View Full Version : Is there a way to stop rust from spreading on my car?

02-04-2001, 12:19 PM
Is there a way to stop rust from spreading on my car?

There is about 4"x6" rust area on the rear fender of my car. I was just wondering if there are any effective treatments to stop the rust from spreading. I don't think I want (read: can't afford right now) to pay to take it to a body shop to have it sanded, primed, and repainted.

Do you have any recommendations?

Thank you.

02-04-2001, 12:25 PM
POR15 (http://www.por-15.com/)

02-04-2001, 07:50 PM
That is rust preventative paint, and covering up rust doesn't stop it from corroding underneath. You will want to wire brush or sand to get down in the pits. Then treat it, then paint it. Auto supply stores are usually handy with what you need for the job, and the sales people "should" know what to recomment.

02-04-2001, 07:58 PM

That is not a rust preventive paint. It will stop the rust from spreading. I have used it myself when I was a mechanic. I also know someone who is the owner of a well respected piant/autobody shop who recommended this stuff.

02-04-2001, 08:44 PM
Roger is dead on POR15 is incredible stuff, I speak from personal experience.

02-04-2001, 08:48 PM
Didn't mean to sound offensive, but if paint or rust is blistering, it doesn't seem likely that any cover up is gonna stop the rust. From everything I've learned you have to get under the rust and to do that you have to remove it. Maybe this is some new revolutionary stuff that I was looking for 5 years ago and couldn't find.

02-04-2001, 09:00 PM
never second guess roger =)

02-04-2001, 10:07 PM
madthumbs, it is really different stuff. It isn't traditional paint in the sense that normal paint dries by letting air out, this stuff isn't porus and gets harder and more durable over time. Buy a sampler bottle, coat a piece of steel and bash it with a hammer, I couldnt even chip it!

02-04-2001, 10:19 PM
Of course it doesn't matter how good POR 15 is if the rust spot is like the one on my car and the panel is rusting from the inside out. (Very interesting and depressing to find rust bubbles that are covered with the car's original paint.) If the rust is on the outside though, POR 15 is a great idea.


02-05-2001, 12:26 AM
Por15 does work but I dought it will do much for your fender. I have had a 67 ford galaxie for about 6 years and when I bought it it had a some surface rust on the frame. I painted just about every part I could get to under the car with a brush and 5 years later none of it has came back through or chipped off. I also did several spots on the body including the 1/4 panels(rear fender). Most places where just surface rust and it also worked there but the 1/4 panels are rusting from the inside out and well can't get a brush in there. It might have helped slow it down a bit though.

02-05-2001, 12:30 AM
Yeah, acutally I wish car manufacturers would put it on the chassis from the factory! When I have my ground up resto done on the jeep the frame will be por 15'ed!

lepper boy
02-05-2001, 12:42 AM
move to a dryer environment.......

02-05-2001, 12:57 AM
Another way to stop the rust is to put a sacrificial anode in contact with the rusting metal.

Get a piece of Zinc and bolt it to a part of your fender that gets wet.

02-05-2001, 12:20 PM
Can POR-15 only be purchased online or via the mail?

Are there any companies that sell it at a retail store?

02-05-2001, 12:28 PM
Unsickle, MerCruiser uses exactly that sacrificial anode method to protect their out-drives from corrosion during use in salt water. It's a nice system, but a little more costly than POR15-ing something. :)

As for buying online, the site Roger linked to has that option on the navigation bar to the left.


EDIT: Oops, misread your post about buying online. I would expect that any good auto store would be able to order it for you if they didn't have it in stock.

02-05-2001, 01:00 PM
Get a new paint job???


02-05-2001, 01:02 PM
What started the rusting. Is / was something rubbing against the medal?

02-07-2001, 05:24 PM

The rust start (probably) from rocks being kicked up to the bottom of the fender and slowly chipping away at the paint.

I wonder how much a good spot paint job would be...

Thanks, edprush

02-08-2001, 04:55 AM
if its light surface rust from the paint being flaked off, then sand it to get the loose stuff off, use POR15 and paint...

if its rust bubbles from underneath, or rust holes, forget it...you need to cut out the rust and weld in new metal....or if its in a lower area thats hard to see you can coat it with bondo and paint

02-21-2001, 01:26 PM

02-21-2001, 01:37 PM

02-21-2001, 01:37 PM
spray it with holy water. makes it go faster too.

02-21-2001, 01:41 PM
rust cannot be stopped. its like cancer, you must cut it all off, then you will stop it.

take care of your car before rust happens :)

02-21-2001, 01:44 PM
that's not entirely true.

Products like POR15 encapsulated the rust and prevent it from spreading. You can get stuff that chemically converts rust too.

In the long run though you have to cut it out...

vi edit
02-21-2001, 02:06 PM

That's one of the great thing about Audi's - all panels are made from galvanized steel :)

02-25-2001, 06:25 PM

02-26-2001, 09:32 PM
POR 15 inside any accessable panels and then spray lots of el cheapo thick tar-like undercoating in any open cavity. Rustoleum generously applied with a brush can substitute for POR 15 but is MUCH less wear resistant. Sand external rust with a sanding block and use POR 15 or generic rust converter and allow to cure. Paint over with spray enamel. (Primer is porous to water and will promptly rust through.) POR 15 has been used by car restorers for many years. It kicks ass.

02-26-2001, 09:50 PM
How many more recommendations for por15 do you need before you stop bumping?