The Car Talk Communities are a never-ending source of material for us, and this week is no exception. A member had a question about the length of time before washing and waxing a car with a brand new finish.
“Hi I was just wondering how long do I have to wait to wash my car after a new paint job. People recommend 15-30 days 60-90 days but it doesn’t say anything about how hot it is outside. The painter who painted my car said I could wash it the next day. I live in Bakersfield,CA and the weather here has been around 110 for a week. So I’m just wondering how long do I have to wait in this kind of weather. Thanks.”
The answers in the Car Talk forum stuck to conventional wisdom about washing and waxing a freshly painted car:
One intrepid soul bucked the trend of waiting anywhere from a month to 60 days:
So who’s correct?
To get a legitimate answer, we got in touch with somebody who knows what he’s talking about. Mike Pennington is the Director of Global Training at Meguiar’s, which puts out a whole line of car care products for both consumers and professionals in the auto body and detailing industries.
Mike is careful to note that it’s tough to give a blanket answer, because it’s hard to say what paint is on your car. “Some more rural areas with less strict environmental protections can still be painting cars with lacquer,” he says, “while more urban areas and states with stricter environmental regulations have all switched to urethane paints.”
Since most consumers aren’t spraying cars themselves, we’ll assume that they’re painted at a body shop, we can cover a lot of landscape by sticking to the most common paints available today: urethane-based basecoat/clearcoat and urethane-based single stage.
The major difference between the basecoat/clearcoat and single stage is how the shine gets applied. With a single stage paint, both the color and the shine are shot out of the same gun, at the same time. Painters may opt to apply multiple coats of paint, but once the final coat is applied, the paint shines the way you’d expect a finished car to.
Basecoat/clearcoat paints are different. Using these types of finishes, a technician sprays the basecoat, which contains the color and any metallic flake. When that coat flashes or dries sufficiently to have the final coat applied, the clearcoat goes on. That stage provides the shine and does a better job of protecting the color beneath from fading thanks to UV rays from the sun.
To answer the question about how long to wait before washing and waxing, you have to understand that once a car comes out of a spray booth, the the finish isn’t exactly “finished.” Due to variations in temperature, or how the paint or clearcoat, hardners and reducers are mixed in the gun and applied, the final finish can have imperfections, such as dust in the paint, orange peel, or minor runs and sags in the finish.
Extreme examples of these defects may require the surface to be resprayed, but once the paint is fully cured — anywhere from a couple of hours to 24 hours — a good bodyshop will rectify them by wetsanding and buffing with some type of polishing compound.
Professional bodyshops simply aren’t waiting around with a freshly painted car in storage for 90 days before they cut and buff it. Paint manufacturers formulate their products to be ready for polishing within hours, not days or weeks.
We took a look at the technical data sheets for several common clearcoats and single stage paints to find out just how long they need to cure before they can be sanded and buffed.
The image below is from the Technical Data Sheet for Nason’s SelectClear 498-00 2K Urethane Multi-Panel Clear. It notes that the clearcoat is safe to wetsand at 1500 or finer, and buff in as little as four to six hours (after force drying in a heated spray booth) or as long as overnight when “air drying,” which simply means leaving the car in a constant ambient temperature (somewhere around 12 hours).
The technical data sheet on PPG’s Concept 2021 Urethane Clearcoat is similar:
It allows machine buffing in 12 hours, or as little as 10 hours depending on the hardener used.
Single stage urethane is similar. We took a look at PPG Omni MTK single stage urethane and the dry time for polish ranges between eight and 16 hours:
If the question is “How long should I wait to wash my freshly painted car,” Mike Pennington says the answer is that it’s ready to be wet down as soon as it’s ready to be wetsanded. However, you don’t want to make more work for yourself down the road, so he advises selecting top quality wash mitts, two buckets for wash and rinse water, and premium microfiber towels for drying.
So if you can wetsand, buff and wash in that amount of time, what about waxing? The answer is surprising, but you need to clearly understand the difference between “waxing” and “polishing.”
Wax (the Ultimate Liquid Wax on the left) has — duh — wax in it. It’s designed to be a UV protectant, and it can inhibit the curing process of new topcoats. However, there are a number of products you can use that are designed to clean and polish the finish, which is the end goal, without inhibiting the curing process.
If you’ve gotten a fine scratch in your fresh paint, Meguiar’s Ultimate Compound (right) is safe to use. For polishing purposes, Ultimate Polish (center) is also safe, and doesn’t have the UV protectants that inhibit the curing process. All of these products can be used as soon as you get your car back from the shop.
Mike also recommends carrying a premium spray detailer like Meguiar’s Ultimate Detailer in the trunk, especially with freshly painted cars. “You want to clean any environmental hazards — bird droppings, for example — immediately from fresh paint.”
One other distinction Mike makes is between a freshly painted car and a brand new car. “Brand new cars have been left to cure for weeks or months before they get to the end user. Those finishes are also baked on at the factory, so they’re ready to be waxed as soon as you take delivery,” he says.
For more from Meguiar’s, visit the website, which includes a ton of great information on caring for your car.