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Shermer321
11-07-2018, 12:59 PM
Well I got the inevitable rust spot on the ol' Hyundai Sonata... Right on top of the windshield on the roof of the car. It is well maintained and I want to keep rust of the car as long as I can. So, I ground out the old rust and used a 2 part polyester glazing putty to fill and sand with a 600 grit sandpaper. And now I am stuck... Should I spray primer, base, and clear or try and touch up paint over a level spot? Not looking for a Jaguar finish but just prevent the rust from continuing for a few more years. Any tips on what you guys would do? I attached a before filler pic (I ground out a little more after this pic to be safe) and after filler. I am not a auto body technician but with a list of instructions I feel I can tackle it. **First post, please move if I am in the wrong spot.
6525165252

infosponge
11-07-2018, 01:21 PM
Disclaimer: I am not an autobody expert

To my knowledge the only way to properly fix it permanently is to re prep and re spray the entire panel. That being said I have seen some videos on YT of people using the 2 stage clear coat in a can and re-clearing partial panels to fix failed clear coat with decent results, I don't see why you couldn't do the same with primer, base coat, and clear coat. If you don't do the whole panel though someone who knows about paint work would be able to notice, and won't have the longevity from what Ive read.

Shermer321
11-07-2018, 01:32 PM
Disclaimer: I am not an autobody expert

To my knowledge the only way to properly fix it permanently is to re-prep and re spray the entire panel. That being said I have seen some videos on YT of people using the 2 stage clear coat in a can and re-clearing partial panels to fix failed clear coat with decent results, I don't see why you couldn't do the same with primer, base coat, and clear coat. If you don't do the whole panel though someone who knows about paint work would be able to notice, and won't have the longevity from what Ive read.

Yeah I figured that is the correct procedure... Just wasn't going to repaint the entire panel based on a thumbprint rust spot. I am fine if you can see it, hell, you could see it with the surface rust. Just wanted to slow it down and protect it. I have spent a lot of time watching youtube videos and looks "simple" enough. My only concern is blending in that small of a spot.

infosponge
11-07-2018, 01:38 PM
If your going into it with that attitude I'd give it a shot. Also I did find that video FYI YouTube (https://www.youtube.com/watch?v=lbSIjsUeWZQ)

BillE
11-08-2018, 08:27 AM
This (to me) is a perfect candidate for using an 'air brush'.

You can, in theory, build up with touch-up paint then GENTLY sand it down...lotza work to make it look perfect-but can be done.

No matter what you use/do...be SURE ALL of the rust is gone. That's tricky area to work on (that rubber edge) is a bear.

Good luck...

Bill

Shermer321
11-08-2018, 08:49 AM
This (to me) is a perfect candidate for using an 'air brush'.

You can, in theory, build up with touch-up paint then GENTLY sand it down...lotza work to make it look perfect-but can be done.

No matter what you use/do...be SURE ALL of the rust is gone. That's tricky area to work on (that rubber edge) is a bear.

Good luck...

Bill

Actually have a good family friend who owns a body shop who's painter will color match and air brush it in. $75 at most. I do have a remaining question, what would you spray to help prevent the rust from coming back? Most forums say grind, clean, fill, then etch primer? How does it get through the filler?

Shermer321
11-08-2018, 09:58 AM
Actually at a closer look there is on little spot that has surface rust that is lower on the ridge. I am assuming I can just use a solid rust convert before it goes in for touch up?

Setec Astronomy
11-08-2018, 10:09 AM
I think that's a great fix for your friend to spray it for $75. How did that spot start--was it a rock chip that wasn't fixed that grew?

The reason I'm asking is with the proximity to the rain gutter it looks like there may be a little more going on there. What year is the car?

Shermer321
11-08-2018, 10:33 AM
I think that's a great fix for your friend to spray it for $75. How did that spot start--was it a rock chip that wasn't fixed that grew?

