Weapons grade steels corrode. Period. This is true whether it is high carbon steel or whether it is stainless steel. If your weapon has a stainless steel that will not rust, that steel is too soft for use as a true weapon.The best way to deal with rust is to prevent it from happening. That starts with the finish on the blade by the craftsman. A true custom mirror finish best resists corrosion, but can cost over $1000 to add to a sword. Do not expect to see any production sword with a true perfect custom mirror finish, though you can see your reflection in the glossy finish we have achieved on a number of our limited production run products (and it is a great value).
After you receive the weapon, if it is stainless steel you should seal it once it is clean before the first use and monthly thereafter. We recommend Renaissance Wax(R), which is inexpensive and available online. It helps prevent fingerprints as well as doing the best sealing job. Second best is Carnauba Wax, which I have not personally used. A small amount is all you need. Too much and the blade will look streaky until you clean off the excess.
Next, clean your sword steel immediately after use. The main enemy is the salt and acid deposited on the blade when you touch it. They are hydroscopic, which means they attract water molecules from the surrounding environment that produce corrosion. The acid itself is also a problem that can produce a black fingerprint on a high carbon steel blade by the next day. I even know of one case where the acid from a pregnant woman’s touch stained high quality 440C stainless steel. Do not touch your steel unless you must. You also need to get the physical debris off the blade. Consider gentle tapping, rinsing and/or a soft toothbrush; do not rub debris so it causes scratching. A damp cloth with a non-abrasive, non-acidic detergent (check out dish washing liquids) is usually fine for cleaning stainless steel but you need to rinse well and dry immediately with a soft cloth. Do not use soap to clean weapons grade stainless or carbon steel blades as soap has a caustic etching quality that may produce immediate tarnish lines. It is definitely bad for carbon steel. If you put sword oil on stainless steel, the steel will be oily and look cloudy. If it was mirror polished you will not see that finish until the oil is gone. The oil may act as a solvent and strip wax sealant from your blade.
High carbon steel swords require far more intensive maintenance. The most labor intensive and expensive is the traditional method required for a Japanese Katana.
A Katana should receive field maintenance immediately after use that entails tapping off debris, a wiping cloth wipe down, and oiling the blade with choji oil and an oiling cloth. Toyama Ryu Batto Do Konjaku Kioi Dojo, Katana Cleaning, http://www.toyamaryu.org/katana_cleaning.htm (10-3-2010). This is buttressed by a normal maintenance at home that night consisting of a tapping debris removal, stripping the oil with fine rice paper wiping paper, using a traditional mildly abrasive powder made from finely ground stone (Uchiko powder) dispensed from a cloth ball then wiping paper, and finally oiling. The Katana is disassembled for each cleaning, held aloft during the cleaning. Use separate clean wiping cloths or paper for every step. You may need to crumple the rice paper prior to use to soften it (then neaten it up). Do not leave too much oil on any part of the sword or it may gather particles that collect moisture. Essentially you need to purchase or gather together a sword cleaning kit plus keep a few clean soft rags handy. You can buy a fairly standard sword cleaning kit online and it is a good idea to read and follow the directions. Some kits come with Paul Chen Hanwei sword oil, which I use. Beware of coarse Uchiko powder, low quality oil and fake product.
You may wish to adapt a more practical cleaning process for your high carbon steel blades, looking to gun cleaning methods for guidance. After removing debris you can use a soft clean cloth with isopropyl rubbing alcohol for cleaning, followed by oiling. There are potential Western substitutes for the choji oil, which is 99% mineral oil and 1% fragrant clove oil, that have been used successfully by various folks ranging from pure mineral oil to some of the gun oils. Be very sure that whatever modern gun cleaning product you use is appropriate and safe for your steel. A friend swears by WD-40, which is both a lubricant and solvent, but others complain it evaporates too quickly or has so much solvent it can damage the steel over time. WD-40, and any product with solvent, may discolor handle material, including even stabilized wood. D-2 is so corrosion resistant it can be treated like weapons grade stainless.
The question of whether or not to wax high carbon steel sword blades is trickier. Several top notch custom knife makers argue that waxing does a better job of protecting a high carbon steel blade than oiling because oil attracts dust. If you go the waxing route for a high carbon steel blade you need to clean then re-wax after every use. I do not use oil solvent during the cleaning stage on a waxed blade.
