i just got an older truck, it is great on the frame and body but it sat in deep snow and the undercarriage is rusted pretty good like the whole exhaust and pretty much anything metal on the bottom..looking into what to do if anything like sand, paint, spray to keep it from making it a bad buy. only 56 but 10 years old
once rust is formed there is no way of covering it and stopping it from continued oxidation.
you can either just live with it till you cannot
you need to strip "all" the rust off to clean metal
then paint or undercoat the entire area
thanks guys for all the input..basically all the rust is on the replacable parts...i replaced the brake hardware already..it seems the rust started this past winter..the brakes themselves were newer but the hardware was crap..the muffler and shocks and pretty much everything under sat in snow and rusted but the body is awesome. Im trying to decide, replace the parts when they rust thru or try to clean em up..its got 56k but 10 years old
There are several ways to attack rust. Rust needs moisture and air to form or to continue to form. You need to brush off any heavy rust, then:
Get some Prep-n-Etch Prep-n-Etch (by StripKleen) or Ospho Ospho (by Skyco) and apply to the metal as per their directions. Both are basically phosphoric acid so wear some gloves. This will halt the rust and etch the metal. Then it's ready for the rust prohibiting paint of your choice, such as Zero Rust or Rust Bullet.
In the case of using POR-15 POR-15, they make their own prep products. MarineClean first takes away any dirt or oils and such from the surface. Then MetalReady is their etching product that goes on next. Both are key to prepping for the POR-15 base. Again, follow their directions.
Eastwood.com makes several products and rusted metal prepping products such as their Rust Converter and Rust Encapsulator Or if it's a boxed frame they make an Internal Frame Paint . They make a bunch of products for automotive rust.
if its on the frame i would take a flap disc on a grinder and get after it till clean. this will knock the rust off without thinning the metal like a grinding wheel.
when thats done i would look at duplicolor undercoat in cans or if you have a gun and compressor i would get a $7 quart of tractor enamel at tractor supply and reducer and shoot the entire thing in enamel.
What I say might not be the popular trend but at least Im not afraid to speak my mind!