The reason I'm asking is with the proximity to the rain gutter it looks like there may be a little more going on there. What year is the car?

I pushed down the rain gutter and there is only a speck of rust there. I plan to use a little rust converter over it after trying to sand the spot. I ground off all of the surface rust above, it never pitted and I caught it soon enough. I can take a better picture of what the channel looks like. The car is a 2011. I didn't see a chunk missing like a rock hit it. Just a couple bubbles, not even flaking yet. Maybe sun damage..

The only question is how to slow/stop it. Wondering if I screwed up putting putty over bare metal without rust converter. I feel I got it all ground out.

Setec Astronomy
11-08-2018, 10:40 AM
I think you were fine with the putty over the bare metal, what bothers me is there looks to be a seam in the picture of the bare metal repair...if you get a rust bubble that didn't start from the paint coming off from the outside, it usually has come from the inside, which I also notice, you have quite a hollow where you sanded...lot of metal came out, which normally wouldn't be from surface rust.

Anyway, if that rust came from "inside" it's likely to come back however you prep it...but it should be ok for a year or two maybe. Hard for me to tell, not sure exactly where on the car that is, and I'm no expert. I like the color of your car, BTW.

Shermer321
11-08-2018, 10:49 AM
I think you were fine with the putty over the bare metal, what bothers me is there looks to be a seam in the picture of the bare metal repair...if you get a rust bubble that didn't start from the paint coming off from the outside, it usually has come from the inside, which I also notice, you have quite a hollow where you sanded...lot of metal came out, which normally wouldn't be from surface rust.

Anyway, if that rust came from "inside" it's likely to come back however you prep it...but it should be ok for a year or two maybe. Hard for me to tell, not sure exactly where on the car that is, and I'm no expert. I like the color of your car, BTW.

I don't know what you mean from the seam? I ground out with a dremel down to bare metal in the shape of a trapezoid, you can kind of tell by where the putty lies. I wanted to go wider than the initial grind. Then roughed up with sandpaper for the putty to stick. It very well might have been a nick I guess I didn't pay attention or take a pic prior. There was nothing wrong with the metal underneath like a pinhole or anything. Just looking for a year or two, its a 2011 Sonata with about 140,000 miles. I may add a little more putty to cover the bare metal portion (obvious low spot). The spot is the top of the windshield on edge of roof and glass rubber surround (pushed down in the picture).

Its not a jag, or large damage, just needed to grind off and recolor to slow it down.

Setec Astronomy
11-08-2018, 10:58 AM
Ok, now I understand where that is, that's a spot that's pretty easy to get a rock chip. I just see something at the top (of the picture) of the ground spot that looks like a rusty line, that edge of the roof panel has to be welded or soldered to the top of the windshield frame, so there's some sort of joint there. Unless that's just sanding debris that got into the joint.

Shermer321
11-08-2018, 11:09 AM
Nope. There is no rust to speak of. Ground absolutely everything. In the grinding picture it was sanding dust. So I ground it out further to guarantee I got outside of the problem area then cleaned. No rusty line, just how the putty filled in. I could probably sand a little more to get the far edge putty cleaned up but I don't feel a ridge at all. I am going to use some rust convert just in case there is a speck I didn't get. Near the rubber gasket is tough to sand, but there wasn't any damage in there from what my eye can tell. I know it will probably rust again in a year or two... Any recommendations on rust convert?

Setec Astronomy
11-08-2018, 11:23 AM
If it's surface rust and you got it all out it shouldn't rust again. I don't have any recommendations on rust converter, I've never used anything that I liked. Is POR 15 a thing? I think Eastwood has some solutions. The man to talk to about this is Accumulator on Autopia.

Shermer321
11-08-2018, 04:04 PM
I don't think POR15 is a great underlayment for touch up paint or body sprayed paint. I may be wrong though. Would just like to hit a couple spots with a recommended rust converter it before he sprays.