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I just ordered new headers and wanted to give the POR product a try On their site they advertise some prep products for the POR-15. My questions are does the POR-20 require the same prep products and what are the prep products? Is it a just a chemical cleaner/etcher?
Karl

I haven't tried the POR-20 yet, but I like their POR-15 stuff. If you have a look at their website they reccommend that surfaces be dry and clean of any oil or rust, and for best results use abrasive blasting for the POR-20 products. They don't specify to use their Marine Clean and Metal Ready products to prep the surface as you would with the POR-15. So I wouldn't expect to have good adhesion with only chemicaly etching the surface. It needs to be mechanically abraded: get it blasted and keep any bare hands off it once it's clean and blasted. Blow it off with clean/dry compressed air and follow their directions for application, dry time between coats, and how to heat the header (in an oven if possible) to over 300°f before considering the finish "durable". If the finish is not baked before installation, there's a good chance you'll damage it trying to install it on your engine. If you're not equipped to do the blasting and bakeing ~conveniently, you might be able to find a local powdercoater who can take care of it.

Thanks Turbo, That is what I was hoping to hear. I ordered a pint of Bright aluminum and I have not received my exhaust yet, but I had already decided to take it to a powder coater if does not fit in my oven.
Thanks Again, Karl

I have used the POR-20 product on my exhaust. I had everything sand blasted and then used acetone to remove and oils. I didn't do the oven baking as mentioned about but ran the motor for a little bit to get it warm a few times..... Well i would say 80% lasted for a few months then it started to rust in several spot under the paint. I think i put a few pics here on the forum some where.
I am not knocking the product just giving you a heads up and follow the instruction

It says on the POR-15 site that the petroleum degreasers/etchers leave a residue that has an adverse affect on the adhesion, but no where on POR-20 does it mention that. I just can't imagine acetone leaving a residure. I am going to use it on my street rail that will not be driven a lot, so hopefully I get some sort of life out of it. If it fails I will wrap it.