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RP-342 "BLACK" Military-Grade Rust Preventive Spray

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  • Cosmoline RP-342 BLACK Military-Grade Aerosol Spray Rust Preventive - Single Can
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  • Same Cosmoline RP-342 Protection - Different Coating Appearances - Clear Amber & Black Concealer
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  • Cosmoline RP-342 BLACK Military-Grade Aerosol Spray Rust Preventive with 6" Extension Straw
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Ships UPS Ground (excluding HI & AK)
IN-STOCK. Ships Same Day (when order placed before 4:30pm EST).

Cosmoline RP-342 "BLACK" Military-Grade Rust Preventive Spray  (12 oz. can)

Our Strongest, Longest-Lasting (and Fastest-Drying) Rust Preventive Aerosol, PERIOD!

   *  Offers the highest concentration of Industrial-Grade Cosmoline® available in a convenient Aerosol Can.
   *  Same product and performance as our bestselling RP-342 "Heavy", but now in a surface-concealing, matte Black!  (not translucent).
   *  1-coat protects all metals, iron, steel (stored Indoors or Outdoors) for Years!
   *  Our thickest, longest-lasting Rust Preventive Spray.
   *  Produces dry-to-the-touch, BLACK petroleum wax coating that CONCEALS unsightly blemishes or surface discoloration. 
   *  Faster-Drying formula allows for quicker handling and/or shipping.
   *  Withstands severe outdoor exposure, salt-laden atmospheres, acid & caustic fumes and other damaging environs.
   *  Repels water and will not wash off in salt water environments.
   *  Will not crack, craze, peel or flake and remains slightly flexible over time.
   *  Exceptional Vehicle Undercoating Product (Autos, Trucks, Buses, Trailers, etc.) - Road salt, debris and chemicals - No Problem!
   *  Aggressively adheres to imperfect surfaces and offers self-abraiding characteristics.
   *  Modeled after Military Specifications:  MIL-PRF-16173, Grade 4 and MIL-C-83933.
   *  Trusted since World War II.  Our Bestselling Aerosol - commercial customers, US Armed Forces, Government & Do-it-Yourselfers.
   *  Your Satisfaction with this product is Guaranteed!*


COMMON APPLICATIONS INCLUDE (but are not limited to):

   *  Vehicle undercarriage / undercoating (cars, buses, trucks, etc.) - Extremely effective, long-lasting - will not wash off.  Road salt, debris and chemicals - No Problem!.....and it looks great!   - See RP-342 Undercoating FAQs.
   *  Parts & equipment storage  
   *  Overseas transportation
   *  Heavy machinery & equipment
   *  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
   *  and any other surface or part that might rust on you... 

RP-342 "Black" is also available in Bulk (gallons and 5-gallon pails).    Learn More

DOWNLOADS:  Product Overview Sheet & SDS Coming Soon.

All aerosol cans come with 6-inch extension straws which allow you to apply product in hard-to-reach surfaces, crevices, gaps, cavities, etc.
* The RP-342 aerosol can can spray while upside down, sideways and of course, right side up....which makes getting the hard-to-reach spots much easier.

VEHICLE UNDERCOATING USAGE APPROXIMATIONS (for thorough, heavy application):
Mid-Size Sedan:  6 Aerosol Cans for Undercarriage.  Add 3 Aerosol Cans for Inside Door Panels, Tailgate, etc..  
Full-Size Truck:  6-9 Aerosol Cans for Undercarriage and Frame.  Add 3 Aerosol Cans for Inside Door Panels, Tailgate, etc..
* In both scenarios, you'll likely have an extra can or two.  However, it's better to have a little too much than run out.  


Make sure surface is reasonably clean and dry (not oily or greasy). Spray uniform coating.  For longer storage durations, a second coating can be applied if desired within 30 minutes.  Complete setting of protective coating takes approximately 1-2 hours after spraying.  Typical first application Dry Film Thickness is 2.0 Mils (51 Microns)

RP-342 "BLACK" can be easily removed with any over-the-counter petroleum solvent. Examples include mineral spirits, paint thinner, naphtha, diesel fuel, or our very own Cosmoline Remover.  Our Cosmoline Remover is very effective, but also considerably more expensive than the other options mentioned.

RP-342 "BLACK" is modeled after the following military specifications: MIL-PRF-16173E Grade 4, Class 1 and MIL-C-83933

* Certificates of Conformance are not available for this product. 

2 years when stored in prudent conditions (cool, dry, shaded).

* Ozone Depleting Substances - Aerosol products were not manufactured, do not contain, and were not packaged using any Class 1 or Class 2 ozone depleting substances as defined by the clean air act.  
* Non-Chlorinated (no chlorinated solvents).


 Product Videos

Cosmoline RP-342 - Vehicle Undercoating Overview
  • Cosmoline RP-342 - Vehicle Undercoating Overview
    Showcasing Cosmoline RP-342 (Military-Grade) Vehicle Undercoat...

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Cosmoline® and Rust-Veto® are registered trade names of Houghton International