TheSamba.com :: View topic - What rustoleum should I use for my underbody?

Sun Dec 06, 2009 3:18 pm

Hey all,

So, I am getting the underside of my car ready for winter... I know I know, I shouldn't be driving it at all, but it's my only car and I need to be able to get places. I will use it as sparingly as possible :(

I want to undercoat it with a budget, I am going to hit the pans with rustoleum rolled on with a roller and brush. But then I saw in a spray can "Truck bedliner spray"... I purchased rubberized spray to use on the bottom over the rustoleum, but do you think the truck bed liner spray from rustoleum would be even better? Seems like it's be tougher and thicker...

What do you guys think?

Thanks much!

Sun Dec 06, 2009 4:02 pm

I have some aftermarket fenders I bought for my jeep and just had them painted. I bought dupli-colors spray on bed liner for the inner fenders. I just finished spraying them today, seems like a quality product. I would do both, couldn't hurt. Don't forget to wash it, that helps keeping the rust away.

Sun Dec 06, 2009 4:07 pm

Don't use the spray-on rubberized undercoating. It traps more water than it repels. Bedliner stuff would probably be better.

Sun Dec 06, 2009 4:37 pm

The BEST thing to use is the Rustoleum Rusty Metal Primer. It is NOT their Red Primer.

The Rusty Metal Primer is the stinky fish oil primer. Looks like the red primer, but works much better!!!!!

This stuff will protect the car for many, many years!

Sun Dec 06, 2009 7:46 pm

I'm so glad I live in SoCal, we drive our VW's year round and don't have to worry about "winterizing" them!

Sun Dec 06, 2009 8:46 pm

drscope wrote: The BEST thing to use is the Rustoleum Rusty Metal Primer. It is NOT their Red Primer.

The Rusty Metal Primer is the stinky fish oil primer. Looks like the red primer, but works much better!!!!!

This stuff will protect the car for many, many years!

So, it's primer, do I need a top coat over that? Or just use primer...

Also, would I use this primer on both the fenders and pans?

Thanks much,

I appreciate the help!

Sun Dec 06, 2009 9:01 pm

Hm....

I just realized that the rustoleum I got today is the high performance protective enamel paint (that is oil-based, and I'm guessing that's fish oil-based). I used one of those stupid auto-pay things and may have forgotten to take the receipt b/c I can't find it anywhere! :shock:

With that said, would this high performance protective enamel be just as good to use since it's oil-based just like the rusty metal primer? If not I can find other ways to use the rustoleum primer that I purchased, no big deal.

Thanks

Mon Dec 07, 2009 4:29 am

I agree, stay away from the spray on undercoating. Time has shown that it's effectiveness is questionable over the long term. It also makes things a real mess when you need to fix something under the car.

IF you have any rust now, take care of that properly, treat it to neutralize any remaining rust, prime it with a good product and paint it.
Put yourself on a schedule checking on the rust at the beginning and the end or winter and take care of anything you find right away.

Learn the susceptible areas for rust, visible or hidden, and pay particular attention to those areas. Some, like inside the rocker panels you can't see and there are pages and pages of ideas how to handle the rust treatment of those areas on this site.

Don't know what part of NJ you are in but I'm sure you are well aware that winter has begun, we got 7" of snow and now it is 20 degrees outside.

Best of luck

Dave

Mon Dec 07, 2009 6:57 am

Just a question - you plan on taking care of underneath, but what about the areas under gas tamk and under tk area ( around Trannie ) Those are wher I wee the most damage due to Winter?
They are much harder to take care of but once you do , You have that peice of mind. I used POR 15 and am very happy with results so far!

Good luck !

Mon Dec 07, 2009 6:59 am

djkeev wrote: I agree, stay away from the spray on undercoating. Time has shown that it's effectiveness is questionable over the long term. It also makes things a real mess when you need to fix something under the car.

IF you have any rust now, take care of that properly, treat it to neutralize any remaining rust, prime it with a good product and paint it.
Put yourself on a schedule checking on the rust at the beginning and the end or winter and take care of anything you find right away.

Learn the susceptible areas for rust, visible or hidden, and pay particular attention to those areas. Some, like inside the rocker panels you can't see and there are pages and pages of ideas how to handle the rust treatment of those areas on this site.

Don't know what part of NJ you are in but I'm sure you are well aware that winter has begun, we got 7" of snow and now it is 20 degrees outside.

Best of luck

Dave

Thanks man. Hah yeah oh goodness, we got about 6" and it's about the same. I live in Sussex County, in the northwestern part of NJ.

