Anyone have any advice for the best way to rust proof an old truck w no body rust yet? I realize its not the best way but I have some clear spray and rattle can under coating spray. If I clean out the fender wells real good and sand down the frame which only has surface rust at this point and coat over that is that good enough to withstand several months of salty midwest roads if I did it each summer or will it still rust out w out professionally done rust proofing?

 

After growing up in Ontario, all I can say if your religious with washing then you might be alright. But most people use that krown rust proofing, or others.

Here's a cut and paste that pretty much sums it up.
1. Wax before the winter

Wax protects the paint surface like an invisible shield. Be sure to apply a good, strong coat before the winter season starts to guard it from corrosive salt. Seal the undercarriage as well, either on your own or via a car-care professional.

2. Keep clean tires

Before winter starts, make sure your tires are clean and salt-free. Then keep checking and cleaning throughout the cold months. Otherwise, they’ll kick up bad winter “stuff” that will pummel your vehicle’s body.

3. Don’t count on the car wash

We’re usually big fans of recycling. But we make an exception for the water used at car washes. If it’s “repurposed” water, then it may contain traces of salt. To ensure total quality control, use a DIY car wash with high-pressure hoses, so you can spray the salt off hard-to-reach areas—like beneath wheel wells and behind fenders. Hose off the undercarriage too. (Or, when you get home, take a lawn sprinkler and turn it on underneath for a few minutes. Change its position accordingly to get the entire undercarriage.)

4. Dodge “salt magnets”

Watch out for driving through large puddles of water. Not only do they pick up a lot of slimy dirt, but they’re also magnets for road-crew salt.

5. Avoid prime salt times

If you have to get on the road in bad weather, avoid doing so right before and after a storm, because you are more likely to run into fresh road salt at those times.

6. Fend off fresh snow

For both car care and safety reasons, don’t drive in deep snow. For starters, you can get stuck and stranded. And deep snow can pack salt into the undercarriage, where it’s difficult to remove. This often leads to corrosion and even drivability problems.

7. Wash while its warmer

In washing salt off in wintertime, do so during the day so the vehicle has time to dry. You don’t want the wet stuff to freeze on your finish after temperatures fall. The outside temperature should be 40°F or higher. To guarantee a “clean machine” all season long, repeat every 10 days. To avoid having the locks freeze, open and close the doors after the job is done.

 

"Rust Proofing" is a misnomer.

Iron is refined from ore and always trying to return to that state.
All the energy used to create it is trying to escape.
This is how those little handwarmer packs work.
Adding carbon (the most active element on the galvanic scale) to make steel only accelerates that process.

As long as there is oxygen and an electrolyte like salt water present there will be rust.
Probably the best way to keep water and oxygen away from steel is an oily wax like cosmoline.
It sticks, seals and is 'self healing' so some extent.

Rust forms under coatings, and fluids will wash or wear away.
Lots of people used to periodically spray the underside of the vehicles with drain oil from their oil changes.
It was a fall ritual here in New England.

 

I oil spray my '89. Even after 5 yrs in Ohio it still is clean(well, oily but no rust) on the underneath. Don't put any spray "undercoat" or such. That will just hold moisture and it will rust under it.

I use "Fluid Film". I get mine in gallon paint can and you can mix it with just about any other oil substance. I cut mine with used oil. You get this cheesy sprayer to put it in and it basically splatters it on. Hooks up to your air compressor. I do mine twice a year, as after winter it will tend to try to wash it off around the wheel wells/frame.

I've done inside the doors(removed the panels), inside tailgate(remove plate), inside hood and front fenders. I also drilled a 1" hole up in the top middle of the rear wheelwells. Sprayed around real good and put a rubber plug in the hole. Keeps the bed from rotting off around the wheels. Be ready to allow it to leave puddles where ever it parks for a few days. It will also stink a bit, but that will wear off in a week.

 

with the bed/cab off, i clean all underneath surfaces. then i spray everything liberally with either ospho, or jasco etch and prime. this is phosphoric acid. it converts rust from iron oxide to iron phosphate. when the conversion is complete, the rust areas will change color from red to flat black. .
once properly treated, i pet a good coat of rustoleum red oxide primer on, then cover with spray on bedliner. once everything is dry, assemble. after a plow or drive in salt condition, just wash the under carrage down.
i have snow plow trucks here in central new jersey that still look just as good as they did when they were put together 20 years ago.

 

I would not recommend using rattle can undercoating. I did it on my truck a few years ago and was completely useless, it just flaked off exposing the rust that was already formed underneath of it. I would use just a rattle can spray paint before using the undercoating again.

But I have heard good results from POR15 when the metal is prepped correctly, which is what I'm going to coat the underside of bed and frame with.

 

The previous owner sprayed some stuff on the frame and under the truck that is starting to peel off. I bought a couple cans of undercarriage coating from Lowe's for like $6 a can so I thought I'd at least try to re do that but I might just take it back. I don't see how it would trap moisture unless it was really humid or wet but I'm not a metal expert. I don't mind a little rust under the truck but my main priority is to keep the body from rusting at the rear fenders etc. The truck already has 3m clear tape all along the rockers all the way to the back from the PO. I've thought about getting the fender done like that too but I don't know if that's worth it or not.

 

Been using cheap 5w30 oil and my ol Harbor Freight rustproofing gun on cars and trucks for years. I have regular rustproofing plugs so I can drill holes and spray into rocker panels, doors and other panels that dont have other access. If you do it once a year slows rust down big time.

Todd

 

Yea, I pulled a bunch of FORD body plugs from trucks at the Pick n Pull. Drilled some extra holes and do the same thing with the Harbor Freight gun. Works great. Just let the truck drip for a day or two. Do it spring and fall.