Any of you ever diy fixed rust on your car?

[repoman0]

I have a New England winter driven 04 BMW that's starting to get some rust bubbling through the paint in a few spots: one rear quarter panel, door sills, inside of the rear doors. I think it's mostly cosmetic at this point, but I'm thinking I should take care of it before it eats through metal, since I probably will want to keep the car for 5-7 more years.

I got a quote from a body shop for over $1700 not including the door repair, and it goes up from there. They do a nice job supposedly ... blast the rust away, prep the metal, paint match and clear coat and warranty their work. I really don't have a huge problem spending $2-3k to keep the car on the road even though I only paid $4800 for it because it's still cheaper than a replacement, and I like the car quite a bit .. would like to drive it until I buy an electric (likely 5-7 years down the road like I said).

That said, it's only cosmetic. I was thinking I could just sand and dremel it away down to bare metal, apply POR15 over the metal, and spray it with a color-matched rattle can and clear followed by buffing. That would cost me a hundred or two dollars in supplies and maybe a few hours of my time. Seems like if done properly it should hold equivalently well to the body shop's work, just might look sloppier. Sloppy is totally fine with me as long as the metal isn't being eaten away.

Any of you ever done a rust repair like this? If so how did it hold? Any tips?

 

[jlee]

It would look positively horrific, but it should work well enough.

 

[repoman0]

It would look positively horrific, but it should work well enough.

Can't be any worse than the rust! The best quote I got that included fixing the rear doors was right near $3000 ... I'll deal with ugly Shouldn't be terrible if I try to keep the POR15 thin and if the spray match is half decent. The only visible spot is the quarter panel too.

Think I'll see what I can do ... will update here with my likely shitty results.

edit: doesn't hurt that the color is BMW's "silver gray metallic" which somehow looks clean after the past year of not washing the car. Should look fairly benign in the end even if I do a terrible job.

 

[EXCellR8]

I'm in New England too so I'm quite familiar with body rust; you can't really stop it, just slow it down a little bit. The best thing to do is see if anyone makes replacement panels and have a body shop tack patch and blend them in; then paint.

It's a trade off... do it yourself and lower the value of the car or spend the money and hold the value. That's just how it is.

 

[repoman0]

^ Yeah, that would definitely be ideal ... but the door sills kind of kill that. Too expensive to justify at that point since that's quite a job to cut out.

The car is beater status, nearly 15 years old and worthless .. but one that I happen to like, and was surprisingly hard to find with all my requirements of 6-speed manual, AWD drivetrain and heated + fold down seats. Value in good shape right now is around $4500 and probably will be more like $1-2k in 5-7 years when it's pushing 200k miles.

 

[EXCellR8]

I hear you... if the car is purely a parts car that drives then do what you can to keep it on the road and prevent further rust. I used to use this stuff by Skyco called OSPHO or something on my old hondas. You use an acid brush to apply to rust spots and it dries black and acts like primer for paint. Worked very well, but I'm not sure it's even still sold, but certainly worth googling.

 

[pauldun170]

^ Yeah, that would definitely be ideal ... but the door sills kind of kill that. Too expensive to justify at that point since that's quite a job to cut out.

The car is beater status, nearly 15 years old and worthless .. but one that I happen to like, and was surprisingly hard to find with all my requirements of 6-speed manual, AWD drivetrain and heated + fold down seats. Value in good shape right now is around $4500 and probably will be more like $1-2k in 5-7 years when it's pushing 200k miles.

I gotta ask...
Is the CEL on?
Whats wrong with the car aside from rust?
What have you had to do to keep it on the road?

 

[repoman0]

I gotta ask...
Is the CEL on?
Whats wrong with the car aside from rust?
What have you had to do to keep it on the road?

No CEL and nothing wrong with it aside from rust. I haven't done anything since I bought it. It probably needs new brakes, a few new bushings, and preventative trans/diff fluid changes but it drives great.

edit: I preventatively replaced most of the cooling system right after I bought the car for peace of mind ... few hours one afternoon and $400 in parts. It had 93k miles at the time

 

[pauldun170]

No CEL and nothing wrong with it aside from rust. I haven't done anything since I bought it. It probably needs new brakes, a few new bushings, and preventative trans/diff fluid changes but it drives great.

edit: I preventatively replaced most of the cooling system right after I bought the car for peace of mind ... few hours one afternoon and $400 in parts. It had 93k miles at the time

Nice....

 

[PricklyPete]

I have done it in the past on some trucks/SUV’s I’ve owned when I lived back east. Key is that I did it the second I saw anything at all. The earlier I did it, the less ugly the results would look. I’ve used small sanders on a dremel with a super steady hand to clear the rust spot. Then just touch up paint/clear coat from dealership. Never looked professional, but good enough for a truck/SUV.

