Recommendations on underbody coating

[CrashBandit]

Any recommendations on what to use as an underbody coating?
The focus is on rust prevention and mitigation.
I'm concerned about using solutions like bed liners due to exhaust heat or such causing it to catch fire, as well as water getting trapped.

What has worked for yall?

 

[barrys]

DO NOT use bed liner. If it falls and water gets in, the water will not dry easily and it will start rust that you will not notice. Alot of people like Por15 or a product from Eastwood, chassis saver might be the name of it.

 

[zr10054]

I personally prefer two coats of a two part epoxy primer after a frame off sand blasting. It's been working for me in the high humidity climate. That's is what I did to Stump Jumper.

 

[CrashBandit]

Do you put anything over the primer, or just use the primer itself?
How has it done with gravel and such kicked up from the road?
Any idea how well the POR-15 handles that?

 

[zr10054]

IMO any coating either POR or Epoxy primer is only as good as the preparation as the coating itself. It's got to stick.

 

[CrashBandit]

Not too worried about that.
I'm going to be dragging it to the back yard, flipping it over, and sand blasting the entire underside of the tub followed by liberal use of solvents and brake kleen.

I'm a bit worried about 1-2 inch rocks being tossed against the under carriage at 80-100 mph creating a break in the paint and a vector for rust.

If I smash it into a bigger rock on a trail, that's a different issue...

It's Colorado so not a lot of worry about rust normally, but if I take it out in the winter the salt will eat it alive.
My '04 Impala has rusted significantly in the last 6 years since I moved here from Virginia, and that has a fair bit of protection on it.
I'm going to have to start replacing suspension bolts soon.

Part of what I want to do with the jeep is head for the mountains in the winter, which means a lot of exposure to salt.
So I'm fairly paranoid about the rust

We have tons of gravel and rocks on the mountain roads, as well as dirt roads with 65mph speed limits.
Getting hit with small rocks at these speeds is very realistic.
For the wheel wells I'm thinking about either making a plastic insert or use a liberal quantity of epoxy and rubber to build a buffer.

I haven't found much in the way of skid plates yet, so I might have to make them to get the protection I want.
It's going to be my adventure vehicle, and I want it to last as long as me :-)

 

[jammer1]

Epoxy primer is excellent for what your looking for. Usually gets a excellent bond on sand blasted surfaces. If not exposed to uv (sunlight) it usually doesn't need to be top coated (different manufactures have different rules for their product). Make sure you get a good coat in the tubs support frames. Used the epoxy on my 2 work trucks. On one of the trucks I didn't put enough paint on the truck and when wet sanding cut a little too much paint off (paint was a Single Stage paint). You can see the primer speckled (about 40% primer to 60% paint). This was 3 winters ago and still looks the same as the day I sanded it. Black truck with dark gray primer. Truck used for masonry work and gets washed twice a year. No rust. If you want to paint, most epoxy primer's have a window (4 to 7 days, check with spec sheet) that you can paint over the epoxy. After this window you have to scuff the primer than paint. Here's a test of one manufactures epoxy. https://www.youtube.com/watch?v=-yA8q4K-_Bo

 

[Belizeit]

I personally prefer two coats of a two part epoxy primer after a frame off sand blasting. It's been working for me in the high humidity climate. That's is what I did to Stump Jumper.

Yeah but Stump Jumper lives inside your house.

 

[CrashBandit]

and so begins my youtube binge for the night.

That's pretty amazing stuff.
I did not know about the window.
I'll have to look into the epoxy primers more, and do the entire jeep in it if it's like that.
I wonder if they make paint(base/top coat) like that lol.

Now to find more destructive testing videos of the stuff :-)
Wow.

 

[jammer1]

This website will have all the info. you'll need. Search epoxy primer. The Body and Paint section has a ton of info. on painting. Should see some of the work they do. http://www.autobody101.com/forums/viewforum.php?f=16

On my cj8 project I acid dipped the tub, body parts I didn't replace and the frame. Everything got epoxy. I like the bed liner look for the floor and underside of tub so if I ever take her out in the rain (will seldom happen) I'm protected if the bed liner fails.

 

[Flatie46]

I had my '81 tub blasted with DuPont Starblast, then primed in PPG EPX-908 epoxy primer. I've still got more metal work to do but after that I plan on paint (the color I want ) plus POR-15 on underside and black paint over the POR-15 to give it the UV protection. I know it wont see much sunlight on the bottom side but just in case. I've seen it turn purple in the past when exposed to light. The black paint over the POR-15 will be a good contrast in the fender wells to the blue outer body.

 

[jmarston]

I used Chassis Saver. It is like por15 but less pricey.