Corrosion Protection For Military Vehicles

1959 - 1978, M151, M151A1, M151A2, Technical questions and discussions, regarding anything related to the M151.
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Corrosion Protection For Military Vehicles

Post by m270mlrs2 » Sat Aug 28, 2021 5:53 am

A friend of mine that works in the reset shop sent me this PS Magazine article. It looks like the stuff is available not sure if its any better than anything else out there. Sorry the pictures did not come through.

Corrosion: Use Cavity Wax to Stop It Dead in its Tracks
Photo by Sgt. Bill Boecker

If you’re a spray paint technician assigned to a Logistics Readiness Center (LRC) or depot, have you heard of cavity wax? It’s a wax specifically designed for corrosion protection.

Cavity wax is applied to combat corrosion in hard-to-reach cavities of vehicles. Some of these cavities aren’t painted and when dirt and gunk accumulate there, it leads to corrosion.

Cavity wax looks like thick paint.

Cavity wax
Cavity wax

Once cavity wax is applied to new equipment, it provides better corrosion protection because it’s applied to hidden cavities, which are often unpainted surfaces. The wax provides protection for several years after application, as long as it isn’t removed.

There are three (3) types of products that have been proven effective to treat cavities.

Standard MIL-DTL-53022 CARC epoxy primer, NSN 8010-01-589-7077, brings a 1.25-gal kit, or NSN 8010-01-588-4312 will get you a 5-gal kit.
NOX-RUST® R-491-115 doesn’t have an NSN. Order it under Commercial Item Description A-A-59295.
TECTYL® 2423 HAPS Free Black doesn’t have an NSN. Order it under Commercial Item Description A-A-59295.
NOX-RUST® R-491-115 is best for vehicles not subject to deployment and redeployment wash requirements. That’s because it remains tacky after drying and may trap bugs, dirt or spores. It can be used on enclosed and sealed interior surfaces.

Both MIL-DTL-53022 Type IV primer and Tectyl® 2423 harden when dry so they can be used on all equipment and vehicles. MIL-DTL-53022 Type IV Primer is better for smaller spaces because it goes on thinner and dries faster.

After a year, the wax looks like this
After a year, the wax looks like this

Maintainers, it’s important to know that any grinding, cutting or heating with a torch can cause the cavity wax to run. Any work which raises a part’s temperature above 160°F should be done before cavity wax is applied.

The wax is applied to vehicles using a Graco® Merker® ESTM air-assisted airless spray-gun, PN 3A0732L, or Graco® SG2TM airless spray-gun, PN 24301. With either spray-gun, you’ll need a Graco® nozzle extension, PN 206496.

Past Challenges of Wax Application

Historically, the challenge in getting to cavities has been that most commonly sold spray lines couldn’t be fed or snaked to reach cavities. By adding a piece of flex line to the extension wand, the line is able to bend around corners and into cavities that were previously out of reach.

Nozzle extension and conical nozzle
Nozzle extension and conical nozzle

The cone-shaped nozzle on the extension wand helps to fully cover the cavity that the wax is sprayed into. Spraying with the cone-shaped extension wand may cause the wax to pool in some areas, but that’s fine. Spraying while pulling the wand from the cavity at a rate of about two (2) inches per second works best. Also, as the extension wand is pulled from a cavity, individuals using the spray-gun should release the spray-gun trigger to avoid overspray.

A future update to TM 43-0139 Painting Instructions for Army Material (Jun 14, w/Ch 1, Mar 16) will include the procedures for applying cavity wax. In the meantime, you can get even more info about cavity wax by contacting the DEVCOM GVSC Materials-Environmental, Coatings, and Corrosion team at:

Here's a link to the milTube video showing the application process.

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Kurt Lesser
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Re: Corrosion Protection For Military Vehicles

Post by Kurt Lesser » Sat Aug 28, 2021 8:14 am

There were problems linking to that site not being able to provide a secure connection but here's one to a 3M site on You Tube with information about Cavity Wax:

A little expensive at $23 per can but hey, if it keeps your vehicle on the road it's worth it!
Kurt Lesser
US Navy, 1969-1975
M996A1 Ambulance w/M101A3 Trailer
M274A2 Mule
M151A1 Mutt w/M416B1 Trailer
M890 Crew cab

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Re: Corrosion Protection For Military Vehicles

Post by Cliffaliff » Sun Oct 17, 2021 11:18 am

How do you feel about undercoating on a M151A2. I don't see any rusted through spots. New owner.

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Re: Corrosion Protection For Military Vehicles

Post by Rickf » Mon Oct 18, 2021 5:22 am

Not a fan of undercoating myself since it hides any future rust. And there will be future rust since this is a unbody and it will rust from the inside out. With undercoating you will not se anything until a huge chunk of that stuff falls off, along with all of the rusted out metal it used to be attached to. With paint you can see rust as soon as it starts and deal with it right away. As far as the wax type cavity sealers, Fluid film is easy to get and use. ... 2599407585
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Star Electric Ordnance
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Re: Corrosion Protection For Military Vehicles

Post by Star Electric Ordnance » Sun Nov 14, 2021 2:57 pm

On both of my rebuilds, I used a spray cavity wax from KBS Coatings in Indiana. You can get an 18" long tube, for the can ,with a 360 degree spray head on it. I coated inside all the drain holes cut in the frame and cross members. Superior penetrating spray. Used it when I had the body upside down and then again when it was right side up.
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1944 WC-56/1969 M-274A5/1968 M35A2/1968 M-543A2/1961 M-151/1967 M-151A1

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