LeeVenHawk

Evening all.. looking for input on the best paint/undercoating finish for all the unmentionables underneath my XJ.. going to brush and blast the grime and surface rust first while I upgrade and want to seal her up tight.. what products work best for you... Thanks in advance...

Radar

I'm currently taking on the same task! i have my tranny and t/c out and i figured why not?! i am using a paint scraper and some degreaser because i have what seems to be a mix between mud and bed-liner under there from a job the PO did on it, i like to call it mud-liner , i am gonna spray some of duplicolors aerosol can truck bed-liner underneath. i like the look of the spray can bedliner, its a bit glossier than the rollon stuff and it dries faster, although it doesn't go quite as far per can as i would like it to.

EDIT: wow i just noticed how old this thread was.....

DaddyCat

alittle reading for you.... If the underneath is rusty I would worry about using undercoat or bedliner that only covers the still active rust. If the undercarriage was blasted to bare metal I'd use an epoxy paint. I'm not going to sand blast my undercarriage so I'm thinking Rust Bullet because you can paint over old paint, unlike Por-15 which the data sheet tells you is not recommended. Prepration for Rust Bullet is less critical than Por-15. I've seen Por-15 projects fail because the multi-step prep process was not fully followed. Done right Por-15 is very very good.

And to add a 3rd option... ZeroRust. I've used the Aerosol paint and it's a very good product.
http://zero-rust.com/auto.html

http://www.rustbullet.com/

http://www.por15.com/

http://www.pirate4x4.com/forum/showthread.php?p=8469193

http://www.hotrodders.com/forum/por-...et-119795.html

http://www.drjing.com/Mini/BLOG/SideBySide.htm

ruglyot

Painting over "still active" rust will , technically, stop the rust - rust needs oxygen to form. Of course, paint will not form a good bond over rust, so that is the benefit of an undercoat. Being flexible and able to absorb shock (like a rock thrown against it!), it will be more likely to stay over a rusted spot. Russ

DaddyCat

It is better to remove the rust you can reach and convert the rust you can not reach. Non converting paints and undercoatings will not stop already present rust (have you ever tried?) And any rust convert coating requires the removal of rust scabs/flakes to work but if you want to belive you're right I wish you good luck. BTW you can undercoat over rust convert paints, best of both worlds, if you like undercoat.

wildbill1

I've been using a product called Fluid Film for several years, but I've heard of an undercoating used in Canada that remains a vaseline-like consistency. I like the sound of that. It will tend to creep into areas that are impossible to access and I don't mind getting under the Jeep every year and reapplying it. It's a good oppurtunity to give it a good going-over.

Hoooper

look for rubberized undercoating, kind of like what they use from the factory on most new cars and similar to what is on the frame rails and other places stock in our jeep. the rubberized stuff you can get from the store seems to IMO be softer/more pliable, but also might scrape off easier

SlackJaw

i'm actually looking to do this as a preventative measure in the near future...what I was looking to do was use rustoleum Rust Tough Zinc Rich Primer and then put a coat of rubberized undercoating over it. I don't see any real rust besides maybe surface rust underneath my Jeep, so I'm just going to clean it up with a scruff pad, wipe it down clean, then spray the Rust Tough on it


great info so far!! thanks!

DaddyCat

The overspray from aerosol undercoat is impressive, it will get on everything nearby, the jeep, the wife's or gf's car, the neighbor's laundry.
Make sure you are protecting what you don't want full of little black spots! Ask me how I know...

kyleag89

I have used rubberized undercoating from Walmart. It comes in a large spray can and is only $4 a can. The color when dry matches the factory under coating. I sprayed my 89 MJ, my 93 XJ, and my trailer and they have held up for over a year now.

Radar

I've tried both the spray undercoat(UC) and the spray bedliner(BL) from duplicolor and yeah the UC does have quite a bit of overspray and i don't like how it looks flat, now the BL on the other hand isn't quite as bad in the overspray department and its a bit glossier, so i would think that it would be easier to hose off the mud that is "Inevitably" going to get on your under body, But the BL is like 10$ where as the UC is like 5$, but i think that the BL is worth it! I am using the BL on my tranny, Tranfercase, underbody, wheel wells, axles/diffs, cargo space and anything else i can think of! I'll post some pics when i start my build thread.

P.S. If any of you are buying your spray stuff from Advance auto parts i found a really good discount code, just hit me up on my profile