---
product_id: 219019337
title: "Cosmoline RP-342 Black Rust Preventive Spray (Military-Grade) 6-Cans"
brand: "cosmoline direct, llc"
price: "92516 Ft"
currency: HUF
in_stock: true
reviews_count: 8
category: "Cosmoline Direct, Llc"
url: https://www.desertcart.hu/products/219019337-cosmoline-rp-342-black-rust-preventive-spray-military-grade-6
store_origin: HU
region: Hungary
---

# Fast 25-min dry time Extreme temp & salt spray resistant Years-long rust protection Cosmoline RP-342 Black Rust Preventive Spray (Military-Grade) 6-Cans

**Brand:** cosmoline direct, llc
**Price:** 92516 Ft
**Availability:** ✅ In Stock

## Summary

> 🛡️ Lock in legendary rust defense—because your gear deserves military-grade protection!

## Quick Answers

- **What is this?** Cosmoline RP-342 Black Rust Preventive Spray (Military-Grade) 6-Cans by cosmoline direct, llc
- **How much does it cost?** 92516 Ft with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hu](https://www.desertcart.hu/products/219019337-cosmoline-rp-342-black-rust-preventive-spray-military-grade-6)

## Best For

- cosmoline direct, llc enthusiasts

## Why This Product

- Trusted cosmoline direct, llc brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **One-Coat Wonder:** Single spray seals metal surfaces with a tough, non-tacky black wax coating that lasts for years.
- • **All-Weather Armor:** Withstands salt, chemicals, road debris, and extreme temperatures without cracking or washing off.
- • **Versatile Protection:** Ideal for vehicles, heavy machinery, firearms, marine gear, and thousands more—join the elite users who never settle for less.
- • **Effortless Application:** Spray on dry surfaces, dry-to-touch in 25 minutes—no mess, no fuss.
- • **Military-Grade Durability:** Trusted by U.S. Armed Forces since WWII for unmatched corrosion defense.

## Overview

Cosmoline RP-342 is a military-spec, fast-drying rust preventive spray that delivers a durable black petroleum wax coating. Engineered to protect metal surfaces indoors and outdoors, it resists salt spray, extreme temperatures, and harsh environments for years with just one coat. Trusted by the U.S. Armed Forces and professionals since WWII, this aerosol spray offers effortless application and long-lasting corrosion defense across thousands of industrial and personal uses.

## Description

Military-Grade Rust PreventionModeled 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!

Review: Awesome - I wish I discovered this years ago. Lasts a long time and looks great. I’m done wasting time sanding under my truck and painting. It doesn’t last or protect as well as using Cosmoline. Came out awesome
Review: This product is all that is needed to rust proof your vehicle ! - I did the entire underside of my truck over the weekend. The results are better than I expected. I sprayed it on all suspensions parts, bushings, coated my leaf springs and immediately noticed a quieter ride. I have used Fluid-film in the past on my trucks and liked the results, except that it stays oily/wet to the touch. RP-342 has exceptional coverage and dries to the touch, it also makes the underside of your vehicle look like new ! I have also tested this using my pressure washer, it does not wash off once dry. I can't say enough about this product, I will never use anything else.

## Features

- OUR STRONGEST, LONGEST-LASTING & FASTEST-DRYING Rust Preventive Aerosol, PERIOD! 1-coat can reliably protect any metal, steel, or iron surface (parts, equipment, tools, machinery, etc.) for Years!.....indoors or outdoors.
- DURABLE & TOUGH – Will not crack, craze, blister, run or “wash off”. RP-342 produces a dry-to-the-touch (non-tacky), amber, BLACK petroleum wax coating (perfect for concealing unsightly surfaces) that stands up to long-term salt spray, extreme temperatures and other harsh environments.
- EASY-TO-APPLY: Just spray onto a dry surface, dries in about 25 minutes; You’re Done!
- TRUSTED SINCE WWII – has been widely used & trusted by the U.S. Armed Forces, government agencies, commercial companies, and DIYers/consumers for generations.
- 1,000s of APPLICATIONS across commercial and private industries. Vehicle undercoating is one of the most popular applications. Easily stands up to road salt, chemicals, road debris and won’t wash off like many other undercoating products. One application/coating can protect for years.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0888PB5G7 |
| Best Sellers Rank | #54,306 in Automotive ( See Top 100 in Automotive ) #138 in Care Corrosion & Rust Inhibitors |
| Brand | Cosmoline Direct, LLC |
| Color | Black |
| Customer Reviews | 4.7 4.7 out of 5 stars (186) |
| Date First Available | May 1, 2020 |
| Finish Type | Gloss |
| Indoor/Outdoor Usage | Indoor, Outdoor |
| Item Form | Aerosol |
| Item Weight | 7 pounds |
| Item model number | RP-342 |
| Manufacturer | Flywheel Distribution, LLC |
| Manufacturer Part Number | 342-1032-6 |
| Model Name | RP-342 |
| Package Information | Can |
| Paint Type | Spray |
| Product Dimensions | 5.12 x 6.38 x 9.84 inches |
| Size | 12 Ounce (Pack of 6) |
| Special Feature | Fast-Drying |
| Special Features | Fast-Drying |
| Specific Uses For Product | Vehicle Undercoating, Car Undercoat, Truck Undercoating, Rust Prevention, Rust Preventive |
| Surface Recommendation | Metal |
| Unit Count | 72 Ounce |

