Found scratches in black coating on under side...

[badtlc]

On my Mazda3, I found some scratches one one side of the car. It is on the panel that runs the length of the side below the doors. This piece is painted the same color as the car on top but as you go down and under the car, this panel wraps under and fades into a black color/coating. WHere this panel then turns down perpendicular to the ground is where the scratches are on the edge. They are down to the silver colored metal beneath. It looks like the car had went over the edge of a curb or something at some point. Could have been there when I bought the car or from when the wife drove it.

Anyway, I was going to ask the dealer if this is a big deal or not and what it would cost to patch/repair/coat it to prevent any future problems. You can't see anything normally but my fear is rust.

Is there anything I can do with very limited tools myself if something should be done and the dealer is crazy expensive?

thanks everyone.

 

[dparm]

Not sure I follow -- are the rocker panels plastic or metal? I would be surprised if they were metal.

 

[joaks]

If it is down to the metal you will want it fixed. A professional grade job will be very difficult to do yourself. Ask the dealer or one of the better body shops for a price. Might not be terrible.

 

[SwampSurvivor]

Did someone go off roading with it?

 

[Trav]

This shouldn't be to difficult if i understand you correctly.
It sounds like the chip guard coating on the bottom of the rocker panel is damaged.

You will need a few things but nothing special.
Masking tape and news paper.
Self etching primer from AA, AZ, etc.
Chip guard (get the black) from NAPA
A rattle can of paint same as car color, don't worry about clear coat over this over the stone guard. A single stage rattle can is fine.

Mask off the area leaving about 6" in front and rear of the damage,
scuff any surface rust and give a light coat of the self etching primer, let dry (20 min)
Shake the chip gurd well and spray a light coat over the primer, wait 20 min and repeat.
Spray the color right over the chip guard.

After spraying the chip guard, remove the tape and move it away from the chip guard a couple of inches before spraying the color paint

http://shop.advanceautoparts.com/p/dupli...content=7140110

http://www.napaonline.com/Catalog/Catalo...4004_0006419341

 

[Trav]

Originally Posted By: dparm
Not sure I follow -- are the rocker panels plastic or metal? I would be surprised if they were metal.

Why would you be surprised? The rockers on your M3 are metal as are most cars. I have never seen plastic rocker panels on any car that wasn't fiberglass or composite like a vette.
Any plastic in this area is a cover, the rockers are structural on a uni body.

 

[badtlc]

Originally Posted By: dparm
Not sure I follow -- are the rocker panels plastic or metal? I would be surprised if they were metal.


Yes, it is the rocker panel. On the very bottom edge back under the car. I didn't think it would be metal but where the black coating has been scratched through it is silver in color.

 

[Doog]

I always mask off another 2-3" on the underside of the rockers when the car is new (or new to me) and spray with rustoleum undercoating. Then I do the bottoms of the inside of each door.

Then the entire underside. This has kept all of my cars rust free for 5-6 years and then I re-coat if I'm keeping the car.

 

[badtlc]

Thanks Trav. I might be able to do that if the estimate comes back too high. I would hope it isn't expensive because I don't care if it looks good. I just want it protected. There is no sign of rust, everything shiny silver. I'm guessing it is fairly new.

I would have never noticed it had the daughters ball not got stuck under the car.

 

[dparm]

I agree with the other suggestions. Try touching it up yourself and see how it looks. Without seeing a photo, it's hard to estimate what a body shop would charge, but I'd guess $3-400ish to properly repaint that and blend it in nicely.

 

[badtlc]

Originally Posted By: dparm
I agree with the other suggestions. Try touching it up yourself and see how it looks. Without seeing a photo, it's hard to estimate what a body shop would charge, but I'd guess $3-400ish to properly repaint that and blend it in nicely.


It doesn't need to be proper. The paint is fine it is just that black coating and you can't see it when looking at the car. I don't need it to look great because you can't see it. The dealer said they can probably scrape off some of the roughness and get it coated for a reasonable price. We'll see what their definition of reasonable is this week.

 

[badtlc]

I'm thinking maybe I should DIY this since there is no rust yet. A lot can happen before friday when the dealer can see it. It doesn't seem bad if I can just take my time and do it right with masking tape and everything.

 

[dparm]

Originally Posted By: badtlc
I'm thinking maybe I should DIY this since there is no rust yet. A lot can happen before friday when the dealer can see it. It doesn't seem bad if I can just take my time and do it right with masking tape and everything.




Exactly. It's not in an easily-noticed part of the car. Good project for the weekend.

 

[badtlc]

if rust does start popping up before I can paint, what kind of brush do I use to rub it off? Would a grill brush work?

 

[Trav]

Any small wire brush, it must be clean, no grease or oil. You could use some 800 grit sandpaper also just make sure you prime it right after whatever you use.

The self etching primer is almost a must, it etches itself right into the metal for a good bond and good protection.
I keep about 4 cans around all the time and use it on every bare metal before applying anything else.

 

[badtlc]

Originally Posted By: Trav
Any small wire brush, it must be clean, no grease or oil. You could use some 800 grit sandpaper also just make sure you prime it right after whatever you use.

The self etching primer is almost a must, it etches itself right into the metal for a good bond and good protection.
I keep about 4 cans around all the time and use it on every bare metal before applying anything else.


Thanks. I'm getting an estimate from a guy this afternoon. If it is too much, i'll go buy the parts. I'll wipe the area with a wet rag, go over with small wire brush, wipe again, let dry and apply the primer. Seems odd the primer is green, but that is the only color that self etching primer comes in. Doesn't matter since it gets covered, just seems odd.

Thanks for the tips. Is this NAPA stone guard good stuff?

 

[badtlc]

The guy quoted me $35 to do the job. I thought that was very reasonable but he said I should just give it a go and if it didn't go well he would have no issues cleaning it up and fixing it.

So I gave it a go and I think it went OK. I got some small bubbles from the primer on a spot that was painted. All the exposed metal seemed to take the primer just fine thankfully. The stone guard ran more than I expected yet was thicker than I expected.

Overall, I think I got the exposed metal protected now and for $17 and about 2 hours time. Only spent about 10 min of that 2 hours doing actual work. Rest was drying time.

Thanks for the input everyone.

 

[Trav]

Yes it thick but thin to spray thats why i said 2 coats. No problem, its underneath anyway and its very good stuff.
It acts like shock absorbing material when hit by stones so the chips don't get to the metal.

Glad to hear you got this squared away before rust got at it.

 

[badtlc]

Me too. I just hope I got it all and don't find any surprises in a few years. I really like this car and I'd like to be one of the first to get 200k+ on a skyactiv-g.