Are you looking for the best auto primers to use when painting over old paint?
You're in the right place.
In this ProPaintCorner guide, you will learn:
- How to prepare your vehicle for primer
- What is the best way to apply auto primer
- Our top-auto primer picks
- And much more!
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U-POL High Solids High Build Urethane Primer Kit With Hardener
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Speedokote SMR 210/211 – Automotive High Build 2K Urethane Primer
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Speedokote Epoxy DTM Primer Sealer Kit SMR-260G/261
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Evercoat 713 Gray Feather Fill G2 Primer
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Speedkote 2.1 VOC Urethane Black Gallon Kit SMR-221B/222
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Our Overall #1 Rated Pick
Updated On August 20, 2021
If you're looking for an incredible primer, this european style multi-functional direct-to-metal primer is your new best friend.
This stuff is durable and offers amazing hiding power due to its high opacity.
It does a great job at leveling out surfaces and it can be air dried for ease of application!
Top 5 Best Automotive Primers to Cover Old Paint
In a hurry? Check out our Top 5 picks below! Keep reading to learn more about these automotive primers!
How to Prepare Your Vehicle For Primer
Knock these three prep tasks off your list before you start priming.
Strip to Bare Metal
Done properly, this job requires that old paint be stripped off before you prime.
Some popular methods include:
- Stripping disks
- Media blasting
- Chemical stripping
Research these at your leisure, and select the method that is best suited for your situation.
The reason why you strip old paint is to reveal any trouble-spots that need attention. This stripping process along with the ensuing steps ensures that your topcoat ends up glossy, silky smooth, and flawless.
Prior to stripping your existing paint, clean the entire auto body surface with a wax and grease remover.
Anyone tackling a full auto body restoration on a hot rod would absolutely strip down to bare metal.
Repair Body Damage
Rust, fender dents, and scuffs all must go before you prime. This sets the stage for the filler and primer that will be applied once you have your smooth surface.
The more effort put towards treating underlying body damage, the better your new paint finish will be.
Rust absolutely must be mitigated. Failure to address it could very well lead to some pesky paint bubbles not far down the road.
Apply Body Filler
There are many various filler compounds available on the market.
Bondo is a popular brand that has been a mainstay in autobody shops for decades. This easy spray version is suitable for autobody applications, dries fast, and is perfect for filling in some small scratches.
Or, you can opt for the traditional putty version that fills deep scratches easily.
Once your body filler has hardened, it must then be sanded down and feathered into the original body lines.
What Are The Different Types Of Automotive Primer?
Use an epoxy primer when hardly any bodywork has been done. Otherwise, a two-part polyester primer's thick finish is best.
These water-resistant primers create a hard, chemically-resistant coating that sets the foundation for your basecoat.
If you have wet sanding equipment on hand, it is the best way to prep between rounds. Sanding epoxy primer with sandpaper tends to clog easily when sanded dry.
This two-part high-build primer is best suited for situations where extensive bodywork has been done. Its high solid content helps avoid shrinking.
Its easy sanding makes it a great choice to use for straightening those wavy side panels.
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What Do You Need To Know When Applying Primer?
This basic information is helpful to know when preparing to apply primer.
There are two recoat windows to know about; coats, and rounds. Your p-sheet tells you the recommended intervals between each. Repaint as directed for the best results.
Coats are laid down quickly in succession, allowing little dry time between each. This short dry time, between coats, is sometimes called a flash-period.
Rounds are a series of coats, with a much larger dry time between each. Often, a round will require an overnight drying window.
You'll use the eye to judge how many coats the vehicle will need. As your tech sheet will detail, the wait time for painting basecoat over primer will increase with the number of coats and whether or not you used filler.
Once your multiple rounds of primer are applied, you're ready to sand and seal.
Sanding, like stripping, is done in various ways. Generally, a sanding block is used.
Your p-sheet will tell you the ideal grit rating.
Spray on one coat of primer-sealer. Let it dry 30 minutes, then you're ready to start laying down your basecoat, topcoat, and eventually clear coat.
Now that you have a solid foundation that details the priming process from old paint to a smooth surface, now's the time to select your primer.
For a high-level video overview on how to spray auto primer, check out this video.
Our Reviews of the Best Auto Primer to Use Over Old Paint
This primer earns our top pick for its versatility.
