Tinwan

Rust Inhibitor-I need to make sure this rust doesn’t come back is there any chemical treatment that can neutralise rust and can be painted ?

meek

I would have thought you would be better off grinding it off entirely to bare metal, properly priming painting/underbody sealing and not bothering with an inhibitor. I don't think rust neutralisers/converters are all that much cop, especially in an area that will be out of view.

Colin 90 C2

I have never used it but POR-15 seems to be the answer.

mpeters951

I have one experience with POR-15 as a result of my best pal's resto shop recommending it. I used it (the 3 step process) to coat rotor "hat" section and the **** is unbelievable in that application. The finish on that part of the rotor is tough as nails. But, I did not go over corrosion in any way as rotors were new.

I would seek expert Porsche body shop/resto shop advice as paint finish, quality, longevity are all down to prep.

springer3

"Rust buster" "rust avenger" and similar products that claim will convert existing rust are worse than worthless (I have read the independent-lab test reports).

There are no shortcuts. Go to the Rustoleum, DuPont or other reputable manufacturer's web site and read the application guides for their products. Surface preparation is key, along with following all the other steps to the final protective layer. If you cannot justify the expense of removing rust to the bare metal, an acid etch followed by a rusty-metal primer will last 100 times longer than rust avenger or other "rust converter" products.

Gelignite

I have used POR-15 and it is brilliant - but only if used exactly as in the instructions. I used it once when it was cold and damp and it bubbled up in a few days, because the condensation that forms on the metal under these conditions prevents it bonding. So if you hear any bad stories about it they probably used it wrong!

Marc Shaw

+1 on the POR-15.

I used it on a number of exposed metal pieces that started out rusty. With proper prep, I have not seen any rust return on any parts up to 4 years old.

Marc

TCallas

There is no question, POR-15

Bull

+1000 for POR-15. It is the 356 owners constant companion!

springer3

I have too and there is no question it is brilliant as a quick fix. I am not saying don't use the stuff - removing rust properly is difficult and not much fun. Just don't believe it is nearly as good as the better steel preservation systems.

Even the best protective coatings eventually fail and need maintenance. Why are the more expensive and labor-intensive systems still used on long-lasting steel infrastructure (ships, factories, bridges, stadiums)? Simple. In independent tests, paint systems on clean and prepared steel out-last the best quick fixes by more than 10 to 1.

If you are already going to the trouble of removing wind shields and fenders to get to rust, spend a extra hour or two to do the job properly. All the proper fixes will come with instructions that should be followed to the letter. They will contain the following basic steps:

1) Remove loose rust with a wire brush, sand paper, or grit blast.
2) Apply phosphoric acid (naval jelly) to remove the adhered rust and passivate the steel.
3) Apply conversion coatings and/or primer containing rust inhibitor.
4) Apply protective and decorative top coats to seal and protect the rust preventive system.

The link below will take you to the NASA corrosion lab. The test panels used for the coating tests are cold-rolled sheet - identical to the sheet steel sold to the car manufacturers.


http://corrosion.ksc.nasa.gov/history1.htm

Jon Hansen

+1
I owned a Porsche / restoration / bodyshop in Michigan for 20 years.
My method; Grind first, then sandblast, neutrailize surface, rust inihibitive primer, caulk seams, followed by a good paint system. We always ued the Dupont system with excellent results.
You can use POR 15 for a quick fix or areas that are almost imossible to access.
I've never used it, but would conder it for inside boxed areas like rockers or frame sections that were starting to show corrosion.


Sweat the details............ you will know even if anyone else doesn't.

it matters.