Okay so my floorboards have some surface rust on them (not all that bad though really) and I'm trying to decide what to coat them with. I'll sand most, if not all of the rust off and use a rust neutralizer.

What stuff should I use? I like the sounds of POR-15 and don't mind spending $50 or so to do it. $50 would get me one quart of POR-15 rust preventative paint and one quart of Metal Ready. Is one quart of POR-15 going to be enough to get the length of the wheel base? They recommend two coats but could I get away with one?

If not, I don't really want to have to buy a second quart of POR-15. I'd rather just use some rubberized undercoating ASSUMING this stuff works almost as good as POR-15 and is easy to apply (how am I going to hold an aerosol can sideways/upside down though?). POR-15 can be painted on.

What are some popular methods out there?

 

I would use the por 15 and forget the undercoating. Por 15 is the way to go. A quart goes a long way. If you properly prep the under metal, It should hold up well. I would spray some cheap spray paint over the por 15 to protect it from uv, even under the car. How I did it was to let the por 15 get to the almost dry stage then i dusted it with the spray paint. (If you try to spray directly over cured por 15 the paint wont stick well, or you have to lightly sand then spray or use their primer.) The method I used worked well, for under a car. I then sprayed a final coat of paint after all had dried.

 

Okay next question then.

Should I use the silver stuff (same cost as regular) to help deal with any pitting? It appears I don't have to get ALL of the rust off, just most of it for POR-15. Then just dust the silver POR-15 with spray paint when its tacky?

 

POR-15 is an anti-rust stuff, and 1 quart will do the entire underside pretty easy.

If you don't want to do the spraypaint route, POR-15 offers a top-coat of various colours.

Check out www.por-15.com and do some reading, I think it'll help...


that's what I'm doing to mine, I'm just a little slow about it

 

I would still put some sort of undercoat on after the paint... It will help with road noise etc.. 3m makes a few types in a can that are pretty good - they are more rubber than any cheapo undercoat that is primarly an asphaltish soft goey crapola. just my 2 cents..

 

oh yeah im talking about under the car, but it prolly wouldnt hurt on the inside anyway - it would hold the water at the top and not let it get to the metal if you get water in your car, and the noise thing still

 

I was planning on dynamatting the car one of these days. Stuff is expensive though, its still like $11 for 4 square feet with my discount through best buy. I'll have to check ebay.

Either way, I agree with the rubberized stuff over the POR-15.

Now, if I do this, should I topcoat the POR-15 and spray it with the 3M stuff, or should I just spray the 3M stuff over the POR-15 while its tacky, etc.?

Also, I want to eventually get subframe connectors...will this make them any more difficult to install?

 

The reason it took me so long to do the SFCs is because I had to clean up and POR-15 where my SFCs got installed.

the top coat for the POR-15 is just to protect it from UV, if you have anything else on top of it, I think it will serve that purpose, again, I invite you to visit their website, it explains a bunch about it.

 

I would let the por cure fully, then scuff the surface lightly with maybe some 400 grit paper, just enough to let the undercoating stuff stick.

 

Yeah I've read all of the info on their site, I'm just looking for past experiences that you guys have had. Thanks for the responses so far guys

 

you could go with the por 15 and then buy the clear and topcoat it with that. Just make sure not to get any on you or youll have it until that skin dies.

 

I wouldn't worry about it underneath the car, unless you have a show car that everyone looks under. POR15 will change color under UV, but it won't affect it's rust-protection at all.

 

ive heard from an older car guy that back in the day he used to soak down his underbody with oil then drive it on a dirt road for awhile. bring it home and let it sit for a while. he said he never had any problems with his floorpans rusting out. dont really know how well i works but is an idea

 

Huh????

 

yah dont ask me lol i thought the same thing. but the guy swore by it that it worked. i guess the dirt sticks to the oil and makes a protective layer that water cant get into. prob cuz water and oil dont mix im assuming

 

makes perfect sense.... they do the same thing to roads....

wouldn't the underside of our cars look good though

 

I have been kicking aroung the idea of Rhino lining the unside of my car. We have a company around here that comes to your house to do truck beds. I would be better if you were doing a build up and had all the stuff out from under your car so every thing could be sprayed. It would make a good under coating and great sound deading.

 

i wouldnt trust the rhino lining. It could break away, especially with the rocks and what not hitting the bottom of your car.

 

I used Duplicolor's truck bed liner spray. Stout stuff, unfortunately, it reacts with rubberized undercoating and peels away everything. If you use a truck liner, be sure you don't have the standard spray undefcoating on prior... mine looked this good for about a month.. now it's al gone and the OEM overspray/primer is exposed once again... (good thing it doesn't go outside to rust..)...

 

I thought the idea behind rhino lining was that it did not chip when hit with rocks, or whatever else was being dropped in the bed? Makes sense that the same would apply if it was the underside of a car. I would think that it would be less likely to chip than any paint.

 

www.secondskinaudio.com makes a good alternative to dynamat, they also have a liquid coating which is paintable/sprayable. Thats What i plan on using on my interior.

I believe when i talked to the guy about purchasing some he said its the same product jaguar uses to deaden they vehicles

 

Ive seen many truckbeds with rhino lining in them and theya re all tore up from moving rocks, wood w/ nails, etc... Im just going from what i have seen.

Por15 isnt paint anyways. It a stronger substance. Try finding testimonials about it. ive heard nothing but good.

 

On a side note, if you look on the label at the ingredients it say's "contents partially unknown" The rumor is it was developed by the military as a coating for parts on stealth bombers. How someone can make a product and not know it's contents. :shrug:

 

I know that POR-15 isn't just paint, I use it. It works extremely well on a bare metal, or slightly rusty surface, will not scratch or chip. But I find that it does not stick as well to a surface already coated, such as the painted underbody. So unless you have the underbody entirely stripped, I am not sure that POR-15 is a good choice to put over a painted surface. Now if you are stripping to bare metal, then I would say go for the POR-15.

I have not had any experience with the rhino lining, just going on what it is supposed to do.

 

Another testimonial for POR-15.

I've used it to do the "topside" of my floorboards, my SFC's, and various other parts. It's worked great so far, but you have to prep it properly as they state on their website. If it's a clean smooth surface, you have to sand, do the Metal Ready thing, etc. That will be time consuming on the whole underside of a car, but not impossible.

I wouldn't bother with coating the POR-15 for UV protection. As stated, it will fade in UV rays, but won't affect its strength.

My car has ugly asphalt undercoating (put on by previous owner). When I put on my SFC's, I had to use a heat gun to scrape off the undercoating where the SFC's go. It was a major pain. Then after the SFC's were welded in, I used POR-15 to cover them and the areas where I scraped.

I definately don't have a pretty underside, but it is protected!