I was thinking of painting the whole undercarriage with por15 and was wondering if anyone has used the stuff. Does this stuff hold up over the long term?

i haven't used it yet, but i've seen a few of our Mazda brethren use and i've seen where hella VW people used it. however, long term reports are seriously lacking.



you have a rotisserie?

I have some, but have not used it much yet. So far it's holding up fine on some rusty hubs on my truck, which I painted as a sort of test. That's just a few months ago.

It's wonderful stuff, but you need to apply it to bare rusty metal. It actually works better on rusty metal than it does on clean or primed.

I am going to pick up a quart and try it out. My 84gs undercarriage is solid but quite a bit of surface rust. The stuff is pretty expensive but may be worth it.

so ur saying not to wire brush or scrape the loose, flaking metal off?

It goes onto rust ok, not sure about that ^, but it is great stuff.

Did a Porsche 914-6 blly in it. Flaked/peeled off within a month. It turns out we OVERPREPPED the metal.



POR-15 is isocyanate based (BAD TO BREATHE) and it cures in the presence of water. So, scrape the loose flakey stuff off and paint it. The trick is to completely cover the metal to encapsulate the moisture so the oxidation reaction that forms rust ceases to occur.



I prefer ZERO-RUST or RUST BULLET