removing deep "surface" rust [Archive] - El Camino Central Forum : Chevrolet El Camino Forums

: removing deep "surface" rust

12-13-2007, 08:42 PM
so as ive been working on the body of my 1969 el Camino more I am begging to realize that at some point someone may have began removing the paint from the car then let it sit and rust then paint over it. So my question is what is the best way to remove this rust? Ive been using a DA sander with coarse paper and it takes it off but some of the rust is like pitted into the metal so i end up removing a lot of the metal too. Ive even tried using a grinder to but this also removes even more of the metal. I was thinking on trying the chemical rust converter that changes rust to black oxide then using body filler to fill in the pits and such. Is that the right way to go about it or should i do something else. here are some pictures to try to help you see what I mean. Thanks for any help

12-13-2007, 09:30 PM
Phosphoric acid.


12-14-2007, 12:44 AM
I've used Naval Jelly before with good results. Stuff is rancid however and you have to wear gloves. I'm not sure what the agent in it is but it does stop the rust although it doesn't coat it.

The Phosphoric Acid sounds like the best solution though. Must be the active ingredient in that spray on rust coverter stuff.


69 tremec
12-14-2007, 01:50 AM
my hood on my 69 had rust like that i went over it with a special type of sanding disc. idk what its called at the moment but it does a great job it looks like a a hard rubber mesh disc that attaches to your drill works great. unfortunatly if its pitted to badly you can get the rust out but then your gonna have to seal and bondo the cleaned pitted spots there. ill get the name of that disc there tomarra its made by 3M tho

12-14-2007, 02:48 PM
This is what I use and I believe it's the same thing that 69 tremec is talking about. It's called a "3M Scotch-Brite Paint & Rust Stripper" although, Craftsman also makes one as well. They're really cool to use, they strip paint, rust and everything without grinding down the metal like sanding and grinding do. And they work great on pitted metal like yours. While rust converter can be a good product for the chassis, floors, etc...I definitely wouldn't use it or anything like it on the body of the car. It's best to remove the rust and clean the metal or replace the metal completely(if it's bad enough).

12-14-2007, 04:23 PM
I have seen those..never tried them though..maybe ill give them a shot.
And I have tried using some rust dissolver stuff that has phosphoric acid in it but it doesn't really seem to be doing much. i put some on on half of the nose piece after i sanded it down a bit so ill see if theres any difference from one side to the other. this is the stuff i am using.

69 tremec
12-14-2007, 06:18 PM
lol thats it! thanks low 75 yeah they work extremly well and are reletivly cheap i think they go for about 8-12 bucks a disc they are worth it belive me!

12-15-2007, 07:15 PM
Sand or bead blasting works great to remove that kind of rust. Just don't blast in the same place for too long, or you will create too much heat and warp the panel. My bed had rust like that from years of abuse. Sandblasting removed it all easily, then you can just fill the pits and make it look new again.

12-15-2007, 10:37 PM
I still believe phosphoric acid will do the job, maybe in a stronger concentration than the jelly.


12-16-2007, 02:30 AM
Sand or bead blasting is the best way to remove rust. Best to get it professionally done. Get them to paint the car in epoxy primer afterwards to seal out any moisture. Use POR15 paint on any surfaces that aren't on the outer body of the car. Use fisholene inside any boxed areas of the body. Your car should never rust again.

12-16-2007, 02:48 PM
Phosphoric acid works fine for light surface rust, which is why the car manufacturers use it to prepare to bare steel body prior to the electrocathodic primer (ecoat). For heavy pitted rust, media blasting or the strip/cleaning disc low75 mentioned is the best option.
See my new post with pics of the bed stripped with surface prep dics to see the results of 2 days work.

L K meano biker
12-17-2007, 05:51 AM
I agree that media blasting would be best, for all the pits and such left over, I would reccomend Slick Sand made by Evercoat. It has a mixture of primer/sealer with liquid body filler. You can find it at any automotive paint supply store, you will be suprised how much time and effort you will save using that stuff. As long as you spray it on evenly you should be able to start out with 180-220 and quickly move to a 400 grit sandpaper. No bondo files or low grit needed to knock down the high points.

12-18-2007, 08:42 PM
My 69' is a rust bucket aswell.

I have been rust converting alot of my interior & structural metal over the last few weeks. It's been alot of elbow grease and I've barely started, but it looks great.

- 1st I scrape and sand all the rust out with anything that works... putty knifes, wire brushes, screw drivers, sand paper. I don't use any power tools.
- I mix a quality liquid converter with the jelly to make it thicker and sticky.
- I paint it onto the metal and let it sit over night, scrape off any left over gel the next day, then sand off the black stuff. Use 40 and 80 grit.
- Some areas need 3-4 coats of converter. If there is rust after sanding, dig it out again, scrape and sand . Keep converting it till it's gone.
- Paint rust converter once more ( just to be sure ), scape and sand again using 120 grit.
- clean the area for primer
- spray epoxy primer.

