Removing Rust

[Andy Sowers]

I recently bought a used scroll saw... the cast iron table had a small amount of surface rust on the table surface... however, the underside of the table is very rusted/pitted.

I was able to clean up the front/working side easily with Bar keeper's friend and WD40. But the underneath is proving more difficult owing to the fact that it has lots of cast iron ribs, and the surface was never smooth to begin with.

My plan of attack was to go at it with a wire wheel, and then use some kind of chemical rust remover to get what's left over. After that, I was considering either painting or treating the backside with something to prevent reoccurence. So my questions are:

1) What works best at removing this kind of rust
2) Any suggestions on treating back surface (I don't think waxing will work) just paint it?

Thanks
andy

[Prashun Patel]

Have you tried Naval Jelly?

I find the EASIEST way to remove rust is to soak things in a citric acid bath. Then you can scrub it off with a wire brush or steel wool.

I use a cup of powder per gallon and let it sit for about 30 mins.
Then rinse and dry immediately with a hairdryer. If any rust 'flashes' on after that, you can wool it off pretty easily.

You can oil the bottom or spray rust preventer on it.

[Matt Ranum]

The cheapest thing I ever used to remove rust was plain ole white vinegar. Soak it a few hours and brush occasionally. I used "Must For Rust" bought at Ace hardware which worked ok and there are lots of people who rave about Evaporust but I've never tried it.

[Scott Hildenbrand]

My money is on some Barkeeps Friend and a scotch pad, with mineral spirits for the liquid to get the powder pasted up.

Gets into the fine pits and grooves that are in a ground cast iron table without issue and cleans those up as well, unlike sandpaper or whatnot. I polished a badly rusted jointer table to a nice shine this way, with no elbow grease.. Just clipped the pad in an old sander and went to town.

EDIT: Ooops.. Nix my whole comment... See you're talking about the UNDER side of the table. For that, I'd say sand blast it. Quick and easy. Just be sure to protect any surface that should not be blasted.. Paint with a good enamel.

[dan sherman]

1) What works best at removing this kind of rust


I used to use Naval Jelly, but stoped because of how corrosive it is. I now use Evapo-Rust, and just love the stuff, It's not-toxic, non-corrosive, re-usable, & relatively cheap (~$20/gal at HF).

[Jeremy Brant]

I had some rust on my jointer and table saw when I got them...not necessarily the heavy rust you're describing. I used the Boeshield rust remover that they sell in the kit with the T-9 protectant and the bit and blade cleaner. The rust remover worked pretty well just letting it sit for a minute or so and wiping/rubbing it with a rag. I would imagine you could use a scotch pat or steel wool to be a little more aggressive and it would work fine. I don't know how much the stuff is individually...perhaps some of the other suggestions would come back less expensive or easier, but the boeshield stuff will work.

[Cliff Holmes]

I've never tried it before, but several people have told me that MaryKate "On & Off Hull Cleaner" is awesome for rust removal. You can get it at Bass Pro Shops (basspro.com)

[Cliff Holmes]

Boeshield rust remover

That stuff is *nasty*, battery acid in a convenient spray bottle :eek:

[Ronald Mancini]

Look up electrolyitic rust remover on the web. This is so easy and effective if the part is disconnected from the machine.

[Ray Chalenski]

I've used the elecrolysis method for rust removal. The results are amazing.The rust comes right off in the bath.Depending on how rusty the part is it may take 1 hour or several hours.The beauty is there is no hard scrubbing or grindinng needed.

[Andy Sowers]

Thanks to all who responded...

I ended up using a wire wheel/hand drill combo to remove the bulk of the rust (this goes pretty fast). In doing so, I realized the rust wasn't as bad as I had thought. So I proceeded to get what rust remained using steel wool/WD40 and some elbow grease. As a last step, I used some bar keepers friend/WD40 like I did on the top... but this ended up just making a mess, as the slurry wanted to collect in the knooks and crannies of the casting. So I spent more time cleaning up this mess than anything else.

Finally, I applied a thick coating of Boeshield and let it dry overnight. There's still some dark grey staining of the cast iron, but hey its just the underside... right?

Thanks again everyone!
Andy

[Jan Rehler]

What is a barkeeper's friend? thanks. Jan in Corpus Christi, TX

[Scott Hildenbrand]

http://www.barkeepersfriend.com/

Buy it at Wally*World, over by the dish detergent and such.

Contains Oxalic Acid, so it can cut through rust fairly easily. Can make a paste in a bowel and dip a wire brush into it on a drill, then use it on non milled areas. Else stick with a scotch pad and possibly mount it up to a sander. Works like a charm.

[Jay Yoder]

That stuff is *nasty*, battery acid in a convenient spray bottle :eek:

You got that right! I have used it with varying results but it really "spotted" up my table saw! and the smell...

[Jim Andrew]

I found that oxalic acid is a good thing to clean the rust out of a gas tank. They say it will not harm the good metal in the tank, as more harsh chemicals will, so after I cleaned the tank on the motorcycle I am restoring, I used some to clean a couple tables on my machines. Plan to use more with bar keepers friend on the table saw. I used 2 tablespoons per gallon of water. Took 2 days to remove the rust from the gas tank.

[Paul Steiner]

I use electrolysis for parts that have areas that are hard to clean and scrub. I use it alot for hand planes, it will take off the rust and paint too. I like it because of all the methods I have used it requires the least elbow grease.

[Keith Hankins]

I use electrolysis for parts that have areas that are hard to clean and scrub. I use it alot for hand planes, it will take off the rust and paint too. I like it because of all the methods I have used it requires the least elbow grease.

What he said + 1

[Steven Hsieh]

I have used Naval jelly....almost every rust remover product out there. The only product easy to use and actually works is Evapo-Rust.
Wipe it on, brush it on...............leave it on for 30 minutes

Come back and wipe it off.

I would then use 400 grit wet/dry sandpaper
You can use any lubricant mineral spirit, lacquer thinner,

I find that denatured alcohol works best for this.

And Best to use scotch brite pad behind the sandpaper.

Sand the surface until it is smooth

Wipe it off after your done.

Then wax it.

[Ole Anderson]

I would have removed the table, taken it to my driveway and had at its underside with my little sandblaster. Then hit the underside with Rustoleum's Universal Hammered spray paint, expensive at almost $8.00 a can, but awesome stuff. For the top of the table, use a razorblade to remove the surface rust to flush with the top, then use 220 grit followed by a scotchbrite pad on your ROS to finish it off, followed by a coat of paste wax. If the top is pitted, you need to passivate or chemically remove the rust before waxing.

[Jay Park]

My favorite way to clean a large surface of rust is turpentine and BarKeeper Friend.
Wet the surface with the turpentine, sprinkle a good amount of BKF and rub with a rag.

Cleans rust fast clean and easy.