painting floor

[68400BIRD]

I have my car flipped over and I am getting ready to clean it all up and paint the underside. I'm not going for original so it does not have to be the stock look. It has a complete floor pan installed along with new outer rear wheel wells and trunk drop offs. I was thinking of painting it with por15 but that will not stick to the edp coating on the new panels. I was thinking of putting the por15 on just the back half which is the original metal. But, I think the primer and paint might lift the pro15. I'm not sure it it will or not. I know if you use any kind of paint from a spray can that it will lift when you use a automotive paint on top of it. So in short what do you guys and gals recommend for a nice overall coating on the bottom of the car? I'm not really into the undercoating look. Thanks for any input and reading my runon sentences. LOL

[Yoda4561]

A good epoxy primer before doing anything else. This will seal out any moisture as well as provide some of the best chip resistance from road debris you can get. You'll probably need to at least scuff the edp for proper adhesion but as long as the panels are clean that should be all that's needed.

Epoxy primers normally need to be covered over due to UV exposure, but on the underside of the car a quality epoxy should last the life of the vehicle. You can leave that as is or paint it over with some regular primer and one of the many chassis paints out there. Using a different color of epoxy/topcoat will make it easier to fix chips or scuffs before the epoxy is worn through. As long as that is intact you shouln't see any chassis rusting.

Personally, unless you plan on sticking mirrors under your car at shows, I'd use epoxy+ undercoating. Something other than the tar based rattlecan crap. I've tried all the rattlecan stuff and none of it is something I'd want on my car. If you change your mind and do this, it's a good idea to let the epoxy cure fully before putting on an undercoat, the chassis paints should be fine to put on a day later since the solvents are compatible, but I'd wait a few weeks before trying to apply undercoatings. I plan on trying some secondskin spectrum on my S10 to see if it's something I want to use on future projects. From all I've researched it or lizardskin look like the best products, but nothing like trying something in person to get a feel for it.

[68400BIRD]

I have a five gallon bucket of Spectrum for the inside of the car. I planned on laying down a good epoxy primer on the bottom but I wasn't sure how that would react with the pro15. I wanted to use the por15 in all of the seams and gaps.

[Yoda4561]

Can't say too much about POR15, I bought some to use on my 72 cutlass. Bought two 6 packs of the small containers, used one on some acessory brackets to get a feel for it, and sent the car off for paint. When I got the car back and was ready to do the floors in POR the other 11 FACTORY SEALED containers were dried rock solid, useless. I'm sure it works great, but I think good epoxy coverage is a higher priority.

Epoxy will stick to damn near anything, so it's probably fine to use over POR. I have no idea if POR will stick to epoxy though. As long as either product is completely cured before you apply the other one, I think you'll be okay.

[68400BIRD]

I did some reaserch and you can spray DP90 over scuffed cured por15 or directly over it after it has tacked up to a slight drag on your finger.

[jackfrost]

POR15 is really intended to be applied to rusty metal. it's not as good when applied to clean steel, it doesn't have as much to adhere to.

my car had been blasted and had a little surface rust in places. I used the POR15 on these, then after it had cured I epoxied the whole thing.

you could probably leave the epoxy as is, or spray on some good chassis black (Eastwood) for extra insurance.

[68400BIRD]

POR15 is really intended to be applied to rusty metal. it's not as good when applied to clean steel, it doesn't have as much to adhere to.

my car had been blasted and had a little surface rust in places. I used the POR15 on these, then after it had cured I epoxied the whole thing.

you could probably leave the epoxy as is, or spray on some good chassis black (Eastwood) for extra insurance.


Yes, I agree it does not stick well to nice clean metal. I only used it in areas that I had sandblasted or in seasoned metal areas. Some of the spots are real hard to get with just a sandblaster. I did a combination of sandblasting,hand sanding,acid etching and then laying down the por15.