It been working wonders, I have no signs of the converter bleeding through the primer, but I did take great care in removing ALL the black residue.

This process would most likely leave behind convereter in the pits, which could react with bondo or primer. Media blasting pitted areas would be preferable but perhaps not necessary.


02-21-2011, 05:45 PM
I am no expert, but I've used mild Phosphoric acid solutions on my tools for many years to remove rust. When applied the rusted metal turns to ferric phosphate. This is a black powder film that needs to be REMOVED before the metal is treated/etched/primed/painted again. IMO it's the best way to remove rust before prepping it for etching/priming/paint. The trick is patience. For small parts you simply soak them, sand or wire brush the phosphate off, and then inspect the part. If oxidation is still present, retreat it. Each time you do, more phosphate will appear (if oxidation is present). You have to remove this! My whole point here is... no matter what folks say... you can't paint over the phosphate (powder coating) that remains. None technical opinion, it's like painting over sludge (or under coating). One other thought, if you get it down into nooks where you can't remove the phosphate (like the inside of a frame) how do you seal that? Encapsulators have no surface oxide to cling to. What do you do then? The whole frame into a muratic bath? I'm rambling... don't flame me.

02-21-2011, 05:56 PM
All that to say... keep using a mild solution of phosphoric acid on the part. Remove the black residue (phosphate) each time it appears with the 3M pad suggested above.

In all the posts I've seen on the internet.. the biggest failure I've seen is... folks use the acid, then expect to work right on top of the residue.

If I'm wrong... some one please correct me.

02-21-2011, 06:01 PM
I've used Evapo-Rust with success on small parts, but it usually takes at least a solid day or 2 of soaking to remove the rust. I don't see it being that great on panels unless you can somehow keep a constant flow on it.

I agree with media blasting as the most sure way to tackle the problem.

02-25-2011, 11:44 PM
i would say if u dont soda blast use por-15 products they work swell but dont mix the products only use there products its about 45 a quart and sprays out of a gun or paint brush on but be neat about it and use it in layers and give it a chance to fill b4 putting a lot on:poke:

02-26-2011, 05:46 AM
CLR is a great rust remover, but you have to let it soak for hours. It's great for small things like bolts and nuts.
Did you know that Coca Cola is also a good rust remover? It contains phosphoric acid. That's why we have no rust in our innards.


10-31-2011, 05:01 PM
naval jelly typically has 5% phosphoric acid in it and its perfect for surface rust removal-if you know how to use it. get your self a few different wire brushes. get fine and coarse bristles. the tile aisle at home depot has nice tooth brush style stainless brushes. sand all the paint off around the area you are working. brush a coat of acid on the pitted metal and scrub with the wire brush. wipe it off with a paper towel before it firms up. apply another coat and scrub again. with each application you will see the lighter pits turn white. with each application you will see more and more pitted turn to clean white metal. continue until you have no dark pits. on heavy rust use a drill bit on deep pits to speed up the process. when the rust is gone clean apply warm water and scrub with a clean fine bristle brush. take sandpaper to the surface to remove the coating left. then use an appropriate brush to scratch the coating out of the pits. blow it all down with dry air and give it a shot of epoxy or zinc primer. this works great on windshield channels without the mess of blasting. on channels make sure you get a good coat of catalyzed paint before installing the windshield. the factory used a thin coat of lacquer paint on the channels which was porous and eventually would rust.

10-31-2011, 07:03 PM
"A Must for Rust" works fairly well. Just don't get on painted surfaces you aren't planning on painting. It will take the color out. 3M makes several different brushes to use with a drill. Each one is a different color. The green ones are fantastic for minor rust or finishing the work out. As mentioned, don't worry about cleaned out pitted areas. A good epoxy leveling primer will fill the holes, and it is self leveling.

10-31-2011, 09:55 PM
Good thread here......the hood for my Elco project has a lot of surface rust. I'll have to try some of the things mentioned here. Haven't touched it yet.....

11-05-2011, 03:18 PM
3m bristle disc is awsome, removes paint and rust last forever.

11-06-2011, 10:53 AM
Is the bristle disc the one with the green plastic bristles ?? Haven't tried one yet....

OK, finally looked at the link !! I'll check those out !

11-07-2011, 07:02 AM
yes, they have like 3 different coarse's. they work awesome for those hard to reach areas to, when you use them the will flare out so its also great for jams to and small curves. you will be very happy with them, make sure you get the adapter to to fit the drill,or the disc holder they call it.