## Product Details

- **Brand:** Cosmoline Direct, LLC
- **Color:** Black
- **Finish Type:** Gloss
- **Indoor/Outdoor Usage:** Indoor, Outdoor
- **Paint Type:** Spray
- **Size:** 12 Ounce (Pack of 6)
- **Special Feature:** Fast-Drying
- **Specific Uses For Product:** Vehicle Undercoating, Car Undercoat, Truck Undercoating, Rust Prevention, Rust Preventive
- **Surface Recommendation:** Metal
- **Unit Count:** 72 Ounce

## Images

![Cosmoline RP-342 Black Rust Preventive Spray (Military-Grade) 6-Cans - Image 1](https://m.media-amazon.com/images/I/51DyRGK+acL.jpg)

## Questions & Answers

**Q: Por15 my van frame, inner fenders, axles, etc now deciding if i need to shoot my chassis black paint & cosmo or if i can skip painting? uv protection?**
A: As with everything, preparation is key. Paint alone does not cut it here in upstate New York (The Rust Belt). In my case, the entire underside of a ‘08 Tundra here’s what I did. A good up close and personal power washing. Then pump sprayed the correct mixture of Salt-Away, rinsed thoroughly and let dry. Did those steps a second time just because I’m ocd. Black Star where necessary, primer when ready and topcoat with black paint. Mask off entire exhaust, rotors, calipers, and anything that could be oversprayed,pull tail lights and fender liners. I used cosmoline rp-342 black, 15, 12oz rattle cans, shaken continuously and done on a nice day with no wind and 65 degrees. Does not need to be sprayed heavily and can be second coated. I used a can or 2 of the “Heavy” amber formulation when coating any of my painted areas, such as behind the cab and front of bed, under tailgate and vulnerable areas in the engine compartment. Definitely dress like your installing fiberglass insulation because this stuff stays “Anywhere it touches”, getting it off of your skin is not fun. All of that work has just been put through a pretty nasty winter here with salt getting encrusted everywhere and anywhere it could, with trips to the power washer when I could, to get it off. I know this isn’t a long test duration, but that cosmoline is holding its own and then some. I will never use anything else when I do another vehicle, worth every penny! This stuff is Mil-spec for a reason.

**Q: Can this be applies over gas metal pipes?**
A: yes but your pipes will be sticky forever

**Q: Can this be applied over rust-oleum automotive rust reformer or vht rust converter?**
A: Yes, RP-342 can be applied over any DRY surface (not oily or greasy) to ensure the best possible adhesion.

**Q: Is Spray can compatible with wands for spraying inside rockers?  cap male or female  - tube on cap or tube on can?**
A: Hello, unfortunately the cosmoline tip is a male. The wands spray top that I got from a different cavity wax company are female. If you’re handy enough, I’m sure it’d be possible to retrofit the cosmoline spray tip to accept the wands brass fitting. My thoughts on that would be to carefully drill the tip to just undersized of the brass and insert, followed by wrapping with hot glue. I know this is possible because I’ve had to hot glue the extension wands onto the spray tips to keep them from dislodging. Hope this helps!

## Customer Reviews

### ⭐⭐⭐⭐⭐ Awesome
*by B***R on December 4, 2025*

I wish I discovered this years ago. Lasts a long time and looks great. I’m done wasting time sanding under my truck and painting. It doesn’t last or protect as well as using Cosmoline. Came out awesome

### ⭐⭐⭐⭐⭐ This product is all that is needed to rust proof your vehicle !
*by A***R on June 18, 2025*

I did the entire underside of my truck over the weekend. The results are better than I expected. I sprayed it on all suspensions parts, bushings, coated my leaf springs and immediately noticed a quieter ride. I have used Fluid-film in the past on my trucks and liked the results, except that it stays oily/wet to the touch. RP-342 has exceptional coverage and dries to the touch, it also makes the underside of your vehicle look like new ! I have also tested this using my pressure washer, it does not wash off once dry. I can't say enough about this product, I will never use anything else.

### ⭐⭐⭐⭐⭐ Great undercoating!
*by S***K on March 2, 2025*

I'm a pickup truck guy, and I undercoat every pickup truck I have. Typically I use a lanolin type coating, but tge lanolin doesn't last long. However this stuff, you can quickly see why it is military grade. Thus stuff coats quickly, easily, and we'll. Better yet, this stuff has staying power, it looks and feels like a crayon type wax. One recommendation, invest in a tyvek suit. Thus stuff will get on you, and it takes a lot of effort to get it off.

## Frequently Bought Together

- Cosmoline RP-342 Black Rust Preventive Spray (Military-Grade) 6-Cans
- Cosmoline RP-342 Heavy Rust Preventative Spray (Military-Grade) 6-Cans
- Rust-Oleum 248658-6PK Rust Reformer Spray, 10.25 oz, Black, 6 Pack

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*Product available on Desertcart Hungary*
*Store origin: HU*
*Last updated: 2026-01-31*