underbody paint

I wanted to paint my underbody for easy clean up/looks good. So i chose shiny black rustoleum because i hear that it cleans up better than flat black. I had a couple of questions though

1. Do you guys use the same paint for the exhaust, skip the exhaust, or use high temp paint.

2. How the heck to u ever get the underbody clean enough to paint? I stuck a sprinkler under the jeep for an hour, then went down to the quick-e wash for underbody bast, but their was still grease/old crusty dirt everywhere. So i took a wire brush to it, and 2 hours later its still not clean enough. Also i cant get a pressure washer wand down their, not unless it had a 90 degree angle at the end of it?

good luck getting all the grease and dirt off of everything to make it clean enough to paint. i used rubberized under coating and the stuff works great. did absolutely nothing to clean up the body and it seems to be working fine for me

I thought about painting over the crap, but was afraid that it would just flake off in time.

it will but what won't? either that or you could do what i'm planning on doing either today or tomorrow and spray it with truck bed liner. kinda expensive but seems like it would not only look better but protect it a wee bit more

Depends on what the under body looks like. Painting over old undercoating or oil isn't going to do much good.
I do mine in sections, I've never tried doing it all at once. Two reasons, some areas are worse than others (I do them first) and getting it all done in a reasonable amount of time (all at once) seems unlikely.
If the undercoating is mostly gone, I scrap the rest off with a wood chisel and then rag it down with solvent. It takes a bunch of clean rags and repeated rub downs.
A long handle scrub brush and Simple Green gets most of the mud crust off and/or most of the grease and oil. I also scrape with a putty knife when needed.
I don't get crazy with the wire brush, just enough to knock the loose stuff off. Then paint with Hammerite gloss black.
Rustolium also works well, Hammerite dries and cures a lot quicker, though it is pricey.
Loc Tite just makes a better undercoating. A little pricey but good stuff.
I've had some good results with the Hammerite water based paints on bumpers and stuff, though I've always used the traditional gloss for the under body. I've been tempted to try the water based Hammerite for the under body, seems like it holds up well and dries really fast.
Hammerite takes some practice to use correctly, lay it on thick and don't go back very much at all, to try and smooth it. I usually use two coats. Find a brush with a large bristle count and not too soft and not too hard. Don't buy expensive brushes, the special thinner to clean the brushes costs more than the brushes do, pretty much use them once and then toss them.
Rustolium rusty metal primer is good stuff also (the automotive primer doesn't impress me much), takes some days to dry and cure up right, but is usually on there to stay, then a coat of gloss black.

Everyone else covered the cleanup/painting process fine - what I'd like to say is, don't use the same paint on your exhaust, it'll fume/burn/possibly set your Jeep on fire. Use high temp paint or nothing.

I have been thinking of doing this myself... not to mention I have my interior torn out so I can weld in new floor pans (which will have to be painted/coated after).

I have been having one of these "crazy WTF would make you think of this" type of thoughts... what if I perform a "controlled flop". By that I mean drain all fluids (coolant, oil, gas, etc etc) and use vehicles/tow straps/winches/whatever I have available to slowly/carefully lower the vehicle onto its side.

I can take the door off on the side that will be on the ground so the mirror wouldn't be smashed, and I have seen XJs that were flopped with *minimal* damage, but all those that received damage were dropped onto dirt or rocks in an uncontrolled environment.. So if I were to slowly lower my XJ onto its side (on grass or soft dirt) do you think it would be able to handle the stresses and not take damage. Granted I may get a couple dents or such, but with the way it looks now that wouldn't change much..

Doing that would allow me to touch up my welds on the bottom of the floor pans and power wash/sand blast/paint everything under the rig. Anyone care to chime in on my dumb plans for world domina.... erm... cleaning the underbody of my Jeep?

themangeraaad said:

I have been thinking of doing this myself... not to mention I have my interior torn out so I can weld in new floor pans (which will have to be painted/coated after).

I have been having one of these "crazy WTF would make you think of this" type of thoughts... what if I perform a "controlled flop". By that I mean drain all fluids (coolant, oil, gas, etc etc) and use vehicles/tow straps/winches/whatever I have available to slowly/carefully lower the vehicle onto its side.

I can take the door off on the side that will be on the ground so the mirror wouldn't be smashed, and I have seen XJs that were flopped with *minimal* damage, but all those that received damage were dropped onto dirt or rocks in an uncontrolled environment.. So if I were to slowly lower my XJ onto its side (on grass or soft dirt) do you think it would be able to handle the stresses and not take damage. Granted I may get a couple dents or such, but with the way it looks now that wouldn't change much..

Doing that would allow me to touch up my welds on the bottom of the floor pans and power wash/sand blast/paint everything under the rig. Anyone care to chime in on my dumb plans for world domina.... erm... cleaning the underbody of my Jeep?

Click to expand...

Um wow i have to be honest with you. thats one of the craziest things ive hear in a while. I have a pretty much spotless 98, so that probably wouldnt work for me to well. my recommendations would be to make sure that you get everything that you could possibly want to do. Frame stiffeners, underbody prep and paint etc.

I think it'd be a lot more sane to find a buddy with a lift, or borrow/rent time on one... Or perhaps use a jack and a bunch of cement blocks to get one side a couple feet off the ground and not actually tip it all the way.

If you're going to do that, make sure the wheels that you're tipping it onto (the ones that act as your pivot point) aren't going to slide out from under you at the wrong moment, your controlled flop will very quickly and disconcertingly become an uncontrolled flop.

Any of you guys try POR-15?

The motor & transmission mounts aren't designed to hold in that position. If you leave it flopped too long it may screw the mounts up.

Steam cleaner?

I learned a long time ago to treat underbody paint as a maintenance item.....I get under mine a few times a year and shoot it with some 99cent walmart flat black(its do for the royal treatment this year before the snow gets here=salt on the roads).If you try to make it last forever by using bed liner or expensive paint you will be disappointed a year or so down the road,especially in the salt belt.

Use a wire wheel on a drill motor and hit all the visible rust spots/dirt spots,spray with de-greaser or paint thinner and let dry.Grab the spray paint and use a plastic tube off of a wd-40 can which will allow the paint to come out thick and heavy.It will also let you shoot paint into hard to reach crevices.If you're feeling really crazy break out the sand blaster and blast the rust before painting.

rinse and repeat annually.