Undercoating Help & Advice

I would like to undercoat my car before this winter. My main goal is to hide the current rust that is visible, but I am also looking to slow it from rusting more and to protect it from winter salt.

I do not want to use any aerosol/spraying products to reduce overspray.

So far, my plan is to use a wire brush and sand paper to clean up any areas needed to be undercoated. Obviously there will be areas which will be impossible to sand out all of the rust completely, so I will just do the best I can. Then I have a product called Rust Converter from RustCheck (which converts rust into a paintable primed surface). Not sure if I should use it though, or if I should look for something which is more meant for heavier rust and undercoating. Basically, I am looking for something to treat the rust before undercoating.

Then once the rust is treated, I will apply my undercoating product. The stuff I am looking at is called Black Asphalt Undercoating with Rubber from Canadiantire. I actually read the only 2 reviews on the product, the first from a Corolla owner and the second from a large cargo van. Both claimed it was good stuff, the corolla review said it had lasted 2 years and still looks great and the cargo van said there was lots left over so it must be a good sized can for $29.99.

Anybody have any experience with doing this? any advice or suggestions on rust treating products or methods?

I think I will try the RustKiller from Rustcheck instead of the Rustconverter. It says its for heavier applications.

I also plan on doing this without removing anything which is going to make undercoating my front sub frame awfully difficult with the exhaust resting on it, well; without making a mess lol

bo what we do here to old classic cars is that we first remove the surface rust and pain the under carriage black and put rubber type asphalt compound from inside on the floor.it reduces the chances of rusting and decrases alot of road noise too.but this is for areas which are less humid and for the outside body holes and metal chipping we just cut and weld another metal piece and repaint it its really worth it in the long run.

Yeah, it adds weight, but it does reduce road noise and rust.

Oh yea, I forgot that it will add weight.

I also forgot to mention that I will need to clean and degrease the metal and free it from any moisture before I apply the undercoating.

I bought a small can of undercoating already but I still need some degreaser, preferably something fast drying that wont have to be wiped off. any suggestions? I usually use varsol but it needs to be wiped off after

I'd look at engine degreasers, you spray it on and rinse it off.

Thanks again. I dont want to have to rinse it off though. I think Ill try a cleaner and degreaser from Duplicolour. I will post back later when I start making some progress

Excellent, keep us updated, I too was looking at doing this to my car. Woulda been good for the Canadian winters eh ;P

I had planned to start prepping some of the undercarriage but ended up spending all day looking for supplies to make a simple bracket. My exhaust heatshield was rusting at the back and ready to snap off and start rattling off the pipe.

So after many applications of pb blaster I was able to loosen off the bolt holding up the heatshield so I can replace it with this bracket I made:

Gave it a quick shot of primer and black paint:

Just waiting for it to dry so I can pop it on.

There, its sturdy as a rock now!

Now I can get back to business. I bought some TSP to start cleaning and degreasing the bottom.

Will TSP remove the old undercoating, or will it just take off the dirt and grease? I dont want to remove the old undercoating. Its still holding up pretty good in most spots



Its just mainly starting to rust where things are attached to the floor, the floor itself is in perfect condition so Im just gonna leave the existing undercoat alone.

i would suggest u to remove your seats and carpet to check your floor and arches from inside of the car also.