Rust-Oleum 248656 Professional Grade Rubberized Undercoating Spray, 15 oz, Black

I've tried many different car undercoatings while restoring classic cars from the 60's, 70's and 80's. This product seems to give you the best bang for your buck.Has good adhesion. (Would say 3M's undercoating has the best, but this is not far off and is considerably less expensive). I always am sure to clean whatever part of the undercarriage I'm coating well before using any undercoating. For areas with surface rust, I use a heavy duty steel brush. Then follow with spraying the area with a quality degreaser, be it foaming or a bulk purple/orange degreaser from a 1gal or larger jug mixed in a spray bottle. Let the degreaser sit on the chassis for at least 30min. And if it's got a big thick layer, you should also metal brush/scrub the area well.I next, rinse it off with a special sprayer I bought for my Dewalt 3100psi pressure washer. It has two caster wheels, and four spray heads and is approximately 22" long. It attaches to the end of the pressure washer spray gun. So if rolls under the car and sprays hight pressure water upwards. Super easy and works great. They can be found from dozens of manufacturers for around $20-25.Next let the undercarriage dry, for whatever time it takes to be totally dry. For frame rails especially, I will hit them with a brown rusty metal primer.Once the rusty metal primer has flashed (15-30min) I follow up with the undercoating. This way if any of the undercoating were to flake off in the future, you will see the rusty metal primer show through, which makes it exceedingly easy to spot recoat with the undercoating.All my classics have impeccable undercoating to this day (california, so know salted roads). This makes them look so nice on a lift or if anyone were to take a peek underneath. But most importantly it protects the car from rust and grime and will insure the longevity of the vehicle.Lastly there are obviously some areas that you want to avoid using undercoating. For the frame rails closest to the headers I use rusty metal primer followed by a high temperature black spray paint. I avoid spraying all suspension components, brakes, the rear diff, transmission and oil pan plus the engine and drive train. Probably other places im forgetting. Gas tanks are optional, if its an older tank I will always do it, if its newer coated or stainless ill leave it. Inside wheel wells are OK to hit I just don't bother because mine stay perfect in California.The latest car to be done is a 1964 impala SS with tons of performance upgrades on a custom air bag system. This car can lay down within 1.5" from the ground, with zero clearance issues.Hope this helps someone.

I used this on the undercarriage of my 2015 jeep wrangler JK, after using another rust convertor previously as well. Months ago it was starting to look like a sad surface rusty state under there. The first thing I did was use a metal brush on all the rusty spots. Don't bother with spinning devices, etc, just use the long brush and some elbow grease. I then used a good rust convertor that converted the surface rust to a black finish on most of the metal. It went on with a paint brush. I probably could have stopped there, as it looked better already, but I wanted to take it another step with a protective coating.That's where this rubberized undercoating spray seems to have helped. I covered all the metal surfaces with this to provide a protective black coat. It sprays on as you would expect. Wear a resporator mask and eye protection at a minimum, and rubber gloves. Then get on down there and spray all your metal parts. I'm not sure I'd spray this on top of rust, but it would probably cosmetically cover it. I put it on the black converted rust. It gave it a, yes, "rubberized" black appearance to the surface. It is a matte finish with a slight dull rubberized reflectiveness. It isn't thick, but it does look to provide that extra protection.Note, I got a 2 pack, and that would be the bear minimum for my undercarriage. It's already mostly black on the frame and metal parts, so missed spots are less noticeable. I could probably use a 3rd can in good daylight with a bright light to see what I missed. 4 is probably too many though.Overall seems like good quality and smooth finish for undercarriage, more functional and less often seen. I'm not sure it would be as useful on a fully visible everyday surface though in terms of smooth looks.This stuff is super useful. I touched up a bunch of worn metal on some other outdoor stuff as well.

Nought it to spray the underside of the wheel well on Mt trailer after a tire exploded and destroyed the inner lining. I bought 6 cans thinking it would take several. One can did complete area and that was 2 heavy coats. Great product.

Love this spray paint. Great colors long lasting great look and the price is unbearable

Good product. Easy installation.

Rust-Oleum undercoating is great for protecting against rust and road debris. Easy to apply and provides a durable, protective layer. It's supposed to be applied to a clean surface but it's a worthwhile investment of time and money for extending the life of your vehicle.

Good product, easy to use, good coverage...

Needed this to undercoat damage that occured on my RV after a tire blowout. Totally sealed the wood so no water could penetrate.