Rust Repair Thread

[Manarius]

I figured...perhaps I could get this stickied and then anyone who has questions about rust can read this thread and ask questions if necessary.

So...you're seeing that bubbling near your wheel wells or anywhere else. If you don't know already...it's rust. The bubbling is the oxidation of the metal underneath the paint. If not taken care of early, the rust will spread and eat through your fender. However, there have been methods created to stave off rust. Today, we'll explore the bondo method of rust repair.

So..you can see in the picture below, the section of rust we're going to focus on today (it's the small section on the right).


In order to repair the rust, you must grind away the paint and rusted metal away from the area you're going to bondo. Should look something like this:


Now, we're going to take this bondo stuff here (which you should use in fairly warm/non-humid conditions):


According to the instructions, you mix the stuff in the can with the stuff in the tube (hardener) proportionally to the amount of area you want to cover (I used a very small amount). You can see the color of the mixture on the cardboard here:


You take your mixture and spread it on the affected area in a semi-fast manner (it will harden within 3-4 minutes):




After it gets hard (I gave it about 1.5 hours) you need to sand the bondo down so it looks good (and you don't have heeping amounts on your car...I did a poor job on this part...I did not sand enough away and I have a small bump where the bondo'd area starts):


After you've sanded it down, hit the area with a nice layer of Rustoleum (or the primer of your choice):


After the primer's dried hit the area with your matching color of spray paint:



After you've completed all that, you should have a decent looking patch for your rust. Note: When you're washing the car, take it easy on your patched areas. Note as well, you don't need to do bondo to fix an area if it's not very deep. You could just get away with grinding, primering, and painting.

[scoobiedoo22]

Maybe I should add a few other tips, just in case this does get stickied and there are more people out there who are as retentive as myself when it comes to our subies and rust. While the sand, bondo, prime, paint does work, there are other paint/body/finish products that I have used that I would recommend. That is coming from the UP of Michigan when there is road salt 10 months out of the year and we love our Subes AWD.

First off, typical gray primer or any acrylic based primer doesn't actually seal out any water. In fact, they are porous and can actually absorb water if it finds its way to the primer surface. Remember, Rustoleum is just a name, not a guarantee that you won't have rust returning in 6 months.

To truly seal out any water, you have to use an epoxy primer, such as PPG’s DP 40 series. These are two-part based epoxies, just like epoxy glues, and should of course be sprayed only on clean rust-free metal. From there you can use your typical filler primers.

I also highly recommend POR 15 for any light surface rust or rust that is occurring on undersides and within body panels, wheel wells, rocker panels…. POR stands for Pain Over Rust and that is basically what you do. Scrape as much of the rust scale off as you can and just brush or spray this stuff on and they guarantee that it will stop any more rust from forming. This stuff was developed by the U.S. Navy for use on our ocean going fleet. Think, steel ships floating in salt water! This shit works but it will cost you, very expensive.

Now if I could only take my own advice and start inhibiting any more rust from forming on my own car. So little time and such a huge list of stuff to do! Plus, the little bit of rust it has just keeps the Legacy looking like the sleeper it is. When I do get around to getting my car as rust free as possible, I will be sure to do a writeup with pics to add to this thread.