Rust is a silent killer, slowly attacking iron and steel. Heavy-duty trucks, suspension bridges and even mighty warships can all be brought low by a little oxygen and moisture. In unfavorable conditions and without adequate protection, ferrous metals can literally dissolve in thin air, turning into a heap of reddish crumbles. And if you have a rusty tool, it's only a matter of time until it's no longer useful.
But rust doesn't have to be a death sentence for a metal surface -- it can be arrested and prevented. A range of products is available today that can eliminate stubborn oxidation rust spots on tools, car parts, antiques and, well, basically anything made of iron, all without the need to painstakingly grind it away or sandblast down to solid metal. Removing rust with chemical rust removers is as simple as tossing any grungy-looking items into a bath of rust dissolver and letting the solution go to work, attacking oxidation without harming the base material and often without affecting rubber, plastic or even a painted surface.
There are many versions of this sort of rust removal product, which are like a whole lot of elbow grease crammed into a little bottle. Some contain hydrochloric acid or phosphoric acid that eats away at rust like termites gnawing on a rotten stump, while others use a fancy-sounding process called chelation to chemically break iron oxide down. Some come in concentrated formulas while others are prediluted in the factory.
We rounded up five readily available rust removal products to find out if they work as well as their manufacturers claim when it comes to removing surface rust. We soaked several rusty steel components in each one, following the manufacturers' directions and diluting if required. The items that got the rust treatment include a section of sheet metal and two different sizes of threaded rod with rust buildup. For consistency, each rusted object was cut from the same overall piece.
Of all the rust dissolvers we tested, Rust 911 is the only one that's offered in a concentrated formula. It mixes with water at a rate of 8 ounces per gallon, or a 16-to-1 ratio, meaning there's enough in our 32-ounce sample to create 4 gallons of finished rust dissolver. And no, using a more potent ratio does not make it work faster. This means Rust 911 is a tremendous value compared to some of its competitors since its per-ounce price is very low, something that makes it more economical to soak larger components in, perhaps automotive parts like bumpers or radiator supports.
Rust 911 is super safe to use, being non-toxic, non-flammable and even biodegradable. If you get any on your hands, it shouldn't cause irritation, but if it does, just wash up with a little soap and water. When diluted, it starts out as clear as water, but over time it turns inky black as it eats away rust. Don't let that darkened color fool you, though: It can be used over and over again until its efficacy is diminished, then you can dispose of it. Depending on your location, you can pour it right down the drain if you want.
In testing, Rust 911 proved to be highly effective, eradicating nearly all the rust corrosion on the sheet-metal sample in about 2 hours, making it faster than some rivals. Unfortunately, it had a little more trouble with the threaded rod test pieces, though to be fair, they may have been slightly contaminated with oil or paint in sections that limited its ability to dissolve the rust. As for soak times, the manufacturer says you can leave parts in this product anywhere from 15 minutes to overnight, though soaking particularly nasty items for days at a stretch likely won't cause any harm.
Like Rust 911, Evapo-Rust is all about safety. It's noncorrosive, emits no fumes or foul odors, won't harm paint and it can be poured down the drain when it's all used up. It won't harm copper, brass, aluminum, rubber, plastic or vinyl, either. About the only warning this product comes with is to rinse your hands with water if you get any of it on them. It's that benign.
But there are two important areas where this product differs from its above-mentioned rival. One, the Evapo-Rust formulation is ready to go right out of the jug, so no dilution is required. And two, it contains detergents, which should make it better at cutting through small amounts of oil, grease and other contaminants so it can wage war against rust. According to the company, you can soak parts for anywhere from 1 to 12 hours. Larger items can be derusted by saturating paper towels in this product and draping them over whatever needs to be cleaned.
Evapo-Rust is slightly yellow in color and somewhat foamy when poured out, while its rivals are crystal clear. Like the competing products evaluated here, this one had no trouble eliminating rust from the sheet-metal sample, eradicating most of it in just 2 hours and leaving behind a smooth surface. It also did an excellent job cleaning up the threaded-rod sections, getting deep in the grooves and removing rust, though it did seem a tiny bit slower to work than the others. Strangely, Evapo-Rust did leave the parts slightly black, darker than the components soaked in competing products, so be aware of that.
Another excellent rust-eliminating product is Metal Rescue. The ready-to-go bath version works straight from the bottle (a concentrated formula is also offered), it's easy to use and highly effective, but that's not all. Again, and this is going to sound redundant, it's water-based and safe to use. It shouldn't harm rubber, plastics, glass or most paints. It contains no VOCs, solvents, acids or other harmful ingredients. Plus it's non-corrosive, non-flammable and non-toxic. The manufacturer recommends avoiding contact with your eyes (Duh!) and suggests wearing gloves when using it, though they're not necessary.
Metal Rescue was similarly effective to the other rust-remover products tested here, easily dissolving rust on the sheet-metal sample and deep-cleaning those sections of threaded rod. Not only that, Metal Rescue is fairly priced and quick to eliminate rust.
There are, however, two words of caution called out by Metal Rescue. Some older paints and inks contain iron oxide-based pigments, and this rust remover product could easily damage them. Also, like other products here, this one will remove sacrificial oxide coatings like zinc phosphate and bluing, so be aware of that. If you're concerned about whether it's safe to soak something in a rust dissolver, test some on a small area first. It's better to be safe than sorry.
Of the premixed, ready-to-use rust dissolvers tested here, WD-40 Rust Remover Soak is a strong value, checking out for around $24 per gallon. Like the products listed above, it's super safe, won't harm other materials and can be reused over and over until it stops working.
