Hewittxj

Want to use por-15 on the entire underside of my jeep so it won't rust this winter how much will I need for two coats? One gallon or less?

Only want to know since one gallon is $140 at my local auto store.

Rere1992

Subbed- I'm also interested.

DieselD

I've heard a little if the stuff goes a long way. I wouldn't mind hearing some first hand experience though.

Slugger

you should just buy fluid film

http://www.fluid-film.com/

apply it once a year and you wont see anymore rust appear.

1 gallon is about 40 bucks and for your first application you should only use about 2 qts.

Hewittxj

Thanks but I not cheaping out my buddy has no floor do to the salt around here.

I am wondering how much two coats is cause I don't want a lot left over

Slugger

Fluid-film isnt cheaping out at all. I would use it instead of any undercoat you can name. it works extremely well. Once sprayed on it creates a wet "film" it doesn't dry and completely seals out and repels moisture. it creates a barrier from the elements. You only need to spray it on once every year. It wont harm your paint, in fact you can even use it to wax your jeep if you wanted. Since youre spraying it on you can get inside your body and doors. I highly recommend it. You should do some research on it before you spend the time and money on por-15. it will stop rust in its tracks and prevent new rust from happening.

Rere1992

Por-15 is the top of its class. You don't need to do it again. With rusted metals, you simply apply and it instantly encases the rust and adheres to the metal. It doesn't come off. With bare metals, I believe you need to use their primer and then por-15 itself. I'd wait for someone whose used it to confirm the "you need primer for bare metal before por-15 itself" info.

andrewmp6

Use undercoating its what its designed for.

Radi

I agree with the Fluid Film for the OP's stated purpose. It creeps into seams and other places the POR will never get. It isn't cheaping out, its' the gold standard in rust prevention for daily drivers.
POR is good for metal that has just light rust or pitting. Can't be any other paint or undercoating on it. If you were going to disassemble the Jeep and media blast it, I'd use it. Not so effective on a daily driver because it's so tough to get the underside clean enough.

In no case should you use plain undercoating. The rust will continue underneath, eventually forming pockets, flakes and bubbles that hold water and salt, accelerating the rot. You are better off with nothing at all.

To answer your question, one gallon should do the entire underside in two coats with some left over.

andrewmp6

He never said if he has rust or not he just said he wanted to prevent rust from happening.If undercoating is apply right it will do its job and last for a long time.

93_xjcherokee

Move to Arizona. No rust here

97TwoDoor

I've used POR-15 extensively-- it's awesome stuff. you're going to need more than one gallon to do two coats well. Make sure you prep well and it will stay on forever. You don't need to media blast it-- use a good cleaning solution (I use their marine clean, cleans the metal). It paints and seals pretty much over everything. It's designed to paint directly over the rust....get it? Paint Over Rust (POR). It's nasty stuff, wear gloves and have fun.

Mill

POR15--or any undercoating for that matter--seems like it would be a pia without a lift. You guys have tricks? Would love an undercoating write up on here.

madmanmarty

Just my .02. I live in PA where the roads in the winter always have salt. I have been battling rust on trucks for years.
1)Wire brush all rust.
2)Use a rust converter.
3)get 4 cans flat black Rustoleum, and do 2 light coats
4) i will be experimenting with Fluid Film this year. I have heard great things regarding its effectiveness.

The above method is a simple, cheap but effective way of preventing/eliminating rust that shows, and with the Fluid Film inside the frame, and places you can not get to with paint or POR.
Let us know how you make out.

CCKen

I have used POR-15 often. I buy the small can and after opening the can immediately pour it into a small Mason jar. POR-15 has a short life when exposed to air that's why I pour the contents of the can in the jar and secure the lid when not in use. I've stored unused POR-15 (in the jar) in my refridgerator for over a month and it's still good. POR-15 cannot be kept in its original can. The lid won't seal tight enough.

I wouldn't attempt to paint the entire undercarriage all at one time from a one-gallon can. It will harden in the can before you're finished.