Tools are a large investment and with the right care many of them can last a lifetime. However, rust can shorten a tools life quickly and taking rust prevention measures is extremely important. While most tool manuals do not explain how to prevent rust, it is relatively simple.
The best way to prevent rust from forming on tools is to control the environment they are exposed to. This can be done can be done in a variety of ways from keeping silica gel packs in tool boxes, using dehumidifiers, to using mineral oil for long term storage.
Rusty tools… So what?
Rusty tools do not only look bad, rust can also affect a tools performance. Tools with hinges or joints must be properly lubricated and smooth in order to work. When a tool starts to rust the surface starts to pit and the action will begin to be rough. Once a tool has reached this point simply re-oiling will not restore the tool to factory condition. At this point you will have to disassemble and restore the tool. Power tools electronics can also be adversely affected by rust. Many of the conductors inside power tools are susceptible to rust. This rust can cause tools to short out and will dramatically shorten their lifespan. In extreme cases rust can reduce a tools strength and could result in dangerous situations. Imagine trying to break free a tight bolt and the wrench snaps.
Rust forms at varying paces depending on many outside factors and the tool itself. First, the type of metal used in the tools can change rates. Bare metal surfaces will rust much faster than treated surfaces. For example, sheet metal will rust in a matter of hours if left out. In addition, environmental factors including oxygen, temperature, chemicals or pollutants, and humidity can change the corrosion rate. Rust can happen without oxygen but it happens quicker when it is present. Therefore, in theory, a tool will fare better submerged in a bucket of water than in the rain. However, I am not recommending storing your tools in buckets of water.
Temperature also has an effect on rusting. High temperatures will increase the rate while low temperatures will slow it down. Chemicals or pollutants such as salt or acid rains will also increase the rusting rate. The last, and most relevant, issue is humidity. Rusting will occur fastest in areas with high humidity. High humidity levels can occur in shops where all other rust factors are accounted for which will lead to rusty tools.
Rust is a natural occuring substance when steel or iron, which is found in many hand and power tools, is exposed to water. As I said before humidity exposure can cause rust in the same way that leaving a tool out in the rain does. In some climates humidity is a non-factor; however, for those of us who have to deal with humidity we need a way to protect our tools.
Silica gel packs are what shoe companies keep in shoe boxes to prevent leather from absorbing moisture. It is essentially porous sand and has incredible dehumidifying properties. In fact it can absorb 40 % of its weight in water. 40 grams of silica gel or a handful of silica gel packets is good for three cubic feet. The packets or containers of silica gel can be rejuvenated in the oven. Simply set the oven at 275 degrees and bake the silica in a safe container with the door open for approximately 1.5 hours. While doing this the silica gel should be monitored closely. Leaving the gel in the oven for too long will burn it and cause it to not properly function. To help in the rejuvenating process many companies will have indicators that change color in the gel.
- Easily rejuvenated
- Needs to be rejuvenated
- Only useful for small spaces
- Potential for burning if using indicatorless gel
Silica gel is ideal for those who use tool boxes as storage; however, for those who keep their tools out in their shop it will not suffice. In this case a dehumidifier will be the best option. Dehumidifiers work by pulling in damp, warm air over refrigerated coils. This causes the water in the air to condense and is then collected in a removable container. Dehumidifiers come in a variety of sizes depending on the size of the space. For spaces under 1500 square feet, about the size of a three car garage, a 30 pint dehumidifier will be sufficient. These will cost somewhere in the range of $100-$200. Water containers on larger dehumidifiers won’t have to be emptied as often; however, bigger generally means more expensive.
- Great for large spaces
- Low maintenance
- Larger than other method
Tool wipes are wipes treated to clean and protect tools. BullFrog wipes are advertised to be able to clean light grime and prevent corrosion on a variety of metal surfaces. Wipes are convenient to use, but for heavy use thy can become expensive. A container of 25 wipes costs 12.00.
- Good for long-term storag
- Constant reapplication
- Not good for excessively dirty tools
Another way to prevent water from collecting on tools is to use an automotive style paste wax. This kind of wax keeps water from collecting on a cars surface and will do the same for your tools. To do this apply a coating of wax to the surface of the tool and wipe off like you would when waxing a car. This should then be repeated from time to time as the wax wears off. This method is great to use before long-term storage or for outdoor use. It is worth mentioning that some waxes may leave a residue on the surface you are working on. This is especially relevant when working with porous wood.
