Undercoating necessary?

The stuff is just a oil and will wash away over time. Lets face it, these products just coat the metal with oil to prevent oxidation.
If you like to reuse things.... Take those 8 quarts of used 0w20 and a brush. Farmers have been doing the same exact thing for years!
That's how a 1950's tractor is still alive today. Not much on a farm goes to waste.

 

I do. Still have a few Home Depot orange buckets full of bolts I took off my totaled car before it was sent to junk yard. For my electronic hobby I blow off SMD components from old motherboards and PCI- cards. Have 3 old alternators, 2 of them were already rebuilt once. That's my general attitude.

Also I'm moving to a new house, it broke me yesterday and I've ordered a dumpster, where most of my garage scrap will go Did 6 trips yesterday moving trash in 6.5' bed and it's not done yet. I'm more good at "reuse" than really needed in life. Still on the edge whether I still need a spare hood, pair of fenders, etc. But the car goes to nr.1 kid in a few years, I'll probably keep them for some time

 

I have the same thing I dont think those are particularly high pressure since its spread out over multiple nozzles. I do use it. I just try not to get to aggressive with the wash, just enough to remove any salt or loose debris under there.

 

Really like the effort that guy went through for the side by side comparisons. Here’s another shorter video comparing just CRC Marine and Fluid Film:

https://youtu.be/eLJWbbUpnH8

Spoiler alert, FF didn’t hold up well in this test, but it seemed to work really well in the earlier video, so perhaps the prep/application wasn’t done right.

I’ve always leaned toward Krown or Fluid Film, but seems like CRC Marine is out performing the majority of products (in both ease of application, and longevity), and cheaper than lots of the others too.

 

Interesting... The thing about the FF in this instance is that laying flat like that it could have been washed off more easily by repeated direct rains whereas when on our frames it is a bit more protected from direct water impact. But based on this and the previous video I am really liking the CRC idea. Only problem is that before applying it we might have to remove the FF (or whatever else you may have used) residue and do some more prep. And remember from the previous video that the CRC is too thin to spray from an undercoat gun so might need a paint gun and nozzle if you use the bulk containers.

Edit: it looks like the CRC is unavailable in bulk containers... at least as far as I can tell.

 

A buddy of mine has a mid-80s Toyota truck. Every year since new, he crawls under the truck in coveralls and gloves, with two tubes of chassis grease and cans of RustCheck. He then greases or sprays every bit of metal he can see, but focusing on the frame.

I'm not recommending this, and you don't want him parking in your driveway for a few weeks after this, but the truck is still in really nice shape.

 

That’s great. I used the website & also refuse to let Crappy tire do anything but sell me over the counter stuff! website last year I may not have looked at Waterloo area when searching.

 

This video is from the same guy who did the side by side comparisons. Seems there’s a new contender over Fluid Film and CRC Marine.

PB Blaster Surface Shield (not to be confused with the earlier product from PB Blaster that didn’t do so well).

https://youtu.be/NE1_EiZIVHs

edit: looks like this was already posted a while back. Apologies for the duplication!
https://www.tundras.com/threads/undercarriage-treatment-yay-or-nay-pros-cons.99051/

 

My 07 that I got from Denver last year was spotless as far as rust goes. So when I brought it back to Pa. the first thing I did was get the thing coated with NHO Black. I'm hoping that the Pa winters and all their salt will be held at bay so I plan on getting mine done annually. Just for the record as I have previously stated, Pa DOT applied 802,000 tons of salt/ brine to our roads in 2021. Do it, you won't regret it.

 

I think they used the same amount on one or two snows we got on this very mild winter here just east of Pittsburgh! My neighborhood you couldn't walk on the street after they made a pass, guess they have to use it up?