Has anybody used it to undercoat a car?

My dad has a '68 fastback that is starting to get surface rust on the bottom. I'm trying to figure out how much I need to coat the whole bottom of his car.

 

The stuff works great. My advice is to remove as much of the surface rust as possible with a wire brush or other tool. Are going to spray it on or brush it on? If spraying I would think 2 quarts should cover the bottom of the car with a little left over. I have never brushed it on so I don't know how much that would take.

 

I was planning on brusing it on. Do you recomend spraying?

 

Either way is fine, I've only ever sprayed it on, if you have access to a gun and compressor thats what I would do.

 

I've used it, works great. I however recommend brushing. It allows you to get into smaller areas better, and work it into the rusty spots good. It will smooth out and look amazing for being brushed on. Make sure you use their chassis black. Standard POR-15 is not UV stable, and will break down in sunlight...