Rust is the relentless enemy of tools, hardware, and everything metal. Whether it’s a wrench left outside or a bolt that’s fused in place, rust doesn’t discriminate.
I just finished a video comparing three popular rust removers: Muriatic Acid, Krud Kutter (The Must for Rust), and Evapo-Rust. I picked these three because they were the winners of the Project Farm rust removing round up, and if you watch a lot of YouTube, you’ve probably seen that video. If you’re like me, you pretty much always check to see if Project Farm has a video before you buy anything tool or workshop related.
The comments section of his video insisted that Evapo-Rust would have performed better in his test had it been combined with heat, so I decided to test that using my ultrasonic cleaner, a 15L from Vevor, which can add heat, ultrasonic cleaning bubbles, or both.
I performed a baseline test (just submersion, no heat, no ultrasonic cleaning), a submersion test with heat, and a submersion test with heat and ultrasonic cleaning.
An ultrasonic cleaner works by heating up a solution and then blasting it with high-frequency sound to create microscopic bubbles on the surface of whatever is in the tank, and those microscopic bubbles help clean (and, maybe, remove rust) from that surface.
I have to recommend the Vevor 15L if you’ve been thinking about getting an ultrasonic cleaner. I use it for cleaning everything in the workshop and it’s really just a fantastic tool. If it fits in the tank, I use it. I wish they made a giant tank version, something the size of a large chest freezer.
I’ve had good luck with the Vevor but I’m sure other brands are also good. If you’re interested, here’s a link: VEVOR 15L Ultrasonic Cleaner (Coupon Code: VEVT5)
What Makes a Good Rust Remover?
We’re looking for three key qualities:
- Affordability
- Effectiveness
- Minimal damage to the base metal
Nobody wants crusty, pitted tools—or to spend a fortune trying to clean them. The ideal rust remover in my workshop is going to be easy to use, effective, and affordable. But in many cases the more powerful rust removers will actually damage the base metal, and we don’t want that, either.
Test #1: Controlled Submersion on Artificially Rusted Nuts
We began by stripping the zinc from standard 1/2″ hex nuts using concentrated vinegar, then we applied a homemade rust accelerator consisting of hydrogen peroxide, vinegar, and table salt.
A spray bottle made misting the accelerator easy, and then we blasted the nuts with heat from a heat gun to speed up the process. Once the nuts were uniformly rusty, we began the baseline tests.
Each rust remover was tested with four rusty nuts, submerged for 10 minutes, 1 hour, 6 hours, and 24 hours respectively. This initial test was to establish a baseline and used only submersion.
The ultrasonic cleaner will be added later, with both the heat, and then the heat combined with the ultrasonic bubbles.
Results after 10 minutes:
- Muriatic Acid: Fully stripped surface rust.
- Krud Kutter: Excellent early performance.
- Evapo-Rust: No visible improvement.
After 1 hour:
- Muriatic Acid and Krud Kutter still looked strong.
- Evapo-Rust remained sluggish.
After 6 hours:
- Muriatic Acid showed signs of aggressive corrosion.
- Krud Kutter was clean and stable.
- Evapo-Rust finally began to show progress.
At 24 hours:
- Muriatic Acid severely corroded one of the test pieces.
- Krud Kutter retained protection thanks to its rust inhibitor.
- Evapo-Rust cleaned most of the surface rust without harming the base metal.
Rust Inhibition and Metal Loss
Krud Kutter was the only product that claimed to inhibit new rust, so I wanted to test that, and left all the nuts sitting out in the workshop for a couple of days let them flash rust. For this test I did not rinse the nuts after removing them from the solutions. They went straight from the rust removers to the open air in the workshop, but later in the tests I did a rinse and re-application of rust inhibitor.
- Muriatic Acid: Significant flash rusting and corrosion due to un-neutralized acid. If you use muriatic acid, rinse and neutralize after to minimize corrosion.
- Krud Kutter: The built in rust inhibitor was the most effective at preventing / slowing flash rusting.
- Evapo-Rust: Moderate flash rusting.
The amount of corrosion on the nut that was submerged in the muriatic acid for 24 hours really was impressive, so I was curious just how much base metal the acid dissolved.
