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RP-344 "BLACK" Military-Grade Rust Preventive Aerosol Spray

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  • Cosmoline RP-344 Black Military Grade - Bulk 5-gallon pail (Ready-Spray)
  • Cosmoline RP-344 Black Military Grade Rust Preventive | Cosmoline Direct
  • Cosmoline RP-344 Black Military Grade Rust Preventive Label | Cosmoline Direct
Ships UPS Ground (excluding HI & AK)
Always in stock. Typically ships the same day order is placed.

FREE DELIVERY - ANY SIZE - LIMITED TIME OFFER  (enter promo code "CLEARANCE" at checkout)

RP-344 "BLACK" Military-Grade Rust Preventive Spray   (12 oz. Aerosol Spray Cans)


RP-344 "BLACK" is like a derivative of our popular Cosmoline Black (Rust-Veto 344) but in a convenient, pre-cut/thinned, ready-to-spray consistency.  In a nutshell, RP-344 is a black, fast-drying, super durable, long-term, rust & corrosion preventative designed to protect steel, iron and metals (equipment) stored indoors or outdoors and/or shipped overseas.  RP-344 "BLACK" is also commonly used a vehicle/truck undercoating and transportation coating that can stand up to all road conditions and chemicals encountered across multiple winter seasons.  RP-344 "BLACK" is a solvent solution that produces a hard, rubber-type black film with a semi-flat/matted, slightly "textured" appearance.  Its rapid drying permits handling in about 30 minutes without injury to the film.

When exposed to long periods of harsh environmental conditions (salt spray, humidity, extreme weather, rain, etc.) RP-344 "BLACK" will not crack, “alligator” or flake.   RP-344 "BLACK" will not flow up to 190 degrees F, and remains rubber-like down to 0 degrees F. Material coated with this product can be welded without removing the coating and/or painted over without any issue.

RP-344 "BLACK" meets or exceeds Military Specification MIL-PRF-16173, Grade 1, which has been employed by the U.S. Armed forces for more than 40 years. 

* Superior Long-Term Rust & Corrosion Prevention Characteristics
* Protects your investment in inventoried parts and equipment in transit (overseas, on the road, etc.) for years.
* Exceptional weathering.

* Fast-drying (dry-to-the-touch in about 30 minutes)
* Coating can be painted over.
* Coating can be safely welded through.
* Extremely resistant to cracking

COMMON USES (include, but not limited to):
* Construction Equipment
* Farm Equipment
* Industrial Tubing, Piping, HVAC
* Gears & Machinery
* Vehicle Undercoating & Automotive Parts
* Transportation Equipment
* Marine Equipment and Machinery
* Overseas Shipping & Transportation
* Oil-Drilling Platforms, Infrastructure & Equipment.

All aerosol cans come with 6-inch extension straws which allow you to apply product in hard-to-reach surfaces, crevices, gaps, cavities, etc.

DOWNLOAD:  Product Data Sheet / Overview

Type of Coating: Dry, black
Flash Point: 105°F min. (40.5°C)

Film Thickness (spray): 1.5–2.5 mils
Drying Time: 30 minutes or less depending on atmospheric conditions and applied thickness,
Low Temp. Adhesion: Will not flake off at 0°F (-17.7°C)

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..  (6-9 Total Cans)

Full-Size Truck:  9 Aerosol Cans for Undercarriage.  Add 3 Aerosol Cans for Inside Door Panels, Tailgate, etc..  (9-12 Total Cans)
* 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. Spray thin uniform film.  For more very long storage durations, a second coating can be applied if desired within 30 minutes.  Typical first application Dry Film Thickness is 2.0 Mils (51 Microns)

RP-344 "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.

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

"Like our Cosmoline Black, RP-344 "BLACK" is truly an exceptional long-term rust preventative and can handle the toughest of applications reliably, indoors or out.  RP-344 "BLACK" offers end-users a combination of desireable characteristics that make this product one of our favorites to recommend.  While many comparable outdoor rust preventatives sprays can take 8-16 hours to fully dry, RP-344 "BLACK" dries in about 30 minutes, saving you time and making packaging and handling/transporatation easier (and cleaner).   When RP-344 is fully cured, it presents a non-tacky, extremely durable, slightly-textured, black rubber-like coating that will stand up to the toughest of environmental conditions.   This product can also be welded and painted over which is not the case with comparable outdoor RPs and a big plus (and differentiator) for customers requiring the flexibility."  

-Thom Stratham, 33 years of field experience-  Any questions?...contact Expert Support.

A quick note about this product and “rubberized coatings”…
We get the opportunity to talk to a lot of customers every week and many express concerns over “rubberized coatings”……namely, that they can blister or crack over time and can actually trap moisture next to the surface they’re hoping to protect. While it is true that there are many cheaper rubberized coatings on that market that can fail as described (blister and crack), we’d like to assure you that this product will not. Our Cosmoline Black (RV-344) and Cosmoline RP-344 Black will provide long-term, durable and reliable protection without blistering, cracking, flaking, etc. If you still have concerns over “rubberized coatings”, we encourage you to check out our Industrial-Grade Cosmoline (RV-342) as it does not produce a rubber-like coating and will, like Cosmoline 344 Black, provide long-term protection from rust and corrosion – trusted since WWII!


* 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.

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