Photography Credit: David S. Wallens
[Editor's Note: This article originally appeared in the August 2014 issue of Grassroots Motorsports.]
Chemistry enhances our lives every day. It causes light bulbs to illuminate, OxiClean to whiten our whites, and Doritos to be delicious. It can also be used to fight rust, a popular adversary.
What Is It?
It’s a watery liquid that chemically sucks rust off rusty parts.
How Do You Use It?
We usually just soak the offending part in a bath of Evapo-Rust, but you can also apply it to a rag and use it like a cold compress. Evapo-Rust can be reused, too. In fact, they say that one gallon of Evapo-Rust can treat up to 300 pounds of steel. (When the liquid has turned black, then it’s no longer magical.)
Does It Work as Advertised?
We’re pretty sure there’s some black magic involved, but this stuff really does make rust disappear. What do you do with the liquid afterward? Its maker recently shared this tip with us: Put it into a garden sprayer and spray it on your lawn. Your grass will appreciate the extra dose of iron.
Evapo-Rust
evapo-rust.com
Photography Credit: Tim Suddard
What Is It?
It’s a thick, paintlike liquid that, according to its manufacturer, bonds to rusty metal.
How Do You Use It?
It’s usually brushed on, although it can be thinned and shot from a gun. Your color choices are black, silver and clear. If it’s being applied to a surface that gets a lot of sun, plan on topping the POR-15 with paint.
Does It Work as Advertised?
Definitely. POR-15 has been a GRM shop staple for years. Once dry, it covers the metal in a thick, smooth coating–almost like a chocolate shell, although this one won’t melt. Once POR-15 is on something, though, it’s permanent–so plan accordingly.
POR-15
por15.com
What Is It?
This one doesn’t fight rust as much as preserve it. Think of it as a non-permanent coating that prevents the elements from making current rust any worse.
How Do You Use It?
Just spray away. Its maker recommends two or three light coats. One can should cover 12 to 16 square feet.
Does It Work as Advertised?
This one is so new that we haven’t even tried it yet. We are fans of Eastwood’s other rust-fighting products, though, like their Rust Encapsulator Paint and Rust Converter.
Eastwood
eastwood.com
I've used both Evapo-Rust and POR-15 quite a few times over the years. My only beef with Evapo-Rust is that it takes a long time. Figure at least 12 hours submerged for anything that could be considered even a little "rusty." Even longer if it's quite rusty and pitted. Still impressive, in that you don't have to be grinding it, or blasting it or sanding it. Just "kerplunk" and forget it for a while as the Evapo-Rust does its thing.
Evapo-rust works via a process called "Chelation", where a mix of chemicals pulls a metal element out of an ionic bond, only here to then be replaced by another element that then drops said chemical out of the compound. What's exactly in it is obviously a trade secret, but the black is raw iron in suspension.
To this, I'd like to add Geoff Croker's video on rust treatment which I think should be made into a wall tapestry and put somewhere in view of any shop that uses metal. The goofy voice he sometimes takes is grating, but he shows what genuinely works best- my "rust treatments" have now almost entirely been pared down to several electrolysis baths, citric and oxalytic acids, and some samples of evapo-rust for things I cannot afford to have pitted.
no mention of electrolysis?
or was this simply advertorial.
In reply to 1988RedT2 :
I don't mind the wait on Evapo-rust. I have used it on bike and guitar parts, too. Set it and forget it. I think I dunked everything in a plastic container fished out of our recycling bin. 
In reply to David S. Wallens :
Yup. Recycle bin is my go-to for suitable containers. Works great for small items. Big stuff is more of a challenge.
1988RedT2 said:In reply to David S. Wallens :
Yup. Recycle bin is my go-to for suitable containers. Works great for small items. Big stuff is more of a challenge.
Reduce, reuse, recycle.
For years, I have used Ospho, it is cheap and effective. It is surprising that Ospho was not listed here since it has been around for decades.
When applied to rusted surfaces, OSPHO causes iron oxide (rust) to chemically change to iron phosphate - an inert, hard substance that turns the metal black. Where rust is exceedingly heavy, two coats of OSPHO may be necessary to thoroughly penetrate and blacken the surface to be painted.
In reply to Scott Skillman :
Is Ospho the same as the so-called Rust Converter sold under a variety of brands? Sounds similar.
POR 15 is wild stuff. Wildly toxic, but also wildly effective.
I love how you brush it on like third-grade art class and it dries like shiny powdercoating.
I'm surprised someone hasn't said "don't get it on your hootus" yet.
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