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Rust is the gardener’s enemy. Every spring it shows up somewhere. Killing it is impossible because it is a chemical reaction to excess water and oxygen mixing to create iron oxide.
The oxide that coats garden tools are what causes rust. The spread can only be delayed. With proper care of your gardening tools, that delay can be for years.
Quality pruning shears should last a lifetime, even if you neglect them by leaving them outdoors, in wet conditions, causing the pruners to succumb to rust.
Should the worst happen, the only way to get rid of the rust from your pruning shears is to manually scrub it off. Acids help soften the rust making rust removal easier.
The two things you need to do remove rust from pruning shears are:
1. Soak the pruners in an acidic solution
2. Scrub the rust away
The short version: Rust is removed by soaking it in an acidic solution. Four types of acid remove rust. Hydrochloric acid, phosphoric acid, acetic acid, and citric acid. Acetic acid and citric acid are household ingredients. Distilled vinegar is roughly 5% acetic acid. Citric acid is a compound in lemon and lime, which is why those are almost always listed as natural cleaning agents. Industrial strength rust removers will be either hydrochloric acid, or phosphoric acid. Hydrochloric acid is the strongest.
Read on to discover the nitty-gritty that will bring the sheen back to your pruning shears.
Removing Light Rust
Distilled Vinegar in a Mason Jar
This method won’t have the rust removed the same day. The pruners need a bath in distilled vinegar for at least 24 hours. If you use normal vinegar, it will take even longer.
Fill a mason jar with distilled vinegar, then leave your pruning shears soaking in the vinegar for 24-hours minimal. The acidity of the vinegar interacts with the rust, causing it to flake off.
Should you feel the rust would warrant a stronger chemical solution, dust the rust with baking soda, then spritz it with distilled vinegar.
Let that solution break down the rust overnight, then use the distilled vinegar bath solution. Expect a couple of days to treat the rust before scraping or scrubbing the rust off.
Alternative natural cleaning agents are lime juice or lemon juice, which contain citric acid.
The chemicals do not remove the rust. They agitate it enough to make it easier to scrub the rust away.
After leaving the metal soaking in a mason jar of vinegar for a day, the vinegar turns brown. That’s some of the rust that was removed that’s turned the vinegar brown. The metal will still be coated.
To remove it, use a wire brush, steel wool, or a heavy-duty scouring pad to scrub the rust off.
Of the three rust scrubbers, steel wool would be the preferable option. Like sandpaper, steel wool is available with different grittiness.
Use course steel wool to grind the rust down, then switch to a finer steel wool to restore the shine without scratching the metal. Only on stainless steel though. Not on cheap dollar store shears that are prone to scratching easily.
Quality shears take on a shine when the blades are polished with a fine course steel wool.
Using Coca-Cola (Classic) for Rust Removal
Coca-Cola Classic (not Coke-Zero or any other proclaimed healthier version) is acidic. It has been claimed to be more acidic than vinegar giving it a reputation as a powerful cleaning agent. That it is, but it is not more acidic than vinegar.
The difference is the chemical composition. Vinegar contains acetic acid, Coca-Cola contains phosphoric acid, a much more powerful type of acid.
Both vinegar and Coca-Cola Classic have around the same pH acidity of 2.5. Coca-Cola is slightly more acidic, but that’s not what makes it a stronger solution for rust removal. It’s the tiny amount of phosphoric acid that’s added.
Even just 0.017% per 100 ml is strong. Acetic acid is weak. Phosphoric acid is a lot stronger so not much of it is needed.
Similar to the vinegar bath solution, Cola works the same way. It needs time to eat through the rust. At least 24-hours.
In the same manner, it doesn’t work on its own. There is always a mechanical approach required to remove rust. Chemicals only soften it.
In the case of the minuscule amount of phosphoric acid in cola, it turns the rust into ferric phosphate, which is much easier to remove.
See it in action in this clip by Reactions:
How to Remove Thick Blankets of Rust from Pruning Shears
The thicker the rust is, the less effective chemical solutions become. The only way to make a chemical work at corroding rust enough to be removed is to thin it down. The fastest way to do that on pruners is to chip away at it with a chisel.
Obviously, you’ll need a vice to secure them in place while you’re hitting it hard with a chisel.
It can take a while with a hand chisel. It’s easier and faster to use an electric chisel. These are just like hand chisels with an automated striking action.
They’re cheap enough to buy but to just clean your pruning shears, it’s probably not the best investment. Especially if you can replace your pruners for less.
For the pricey, robust pruners that’s like your prized possession for helping around the garden that’s been accidentally neglected, the electric chisel option could be your saving grace.
Alternative Power Tools to Remove Rust
Multi-Purpose Oscillating Tools
These are the go-to tool for multiple small jobs around the home, and in this case, for the garden tools, too. Removing rust can be one of those jobs it tackles effortlessly, but you need to be weary of what you use.
Oscillating tools sand the rust down. Start with the coarsest attachment to thin the rust down first. As you get closer to the metal surface, change the attachment to one with a finer grit so as to avoid scratching the metal.
This is essentially using sandpaper at an extremely high speed. It will remove rust, but it’ll also damage the surface of the metal.
Grinders and Power Drill Accessories
These are suited for bigger repair jobs such as removing rust from loppers, spades, and garden rakes, rather than a smaller pair of pruning shears. Provided you have a vice device to hold the pruners steady while you work on the rust, they’ll get the job done.
One thing to be careful with is the pressure applied over the blade. As well as chipping away at the rust, they can also affect the sharpness or bluntness of blades on pruners.
Three attachments for power tools suitable for removing rust from pruners are a wire wheel, a cup wire wheel, and a stripping disc. The stripping disc is best used on the flattest surface of metal.
As you inch closer to the blade, switch to the smaller “cup” wire wheel applying very little pressure so the tool just brushes over the rust surface.
Angle the wire brush downwards so as to avoid blunting the blade. If you do need to restore sharpness to the blades of your pruners, a diamond file is the way to go.
When you’re effectively scraping with excessive force, the key is to know when to stop.
Once the rust is reduced to just a fine surface, a chemical rust removal solution can be soaked over it, then the rest can be scrubbed off with a scouring pad rather than sanded or scraped off with force.
Strong Chemical Rust Removers
Two of the most acidic solutions that tackles rust removal fast are hydrochloric acid, and phosphoric acid. Hydrochloric acid is the strongest of all rust removal solutions.
For cleaning your pruners, it’s probably going to be too strong as it also strips the protective coating off the steel.
The stronger the chemical is for rust removal, the less time your pruners will need to be soaked in the solution.
The key to using phosphoric acid efficiently is in the timing. Once the discoloration begins, start mechanically removing the rust.
Leaving the pruners bathing in phosphoric acid for too long will strip the protective coating, leaving it susceptible to flash rusting in the near future.
It must be noted that when working with any industrial strength solution, care needs to be taken. Especially with acids.
Safety gloves and eye protection should be worn, and you’ll probably want to wear a mask when working with this stuff. The fumes are strong! Like, eye-watering strong.
Always follow the instructions provided and read the safety instructions that come with the product.
Preventing Rust from Returning
Rust is always going to be a risk. The only tried-and-tested method for effective rust prevention is lubricating all parts of garden tools before storing them away for winter storage.
For years, regular motor oil was the go-to solution. Nowadays, any multipurpose oil/lubricant will serve the same purpose.