture entirely by providing a non-porous surface which can't be penetrated. Urethane primers don't seal this way but are more useful as filler after bodywork is done on a vehicle that already has a coat of epoxy primer.Is rustoleum primer an epoxy primer? ›
Rust-Oleum® 145 Water-Based Epoxy Primer is a two component epoxy primer, and stain blocker designed to improve adhesion to the roofing substrate. Relevant substrates include: Weathered Single-Ply, Asphalt, Modified Bitumen, EPDM, TPO, Aluminum, and more.What is the advantage of epoxy primer? ›
BENEFITS OF AN EPOXY FLOOR PRIMER
Epoxy primers are thin, providing a better adhesion as it penetrated into the concrete substrate allowing a better bond. Primers provide a better chemical bond when using thicker epoxy base coats. This results in a longer lasting and a more durable concrete floor coating.
800 Roller Covers are thin polyurethane foam covers and are the only roller covers recommended for applying epoxy. The thin foam allows you to control epoxy film thickness, avoid drips and runs, and get a smoother epoxy coating overall.
Can epoxy be sanded and painted? ›
Yes providing the surface of the cured epoxy has been sanded to give a key for the mechanical bond which will form between the paint or varnish and the epoxy. The surface should be matt and dust free before painting or varnishing.Can I use paint thinner for epoxy primer? ›
Thinner for all Sea-Line epoxy primers. It is very important to use paint thinners, which provide the appropriate parameters of paint – flow, pot life, time of drying.What grit sandpaper before epoxy primer? ›
If you are happy with the primer, all that needs to be done is a quick scuff of the panel with a Gray Scuff Pad or 400 grit sandpaper and you are ready to paint and clear. If you are going for a more finished look you can apply High Build Urethane Primer and level with 320 Grit Sandpaper on a Sanding Block.What is the difference between epoxy and enamel primer? ›
Epoxy Paint is suited for application where higher corrosion resistance, wear & tear resistance is desired. Enamels are for general purpose application in less demanding environment. Single pack epoxies however will need to be overcoated using an appropriate topcoat when exposed to extreme outdoor conditions.What thinner do I use with epoxy primer? ›
411 Epoxy Thinner is to be used in 4082 Epoxy Primer.What thinner to use for epoxy primer? ›
Epoxy Primer Thinner 200 is used as a thinner for 2-part epoxies like TotalProtect, Aluminum Boat Barrier Coat, and 2-Part Epoxy Primer systems (surfacing, high-build, and clear). It is also used as a pre-paint surface prep solvent for inflatable boats, and to clean painting equipment.Is epoxy primer tough? ›
#1107 Epoxy Primer is a premium, two component, low viscosity epoxy primer. When dry, this primer forms a tough but flexible film over the substrate, creating an ideal surface for coatings to adhere to. This high solids primer offers excellent penetration which results in superior adhesion.Why is my epoxy primer peeling? ›
In summary, the peeling off of the epoxy zinc-rich primer is generally due to two aspects: the wrong choice of paint or the inadequate treatment of the substrate. Therefore, before buying paint, determine what paint should be used, and clean the steel plate floor before construction, and polish the rust to SA2.Does epoxy primer need top coat? ›
Application of topcoat should be done within 7 days after priming to ensure good intercoat adhesion, otherwise re- application of primer is needed.How long to wait between coats of epoxy primer? ›
Wait 3-5 Hours & Pour the Second Coat of Epoxy Resin
Second, to save you some time, you can wait 3-5 hrs after your first pour, to where the resin has reached a jelly like state.
Can you recoat epoxy primer? ›
Once you have applied your first coat of epoxy, the second one can be applied in a general window of 10 to 24 hours. This window is temperature based and can change by a few hours according to the temperature. Always check with the manufacturer first for recoat times.How long does epoxy primer setting take? ›
The primer rapidly cures in 3 hours allowing you to prime & paint the floor in 1 day. The primer is suitable for sound concrete protecting & sealing your surface ready to paint. By using a primer you improve the coverage of your top coat, as well as improving the durability of your epoxy floor paint.How long does 2 part epoxy primer take to cure? ›
Drying Full cure in 12 hours at 68°F. IR Drying: 35-40 minutes at 140°F After 20-30 minutes / 68°F (20°C) recoatable wet-in-wet If recoated after 24 hours, the 2K Epoxy Primer Filler has to be sanded first.How thick is epoxy primer coating? ›
The optimum epoxy thickness is 6 mils +/-2 mils or 150 microns +/- 50 microns as measured by either a wet film gauge or a dry film electronic instrument. On larger OD pipe joints and profiles, some thinning may occur.Can you paint over epoxy without sanding? ›
Since the epoxy has cured a chemical bond is not possible so what is called a mechanical bond is needed. This simply means that the cured epoxy has to be lightly sanded before the next coat is applied: the first coat should have a matt, almost white, surface.Do you need primer over epoxy primer? ›
A primer coat prior to painting over epoxy is quite beneficial because it provides a uniform color base and is easier to sand than epoxy resin. It is generally not necessary to use a primer in order for a suitable top coat to adhere to sanded epoxy resin.What grit sandpaper for sanding epoxy primer? ›
Grits from 60 to 1000 are available, although you should only need 60 to 80 grit for initial abrasion, and 180 to 220 grit or maybe 320 for final sanding prior to priming or varnish. If your cured epoxy has runs and irregularities, I suggest starting with 60 or 80 grit sandpaper.What is non sanding epoxy primer? ›
DTM 1400 primer is a direct to metal corrosion resistant modified epoxy primer. Precision's DTM 1400 can be applied to provide a smooth high grade surface for finish coating with PC3, PC4 or PC5.Does epoxy primer fill imperfections? ›
You can also eliminate imperfections and create a flat surface by applying filler over epoxy or primer surfacer before you paint. One-part epoxy primer works as a starter coat for steel and a final sealant before painting.Is epoxy primer a sealer? ›
Epoxy primer is a sealer that produces a good surface finish on applied top coats. A two-part epoxy primer contains zinc phosphate, which acts as a corrosion-inhibiting pigment. Epoxy primers can be used to waterproof materials that consequently protect the bare metal from oxidation.