What can I use for undercoating a car?
 

Well actually, it's my truck. It is 20 years old but still in very good shape. Underneath, it looks like there is surface rust that I would like to stop. So because I like to do things myself, and I am a cheap @ss, I was thinking I would take my garden sprayer and spray something on it.

The question is what?

Or might I be better to get under there with a few spray cans of Tremclad and paint it all black? They have a special spray paint that is supposed to bind with rust.

I don't mind a few drops in the driveway, I have two diesels that have dripped all over the driveway anyways.

Thanks

I would scrub it with a wire brush and paint it with POR-15. I've never been a big fan of slathering undercoat on a car.

http://www.por15.com/

works great! Use a gas mask.

I like Rustoleum, which is cheap. I just painted a dump trucks frame with the stuff and it came out pretty nice.

Grind all the lose rust down so you start with a good clean surface, than slap it on. I started with the rusty metal primar and put a finish coat of flat black over it.

I don't like the rubber undercoating stuff, it traps water.

Oops! You beat me to it.

Hey, It's all good, you validated my response AND provided a link!

I used truck bed liner spray after repairing some underbody areas. Its very tough, and thinner than regular rubber undercoating.

http://www.***************/productpage.aspx?cid=23&sid=347&pid=100250

Good stuff........

A word of caution regarding POR15....As they say on every can, "We know what permanent it..." And they mean it. If it dries on your skin, you will wear that paint for weeks.
Good stuff.

I have used POR-15 as well as Rhino Liner as undercoating. I know the latter says it's not to be used as such, but it's worked very well so far to coat the rockers on my Jetta. I tried to strip as much of the factory rubber undercoating off as I could as moisture had gotten underneath and rust had started to form.