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Rust remover

Started by spolij, November 26, 2020, 09:24:09 PM

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spolij

Getting ready to paint. 66 deville conv. whats a good rust remover? Heavy and surface rust? Aerosol vs brush on? Not doing the frame. Doors hood trunk, fenders. Might buy a sand blaster.

Bobby B

Grinder or 80 grit on a DA. If you're thinking of sandblasting, prepare yourself for a car full of warped panels.
Nothing really removes rust without taking it down to bare metal. It will come back if you don't.
                              Bobby

1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

yachtflame

I recently stripped the frame of one of my other,  non Cadillac cars. It had bee under coated some years ago and it was peeling up in areas leaving air or rust pockets. I used Oven Cleaner and a scraper to get it off, then sprayed it with Metal Prep from Home Depot to neutralize the rust. I did it twice then pressure washed the frame. Once it dried, there was a white residue that I wore brushed off before painting. I did this to my 1931 Lasalle ccp 12 years ago and there’s not a blemish on the frame.
Just my 2 cents.

Wayne
Wayne Elsworth
CLC #17075

savemy67

Hello John,

Do you have any pictures you can post, so we can get a better look at your situation?  I am not sure I understand what you are trying to do.

If you have heavy and surface rust on your panels, you will get the best results if you remove all material to bare metal in the affected area.  If you have large areas of surface rust, you will get best results by stripping the entire panel.

You can remove material using chemicals, or mechanically by sandblasting or sanding.  As Bobby mentioned, there is a potential to warp panels with sandblasting, especially on the large, flat areas of the panel.  Another consideration, if you think you might want to try sandblasting, is that you would want a good-sized unit to do the job quickly.  A good-sized unit requires a good-sized compressor (two-stage, 220v, 80 gallon tank, 15+ CFM) if you are going to sandblast a car body.  You can sandblast with smaller units, but it will take longer.  And if you can't get the moisture out of your air line, your sandblast gun will clog often, making the job more time consuming.

There are chemical rust removers.  Some work by chemically altering the ferrous oxide (rust).  Others work by encapsulation.  There are also chemical strippers which work mostly by dissolving paint.  You still have to address the rust after using a stripper.  In any case, if you use a chemical of any kind, you need to fully neutralize the chemical before applying any coating, or else the new paint will fail.

Without seeing your particular situation, you may want to consider an electric sander capable of using discs and wire wheels/brushes, and a small sandblaster for corners, deep pits, edges, etc. where a disc or wire wheel can't reach.

I recommend you do your homework regarding material removal, tooling, and technique, so you can make an informed judgement.  If you will be painting the car yourself, research that subject as well, in conjunction with the preparation.  If you are going to have a shop paint the car, you might want to establish a relationship with that shop.  Few shops want to take responsibility for someone else's prep-work.  Good luck.

Respectfully submitted,

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

dn010

I am in the middle of this with my 57 right now. I've done several cars in the past using a variety of methods and here is what I've found:

Sanblasting - good for cleaning up parts or hitting rust spots if you're not taking the entire panel down to bare metal. In addition to what others have already said regarding sandblasting and warping panels, if you're stripping a panel it takes forever especially if you don't have a good compressor, it leaves media everywhere and just when you think you got it all off the car ready to paint, when you paint you'll probably find a pocket where the media collected and it will scatter all over your fresh paint ruining your job.

Air sanding - you burn through disks like crazy and it also takes forever, hard to hit contours in panels.

Now that they banned methylene chloride, there are no longer any good liquid paint strippers out there that I have found.

So, where does that us? I am using a SCT Contour tool from Eastwood with an "abrasive" drum on it (you can get the tool and drums much cheaper on Amazon, it won't be the same tool but it will work just as well). The tool and drum eats through the paint and rust quickly but you have to be careful not to leave it in the same place too long or you risk heating and warping the metal, it didn't happen to me but it is possible. My 57 sedan will take two drums to completely finish removing the repaint, the original paint and the original primer they used. It can do most contours I have but in some places like the taillights, I used a paint and rust scrapping disc from Lowes on a drill, pretty much the same material as the abrasive drum. It is still time consuming and you'll want to wear a mask but this is the fastest method I have found so far if you are stripping an entire panel.

After I removed all the paint and as much rust as I could, I used Ospho (amazon) on a sponge to etch the metal and convert any rust missed on the panel. Then I primed with self etching primer and followed up with urethane primer in preparation for my urethane topcoat. I am confident I will not have any rust for quite some time.
-----Dan Benedek
'57 Cadillac Sedan Deville 6239DX
'81 DMC DeLorean

35-709

Ospho (phosphoric acid) is good stuff when used as directed and I have used it on several cars.  Don't have to internet order it --- Lowe's, Home Depot, True Value Hardware stores, and my local auto paint supply store here where I live in Florida all have it.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Glen

#6
I second the use of Ospho.  It converts the red rust to black rust that is stable and not cancerous.  Its available at many hardware stores. 

From the internet:

OSPHO has the consistency of water and treats up to 600 square feet per gallon. When applied to rusted surfaces, OSPHO causes iron oxide (rust) to chemically change to iron phosphate - an inert, hard substance that turns the metal black.
Glen Houlton CLC #727 
CLCMRC benefactor #104

yachtflame

You can get phosphoric acid under the name of Metal Prep at Home Depot.
Wayne Elsworth
CLC #17075

LaSalle5019

Just be be careful if you use Phosphoric Acid.  Fully protect your skin and eyes. Getting on your skin...you won't know you did damage until hours later and then you are in for a very long and painful recovery.

