Undercoating opinions?

I am sure this has been discussed in great detail but just wanted to get some more opinions. I just got a new 2023 TRD OR and will be using it over the next six months for work. My work consists of driving on SoCal beaches so it will be in contact with sand and ocean spray semi-consistently.

My company has offered to pay for an undercoating and what they have done with all of their work trucks in the past is used a company that uses rhino lining on the underside. I have now read a lot of conflicting opinions about this and how it may actually trap rust but if it's a new truck without already existing rust is that still the case?

 

The issue is if there is ever ANY break or pore in the coating. Now there is a way for moisture and oxygen to get to the metal.

I'm a huge fan of fluid film or wool wax. We don't maintain the underside of our vehicles the way we maintain the top side, as such you want a different way to protect it. In this manner I feel the creeping action of FF or WW maintains the consistency of the coating (where it can).

 

Seems like FF would trap a lot of the sand from the beach and be highly abrasive…not sure though.

 

Idk about California, and the use of rhino coatings for rust protection, only that they don't work well here in Connecticut where we get a lot of salt, and brine use on our roads during the winter months. Those linings can chip, and start bigger issues once moisture gets under them. So far I've found cosmoline RP-342 to be by far the longest lasting.

 

Thanks for all the inputs, it makes sense that once there is a hole in it it will trap moisture so I guess I will look for alternative options. The sand may be a problem getting stuck in other things I want to use as undercoat but there has to be something that checks all the boxes

 

Looks like there is a shop near me that will do a Cosmoline RP-342 underlining so sounds like thats something you would suggest?

 

I don't think anything is perfect as most rust inhibitors will require a yearly reapplication or at least an inspection.

 

Well the company will pay for it to be redone each year, although I don't necessarily plan to work there much longer than a year, but want to find what will work the best for the uncommon consistent sand/ocean water contact.

 

That stuff works for me here in New England, as I've tried the fluid flim route which only works if it's reapplied every 6 months. So far after 3 years with RP-342, it's 99% still on the chassis with very minor spots washed away around the rear leafs that are high abrasion areas. You pressure wash the chassis well on a new truck the day before applying this stuff, and it will stick like glue.

 

Since you guys deal with salt on the undercarriage a lot I can assume that my salt water situation is similar so might just go with this route. I can apply it, but since my company will pay for it, might as well have it professionally done haha plus the shop has a lifetime warranty including yearly touch ups.

 

If whatever you use stays sticky / tacky, the bottom of your truck will look like a powdered donut after a few trips on the beach. I can't imagine having a bunch of sand stuck to the undercarriage being a good thing.

 

I cosmoline sprayed mine in Fall 2021 and it has remained in place for two winters. You can still see the reddish/brown film over the white stickers on the frame. Will probably reapply this Fall.

 

Does it remain sticky, as in do you think the sand would stick to it or does it seem hardened on the outside?

 

Cosmoline dries in 4 hours. Didn't notice any particle adhesion whatsoever.

 

Awesome, well seems like cosmoline is the way to go as opposed to rhino liner

 

It does not. It dries

It's not terribly expensive either. I bought a case of 12 cans on Amazon and only used five or six, so I have another application when I'm ready. I dropped the spare, covered anything that looked sensitive or pretty (like connectors and my black exhaust tip) with foil, put on a DuPont overcoat and respirator, and started spraying!

 

Just checked. 12 can case of RP-342 Heavy is going for $145 on Amazon. I paid $134 two years ago, so not a terrible inflation rate.

 

I use

$53 CRC 06026 Heavy Duty Corrosion Inhibitor, 10 Wt Oz (6 Pack)

CRC 06026 Heavy Duty Corrosion Inhibitor, 10 Wt Oz (6 Pack)

read the product spec

 

The rp-342 cosmoline dries in 1 hr., then remains semi-hard with a waxy texture. It has never attracted the dirt that fluid flim use to when I had my tundra. After 3 years with cosmoline, I haven't ever washed the chassis yet. It's only had the water on the roads when snow melts, or it rains. The frame is dirty, but it hasn't collected that heavy mess that fluid flim use to attract. You can't find one spot where rust has formed.

 

Yeah, the CRC is a good product too. It was either that or cosmo and I chose cosmo. I'd be willing to bet OP would be happy with either. Neither will hold sand, which was a vital concern for me, as I too drive my Taco on our powder sand ocean beaches here in Delaware for surf fishing. That's why I steered clear of the "wet" treatments like fluid film.