Every steel and cast iron tool you own have one common enemy that is constantly working to undermine your effectiveness with that tool. The enemy attacks while you are sleeping because it never rests. The enemy can get in from the narrowest of cracks, and in fact it thrives in confined spaces. That enemy is rust.
Yes, rust and corrosion will make your tools more difficult to use, and if you do not take action it may even render your precious tools useless. Some tools may be rejuvenated and brought back to life, however many are damaged beyond repair.
But there is a simple regimen of maintenance that you can perform annually, or optimally once in late fall and once in early summer, that can keep your tools protected and safe from transient atmospheric moisture, the most common cause for rust to develop in your workshop. If you have a problem with actual water accumulation in your workshop, where water is pooling, dripping, or otherwise entering your workshop from a source other than simple moisture, you have bigger problems and I suggest you deal with those problems post-haste!
Except for locations with extremely dry climates, there is a fair amount of moisture in the air that we breathe. Without that moisture, life would truly be difficult for us since most of us would be forced to deal with continual nosebleeds and we would not be able to go far without a glass of water to ease our parched throats.
The actual amount of water that a certain volume of air can hold is determined by its temperature. The hotter the air, the more water it can hold, and conversely the cooler the air the less water it can hold. This is where things become relevant for woodworkers. Whenever a volume of air is cooled, that water has to go somewhere.
Think of a warm summer day outdoors, and imagine yourself with an ice-cold glass of your favourite beverage. What do you see on the outside of your imaginary glass? Condensation! Some call it dew, but it is essentially the same thing. The warm air touches the cold glass, and the water contained in the air is forced out because the colder air can not hold that much water. It emerges on the surface as condensation.
The same process happens in your workshop or garage. The workshop is essentially a large volume of air surrounded by many surfaces (the walls, the tools, the floor, etc.) Now as the warm day ends and the evening progresses, the workshop will tend to cool down. The moisture that was in the air in your workshop has to go somewhere, and just like your imaginary glass it will condense onto the surfaces. If the temperature difference is not that great, or the humidity of the air (the amount of moisture it is holding) is not that great, you may not be able to see actual drops of condensation, but take my word for it, condensation is forming and it will work on your tools!
You have three basic choices for how to deal with this condensation.
Controlling the ambient temperature and humidity of your workshop is a difficult and expensive ordeal. If your workshop is a garage, just opening your garage door can upset the balance of moisture that you have worked to achieve. Keeping your tools in an appropriate container is a great option, though it is often impossible to do for larger tools such as your table saw or jointer.
Wax, on the other hand, is something that you can apply to your tools then continue to use them as you normally would. Other than applying it one or two times a year, it does not interfere with your woodworking. Wax creates a barrier on the surface of your tools, keeping the moisture in the air from contacting the metal itself, thus preventing rust.
But why wax, you may ask? Why not use oil, Teflon, or some other product? As a woodworker, wax is very friendly to your tools and the wood itself. It will adhere to the surface it is applied to, will not transfer to the wood you run over that waxed surface, and therefore it will not interfere with the finish you choose to apply to that wood.
Oil is something else you can apply to your tools, however oil has the distinct disadvantage of transferring easily to your woodworking project, which will then interfere with the finish you apply afterwards (unless that finish involves oil, of course). Also, since oil transfers, by its very nature less of the oil will be left behind to protect your surface with each pass of your workpiece!
The process of waxing my tools involves the wax, a couple of clean lint-free rags, and in my situation I needed a sheet of sandpaper though 000 or 0000 steel wool would have have been suitable as well.
Of course, before you add any wax to your tools you should remove any and all rust from the surfaces of your tools. This is an easy task, and simply involves a bit of elbow-grease. As you can see in the image to the left, my jointer has a small amount of rust forming at the edge of the outfeed table.
When you are cleaning up your tool, remember to remove rust from all the surfaces. The flat tables, the vertical surfaces, and also non-working surfaces that are made from metal. Do not remove any existing paint because that paint is already a barrier to moisture, however if that paint is already compromised from rust, you should remove the rust and some of the surrounding paint to ensure you can apply wax to that surface.
Remember to remove any rust, dust, and sawdust from the tool.
The layer of wax that you are applying should not be thick! The solvent in the wax and a little pressure will ensure the wax penetrates into all the cracks and scratches of your tool. You should barely be able to see the wax that you have just applied, similar to the look of having wet down the tool.
If you apply the wax too thickly, you are just wasting the wax and you will have to waste some time in the next step, since all that excess wax will have to be removed... the hard way.
The way to remove this excess wax is to buff the surface of the tool. Use a clean rag that you have folded into multiple layers, and buff the surface of your tool until the white layer has been removed and your cloth slides smoothly over the tool's surface. Buff all the surfaces to which you applied wax, and be sure you do not shove wax into any inaccessible corners as this will leave an unsightly reminder of your inattention.
Once your tool is buffed up, the surface will shine as shown in the image above and to the right.
Because of this, its top surface occasionally develops a fine sheen of rust. The effect of this rust is to make it much more difficult to pass wood over the surface, and it also produces small rust-coloured scratches on some soft woods.
The process for table saws are the same as anything else. Sand the surface (photos below) to remove any visible rust, apply the wax, buff the surface, and voila! Your table saw is now set to work smoothly. Just look at this photo below that shows the table top after it has been cleaned up. The rust is gone, and the surface is slippery-smooth!