For best results, the manufacturer recommends getting rid of as much oil and grease as possible from the items you're looking to soak. It's a good idea to remove loose debris and dirt residue, too, with coarse sandpaper or wire brush. Completely submerging things is the way to go here, and once parts are finished, rinsing them off with water and drying them is smart. A quick spray of oil, such as WD-40, will prevent surface rust from forming again, which, chances are, is not something you want.
Despite its low cost, WD-40 Rust Remover soak did a great job on both the sheet metal and threaded-rod samples. It removed stubborn rust from deep in the threads and left the sheet steel smooth and clean, complete with an almost-galvanized look. Impressive stuff, especially for the price.
Finally we come to POR-15 Rust Remover. This iron oxide-dissolving solution is different from all the other products highlighted here. For better or worse, it contains phosphoric acid, as well as some other nasty-sounding chemicals. Still, it's safe on PVC, Viton and most paints, plus it's reusable and biodegradable. However, and this could be a big caveat, it has far more warnings than any of the other rust dissolvers listed here. Both a skin- and eye-irritant, the acid solution should also be used in a well-ventilated area. Keep it away from heat, sparks, open flames or hot surfaces. And it goes without saying, but on the off chance you get thirsty while working in the garage, don't ingest this product. Seriously, it's not Dr. Pepper.
With all that out of the way, POR-15 Rust Remover is perhaps the most effective product evaluated here to clean rust. It starts working in as little as 20 minutes to clean up heavily rusted metal, though, of course, you can soak things for much longer than that, even overnight. Without scrubbing or other work, one gallon of POR-15 Rust Remover can eliminate rust from up to 300 pounds of heavily oxidized steel. It will not harm unrusted steel and is safe to use with other metals.
In testing, this product proved to be highly effective. After soaking for 2 hours, the rusty samples were little changed, but after 4 hours they practically looked like new. POR-15 soaked deep into the threads and broke up rust, leaving a clean surface behind. Just like other rust removers, it darkens as it dissolves, turning black the more you use it. If you don't mind taking a few precautions while using this product, it works well.
Comparison of best rust dissolvers
||Rust 911||POR 15 Rust Remover||Evapo-Rust||Metal Rescue||WD-40 Rust Remover Soak|
|Formula||Concentrate||Ready to use||Ready to use||Ready to use||Ready to use|
|Dilution||8 ounces per gallon of water (16-to-1 ratio)||--||--||--||--|
|Recommended soaking times||15 minutes to overnight||20 minutes to overnight||1 to 12 hours||2 hours to two days||30 minutes to 24 hours|
|Price||$38.75 per quart||$10.25 per quart||$9.99 per quart||$32.81 per gallon||$22.51 per gallon|
|Unit price||7.6 cents per oz||32.0 cents per oz||31.2 cents per oz||25.6 cents per oz||17.6 cents per oz|
|Other features||Non-hazardous, non-toxic, non-flammable, biodegradable, safe to use. Can be reused over and over. Brightens copper and similar alloys. Neutral Ph.||Safe on PVC, Viton and most paints. Reusable and biodegradable.||Can be poured down the drain when used up. Contains detergents to help cut through oil and grease, safe for paint.||Contains no VOCs, solvents, acids or other harmful ingredients; non-corrosive, non-flammable, non-toxic; can be poured down the drain; water-based solution; should not harm rubber, plastics, glass or most paints.||Biodegradable ingredients; safe for rubber, plastic and paint; non-toxic, acid-free, contains no VOCs, 100%-biodegradable formula. Can help brighten copper, brass and similar alloys.|
|Warnings||Wash with soap and water if skin contact occurs.||An eye- and skin-irritant: Use in a well-ventilated area, do not ingest, keep away from heat, sparks, open flames or hot surfaces.||Rinse hands with water after use.||Avoid contact with eyes. Gloves recommended but not necessary.||Can be poured down the drain. May cause skin irritation after prolonged contact. Wash with soap and water if skin contact occurs.|
6 things to know about rust removers
- These rust-dissolving products are intended to be used at room temperature. If your garage or workspace is freezing cold in the winter or if the attic of your townhouse gets boiling hot in the middle of August, you might want to consider finding a more temperate place or time to use them for maximum effectiveness. Cold temperatures, in particular, can slow down these chemical reactions.
- Another thing that enhances the efficacy of these products is cleanliness. No, you don't have to spit-shine the parts you're trying to de-rust, but if you clean off any heavy dirt and remove grease and oil, they will almost all work much better.
- Four of the five products tested in this article are safe to use, containing no solvents, acids, VOCs or other nasty ingredients. If you get any of these on your skin, just wash up with soap and water and you should be fine. Nearly all these rust-dissolvers are also environmentally friendly and will not harm other materials like plastic, rubber, paint or non-ferrous metals.
- Some rust-dissolvers come in concentrated form and must be diluted with water. Others come premixed and are ready to use right out of the container. Depending on how many components you're looking to clean up and how severely they're rusted will determine which product will work best for your application.
- Be patient! Unlike a T1 internet connection, none of these products deliver instantaneous results. Time is your friend. Depending on how severely rusted the parts are that you're trying to clean up, soak times can last from 15 minutes to two days.
- When spent, most of these rust dissolvers turn black and stop working. At this point, they're generally safe enough to be poured right down a drain, making cleanup and disposal a snap. But please read the directions or any accompanying legalese to see if this is permitted in your area.
You'd be a fool not to buy some
Whether you're working on a crusty carburetor base, revitalizing an old axe head you inherited from grandpappy or even sprucing up some antiques you just picked up from a garage sale, rust-removing solutions can be super handy. In certain applications, they essentially eliminate the need for sandpaper, steel wool and wire brushes, plus the associated time and effort required to clean things up.
While each of the products tested here has its peculiarities, all of them are highly effective and, perhaps best of all, exceedingly affordable. There's no excuse not to have a jug of this stuff in your garage or workshop.