George's Limited XJ

Hi everyone,

If this should be in Cherokee Talk, I apologize.

I plan on undercoating my Jeep this spring when it gets warmer out. I have little to no rust on my Cherokee's body to begin with, but I want to keep it that way/make it better. I was wondering what brand/type of undercoating you guys recommend.

What have you found best for the job?

Thanks,
George

canada_man

mud

jeep99lifted

Rhino line or rustoleum textured both work good ones more expensive than the other.

99Classic

I've had lots of problems with rustoleum undercoating. All the rubber bits run to the lowest point and everywhere else just has thin paint

JeepsAreForSpeed

I dont think it's a good idea to undercoat a vehicle unless it's brand new because of moisture getting trapped and making it worse. I use used motor oil.

jeep99lifted

I know people that have it but they had the jeep angled and slow layers also.

Radi

This.

Undercoating (like sold in spray cans) is usually a bad idea. It traps moisture and eventually peels and cracks. Those cracks let moisture, salt, dirt etc in, trap it and allow rust to get started under the undercoating where you can't see it.
You want something that is self-healing or wax-based. Fluid Film is a respected brand.

salad

Like Radi said, self-healing is essential. This spring I'm going to be covering all of the metal I can with bedliner then going over everything with the asphalt undercoating. This stuff apparently never really dries. I expect a certain amount if maintenance (2 years is fine, I could live with yearly). Oil is very successful but I don't want to leave a mess if I take the Jeep through water That said oil in the nooks and crannies, like the body, rockers, and frame rails is essential.

George's Limited XJ

Thanks guys. I've read about the motor oil coating but I really wouldn't want to make a mess. That being said, if I did use oil I would use a very light coating. I was leaning towards the roll-on undercoating market rather than spray-on or rattle-can.

Any opinions on the roll-on types? What to use? How to prep? I've heard lots of good things about these, just have never been able to find all the information complete and in one location.

Thanks again guys, I appreciate all of your opinions.
-George

Radi

I don't know of a roll-on rustproofing material. It's normally sprayed so it can get into the nooks and crannies a roller won't hit. Roll-on is more typically bedliner type stuff.

BTW if you are going to use oil, use bar and chain oil meant for chain saws. It's nice and clingy, makes less of a mess and contains some phosphoric acid that'll make light existing rust inert. If you really want a project, melt a couple of wax toilet rings in with it and spray while it's still hot. That's probably equal to or better than any commercial product.

salad

Yup I've seen rubberized undercoating that comes in a can. It's just the same rubber stuff that dries and flakes, but with less paint thinner than the aerosol version. Meant to go on with a brush but you could roll it on... same problem though.

That's neat about the chainsaw oil containing phosphoric acid, Radi. It should creep up into the normal cracks oil would eventually get into, unlike possibly just spraying a muratic or phosporic solution up in there.

Up here we have Krown and Rust Check making undercoating-specific oils. They're quite thick and apparently the Krown stuff is "non-toxic", but I still wouldn't want that washing off in a random river.

Cherokee89

I have used roofing tar with good results for a long time now, after doing rust repair on vehicles. Preparation is the key for a good result. After finishing welds I coat with etching primer and paint and after that tar. The thinner types can be sprayed on with a spray gun, and the realy thick stuff is perfect sound dentening. If you need stronger to protect from gravel in wheel arches, blend in straws from fiberglass to make it stronger. I have used this for the last 30 years working with my cars here in the rustbelt in south west Sweden.

crimsondragon

Interesting tidbit about mixing in fiberglass. Do you put on a coat, soak glass mat in paint, then put the glass mat over the first coat?

Cherokee89

I use cut up fiberglass mat 1-2 inch long straws when I not can get it from a fiber glass boat builder factory. It is the straws that come out from the chop up spray gun I use. I go the factory and talk to the boss there and they fill up a big bag for about $10 that will last for a few years.
I mix it in the tar using a cement mixer attached to drill and a big bucket.

Turbo X_J

Long time ago I worked for a place (we competed with Wurth et al.) we imported & sold Berner hardware & chemicals among other things to Indie repair shops:
http://shop.berner.eu/berner/export/category/736222/Whole+product+range/Chemicals/Painting+priming+and+marking/Undercoat
My connections are long gone, maybe you can find a US distributor near you.