If you’re the DIY type who likes home projects and working with tools, you’re going to run into rust sooner or later. The good news is you can remove rust from metal or tools with just a little work and the right equipment. Here, I’ll go over the 2 main ways to get rid of stubborn rust and also how to prevent the rust in the first place which is even better.
Grinding and Sanding
The first method is simply grinding or sanding the rust off. Of course, any paint is going to come off too. This is my go-to method for any moderate to heavy rust because you end up with a nice, smooth finish and avoid using chemicals. More on the chemical options below.
For larger areas of rust and uneven surfaces, an angle grinder with a strip disc or wire wheel works great. If you don’t have an angle grinder, you can usually pick up a decent one for under $50.
This is a great tool to have in general for all kinds of uses – cutting, grinding, buffing – so I’d recommend picking one up if it’s in the budget. When using a grinder this way, you want to be sure not to stop in one place too long or you’ll end up gouging the metal.
Another option is to get a strip disc or wire wheel with a shank that you can fit on your power drill. The drill won’t have as much speed or power as the grinder, but you can still get the job done with a little more work.
I find the angle when using a drill can be awkward on your wrists. Maybe not an issue for younger readers but it can be annoying if you have wrist or hand arthritis.
For flatter surfaces and less severe rust, a regular hand sander or random-orbit sander will do the job.
You’ll want to start with a coarse grit sandpaper and work your way up to a medium or finer grit depending on how smooth of a finish you want. Remember the lower the grit number, the more coarse it is:
- 60-80 grit: coarse
- 100-150 grit: medium
- 180-220: fine
- 320+: super fine
If I’m just trying to knock the rust off an old wheelbarrow, 80-120 grit is plenty. But if it’s something I care about more, like my grill, I’m going to go up to 180-220 to get a nice smooth finish before repainting.
It’s also important to choose the right type of sandpaper. The best sandpaper for metal is silicon carbide.
Silicon carbide is a really hard abrasive which is great for metal and won’t wear down as fast as aluminum oxide sandpaper.
Emery cloth also works well on metal. It has small particles of emery glued to a cloth backing that won’t rip or tear like many paper-backed sandpaper. Either one works great.
If your project has lots of hard-to-reach corners or detail areas, you’ll want to consider an oscillating tool or mouse detail sander. If even those are too big, a dremel tool can get into really small spaces with sanding attachments as small as 5/16” in diameter.
Of course all of this grinding and sanding is going to kick up a lot of rust and dust into the air, so you’ll definitely want to wear eye protection and a mask to stay healthy.
Chemical Rust Removal
Acid-Based Rust Removers
If grinding and sanding isn’t for you, there are several chemical rust removers that work well. Some are acid based, using either muriatic or hydrochloric acid. These work well but they’re highly toxic and give off lots of fumes.
If you use these, you’ll want to work in a well-ventilated area with gloves, long sleeves, eye protection and a respirator.
Acid-Free Rust Removers
There are also several popular water-based, acid-free products on the market. You might think these would be wimpy but they can work just as well as the acid-based products without all of the downside of toxicity and fumes.
You can get these in several forms:
- Liquids: good for soaking smaller items. Of course, you need something to soak it in so this is usually only good and affordable for small items like saw blades, knives, screwdrivers, and the like.
- Gels: Better for larger items you can’t soak or for vertical applications where you don’t want it all running off the metal
- Mixes: you mix these with water and can spray them on. Good for vertical applications
The downside here is time. You’ll usually have to let the item soak or sit for several hours, sometimes overnight depending on how bad the rust is.
And, despite what the ads say, you’ll probably have to do it a couple of times and do some scraping if you’re dealing with heavier rust.
How to Prevent Rust
Rust forms when the iron in metal comes in contact with water molecules to form iron oxide flakes. These flakes fall off and expose more fresh metal to water, leading to more rust. So the key is… to avoid long-term exposure to water!
Keep Your Tools Clean and Dry
This doesn’t mean your tools can’t get wet. What it does mean is you don’t want to leave them wet. This usually happens when you leave tools outside in the rain or in a pile where they can’t dry.
In more humid climates, this can happen in the garage too. In these areas, you’ll want to install a humidifier. Another trick is to use moisture-absorbing gel packs in your toolbox.
Water is also stored in mud or dirt so make sure to give them a wipe down before you store them.
Use Stainless Steel or Galvanized Metal
Stainless steel contains iron, but it also contains chromium which will help prevent rust from forming in the first place. You can find many tools such as wrenches, screwdrivers, and drill bits in stainless steel.
Galvanized metal is coated with zinc which acts as a protective layer, keeping the underlying metal rust-free for years. You can find all kinds of building hardware, roofing, wire, and nails in galvanized metal.
Use a Protective Coating or Rust Inhibitor
There are several commercial rust inhibiting sprays and wipes available on the market. Or you can go old school and use a light coat of machine oil or automotive wax to protect your tool from any water.
The trick with all of these is feel. Some have a sticky, gummy feel which might be ok for say a screwdriver but wouldn’t be good for a blade.
Attack Rust Early
Rust flakes off, exposing new metal to the elements which leads to…you guessed it, more rust. That’s why rust just seems to spread once it’s taken hold.
The important thing here is to tackle rust early as soon as you see it. Cleaning off a couple of inches or rust is much less work than having to work on cleaning off a whole tool.