- Easy application
- Good for outdoor application
- Leaves residue on some surfaces
- Constant Reapplication
Mineral oil is another option and for some the better choice. It is similar to WD-40 but won’t leave a thick residue. Mineral oil is hydrophobic which means it repels water. Like wax it is great for long-term storage and outdoor use. It is also very cheap and can be found at most big-box store. If you are working with wood using mineral oil may have less effect on the woods surface than wax. However, taking proper precautions and using the tool on a small test piece of wood is not a bad idea. Simply apply a light coating to the tool and repeat when necessary.
- Easy application
- Less residue than wax
- Good for outdoor application
- Constant reapplication
- Potential to leave a residue
Clean Your Tools
Cleaning tools has a multitude of benefits including rust prevention. Tools that are covered in dirt, grime or even wood shavings can rust quicker due to a variety of reasons. Luckily this problem is easily alleviated with a few simple tools and precautions. Dawn dish soap is one of the best grease and dirt removal products on the market. After working on cars or in other dirty situations taking a few minutes at the end to clean tools will greatly improve their chances of remaining rust free. Dawn recommends mixing a teaspoon of soap to one gallon of water and using a sponge or towel to easily wipe away grease and dirt. Follow this up with some additional rust prevention tools such as mineral oil to further protect tools.
In many shops tools pull double duty working with metals and wood. Working with wood creates a fine dust that settles on everything. Wood dust easily absorbs water in the air creating a high humidity environment. This dust will then promote rust on any metal surfaces it is on. Simply wiping down metal surfaces after working will prevent this problem. For extra dust prevention and less time spent cleaning a vacuum system can be installed. Vacuum systems, while expensive, are incredibly effective at keeping spaces clean and will also remove dust from the air which will protect your lungs.
Storing tools outdoors is the least ideal scenario and rust prevention will be difficult in inclimate weather. In certain areas outdoor storage will almost certainly result in rust. However, there are steps that can be taken to ward off rust for a time. As I mentioned earlier rust forms when metal comes in contact with water, so our goal is to keep water off of the tools. To do this outdoors we have protect each tool individually. If the tools are in a tool box use silica gel in the box and apply mineral oil to each individual tool after each use. Storing individual tools outdoors introduces a large variety of problems including theft and is not advisable.
Even with all the proper precautions occasionally forgetting a tool on the porch can happen. However, this does not mean the tool is doomed as there are many effective rust-removal techniques. Properly restoring a tool generally requires two basic steps, rust-removal and restoration, which can vary in complexity.
Rust can be removed from tools in a variety of ways. An easy way to remove rust is by using a corrosive rust removal chemical. When using these chemicals it is important make sure that it will not hurt the tool you are trying to restore. Wooden handles or rubber components may not fare well in chemicals. In these cases a wire wheel can remove a majority of the rust. An alternative route is to make your own rust removal solution. This can be done with vinegar, salt and baking soda.
First, fully submerge the tool in vinegar and add salt at a ratio of two cups for each gallon of vinegar. Leave the tool in the solution for the next 12 hours. Keep in mind the longer you leave the tool in the solution the more rust will come off. After this use a 3M style pad to sand off any remaining rust. Finally, to neutralize the salt and vinegar solution submerge the tool in water and baking soda. This should be mixed at a ratio of one cup of baking soda to one gallon of water.
Following this, one must smooth the surface of the tool. Rusting causes metal to pit and to achieve the original quality of the tool simply removing the rust will not suffice. After removing the rust use a range of sandpaper to remove pits and restore the surface to factory quality. Start with coarse paper and work down to less coarse.
Depending on the tools original finish the last step can vary. For some tools a protective paint may be necessary. For tools that have no original coating applying a wax or oil to the surface will help to prevent rust from forming in the future. Tool restoration is fussy and time consuming; however, for some tools the time spent on restoration is time well spent.
For craftsmen tools are incredibly important. They are a large investment and are important in getting work done. Fortunately, tools can last a lifetime with the right care. In many areas around the country rust is the largest threat to a tools longevity, but it can be prevented with simple steps and inexpensive tools.
Article At A Glance
- Metal rusts when it is exposed to water
- Rust adversely affects a tools performance and life-span
- Different environmental factors and the tool itself can change the rate of corrosion
- Rust prevention takes on many different forms
- Keeping tools clean
- Using a mineral oil or paste wax coating for long-term storage
- Storing tools in a humidity controlled environment
- Rust-Removal is a multi-step process that requires a large time investment