Hey I'm looking to undercoat my 97 tj and read on here about POR 15. How hard is it to use and what steps do I need to know to prep the frame and under carriage? Anyone have any before and after pics? Thanks for the help
My experience has been that Por-15 works great. Just follow all the instructions on the can, which means sand/grind/grit blast all the loose paint and rust. Follow with a thorough clean (they recommend Marine Clean), use Metal Prep to etch new or shiny metal, then 2 or 3 coats of the Por-15. Topcoat with their stuff or Rustoleum and you'll have a finish that holds up well for years. I have a full set of coil springs on one of my trucks that I painted at least 12 years ago that still are shiny black (after you wipe the dirt off them). I had the front springs off a few weeks ago because I just got around to sanding off my front axle for a full Por-15 paint job. I was slightly amazed that they look so good after so long.
The stuff is a bit expensive, but it does really seem to work well.
I just did my skid to kill the beginning of rust where it bolts to the frame. The stuff goes on easy, follow instructions and allow time to dry between coats.
Cons: lots of prep (like with any good paint job) and you need to put down some tarps. Also if you are doing your undercarriage you need to get a tyvek suit and plenty of rubber gloves. If that crap gets on you it's like getting a henna tattoo, won't come off for a week!
I just recently used it on mine and love it. I'll snap a few pics this weekend and PM them to you. It's already been pointed out that it's quite expensive but, in my opinion at least, it's well worth it. Guess we'll find out in 5 years.
For prep: it's not quite as meticulous as other jobs, which I enjoyed. You need to sand or wire brush the surface rust off but you certainly don't have to get it down to bare metal.
The materials: The marine clean goes a long way and does a good job and you can see the prep n' ready work almost instantly. As for the Por-15, I used the entire pint to do my frame, skid plates and touch up a few spots elsewhere, such as the tub. I found that rollers worked a fair bit better than brushes and the stuff is so strong that you can't salvage a brush at the end of the day so toss it right into the garbage. You can buy a super starter kit for $21 but you will need more Por-15 (likely 16-20 oz for the job you're interested in) and perhaps even more prep n' ready. If you plan on spacing the body work out over a few weeks or even months I'd recommend several smaller cans as they're damn near impossible to open after resealing.
If you're on a budget, some of the other posters have also recommended Rust-oleum Bedliner as an alternative. May be worth looking into more, there's lots of posts on that stuff.