TheSamba.com :: View topic - Spray can undercoating over old stock undercoating ?

Tue May 28, 2013 3:47 pm

I was wondering has anyone used spray can undercoating over stock undercoating? My car will be a daily driver and I do not feel the need or want to remove all the old rubberized undercoating from the bottom of my car just to add more of the same. But there are places where it's chipped off, thin or just crappy looking. I'd basically like to just freshen the whole underside up and make it look fairly nice. I see that rustoleum sells an inexpensive spray can of rubberized undercoating. I'm considering using this over my stock stuff. Would this work out ok for my needs? Would the original stuff even need much scuffing up (seems like it would not to me). I thought I'd just pressure wash the old coating and go to town with the spray can after all is dry. I would probably go thin over the original coating so as not to build up a huge thickness. Has anyone gone this route? Opinions, advice ? Thanks.

Sun Jun 02, 2013 3:27 pm

I have to replace the entire floor of my 73 squareback. I would definitely clean it well, lose undercoating would not be good. I was wondering what to use under mine as well. There are a number of products out there.

Sun Jun 02, 2013 5:30 pm

yea, I will go over everything lightly with a wire wheel to remove any loose stuff.. but I've already picked up a couple cans of the Rust-oleum rubberized undercoating, sitting in my garage waiting to be used. $5 a can at AutoZone, no shipping. I imagine it will do just fine for a driver, if I was doing a full on restoration and planned to enter shows.. I might go another route.

Thu Oct 09, 2014 1:25 pm

Sorry for reviving some old threads but I thought it would be best to post here.

Im in the same situation. I want to protect the underside of my 72 bus.

I do not want to remove the factory undercoat as most of it is in good shape, but in some areas it has peeled off and is showing surface rust.

I was thinking of wirebrushing the loose areas, and the bare areas then applying a rust paint such as eastwood rust block, or POR15. But after that I wanted to put on a similar product to the factory. I do not drive my car in salt and try to avoid rain so its more of a peace of mind.

I was thinking the 3M undercoating spray or the eastwood undercoating spray:
http://www.eastwood.com/ew-rubberized-rust-encapsulator-blk-aero-15-oz.html

http://www.amazon.com/3M-03584-Professional-Rubberized-Undercoating/dp/B002H9CMCQ

Then there is this product that Ive heard good things about:
http://www.noxudolusa.com/product/noxudol-900-aerosol/

Any thoughts on these vs each other?

Right now it looks like this:

Some areas in question that I want to clean up:

There is a place in town that says they will do it for about $400, I dont mind paying the extra to have it done right. They can lay down a thicker material with proper guns and said they powerwash, then wirewheel any loose areas, prime exposed areas then apply an undercoating that dries hard.

Fri Oct 10, 2014 4:48 pm

All the rattle can spray on undercoats I have used were VERY thin, nothing like the original stuff. I have used this 3M schutz. Its the real deal and it works very well, seems to hold up well. Keeps noise down too. Good idea on killing rust first.
http://www.amazon.com/3M-08864-Schutz-Rubberized-Coating/dp/B000PEQGMM