Does Kilz Stop Rust?

Preventing rust from occurring with your metals, especially on your gate or automobile, can be challenging. It is why most people opt for preventing the formation instead of removing rust. There are many materials you can consider, and while most people vote for Kilz, does kilz stop rust?

No, Kilz Primer does not stop rust. Kilz Primer is a water-based primer and sealer. It works by preventing existing rust to a greater extent than other primers.

Also, kilz on its own does not have the potential to stop metal from rusting, but it is often used as a primer when planning to paint a piece of metal to stop rust. What does this mean? We are saying that kilz is only a foundation layer for the real work of rust prevention.

Most metal surfaces are rough and hard to paint directly. This is where kilz comes in as it is applied to the tough metal.

Once applied, the water-based primer adheres to the rusting surface of the metal and provides a good ground for the process of painting to be carried out. Kilz is popularly used in the automobile industry in rust prevention of car parts (interior and exterior).

What Primers Are Best for Use on Metals?

You know what primer is best for your use when you know the type of metal surface that you’ll be working with. There are different primers on the market that are manufactured to answer different needs. If you have untreated metals which are more susceptible to rust upon exposure to air or moisture, using Iron oxide primer is the best option to go for. Iron oxide is also used during the process of galvanization of metal as a primer before the addition of the zinc layer.

What Primers Are Best for Use on Metals

How Does Kilz Work?

The unique thing about kilz primer is that it starts off the process of rust inhibition in metals by binding to surfaces that are hard to paint. All they do (or are meant to do) is to block all pores in the rusting metal before painting or galvanising is done as the case may be. To build on the fact established earlier, kilz is a water-based primer, which implies that once it is applied to metal and left unpainted, after a while it would start to break down or decompose into a chalk-like form. This decomposition of kilz may cause more deterioration of the metal to occur.

How Does Kilz Work

How Long Does Kilz Last?

Kilz will usually dry up in about half an hour once it comes in contact with any surface. After the kilz is dried up, you can then proceed to the topcoat or recoat it with oil-based paints or latex after an hour of applying the primer.

Is There Any Difference between Kilz and Kilz 2?

Although both primers are similar, there is yet a striking difference between their level of viscosity. Kilz is rated to have a viscosity that ranges between 95 and 105 KU while kilz 2 has a similar viscosity level with kilz ceiling paint. This particular type is more viscous and mingles well when used as a primer for painting. While kilz is used generally for metal painting, kilz 2 can be categorised for use in wall and ceiling painting because of their difference in viscosity.

Is There Any Difference between Kilz and Kilz 2

Application of Kilz on Rusting Metals

Now that you are aware of the key role that kilz plays in preventing rust in metals, we must demonstrate how to apply the knowledge either for personal use or industrial use. Explained below are the processes involved in rust prevention in metals using kilz as a primer.

Application of Kilz on Rusting Metals

  • Prepare the Metal: Start by brushing the metal surface to get rid of rust particles. This is not mandatory as you can always proceed to apply the primer on the rough metal surface as is. This will only help eliminate the chances of rust particles chipping the kilz layer. Also, this has to be carefully done so you don’t make the metal too smooth.
  • Apply the Primer: Next is to apply the primer (kilz in this case) on the metal surface. If you are galvanising the metal, always ensure that the metal surface is as smooth as possible to allow chipping or cracking from inside. Applying the kilz primer will stop the underlying metal from trapping moisture in its pores.
  • Now You Can Paint: It is recommended that you start painting once the primer is completely dried up to avoid reactions that will affect negative change to the metal you are trying to protect from rust.

Advantages of Using Kilz Primer to Stop Rust

Similar to iron oxide primer and zinc finish, kilz also has its advantages. You may think of it as the rate-limiting step in preventing rust in metals. Although kilz cannot stop rust, yet without it, a major rust-resistant finish cannot be applied. Kilz help in preventing rust in the following ways;

Advantages of Using Kilz Primer to Stop Rust

  • It creates the needed surface for painting and galvanising to take place
  • Because kilz is water-based, it makes it easy for paint to adhere to the surface of metals
  • It prevents metal pores from trapping moisture from the atmosphere
  • Kilz does not wash off the metal surface easily


Kilz is an important part of rust prevention in metals but does not have the ability to stop corrosion from happening. With the application of kilz and other primers like iron oxide, rust prevention is as simple as slicing through hot butter. The phenomenon of rust prevention in metal by painting is not complete without talking of primers like kilz. Remember that primers are only effective to the degree of their usefulness. Before setting out to paint those rusting metals in your backyard, know what primer works for you best.

Evan Cooper

Evan Cooper

Hi, I’m Evan Cooper, the founder and an editor of this site, Doesitrust. I’m a chemical engineer and working in a rust-eliminating paint manufacturing company. Besides this profession, I’m a researcher and blogger.

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