How To: Apply POR 15 for Rust

Apply POR 15 for Rust

The Problem

If you are working on a car restoration project, then you are going to faced with rust damage. This problem can't be overlooked, as the entire project depends on repairing and eliminating rust. This would be like laying down new carpet to a house that was flooded, without cleaning the mess and making necessary repairs before laying the carpet down. The problem will still be there and the new carpet will be ruined.

Sure, we can paint over rust and it will look good, but this will not last. The rust is still under the paint and spreading. So if we want the the car to last, steps must be taken to stop the rust from spreading.

Rust Repair Methods

During this Mustang rebuild, I've demonstrated several ways to stop the rust. In this method, I am going to demonstrate the POR15, which has been around a long time and used by many restoration shops.

What Is Rust and How to Stop It

Rust is a reaction that is caused by exposed metal to oxygen and water. This caused the metal to start corroding. Once this process starts, it continues to spread until the the metal has completely corroded away or until the rust and been repaired and protected with corrosion protection. This basically seals the metal to protect it from oxygen and water.

With that said, a two step process must be followed to prevent rust from ruining a restoration project. The rust must be stopped chemically or mechanically. The POR15 is a system to clean and prep rust, which stops the rust chemically. An example of mechanically stopping rust is sandblasting the rust off. The second step involves protecting the metal from oxygen and water to prevent rust from reoccurring. With the POR15 system, this is the coating material.

In part 1, we are going to demonstrate how to prep the metal chemically using POR15 products.


  1. We removed as much of the rust we could using a wire brush, sanding, and scuffing using a red scuff pad.
  2. Once we removed as much of the rust, we vacuumed the floor pan using a shop vac.
  3. Then we mixed and applied the POR15 Marine Clean to the surface. Mixing ratios and application direction in video. Rinse thoroughly with water and allow to dry.
  4. Apply the ready to spray POR15 Metal Ready spray. Directions in video. Rinse and allow to throughly dry.

The POR 15 directions state that if the metal has been sandblasted to bare metal, the Marine Clean and Metal prep stages can be skipped and move straight to the POR 15 stage.

Applying POR 15 to Floor Pan

There are basically 3 ways to apply POR 15. You can spray with a spray gun or airless sprayer, roll it on with a paint roller, or brush it on with a paint brush. We decided to use the brush method and it worked well. The paint brush streaks flow out and it looks good. However, we were not too worried about how it looks, as we are going to cover most of the areas we coated anyway.


  1. Wear PPE (gloves, respirator, etc.)
  2. Mask or protect floor or areas that you do not want the POR 15 to get on. (We got some on the floor and it is hard to get off.)
  3. Mix coating using a paint stick. (Do not shake or place on a shaker)
  4. Apply 1 coat using a paint brush to all areas that were prepped and ready.
  5. Allow to dry 2 to 6 hours (dry to touch) and then apply a 2nd coat.

That's it, now allow it to dry. It will dry to a hard coating. That was our first time to use this specific brand and I think it worked well. I had a few comments from part of of other products to try, which I may in an upcoming video.

We do have a few rust holes to go back and weld in new metal. We also need to prime and apply seam sealer to all seams in the floor pan. Then we are going to lay down dynamat or something simmilar to reduce heat and noise into the passanger compartment.

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