Test concluded.


Where I live, rust is an issue. If you were to consult this map of the automotive rust belt you would realize how bad of an issue it can become. Especially to those of us with older vehicles.

This was an attempt to find a more permanent form of undercoating. The two most prominent products are Amsoil's metal protector and various forms of rubberized spray undercoatings. The rubberized sprays harden over time and chip, allowing moisture to creep under it, obscuring a rotting floor until you have a giant hole held together by a sheet of rubber. The Amsoil on the other hand is an impermeable wax like substance that supposedly does an incredible job of resisting road salt. The only downside, and a big one to the lazy(me) among us, is it needs to be reapplied periodically.

Items Used:

1. 3 pieces of steel. Two small and one large. All cut from the same piece of sheet metal.


2. Miracle Paint. A similar product to POR-15 but has a slightly thicker consistency. I first learnt about it here, but it can also be purchased from the manufacturer, here.

3. Through the Roof(brush on version). This product is a clear synthetic rubber. I've used it for both its intended purposes and not. I thought it might act as a good permanent barrier as opposed to the sprays. *Not heat resistant. Don't use near exhaust*

The Experiment:

One of the small pieces was left untreated, the other coated only in MP. Half of the larger piece was coated with the MP. Then a layer of the synthetic rubber was applied to about 2/3 of the piece. A small portion of steel was left untreated and exposed.


Using a mixture of rock salt and water, I would occasionally and infrequently pour a small amount into the tub which contained the pieces.

There were small holes(cracks because I dropped the tub) which would allow the mixture to drain out. Any residual would evaporate over a short period of time. They were left outside on the middle shelf of 3-tier shelf I keep outside. Prior to an update post I would rinse them thoroughly with clean water.


Test Begins: 3/17/14

Update 1: 3/24/14


Update 2: 3/31/14

Update 3: 5/5/14


Update 4: 6/24/14

Update 5: 9/2/14


Update 6: 1/28/15 It really bugs me that I didn't take a similar image for this one.

Final Update:


There is definitely some evidence of rust on the small MP coated only piece. It is UV sensitive and they instruct that it be topcoated with something else if it will be exposed to sunlight. While kept out of direct sunlight, it was outside the entire time. Perhaps that and the lack of any further topcoat led to the rust forming.

No surprises here. Looks a little more like a Wendy's patty than I had anticipated.


brb going to Wendy's

The rust had begun to worm its way underneath. :( This is exactly why I didn't cover the entire piece. I wanted to see how well it would fend off any encroaching rust.


Because of this, I decided to peel up the rubber. I smacked the piece against the edge of a table a few times to knock off some of the rust.


While it did start to work its way underneath, it held up better than I had thought. The way the rubber had started to change color had me worried that it had started to rust underneath of its own accord. Turns out it was just stained.

The very edge peeled up easily, but it got more difficult from there.


Overall, I'm happy with the performance of the Through the Roof product. I was a bit haphazard with my application of it, applying it too thickly at points, which led to bubbles. They eventually pop, leaving a nice little rust prone pocket. My main worry was how it would react to the salt. Would it get brittle or dissolve over time? The answer is nope. I feel if applied in a thin coat, uniformly, it will do an adequate job.

My car will be the next test bed.