Are these black spots rust?

[lancesir]

Anyone have experience with fixing rust spots?

I did it before on a smaller stone chip that just started to rust. I sanded down to metal and then filled with primer and then touch up paint and its been holding up well.

Now I just noticed a much bigger rust spot with bubbling. I talked to a body shop and the guy recommended me to just do the same as I did before. So I went ahead and sanded down to metal again, but this time noticed little black pits in the metal. Does anyone know if the black pits are "normal"? Or the spots are rust and I need to keep sanding until a smooth metallic finish?

Here's a photo I took with the phone

http://s21.postimg.org/yye1rv9pv/image.jpg (http://postimg.org/image/yye1rv9pv/)

Any advice would be great thanks!

[Manpreet]

those are rust spots had those on my car had to cut out the metal and put a new patch, you can keep treating the way you are doing it now and slow down the rust a bit, but its going to come back and eventually turn into a hole

[ace_master]

Someone once told me that you can drill small holes into pitted body panels and use a welder to fill the holes back in, followed by grinding and sanding the surface down smooth. I would NOT go this route unless you do a lot of homework first, as I'm sure it's not the most effective option.

[ace_master]

Depending on where it is... If you can get in behind it afterwords, it wouldn't be a bad idea to sand the back side of that spot, put a little metal primer, and rust paint on the back side.

[lancesir]

Thanks for the quick replies
Looks like its worst than I thought

I can't get to backside its actually rusting at the edge of roof by the windshield. Will putting some rust remover before primer work? Or just delaying the inevitable?

[ace_master]

The thing about rust is that if you don't get it all, it will eventually just grow again once the slightest hint of moisture gets to it.

I would just clean the holes out is a small wire brush (the kind that looks like a toothbrush from hell). Once it's fully cleaned out, get some metal primer into the holes to seal them (make sure it gets right inside the holes, and there's no air bubbles under it), then enough primer/filler to fill the holes completely. Sand it down with a fine grit, and get your paint on.

[Dave_The_BMXER]

I've used POR 15 in situations like this for decent results.

[Flagrum_3]

Slightly diluted phosphoric acid (70%), will actually do the job. I think you can purchase some at Home depot under the Behr name. Just a few drops right on the spots. Used this method years ago.

_3

[lancesir]

Thanks for the replies everyone!

So I did some more work on it these few days and unfortunately I think I've hit a road block, because I definitely see rust on the edges behind windshield molding. I could just clean and touch up what I can see, but all the body shops I've take the car to say if there's rust under the glass molding then it will just creep up all over again.

I might have to bite the bullet and have the shop take the glass out to do a "proper" fix.

Btw, side question, does anyone know if roof wrap/vinyl is effective for an extra layer of protection? It would be nice to put an extra layer or protection near the glass edge once it's all fixed up. CF wrap could be good look for my roof LOL