What's the best way to remove rust?

[jeryst]

My Cuda project had a vinyl roof, and the whole roof is very rusty. It's completely rusted through along the back sides. I'd like to remove the rust so that I can see exactly what I have to work with. I don't want to have it sandblasted, and I don't want to just cover it with POR-15 or Rust Bullet. There are no media blasters close to me either. What's the best way to remove the rust over a large area like that? Is there anything that will dissolve the rust leaving the bare metal?

[360 'CUDA]

You can try thinned down Muriatic acid. (pool acid)  It gets down to the metal fast but you have to be carefull

Clean and wetsand everything when your done and don't breath the vapors 
Also, be ready to prime the area or it will rust twice as fast

[360 'CUDA]

Here are a couple of pics I posted over a year ago. The car sat with no paint on it for a while and I gave it the "treatment" I mentioned.

[jeryst]

Has anyone ever used evapo-rust  (www.evapo-rust.com) or Strong Arm Spray (www.strongarmspray.com)?

I actually bought a can of Strong Arm Spray at a car show (Expensive at $10/spraycan), and they claim it will do just about everything but cure the common cold. I've used it to free stuck parts, clean and shine vinyl, drill bit lubricant, and I have to say it has worked better than anything I have tried. I never tried to unstick an engine with it, but I have an old 340 and a 331 hemi that may be prime candidates. I even used it to remove rust from some small parts, and it worked very well except that you have to use a brass brush, and I don't want to have to go over the entire roof with a brass brush. Of course, the evapo-rust is made for parts to soak in it, and I won't be able to soak the roof, so that is also a problem. Both of these products are biodegradeable, don't produce dangerous fumes, and you can touch them without any harm, so I would like to use something like that instead of an acid. And one other thing about the Strong Arm Spray; They claim that once it removes the rust, you can leave it on the metal to keep it from flash rusting, and that if you just wipe it down, it will make the paint stick better. I'm skeptical about those claims, but hey, you never know. Maybe one of our member bodymen can give it a try.

[360 'CUDA]

Show us some pics when you get done.  Always looking for a good product 

[moper]

I dont know fo any way to permanently stop rust except abrasive removal or cutting out and replacing. The other products will work to slow it down a little or a lot...but it will always come back. In a roof panel, I would not cut corners. Cut it all the way out and replace it. Especially if it's rusted thru completely.

[73EStroker]

Jeryst - there is a product up in Canada  called rust mort. I am sure you can get it down in the US. It is acid based and yes it works and yes you must paint it quick otherwise rust sets in quick. The metal will have a real dark look to the rusted bits and be real hard when it is dry. That is when you paint - usually after a day or so of drying under cover. Also please remember that primer soaks up moisture like crazy so before final painting sand it down and reflash the primer within a few days before final paint. Otherwise you can get those nasty little moisture bubbles in your paint.
I agree with Moper though - do it right the first time. It is the cheaper way to go.

[360 'CUDA]

I'm still trying to figure out why the way I did it was wrong   

[moper]

Not sure what you mean by that... If it worked well enough for you...was it wrong? I can see spots on your steel fender. I know of no product chemical or otherwise that will totally stop rust forever. If you live in a mild climate, you will more than likely never see it again. So, your way worked for you. You can remove rust mechanically, or you can neutralize the exterior layer(s). But once it's in the steel, it will rot again, unless the layer you neutralize is the only thin layer left. I've seen several frames coated in products like POR15, that seal and neutralize. They end up rotting under that sealed layer...lol. Then again, everything rusts in the northeast...lol.

[FY1Cuda]

I cast my one vote for Evapo-Rust. We had a rusty roof from a leaky vinyl top and got every bit of rust off.  We first wire-brushed the top with electric drills and wire wheels paying special attention to getting the pitted areas as clean as possible.  After that we covered the roof with old towels and saturated them with EvapoRust.  It is a watery, non-toxic, non-acidic liquid available on-line.  The stuff really works.  You can put a rusty manifold in a bucket of this stuff, pull it out in the morning, and the manifold is clean, grey cast iron.  On the roof of the car we kept the towels wet and covered them with plastic to slow down evaporation.  After a day of that, we rinsed, fine sanded, and primed.  Check out EvapoRust.  You will probably need 2 or 3 gallons for the roof, so think about getting the 5-gallon jug of it and using it for other rust removal projects.

[360 'CUDA]

Not sure what you mean by that... If it worked well enough for you...was it wrong? I can see spots on your steel fender.

I guess what I'm trying to say is any product you have to spend tons of money on is a waste if all you have to do is hit it with some acid 
I did the fenders on that car in a couple of hours and all by hand.  Of course you can see "spots" but this is a great starting spot for the real bodywork to begin. A little DA action and some primer and this fender is back in business for pennies.
Try it on a piece of rusty scrap to see what I mean

This is the right way to do this, especially for roofs where you don't want to do a bunch of grinding

Any product you can buy for removing rust has acid in it so why not go the direct route ?

[moper]

Ah. That makes sense now...

[jeryst]

I'm a klutz, so I stay away from acid and sharp objects. The evapo-rust and strong-arm spray say they are non-toxic and can be handled safely.

[FY1Cuda]

If you go with Evaporust, remember that it's watery, so if you have rust-through on the top, you'll have to work out something that keeps it from leaking away.  You may try some duct tape on the inside of the roof where the holes are, but I'm just thinking out loud.  You might also hang some thin plastic drop cloths from the drip rails so the stuff doesn't drip all over the car.  The roof we worked on is still perfect after five years, so I'm a believer.  By the way, I've used Rustmort on another project car ten years ago, and got rust bubbles a month or two after the car was painted, so I don't have the same confidence in that product.