The standard 4-to-1 mixing ratio allows it to adhere well as a primer.
Or, thin it to use as a sealer.
You want a 1.8 spray tip on hand when spraying this primer.
Air drying, I.R. curing, and dry baking all work fine as drying methods with this U-POL urethane primer kit.
This all-arounder primer from Speedkote is nice. It lays down thick and you can thin it with the half-part of your choice.
Its fast flash and cure time explains why it's become a first-choice among mobile repair services.
High-build indeed, this urethane primer will vary in the number of coats needed by the quality of your basecoat.
Get that bottom layer impeccably smooth, you won't regret it.
If you happen to live in either California, Maryland, or Deleware, you'll have to order the SMR-221 formula that is lower VOC, and that meets those states' more strict rules around volatile organic compounds.
The Department of the Environment for the State of Maryland published this document to explain why their state has decided to follow California's lead as regards VOC regulation.
The 260G formula epoxy primer-sealer from Speedokote is your easy choice for most paint jobs that don't entail extensive body repair.
Spray this epoxy primer with a 1.3 tip and it will lay down about as smooth as you could expect epoxy primer to be.
This paint has a nearly flawless customer feedback record.
Even for its slightly higher price, its ease of use and flawless finish make it, for many, worth the extra investment.
This polyester primer is considered premium grade by most for its high-build, high-solids content.
It is, however, not likely to become your one-and-only, one-and-done primer.
If anything, it's more of a perfect second coat primer.
An epoxy first coat, the polyester second, and a urethane primer topcoat is one strategy you may explore.
If your spray tip is smaller than a 2.2, you'll definitely need a reducer.
When sanding, use no finer than a 150-grit block. You may also consider topping the Evercoat 713 with a finer urethane primer that can be sanded more finely.
This is essentially the low-VOC counterpart to our best value pick, the Speedokote SMR-210/211.
It's a fast-drying, easy-sanding 2K urethane primer known for great color and gloss holdout.
You will need to top it off with a urethane topcoat, so be advised that this formula is not intended as a stand-alone primer.
The U-Pol Urethane Prime Kit earned our top pick for its versatility.
That it can be used as a primer and as a sealer is a major competitive advantage for it.
It's priced competitively and does excellent in customer feedback surveys.
High opacity coverage, paired with the excellent film build makes this European-styled primer an excellent all-around option for many automotive paint jobs.
Final Thoughts on Automotive Paint Priming
Often times, your primer kit will call for a specific percentage of reducer to be added to your mix.
For urethane primers, consider this popular reducer from Speedokote.
And if you're using an epoxy primer, this Owlgrip is a trusted choice.
Here are a few more related topics to the world of automotive priming and painting that you may like to consider.
The Lacquer Hype
You'll sometimes hear it recommended to only use lacquer when restoring existing paint on a vehicle. Don't be so quick to take this advice.
A ground-up 1957 low-mile Chevy Corvette restoration may call for a lacquer finish if it's intended to be put in a showroom or sold at auction.
This lacquer material is what you'd generally see used for what is called a 100-point Concours restoration. That basically involves vehicles being restored to factory conditions, or better.
Lacquer creates a strong chemical bond by permeating deep into the sheetmetal. Unfortunately, these lacquer primers' finishes only hold up under the elements for a short while.
It's not uncommon that cars painted with it eventually show crazing and wrinkling. To repair those would require stripping the paint, once more, right down to the bare sheetmetal.
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Every auto primer on the market includes an accompanying P sheet also known as a tech sheet. It contains all the information you need to to use that particular paint product, such as:
- What it can be sprayed over
- How to prepare the surface
- What type(s) of spray gun to use
- Number of coats
- Recoat windows
- Dry times
- And more...
The 15 Degree Rule
Ambient air temperature is crucial when using a two-part primer, such as one including a hardener. Here's how the rule works:
- For every 15-degrees above the recommended standard conditions, dry time and pot time may be reduced by half.
- For every 15-degrees below the recommended standard conditions, dry time and pot time may be doubled.
Wear the Proper Safety Gear
Whenever spraying paint be sure to wear a properly-fitted NOISH-approved activated charcoal cartridge respirator.
As you sand down layer upon layer of old paint, stay confident. You want the smoothest surface possible before you lay down primer and that means taking off before you put on.