The Truth About Using Plasti Dip Over Rust

At some point, a bit of rust on your car is going to be inevitable, considering that most car bodies are made of steel or some other metal. So unless you happen to be the proud owner of a carbon fiber car (unlikely if you’re not a race-car driver), you will eventually have to find a way to fix it. Many people turn to plastic dip spray to help prevent their cars from rusting further.

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Can I use Plasti Dip over rust?

Plasti Dip over rust will continue to get worse underneath the Plasti Dip unless said rust is removed first. Unless one sands away all of it before they coat it in Plasti Dip, they are only covering the problem, not fixing it.

Want to know how to remove rust from your car and prevent it in a way that looks the best? The rest of this article will go into more detail on why and how to Plasti Dip your car with rust in a way that sticks!

How Rust Starts and Spreads On Cars

Rust is a chemical reaction that occurs when iron interacts with oxygen and water; hence the more scientific term for rusting is oxidation. Iron reacts quite easily with oxygen, and considering that virtually every car these days is made with a steel body (steel being mostly iron combined with a little carbon).

However, every car is vulnerable to rust. Humidity, changes in temperature, and even road salt can exacerbate the process of oxidation, especially if a car doesn’t have the proper paint to prevent it.

The problem with rust is that once the oxidation reaction starts, it tends to spread like mold on bread. The process occurs at the atomic level, meaning that all it needs to continue is microscopic amounts of water, oxygen, and iron. The only way to prevent rust from spreading is to remove all of it in the first place and then seal the exposed areas in as dry an environment as possible.

What Happens if You Plasti Dip Without Removing the Rust First?

When you plastic dip parts of your car with rust, it will slow the process of oxidation down significantly, but this option is not the best long-term unless you are using it as a temporary measure in the first place (say, with something like some old rims you intend to replace soon anyways).

This is because when you Plasti Dip a car, you are sealing the parts under it away from new exposure to water and air (good) but the water and oxygen that makes up the rust are still there eating away at the car (bad).

Over time (months and years worth of it), your car will still get worse underneath, and you may see bubbling or uneven spots of Plasti Dip on your car, which will only continue to get worse over time as well.

When you paint your car, you want it to look as even and smooth as possible, and this isn’t really possible if you leave rust untreated (especially really bad rust spots). And when it comes time to remove the plastic dip for when you want to do bodywork or add a new paint job, doing so will be harder than it would be with a rust-free car.

The short answer: Plasti Dip is an excellent temporary fix for rust, but not a good permanent one on its own.

The Correct Order for Plasti Dipping a Car with Rust

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The first step in properly removing and coating rust is first to get rid of ALL of the rust the best that you can. This article details the process in more detail quite well, but the simplified first steps are as follows:

  • Protect the rest of the car with poly sheeting and use masking tape to keep it in place right above where you’re going to work.
  • Use sandpaper to sand away the rust till it’s all gone.
  • Fill any pits in the metal with body filler
  • Clean the area with detergent and dry it off thoroughly

The next few steps differ from the above article’s list, as if you are using plastic dip you aren’t going to be using normal paint on your car. At this point, your best option is to cover the affected areas with a rust-proof primer and then sand that down.

After a few good coats of the primer and after it is dry, you can then plastic dip the car as you would normally. This is where the plastic dip is going to come in handy: it will help seal away your car’s body from any further rust, and in combination with the primer, should look smooth, and should even stay on for a good amount of time.

Of course, make sure to use several coats of plastic dip (5 minimum) for a longer-lasting and more durable coating for your car, and be aware that clear coating can be added on top of the Plasti Dip if you want a shinier and even more protective covering, though it will make the plastic dip coating harder to remove if you want to swap it out for a different color.

An extra tip: don’t do this sort of work on a particularly humid or rainy day if you are working outside; doing so will make the moisture in the air work against your rust removal efforts!

Using Plasti Dip Without Sanding

Of course, not everyone has the time and money on hand to do a full day’s worth of restoration on a car to get it to the point that it is rust-free. Sometimes you just need something that’s going to get your car through the winter.

If that’s the position you are in, then you will likely be better off plastic dipping your car like in the following video than you would be just letting the rust spread faster. As mentioned in the video, bodywork is expensive and time-consuming, and plastic dip can help preserve your car from total ruin now until the point that you can afford to make pricier repairs.

Not to mention, that a smooth coat of plastic dip looks a lot more presentable than a rusted-out car, even if the repairs are only skin-deep.