Permatex Rust Treatment converter 16 oz — 1‑step rust-to‑polymer, paintable primer

This concentrated 16 oz formula is designed to stop corrosion on a wide range of metal surfaces by chemically converting flaky rust into a stable, adherent coating. Applied by brush or spray, it reacts within minutes to replace loose iron oxide with a tough black polymer that protects the substrate and acts as a paintable primer. It’s formulated for use with body filler and fiberglass and performs best between 50°F and 90°F (10°C–32°C), on surfaces not exceeding 200°F (93°C).

How does Permatex 81773 stop rust so quickly?

The product contains active chemistry that reacts with iron oxide to form a new, bonded polymer layer instead of simply masking rust. This conversion process eliminates flaky rust and creates a cohesive surface that seals the metal from further oxygen and moisture exposure.

• Reacts with rust to create a black polymer coating in minutes
• Displaces loose scale so metal is stabilized for painting
• No sanding to bare metal required for many applications
• Works on automotive, agricultural, marine topsides and industrial parts

What surfaces and temperatures are appropriate for use?

Permatex 81773 is suitable for steel and ferrous metal parts across many environments, including trucks, trailers, tanks, fences, and farm equipment. Avoid applying to automotive exterior sheet metal repairs; the product is intended for structural, mechanical, and non-visible sheet metal applications.

• Recommended service temperature range: 50°F–90°F (10°C–32°C)
• Do not apply to surfaces hotter than 200°F (93°C)
• Approved for pipes, valves, decks, hatch covers (topcoat with marine paint)
• Not recommended for exterior body panel finish work

Can I paint or use body filler over the treated area?

Yes—once the rust converts and the black polymer film forms, the surface accepts most primers and paints and is compatible with body filler and fiberglass repairs. The cured coating acts as an excellent base layer, improving adhesion and extending the life of the topcoat.

• Tough polymer finish serves as a paintable primer
• Formulated for use with body filler and fiberglass repairs
• Allow adequate cure time per product instructions before painting
• Topcoat with suitable marine or automotive paint where applicable

How do I apply Permatex rust treatment safely and effectively?

Surface prep and application method affect results: remove grease, heavy scale and loose flakes before treatment, then brush or spray the liquid over the rusted area for complete coverage. Work in a well-ventilated space at recommended temperatures and follow safety directions on the label.

• Clean surface of oil, grease and loose rust prior to application
• Apply evenly by brush or spray to saturated coverage
• Allow minutes for the polymer coating to form; follow cure timing before sanding or painting
• Use appropriate PPE and ventilation during application

Who is this for? Permatex 81773 Rust Treatment is aimed at mechanics, fabricators, fleet and farm maintenance crews, boat owners (for topside repairs with proper topcoats), and DIYers who need a ready-to-use rust converter that also functions as a paintable primer. It’s especially useful when full metal replacement isn’t practical and you need a quick, durable way to stabilize corroded components prior to filler work or repainting. Keep in mind it’s not intended for final automotive exterior sheet metal finish panels.