TL;DR Best way to remove heavy amounts of surface rust and what to coat it with, until I can get it painted.


Hey All,

I started this project about 6 years ago. Ran out of time and money so parked the car and haven't touched it since. Huge mistake, but it's time to finally get going on it again. I want to do a majority of the body work myself, so I was looking for some advice from the experts.

I was curious to see what the approach would be for some of you. I'm currently working on half the car. My major concern is the heavy amount of surface rust that has presented itself from neglect. I tried using CLR and sanding a small area, but figured there has to be a better way. Would I better off using an angle grinder with wire wheels, or investing in a sand blaster? Also, I was considering using some Rust-o-leum automobile primer to cover areas I do, until I can get it coated with an epoxy primer.

Basically, I am just looking for advice on the best way to approach this project taking into consideration that I cannot take it all down to bare metal and primer it at once because of time constraints. After a majority of the body work is done on the back half I intend on doing the front half. Afterwards, I plan on taking it to a shop or finding somebody on the side to do final body work and paint. I am not looking for show car quality, but something that looks decent. Any advice would be much appreciated.

Thanks,

Eric

 

Eric, I've used one of these before to remove rust quickly:

https://www.amazon.com/3M-9099DCNA-L...rds=rust+wheel

After you take it down to bare metal clean it thoroughly and spray it with sandable primer from a rattle can.

 

The effectiveness of any mechanical removal method (scotchbrite wheel, DA sander, whatever) will depend on how deep the rust has pitted the metal. If the pits are deep, you will either have rust remaining in the pits or will have to excessively thin the metal to get it all. Careful media blasting by someone who knows what they are doing is the quickest and most effective method. Obviously there is a significant risk of warping low-crown panels like the roof if this is done incorrectly. Bottom line is lower air pressure and blast at a shallow angle, not directly head-on. Move around a lot to avoid hot spots. Nothing else is as effective.

No, soda blasting won't work, you need crushed glass or similar aggressive media.

 

Thanks for the replies.

Olds64, should I just use a cheap primer for now to get it covered and stop the rust like rust-o-leum automobile primer? I've used this stuff before and it seems to hold up pretty well - I'm just worried about it effecting coats I do in the future. Or, would I be better off using an aerosol epoxy primer? I've seen Eastwood sells a rattle can that has a two-chamber design.

Joe, I've done some sand blasting before on engine and suspension parts when I had the front end torn apart. I'll probably use an aluminum oxide, or would you advise against that?

 

Aluminum Oxide is very aggressive. Again, there's a big difference in blasting thin, low crown sheetmetal vs. thick parts like suspension arms. As I suggested above, I'd go with a crushed glass media like that sold by Brut or TP Tools.

 

Eric, a Rust-oleum rattle can from your local parts store will work fine.

 

Thanks for the advice. Going to get as much rust out as I can using wheels and sand blasting harder to reach areas. Rust-oleum has a product called Rust Reformer which converts rust to a paintable surface. I'll spray this on in case I miss some rust in the pits.

 

The best product I have found for treating rust is "Ospho". Available at hardware stores. I buy it by the gallons. No doubt blasting is the preferred method. If blasting is a problem, then I would take a 9 inch grinder with 80D paper on it and smooth grind all the paint and go over the rust area. The rust will still be in the pits. Then I would go over the area with a 4 inch wire cup on an angle grinder. That is going to clean it pretty good. Then I would treat the area with Ospho. If you put the Ospho on, let it dry overnight, wire cup brush it again, and Ospho again, you can get it all. Repeat Ospho till you are sick of doing it. I did that to a car roof one time and did not prime it for over two years and only had Ospho on it. I also only spray catalyzed primers (2K). Anything else will have to come back off.

 

All blast media comes in different mesh sizes. A 120 mesh aluminum oxide is almost as fine as soda and will leave a really nice anchor pattern. "Aggressiveness" isn't media based it's particle size based. Higher the number the finer the particle (except glass bead) therefore the smoother the substrate.
You are spot on about pressure, shallow angles and keeping the stream moving to avoid not just heat but physical stretching of the surface though.

 

Rust removers can also be bought at any local auto parts store. I've used the Permatex Rust Dissolver before. It works great.

http://www.oreillyauto.com/site/c/se...2159/C0171.oap

 

If you can find some one to walnut blast and then follow up with the Ospho or
similar primer etch, it will last quite a while if in a covered bldg. If not flash
rust will appear soon. Here's a shot of the 69, done probably 5 yrs ago.
This pic was taken last year about this time.

 

Fair enough. My comments referred to the commonly available media, as sold by companies like TP, Eastwood, Brut, Tractor Supply, and HF. They typically only sell one grade of al oxide, and it is fairly large mesh size. Their ground glass media runs 40-80. You are correct in that a real blasting media supplier offers different mesh sizes that can be matched to the job at hand.

 

How is your project coming along ?

Eric