Underbody Coating ??????

[bllabong89]

I need some help on doing an underbody paint job on the bottom side of my car. It has the factory underbody coating on it still so I need a little help. Will I need to sand off all of the underbody coating or can I just clean it really good, hit it with a scotch brite and apply new undercoating/truck bed liner?

I was planning on using POR-15's POW-R-LINER truck bed lining because I have used the POR-15 Rust preventative and I really like it. Any help would be appreciated.

[bersh240]

the more you take off the better. i used a paint stripping wheel.
sanding that stuff is a pita.

[bllabong89]

yea, thats why i was asking because i would rather not sand if possible but i want it to look good so if thats wat it takes, thats wat is gonna happen

[DMan II-40]

I would use like a wire wheel on a drill or some s***, then if your really want to sand it. That underbody paint should fill in the imperfections left from the wire wheel anyway so I don't think sanding is necessary.

[bllabong89]

yea, im not worried about the imperfections really of the wire wheel/sanding pads as much as I just want the new stuff to stick and not peel or crack off

[krash]

mine just peels off........lol

[DMan II-40]

yea, im not worried about the imperfections really of the wire wheel/sanding pads as much as I just want the new stuff to stick and not peel or crack off

Then after you get the crap off clean the surface good and it should stick just fine.

[bllabong89]

So I emailed POR-15 and asked about the truck bed liner around the exhaust areas...they told me it will withstand about 200 degrees F so I dont think it will work. Does anyone else have an idea of another good/reputable brand that I can use. I only want to have to do this once.lol...Thanks for your help NICO

[Warped161]

if you dont want to scrape off the undercoating you can try dry ice. I used it to strip the sound deadening from my interior and it worked great. just a thought. theres a link to my thread below my sig.

[bllabong89]

I suppose I could try that...Im just not sure how well it will work without having the car flipped over on a rottiserie or something

[S13AL]

I always thought rhinoliner would work well. As for the exhaust problem maybe you could put a heat shield on top of the coating to protect it from the heat. The same shiny foil people have in their engine bay near a hot turbine.

[Warped161]

lol you could use some stacked 2x4s to hold the dry ice in place.

[motoman399]

Make sure you scuff it with something rougher than a scotch brite I would use at a minimum of 220 grit maybe even 180 you don't want in peeling off like stated above

[DanThaMan]

The por 15 should work fine, theres plenty of air space between the exhaust and the underbody, it probably won't get that hot... Think about it, 212 degrees boils water, I don't think there's that much exhaust heat under there. Or you could just drive it hard for a while, get out and check with one of those infrared thermometers to know for sure though.
-Danny

[kozanatos]

Clean it as good as possible, scrape off anything thats loose or chipping, spray over it.

Put your car up on jack stands, get a full face shield ( like a riot mask ) and get a bucket of water, and some degreaser, and one of those scrub brushes, something with medium sized bristles so you can get in the bumps

get on your back and start scrubbing, and you are going to get wet! (seems to me the face protection would be pretty important, wear junk clothes xD )

Here is a build thread where somebody cleaned their whole undercarriage... BUT its a civic xD
http://www.honda-tech.com/showpost.php? ... tcount=386
^ exact post
v page with the post 3/4th down the page
http://www.honda-tech.com/showthread.ph ... 27&page=16

I think he said he dislike'd 3m's rubberized coating in a spray can, dont remember, was a long time ago i read that

[bllabong89]

thanks guys. I guess I will start by cleaning it up as good as I can and go from there. The only thing that I want to get rid of is any rust...thats the whole point to going into it this deep, ya kno.

thanks for the link, i read through that thing so I will try that route first. If it still looks a little sketchy, I will try and remove it completely.

[kozanatos]

Post back your findings pliss

[1SickSilvia]

Post back your findings pliss

You should atleast peep of the old cracked undercoat, the wire wheel is also a good idea. You can buy undercoating in spray can form, just make sure to mask off anything and everything you dont want that stuff on.

[daves240sx07]

I used a scraper and a propane torch.Heat just until it starts to bubble.Now i did have allot of things removed so be careful where u heat.If your not looking for a car show finish than if it's not rusty i would leave it alone and get it oil undercoated.To get rid of the rust the best way is to sand blast it.Messy but works the best.Than undercoat.Lots of undercoating options out there,again after done get it oil undercoated.If you are looking for a car show finish than remove all undercoating sand than paint and clear coat it.Lots and lots of work this way but looks amazing,and more rewarding. Just my 2 cents. hope it helps.

[hbpignosePA]

there are factory heat shiels correct?

if your worried take those off and paint with high temp paint

and undercoat underneath that.

ive done my whole car; minus the front wheel wells.

i used an angle grinder and a wire wheel.....biggest b**** ever.

looks clean tho.

it did chip a bit where the exhuast is, but im not too worries since it has heat shields.



i used truck bed liner,it wasnt POR 15 product.

check my build thread for more details

[kozanatos]

cbus240-s-build-thread-t494224.html
There is somebody doing it also, half way down the page... might as well keep an eye on it, it looks like he will continue

[bllabong89]

yea, thanks. it always helps to see what methods other people are doing so i can take the best of everyones and do it right

[daconkiftador]

Has anyone had any luck sand-blasting the bottom of their car to strip the undercoat before redoing?

[kozanatos]

yea, thanks. it always helps to see what methods other people are doing so i can take the best of [everyone] and do it right

Exactly! I try to bookmark cool stuff that I want to do (or at least remember some of it ! )

Has anyone had any luck sand-blasting the bottom of their car to strip the undercoat before redoing?

Good idea! Maybe try a hand sand blaster first? Success > Send it off to somebodies shop to get the whole underside done ?
Sheesh I cannot imagine how dusty that is though. In my head it makes sense only to do that if your car is a rolling shell or will be repainted eventually. If it is a shell maybe just do the whole thing to x_X

//Edit
Shell = roller, no interior, not nice wheels, etc.

[bllabong89]

yea. my car is almost to the shell state. i am working on getting my wire harness' out to go thru everything. I am also going to pull the motor soon. I have all of the interior out from the dash to the trunk. I just have the car on stands because I am in the process of doing evo front brake upgrade, 5 lug and replacing my old suspension with the new stuff.

I would like to be able to do all of the prep work myself and not have to bring it anywhere because it doesnt even have hubs on it.lol

[l2edken]

always wanted to try this s***, seems like its what your looking for, plus the added thermal protection...
http://www.fatmat.com/liquid/gallon.html

[bllabong89]

yea, I am going to look into that. good lookin out bud