Rust is the enemy of every vehicle, frame, and metal surface. Once it starts, it spreads — and conventional paint alone won't stop it. POR-15 is the professional-grade solution trusted by restorers, fabricators, and mechanics for decades. This guide covers everything you need to know about using POR-15 to stop rust permanently.
What Is POR-15?
POR-15 (Paint Over Rust) is a moisture-cured, high-build coating that chemically bonds to rusted metal and creates a rock-hard, non-porous barrier that prevents rust from returning. Unlike conventional paints that sit on top of rust, POR-15 penetrates and locks it in place. It's used on frames, floors, engine bays, fuel tanks, and any metal surface exposed to moisture and corrosion.
The POR-15 3-Step System
POR-15 works best as a complete system. Here's the professional process:
Step 1: Clean & Degrease
Start with a thorough cleaning to remove oil, grease, wax, and contaminants. The POR-15 Cleaner Degreaser is formulated specifically for this purpose and prepares the surface for maximum adhesion. For larger jobs, the POR-15 Cleaner Degreaser is the economical choice.
Step 2: Remove or Treat Rust
For heavy rust, use the POR-15 Rust Remover to dissolve rust chemically without scrubbing. It's a water-based, biodegradable formula that converts iron oxide into a stable compound. For light surface rust, POR-15 coating can be applied directly — it actually bonds better to slightly rusted surfaces than bare metal.
Step 3: Apply POR-15 Rust Preventive Coating
Apply POR-15 Rust Preventive Coating in thin, even coats. It's available in multiple colors:
- POR-15 Clear Rust Preventive Coating — ideal when you want to see the metal beneath or apply a topcoat
- POR-15 Gray Rust Preventive Coating — a popular color for frames and undercarriage
- POR-15 Gloss Black Rust Preventive Coating — great for smaller touch-up jobs
- POR-15 Semi-Gloss Black Rust Preventive Coating — the most popular color for frames and undercarriage
- POR-15 Silver Rust Preventive Coating — ideal for underhood or areas where you would like a nice decorative metallic finish
Browse our full POR-15 Rust Stop Products collection for all available sizes and colors.
Application Tips for Best Results
- Work in humid conditions — POR-15 is moisture-cured, so it actually cures faster in higher humidity (50–75% RH is ideal).
- Apply thin coats — thick coats can run, wrinkle or take much longer to cure. Two thin coats outperform one thick coat.
- Don't expose to UV — POR-15 is not UV stable and will chalk if left exposed to sunlight. Always use POR-15 Topcoat products for exterior applications.
- Work quickly — POR-15 skins over fast. Close the can between uses and clean brushes immediately with urethane reducer.
- Wear gloves — once cured, POR-15 is nearly impossible to remove from skin. Nitrile gloves are a must.
Where to Use POR-15
- Frame rails and crossmembers
- Floor pans and trunk floors
- Engine bays and firewall
- Fuel tanks (use POR-15 Fuel Tank Sealer)
- Wheel wells and undercarriage
- Trailer frames and equipment
- Any bare or rusted metal surface
Shop POR-15 at VirtuColor Supply
We carry the complete POR-15 product line including cleaners, rust removers, rust preventive coatings, and topcoats. Browse our POR-15 Rust Stop Products and Automotive Rust-Prevention Paint collections to get everything you need for a permanent rust fix.
