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Your cart is empty. Military-Grade Rust Prevention
Modeled after Military Specifications: MIL-PRF-16173, Grade 4 and MIL-C-83933.
Application:
IMPORTANT #1: Make sure your surface is clean and dry (not oily or greasy) to ensure best possible adhesion.
IMPORTANT #2: RP-342 is a heavily-concentrated rust preventive. For best results, each spray can should be shaken vigorously for about 2 minutes to ensure a uniform coat. The aerosol cans should also be shaken intermittently during longer application sessions.
GENERAL INSTRUCTIONS - Spray a generous, even coating on your surface and let dry. While a single coating will provide exceptional protection, additional coats can be applied if desired. If applying multiple coats, always let previous coats dry completely before applying the next coat. Ideally, it’s always preferable and recommended to apply over a non-rusted surface, however, RP-342 can be applied over moderate surface rust. RP-342 will prevent surface rust from spreading. RP-342 should not be applied over flaking or pitted rust…..these advanced types of rust should be treated prior to applying RP-342. The typical first application dry film thickness is 2.0 Mils (51 Microns).
Common Applications Include (but are not limited to):
- Vehicle undercarriage / undercoating (cars, buses, trucks, etc.) - the most popular application!
- Parts & equipment storage
- Overseas transportation
- Heavy machinery & equipment (storage & in-use applications)
- Packaging
- Dies, molds, lathes, shafts and beams
- Offshore drilling equipment, platforms & infrastructure
- Farm implements
- Boat shafts and propellers
- Marine fittings
- Rifle & other firearms preservation / storage
- Garden tools & lawn mower blades
- 1,000s of applications! Reliably protects any surface that might rust on you!
ED LUHRMAN
Reviewed in the United States on February 20, 2025
Thick and easy to work with
Joshua
Reviewed in the United States on February 2, 2025
Great product, applies easy, stays on through mud, salt , pressure washing and sun. Smells good. Arrived quick packaged well.
Hans
Reviewed in the United States on April 9, 2025
Everything from gun stocks to car parts works amazing
RaMona Schmitz
Reviewed in the United States on September 10, 2024
Worked for me
Customer
Reviewed in the United States on August 28, 2024
I use this a a protective coating under my vehicles for winter, coats well, easy to apply, has "straw" to spray into small areas.
dan piunno
Reviewed in the United States on May 24, 2024
this is the real stuff , won't wash off , I sprayed break lines and under side of my car , drys nice won't come off unless you use gas or kerosene.
Michael J. Standafer
Reviewed in the United States on May 29, 2020
Bought this because it gets great reviews...and I give it a great review as well. Everything rusts in New England, unless it’s slathered in the rich smooth glorious goodness of high quality cosmoline. Works real nice on basically anything that rusts. My personal favorite is for vehicle undercoating.
Anon
Reviewed in the United States on October 20, 2020
Original use for undercoating car. After multiple washes and salty/rocky roads, >98% still on and looking good. Used method of: brushing/sanding rust, clean, rust converter, and then RP 342. Reapplied a couple areas for longevity. Will have to see how long it lasts. Sprayed spare heavily rusted metal (no cleaning) and some galvanized steel to see effectiveness or reaction. Bought 6 bottles, only used 2 for undercoating - only did frame (rest of car AL).Coated tons of outdoor appliances - trailer, garage door, shelf, etc. All looking good.UPDATE: June, 2023- Ok, so I have done a lot of testing with various rust preventatives. Couple ongoing tests outdoors, under cars, etc. Mostly focused on lanoline (Fluid Film, Blast Surface Shield) and cosmoline (RP-342, AMS Oil Heavy Metal Protector). Main takeaways:1- Do NOT use only Rustoleum rust converter spray. Does not protect well, flakes off over time, rust continues underneath. Unless there is mild rust or very clean new surface, it will chip and/or flake away over time. Can coat Rustoleum with Fluid Film (FF) or RP-342, but why use Rustoleum in the first place?2- RP-342 works well with mild to moderate rust, not heavy rust. Be sure to scrape and wipe most rust away.3- RP-342 works best with no physical contact. If a major scrape/dent, RP-342 will not cover all of it. I like putting this on car frames and inside car frames where no road grit will wear it down. Use FF for commonly exposed areas to movement/rocks/etc.4- Haven't had a galvanized steel reaction yet, but could do better testing here.5- Fluid Film vs RP-342? Depends on use, either is fantastic. Think of RP-342 as a heavy mule. Does all the hardlifting, but can't knock it over (big scratches) or move it (does not seep once dry). Stays put and provides excellent protection. Fluid film is thinner, yet sticky. Attracts dust and bugs (no biggie), seeps into new scratches, eventually can be washed off (like, eventually and takes a lot to do it).I found RP-342 to be better at resisting water, but not scratching.Best of both worlds: Do the primary coat or two with RP-342, let dry. Spray FF on select areas for even better protection.
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