 

[thedarkwolf]

Sure

lol
That was just a "I need to pass inspection and don't give a shit how it looks" job on my old 89 dodge caravan beater. It was still "good enough" 5 years later when I sold it. I've also done some half assed surface rust fixes to just slow the rust down till I get a chance to get a car painted using POR 15 and then never got around to getting the car painted and years later the POR 15 was still doing its job.

 

[monkeydelmagico]

Locktite rust neutralizer. Been using it for years on a variety of beaters including the notoriously rust prone mazda proteges. Wipe off the dirt and apply with sponge brush. No additional prep or sanding. Slows the rusting process way down if you do it every season at the first signs of rust.

The times I have gone down to bare metal, filled, sanded, primed, sprayed, clear coated have been a monumental wastes of time. The rust comes back after a couple seasons.

 

[BurnItDwn]

good thread!
Full of bad, good, and medium ideas..

Reminds me ... surface rust started on my 08 Fozzy in a couple spots, maybe I'll wash it and put some rust neutralizer before winter

 

[Pacfanweb]

Yes, they still sell Ospho. It's acid that neutralizes the rust and forms essentially layer of primer over it.
Other products also have acid that does the same thing.
POR 15 does not neutralize, it encapsulates and keeps moisture from getting to the rust. It works okay, but I prefer to kill the rust with acid first, or better yet, have it sand blasted perfectly clean.

Yeah, you could do it yourself but unless you know what you're doing and have the tools to do it, it's going to look like leftover ass. If you care how the car looks, have a body shop do it.

 

[repoman0]

I don't care too much how it looks, would like to do a half decent job that passes the 15 foot test and stops the metal from rotting but I don't need perfect. The door sills are what I'm most worried about and I really don't care at all what they look like.

I've been trying to figure out the best method here .. Angle grinder + cup wire brush seems like the way to go to remove the rust scale and bubbling paint. I've been wanting an angle grinder anyway. Seems like some of you have had difficulty with rust coming back going straight to bondo, primer, paint and clear ... so maybe apply this Ospho stuff to the ground away mostly bare metal? Then filler on top of that if it looks extra crappy and I'm feeling motivated. Otherwise just spray primer, paint and clear using one of these paint match kits: https://www.paintscratch.com

Is there a better product to apply to the metal if I'm planning on angle grinding as much rust away as I can?

 

[paperfist]

I don't care too much how it looks, would like to do a half decent job that passes the 15 foot test and stops the metal from rotting but I don't need perfect. The door sills are what I'm most worried about and I really don't care at all what they look like.

I've been trying to figure out the best method here .. Angle grinder + cup wire brush seems like the way to go to remove the rust scale and bubbling paint. I've been wanting an angle grinder anyway. Seems like some of you have had difficulty with rust coming back going straight to bondo, primer, paint and clear ... so maybe apply this Ospho stuff to the ground away mostly bare metal? Then filler on top of that if it looks extra crappy and I'm feeling motivated. Otherwise just spray primer, paint and clear using one of these paint match kits: https://www.paintscratch.com

Is there a better product to apply to the metal if I'm planning on angle grinding as much rust away as I can?

Definitely want to grind it. If the rust has been there a while one of those spot sandblasters are handy to get into the pitting.

You want to use a bare metal primer. Eastwood carries it if there’s nothing locally.

Biggest thing with the paint is it’s going to be layers below what you didn’t grind. So you have to build that up with primer or putty and feather out the factory paint. There’s a detail guy on YouTube AmmoNYC who has some great videos on minor repairs like this.

As for the paint I know you said you didn’t care but it’ll never match. It’s metallic, old you’re using spray cans.

 

[repoman0]

Cool, thanks. Bought my supplies:

Dewalt 11 amp 4.5 inch angle grinder
Cup wire brush
Ospho metal prep
Bondo fiberglass filler
Various sandpaper up to 2000 grit
Paintscratch.com A08 paint code spray kit

$220 including a nice tool I need anyway. We will see ...

 

[paperfist]

Hmm usually fiberglass filler is meant to repair rot, it’s a little thicker with the hairs in it. If you’re just doing surface rust it might build out to far.

Whatever you do don’t use a lot if you’ve never used it before as it’s a nightmare to sand off.

 

[mindless1]

^ Fiberglass bondo is easy to sand off with an angle grinder and sanding disc. Just stop before you've gone too far then use a hand block to finish.

 

[evident]

It would look positively horrific, but it should work well enough.

I did the dremel, and POR 15 route on the inner wheel well of my old honda. It was not in a visible location at all, luckily the car was black as well. It looked good enough after i used touch up paint, but it would have looked terrible if it was on a door or something.