Classic Car Rust Prevention: How to Seal the Floor Pan of Your Ride with POR-15

So, you bought a “new to you” project car and want to start the build right. That means tearing out the interior and making sure the floor pans are sealed and rust free. If you find Swiss cheese, check out this article on how to replace your floor pans. If you find minor surface rust and the occasional pinhole, keep reading and we’ll show you everything you need to know about classic car rust prevention.

How Do You Remove Rust From Car Floor Pans?

If it’s just surface rust, the most effective removal process is simply using a grinder with a wire wheel to clean up the old sheetmetal. Then, make sure you properly seal the floor pans, otherwise you’ll quickly end up right back where you started. If the rust looks more like asphalt than old steel, refer to the story we mentioned above.

How Do You Fix Pinholes in Floor Pans?

Pin holes, everyone’s got ’em! If they are few and far between, the quickest way to fix pinholes in your floor pans is applying a sealer like POR-15. Most of the time, like their name suggests, pinholes are very small and non-structural. So all you really need to do is some basic classic car rust prevention and seal up your floor pan from outside elements.

If you find yourself with holes that a dab of sealer can’t easily fill, you might want to think about repairing your floors with patch panels instead.

How Do You Stop Rust From Spreading?

Once you’ve determined that the floor pans of your classic car are in fact solid, it’s time to make sure they stay rust free. To stop the rust from spreading, you’ll need to grind off any remaining surface rust and seal the metal with a proper rust prevention product.

What Is the Best Rust Prevention Product?

We used POR-15 to seal the floor pans of our newly acquired 1963 Nova to get it ready for the rest of the buildup. If you are looking for the best rust prevention product to undercoat your classic car, check out our other story on The Hows and Whys of Undercoating.

Enough beating around the bush—it’s time to stop talking about sealing your floor pan and actually tell you how to do it.

  • Remove all the interior including seats and carpet
  • Scrape off as much of the old seam sealer as you can
  • Use POR-15 Metal Prep on all surfaces to be sealed
  • Use a wire wheel to grind off any surface rust
  • Spray and wipe the floor pans with POR-15 Cleaner Degreaser
  • With a foam brush, apply two thin coats of POR-15 Rust Preventative Sealer
  • Allow four to five hours to cure completely


Article by: Taylor Kempkes, Christian Arriero

Written by Maddi Hennessey

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