I used a company that had a "dustless" media blast system (uses water) to do my car body but mine was a frame off process.  No heat or warpage concerns and it can be controlled better from getting into everything as there is minimal dust so is used for doing panels on an assembled car more frequently. 

Just more info and food for thought.
Scott

cadillacmike68

Quote from: dn010 on November 27, 2020, 11:15:59 AM
I am in the middle of this with my 57 right now. I've done several cars in the past using a variety of methods and here is what I've found:

Sanblasting - good for cleaning up parts or hitting rust spots if you're not taking the entire panel down to bare metal. In addition to what others have already said regarding sandblasting and warping panels, if you're stripping a panel it takes forever especially if you don't have a good compressor, it leaves media everywhere and just when you think you got it all off the car ready to paint, when you paint you'll probably find a pocket where the media collected and it will scatter all over your fresh paint ruining your job.

Air sanding - you burn through disks like crazy and it also takes forever, hard to hit contours in panels.

Now that they banned methylene chloride, there are no longer any good liquid paint strippers out there that I have found.

So, where does that us? I am using a SCT Contour tool from Eastwood with an "abrasive" drum on it (you can get the tool and drums much cheaper on Amazon, it won't be the same tool but it will work just as well). The tool and drum eats through the paint and rust quickly but you have to be careful not to leave it in the same place too long or you risk heating and warping the metal, it didn't happen to me but it is possible. My 57 sedan will take two drums to completely finish removing the repaint, the original paint and the original primer they used. It can do most contours I have but in some places like the taillights, I used a paint and rust scrapping disc from Lowes on a drill, pretty much the same material as the abrasive drum. It is still time consuming and you'll want to wear a mask but this is the fastest method I have found so far if you are stripping an entire panel.

After I removed all the paint and as much rust as I could, I used Ospho (amazon) on a sponge to etch the metal and convert any rust missed on the panel. Then I primed with self etching primer and followed up with urethane primer in preparation for my urethane topcoat. I am confident I will not have any rust for quite some time.

Mmethylene chloride is only banned for consumer use. Us duma$$es don't know how to do ANYthing so the gubmint has to step in like this....
Regards,
"Cadillac" Mike

Glen

Quote from: LaSalle5019 on November 29, 2020, 04:14:24 PM
Just be be careful if you use Phosphoric Acid.  Fully protect your skin and eyes. Getting on your skin...you won't know you did damage until hours later and then you are in for a very long and painful recovery.

I've never had any problem, but I am not very sensitive like that.  Having said that it does not hurt to wear gloves etc. for protection.

I've attached the MSDS to help folks to decide for themselves.   
Glen Houlton CLC #727 
CLCMRC benefactor #104

spolij

Stephen never heard of that. Guess I'll check my classic car.
I'm not going to sandblast the body itself only parts of the undercarriage is the engine bay, fender wells front frame etc. see the pictures. There is very little rust on the body itself certainly not enough for power equipment, just hand sending.
I've used muriatic acid. Potent stuff think I'll stay away from acids if possible.
dn010 ospho I'll check that out I was planning on using a self etching primer from Eastwood. The areas I sandblast on the rear of the car will get under coating. Under the wheel wells and whatever frame members are exposed will also get undercoating. The top of the wheel wells in the engine compartment will get high heat paint.
Christopher no heavy rust on the body just to rest areas that went through the body easily fixed. Pictures are posted my compresses are not the most powerful but I'm hooking them together. They do meet the requirements of the sandblaster than on buying from Eastwood. And it has the water separator. YouTube, manufacturers sites and this forum are my homework. LOL I'm going to paint it myself. I have painted three cars. Unfortunately that was 50 years ago. Little rusty like my car.

Wayne oven cleaner? That's a new one

Bobby the paint is in great shape I'm just going to rough it up prime it and paint it.

spolij

Steven Which episode? There are too many to brouse.

Quentin Hall

I concur with every one saying phosphoric acid. You should probably post photos of the specific areas that are the problem.
I dip whole panels in phosphoric to remove all traces of rust then gentle glass bead blast then back in phosphoric so that I can repair areas and n bare metal. Here is a 53 Eldo door mid repair.
53 Eldo #319
53 Eldo #412.
53 Eldo #433
57 Biarritz
53 series 62 conv
39 Sixty Special Custom
57 Biarritz

spolij

Quentin Wow that's clean.Did you buy a tank that big or make it?

Quentin Hall

I just cut the top off a 1000 ltr water tank.
I strip the door with paint stripper to get the bulk off.
I buy two 20 ltr undiluted food grade phosphoric acid from the chemical co. Dilute 7 to 1. I can drop a whole door in there after a preliminary clean. Let it soak for two weeks. It softens everything up. The heavy rust is attacked and dissolves.  Then the blasting only tears away the remnants of paint and the panel without tearing away the metal which is softer than rust.
After blasting it goes back in phosphoric for 10 minutes and that protects the metal for metal repairs and welding. It’s really humid here so I usually give them a wipe down with phos if I notice any surface rust.
Once all repairs are done I repeat a full wipe down in phos and then begin epoxy primer.
53 Eldo #319
53 Eldo #412.
53 Eldo #433
57 Biarritz
53 series 62 conv
39 Sixty Special Custom
57 Biarritz

carlhungness

   Need more specifics, what are you trying to do overall? I recently had my frame
blasted by the dustless method, and it is pretty dustless. They use ground up glass, cost me $400 plus I had a dozen extra parts. Came out perfectly. A journeyman with one of these machines can do panels without warping too.