Weight Loss Results:
The average nut weighed 15.81 grams prior to the submersion tests (but after removing the zinc coating). The muriatic acid caused damage to the base metal even after just 5 minutes, with the damage getting progressively worse the longer the nuts were left submerged in the acid, culminating in 20% loss of material with 24 hours of submersion.
The Krud Kutter and Evapo-Rust were both very gentle and caused no notable damage to the base metal, even after 24 hours of submersion. Both formulas are gentle and will continue on to the next round of tests.
The Sonic Cleaning Upgrade: Heat + Ultrasonic Power
Using a heated ultrasonic cleaner, we combined rust removers with 60°C (140°F) water to see if heat and vibration could boost performance. Ultrasonic cleaners use high-frequency sound waves to generate microscopic bubbles that gently scrub surfaces.
First Test – Heat Only:
For both the heat-only test, and later, for the heat + ultrasonic cleaning test, the submersion intervals were 5 minutes, 15 minutes, 30 minutes, and 1 hour. The timelines were accelerated to test if there is an advantage to using the ultrasonic cleaner. If it isn’t more effective (faster and more powerful), what’s the point of using it at all?
Due to the heavy corrosion that the muriatic acid caused, it was disqualified from further testing, which focused only on Krud Kutter and Evapo-Rust.
The Krud Kutter continued to outperform Evapo-Rust in the heat-only tests, but Evapo-Rust was closing in fast. It’s performance improved significantly compared to the submersion only (no heat) test, with the 15 minute in heat matching the performance of 24 hours without heat. At this point you may be wondering why we would even bother with Evapo-Rust if Krud Kutter performs so well right out of the box (or jug, in this case). Well, Krud Kutter is a lot more expensive. I bought it for 48 cents an ounce while the Evapo-Rust was only 20 cents per ounce, and the Evapo-Rust is highly reusable – you can use it many many times before it loses potency, which drives that cost even lower.
Heat Only Test Results
The Sonic Cleaner Advantage: Visual Results
Using lightly rusted bolts and more nuts from the original batch, we ran 5 minute and 15-minute tests in the ultrasonic cleaner with both Krud Kutter and Evapo-Rust.
After just 5 minutes with the heat + ultrasonic cleaner going full blast, Evapo-Rust had caught up to Krud Kutter in effectiveness. After 15 minutes, both nuts and bolts were completely spotless and there wasn’t a single indicator of any rust.
They cleaned up so well that you couldn’t really tell they’d ever been rusty at all. Take a look at how nice the threads look, and then compare them to the control bolt to see what they looked like just a few minutes earlier. What a transformation.
We then rinsed all cleaned pieces in Krud Kutter and left them for 48 hours to test the rust inhibitor again. Results showed better protection than untreated parts, but still not flawless.
Evapo-Rust vs Deep (Pitted) Rust
I wanted to see just how effective the Evapo-Rust + Ultrasonic Cleaner combination would be at tackling deeper, pitted rust, so I tested it on a rusty wrench with deep pitting and while it didn’t restore the chrome finish (that would be impossible), 15 minutes in the ultrasonic cleaner removed every bit of visible rust even in the deeply pitted parts.
Conclusion: What’s the Best Rust Remover?
Here’s how they stack up:
| Product | $ / Ounce | Pros | Cons |
|---|---|---|---|
| Muriatic Acid | $0.08 | Fast, cheap | Corrosive |
| Krud Kutter | $0.48 | Effective, inhibits | Pricey |
| Evapo-Rust | $0.20 | Gentle, reusable | Slow w/o heat |
If you’re looking for effectiveness right off the shelf, Krud Kutter The Must for Rust is hard to beat. It was more expensive but was the most effective. If you’re willing to wait for results, or can combine your rust remover with heat (or heat + an ultrasonic cleaner), I highly recommend Evapo-Rust. Combining it with the ultrasonic cleaner produced the best combination of effectiveness, affordability, and non-corrosiveness.
Recommended Products
- Silicone Tray: Chemical-resistant, heat-proof. Great for small parts. (Available on Amazon)
- Ultrasonic Cleaner: Transforms how rust removers perform. (Available from Vevor) | COUPON: VEVT5
- Evapo-Rust (Available on Amazon)
- Krud-Kutter (Available on Amazon)
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