What do you guys recommend I do with this rust?

[NasaGT]

I've got a question for the rust experts. I'm getting ready to repaint our 87 5.0 LX. Even though it has been pampered all of its life, it has developed some rust on the roof (and a few other spots). Over the last two years little rings of rust appeared all over the roof. So I sanded the paint and rust off, and now the metal looks like this:

Each of these marks correspond to a bit of rust. I'm assuming that all of this must be removed before painting - whats the easiest way to take care of this problem? Using the high speed sander with 40 grit works, but its slow going. There's so many on the roof that I'm wondering if theres a better way.

Thanks!

 

[FasterThenU72]

rust converter then primer is all i have ever done, and my car is absolutely rust free

 

[BB1966]

Some stuff called Metal Prep or Etching(SIC?) primer.

 

[86T-Top]

Sand blast it, but be carful not to warp the roof.

Mario

 

[one2gamble]

I have that on my car pretty bad in some spots..try and get as much out as you can and then use a rust treater. We use this stuff called Rust Mort in the shop and have never once had a problem.

 

[allcarfan]

a $15 sandblaster and some play sand that has been sifted should do the trick. Its hard to tell exactly how big those spots are in your picture. You could just spot blast them. Although, I think if you used sand paper, you would not have a problem. That rust is not bad at all.

 

[Edbert]

You call THAT 'rust'?

LOL, you should see what happens to an outdoor Stang after ~40 years. They don't call 'em Rustangs for nothing ya know. If you cannot see light through the metal it aint an issue

Seriously, put some encapsulator on it, sand, re-apply, sand, prime, sand, prime, paint. You should be good to go.

 

[darkness falls]

Don't waist your time sandblasting it, if its on the roof, don't risk the possibility of warping it with a blaster. Use some elbow grease and a orbital grinder (or block and sandpaper) and just work them out. Those aren't bad. You should have seen the inside of my car under the roof, it was all rusty red, completely oxidized.

 

[NasaGT]

lol - its definately pretty tame rust.

Thanks for the replies. I should have put something in the pic to illustrate their size. The largest one in the pic is about the size of a no. 2 pencil eraser. They aren't that big, and the orbital sander wipes them out in 2-3 seconds. But there are hundreds of them on the roof and I was hoping there was a faster way.

Oh well, I'll take em' out one by one!

 

[RajunCajun]

3m rotary (drill operated) abrasive wheel, $8.47 last i checked almost everyone carries them, if you have a pneumatic air die grinder you can chuck it up to it and get rid of it all VERY fast \
heres what it looks like semi used but you get the idea

 

[krash kendall]

-They aren't that big, and the orbital sander wipes them out in 2-3 seconds.
-I was hoping there was a faster way.

If you are reluctant to invest this much time in something minor, what are you going to do with the major work (sanding and prep.)?

 

[NasaGT]

If you are reluctant to invest this much time in something minor, what are you going to do with the major work (sanding and prep.)?

Not reluctant, just thinking that maybe an application of a rust remover (or something) would be easier. I had planned to sand them all out, it just occured to me that maybe the experts on this board might have a better solution. Why take the hard path if someone knows the short one?

 

[krash kendall]

I took you words out of context for a reality check into what an easy job it will be - just to get you motivated!

 

[darkness falls]

 

[TOM B]

No No No,,, You are as far as you want to go on that rust, do not blast do not sand anymore, that is not any problem. what you want to do is use a etching primer. like Marten senior "metal etch" or PPG "self etching wash primer". These primers have a rust inhibiter in them to stop rust like yours dead in its tracks. then the metal etch primer must be coated with a regular primer or a primer surfacer if you need to fill a little. ETCHING PRIMER MUST BE TOP COATED WITH A REGULAR PRIMER OR IT WILL DRAW MOISTURE AND RUST IF LEFT EXPOSED.
If the rust is deep and loose then sand with 40 or 80 grit to get out the loose stuff then use metal etching primer.
Metal etch primers can be sprayed over body filler but very lightly, dont wet it down. Always use a 2 part body filler and always use a 2 part pin hole filler puddy.
NEVER use 1 part spot filler primers like what comes in tubes and has no hardner also called glazing puddy.

 

[NasaGT]

3m rotary (drill operated) abrasive wheel, $8.47 last i checked almost everyone carries them, if you have a pneumatic air die grinder you can chuck it up to it and get rid of it all VERY fast \
heres what it looks like semi used but you get the idea

I bought one of these abrasive wheels, it works great! Barely touch these spots and they are gone.

 

[NasaGT]

No No No,,, You are as far as you want to go on that rust, do not blast do not sand anymore, that is not any problem. what you want to do is use a etching primer. like Marten senior "metal etch" or PPG "self etching wash primer". These primers have a rust inhibiter in them to stop rust like yours dead in its tracks. then the metal etch primer must be coated with a regular primer or a primer surfacer if you need to fill a little. ETCHING PRIMER MUST BE TOP COATED WITH A REGULAR PRIMER OR IT WILL DRAW MOISTURE AND RUST IF LEFT EXPOSED.

I've been spraying DuPont products for many years now, I'm not familiar with an etching primary as you mentioned (and someone else above). I've got an Epoxy primer that I've alwys sprayed on bare metal, and it also requires a regular primer to sprayed on top of it.

I guess I've got some "primer" research to do ... thanks for the info!

 

[67GTFastback]

You call THAT 'rust'?

LOL, you should see what happens to an outdoor Stang after ~40 years. They don't call 'em Rustangs for nothing ya know. If you cannot see light through the metal it aint an issue

No kidding, now this is rust.

Seriously, you will be fine if you follow the advice given in previous posts. If you want to check out the rest of this car (a car I think should have been crushed but I agreed to do it for a firend), go to http://www.classiccorral.com/67coupe.html. I now have the floors in, all fender aprons are in, the car is sanded down to bare metal, replace the tail light panel and then reinstall the cowl.

 

[FasterThenU72]

wow, i thought mine was bad, but that floorpan takes the cake

 

[67GTFastback]

wow, i thought mine was bad, but that floorpan takes the cake

It is the whole car, the rockers, the frame rails (front and back), floor supports, engine compartment, etc. Everything on this car would normally be a complete write off.