Just about to apply this to the sills and floorpans of my 1989 944 to top up the original stuff Porsche put on 31 years ago. The fact the car is even here still is testament to this rubberised rust preventer. If there’s a gap in the rubberised stuff and water gets to the metal it’ll rust and why wouldn’t it? If you regularly maintain and repair the underbody finish the car will last indefinitely.
@@C0ckZilla he probably means rust can still advance if present when applying this, and you cannot see what is underneath rubber until it is way too late.
@@C0ckZilla the rubber acts like a skin over the metal. Just like if you were to put a sheet of cling film on your arm. Over time it sweats in between the rubber and the metal. With changes in the weather, humidity and heat as well as rain more and more moisture builds up between the rubber skin and the vehicles body which not only creates rust but significantly advances it. This is why rubberised coatings have all but disappeared from the limelight. The newer coatings which are recommended are bitumen or paint based that use a solvent as a vessel. It sprays on, the solvent evaporates leaving behind a tough, durable finish that is bonded to the metal and won't separate or have spaces between it for moisture to build or sit.