So, are you saying it's okay to use the rusty metal primer though? I'd like to protect the bare metal, ya know? There is no rust on the car as this is an AZ car. I would like to keep it as close to rust free as possible, :wink:

Thanks for the advice, I appreciate it!

Mon Dec 07, 2009 7:01 am

dgrnga wrote: Just a question - you plan on taking care of underneath, but what about the areas under gas tamk and under tk area ( around Trannie ) Those are wher I wee the most damage due to Winter?
They are much harder to take care of but once you do , You have that peice of mind. I used POR 15 and am very happy with results so far!

Good luck !

Well, I bought a brush and am about to purchase some spray cans of the rusty metal primer so I can reach those places. I definitely plan to do under the gas tank where the master cylinder is as well.

Where around the tranny gets rusty?? I will definitely get everything in sight and try to get whats not in sight with the rusty metal primer to protect is as best I can.

Thanks

Mon Dec 07, 2009 7:55 am

If you seriously want to know where these cars rust, contact me and stop by my house some day, I'm not that far away, in Western Morris.

I've a 57 under a tarp that will graphically show you how a VW rusts!!!

The rocker panels, 1/4 panels, bottoms of doors, and below the fuel tank as well as parts of the rear suspension.

Like I said you need to identify and head off the unseen rust spots. One of the earliest, and it is never seen early, is where the running board bolts onto the rocker panel, totally hidden, a great place for salt and moisture to just sit and do it's evil deed.

Dave

Mon Dec 07, 2009 12:13 pm

I read your original post and wondered why not use POR-15.

Mon Dec 07, 2009 1:14 pm

pantone149 wrote: I read your original post and wondered why not use POR-15.

For POR15 to work right, you really need to have CLEAN surfaces. Then it HAS to be top coated to be protected from UV light.

If you have an old rusty/crusty or even a solid car that you can't completely strip the area being worked on, the Rustoleum Rusty Metal Primer works extreamly well.

Just remove any filth, grease, and dirt and maybe wirebrush away the loose stuff. Then brush it right on.

I have a 356 out back that was done this way in the early 70's. It's been sitting outside ever since and the areas painted with this stuff are still as solid as the day they were painted! Other areas, don't exsist anymore.

This stuff works, requires little prep, and is not very expensive.

But it HAS to be the RUSTY METAL PRIMER. It is different from their red primer!

Mon Dec 07, 2009 5:05 pm

Dr. Scope is right as usual. POR15 is very prep-intensive- may as well be prepping for a finished paint job. Rustoleum cares alot less about what it sticks to- it simply sticks. There is a wealth of info available in the bodywork threads- but it sounds like you want to do all your research and work within a 36 hour time frame. Haste makes waste.

Tue Dec 08, 2009 6:56 am

Foe easier application of the Rusty Metal Primer, find a Shutz body spray gun and bottle. It will lay it on thick and can be put in places a brush wont reach. Can be coated in half the time, but be sure to tape up good, because it can create a mess.

Tue Dec 08, 2009 9:26 am

I used ZeroRust because it's half the cost of POR. I brush-painted three coats onto the pan when the body was off then the chassis sat outide for two years, in Wyoming. I never got around to painting the underside. After two Wyoming winters outside there's still no rust anywhere on the pan. Now the body is back on and I'm painting the underside. Two coats on so far, two more if the gallon I bought three years ago lasts.

crvc

Tue Dec 08, 2009 10:33 am

From the POR-15 website under "Application Instructions". I live in the South East. This stuff works great on rusty metal.

APPLICATION PROCEDURES
Surface preparation: Rusted surfaces are best; seasoned metal and
sandblasted surfaces are also good. Surface must be dry and free of
grease, oil, or other foreign substances.

...POR-15 likes to adhere to surfaces with
“tooth” rather than smooth, glossy surfaces.

I do, however, agree that you need to top coat if the area will be exposed to sunlight.

Tue Dec 08, 2009 11:15 am

Thanks for the help guys.

I did the job yesterday with the rusty metal primer and then topcoated it with black rustoleum top coat and then hit it all with truck bed liner.

I'll have pics up in a bit.

Thanks again for all of the help!

Tue Dec 08, 2009 11:33 am

I also use the product called ZeroRust. The only prep involved is wire brushing off the rusty scale and then wiping it down, that's it. It's made to adhere well to and encapsulate rust but can be used also over clean metal or existing paint. It takes longer to cure but doesn't run of risk of chipping off like other products under a sharp blow or impact (eg. rock chip). You can also get it in many different colors and it's inexpensive. If you do a search there have been a number of tests done and it fairs better than POR15.