Use common sense storing your sword. Never store any steel blade in or near a leather sheath or case. The tanning acids from the leather can rapidly corrode steel. Vapor from the leather can do the same thing. Store your blades in a dry, non-humid spot at a reasonable temperature. I store my Butterfly Swords on a paper towel in a dry cabinet, out of the sunlight so the handles do not get bleached. Make sure the edge and flat are not under pressure, and pay close attention to where the blades are before you reach for the swords. You may wish to put a desiccant in the storage area to help absorb moisture. Check your weapons for condensation after you transport them, especially if you are going to leave them in a carry case. If you plan on storing a weapon in a wood or metal case, remember that the case can seal in moisture. If the steel is high carbon, first clean then drench the sword with sword oil. Check your stored weapons regularly.
Military knife users frequently ask for a non-reflective blade treatment. On the high end, that can take the form of bead blasted 440C, which increases its susceptibility to corrosion, or hot blued high carbon steel, which helps reduce its rate of rust. The bluing will erode over time. You will also find knife blades on weapons from $20 to $300 coated with a variety of coating materials ranging from paint to high tech formulations (and lots of claims that the maker’s specific proprietary coating is the best). These coatings cover everything except the sharp edge. They wear off. Water and debris can get under the coating. While they may keep moisture off a specific portion of the blade, they also prevent you from personally determining whether the weapon you received was made of the steel, and with the finishing, that you paid for. If you see these coatings on anything other than an inexpensive knife, it should raise an immediate red flag and you need to have a lot of trust in the manufacturer. Satin finished D-2 and D-3 high carbon tool steel have a natural coloration that may satisfy the needs of a tactical user.
Once steel corrodes, you should clean it quickly before the spots widen and deepen. The smartest way to remove rust from steel is to polish the rust off.
That means you generally either need access to a professional sword polisher or know how to polish a sword and be very patient. If your blade is a mirror or glossy finish, or lamellar steel, this is a big deal (especially if it is an expensive antique Samurai sword). If you do the work yourself, be sure to avoid polishing one spot too deeply or to a different grade of finish than the rest of the steel.
If you have a high carbon steel satin finish blade, however, you are in luck. Spray the blade with WD-40 as a lubricant and use superfine grade #0000 steel wool to remove the rust, stroking in the same direction as the existing grain. Do not do that on a glossy or mirror finish blade because you can leave fine scratch lines and may even strip the finish down to satin. Do not use steel wool on stainless steel because you will embed rust prone molecules of carbon steel in the stainless. You can, however, find a non-metallic 3M Scotch-Brite pad equivalent.
There are a number of commercial products out there to remove rust from steel, such as Naval Jelly. Not only will Naval Jelly remove rust from your steel, it will strip the finish and soak into the steel leaving a stain. This is true whether your weapon is a high carbon steel Jian, a combat steel Butterfly Sword, or one of our stainless Steel Butterfly Swords. That may not be a big deal on the steel plate of a battleship (that gets painted), but it is not how you want to treat a fine weapon. Assuming you followed the Naval Jelly directions and did not leave the pink glob of jelly on your steel for more than ten minutes, it should be possible to steel wool or polish off the tainted surface steel. But if you are going to have to do that, it makes sense to skip the liquid acid product and just gently polish out the steel to begin with. I tested a liquid rust remover specifically formulated for stainless steel and it turned a pair of our swords into a moonscape. The same product worked fine on a kitchen knife. As a general matter, always find a small innocuous spot on your metal to test a product before widespread use.
WD-40 oil can help soften or remove debris from various surfaces. While I have removed some low-hanging fruit grains of rust with WD-40 during preliminary cleaning, it is not a rust remover. I put some on one of our Butterfly Swords and it did pretty much the same thing as any oil on glossy finish stainless steel, which is to cloud up the finish (and make the sword oily) until it was removed. It did not hurt the steel, but it is a solvent and can remove the sealant wax.
A lot of Butterfly Swords have brass fittings, as do my doorknobs and Kohler faucets all of which have tarnished. While pure brass cannot technically rust, it gets dull over time and the oxidation of the copper looks a lot like rust to me. The first thing you need to know about a brass D Guard is that it always looks better in the online picture than on the sword you receive. Ignore the opportunity for the manufacturer to re-polish the specimens prior to photography, or the possibility that the manufacturer never intended to polish your swords to a shiny luster as advertised, the odds are that your swords sat in a warehouse for a period of time prior to your purchase and the brass dulled during that period. A brass polishing product (one of those fluids you need to test on a sacrificial spot first) can help shiny up a dulled finish, but it is not a magic bullet and I would not want to get any on the blade without knowing the consequences. You may need to use a lot of muscle going back and forth with a rag to polish the D Guard, and don’t expect the polishing fluid to remove the not-rust patina. You can get a shinier finish with less work, and take off patina, by polishing the brass with grade #0000 steel wool, and chances are good you will not care about any fine scratch lines. I know of two ways to help slow brass from tarnishing. The first is to gold plate it. The second, as recommended by a locksmith for my doorknobs, is to varnish it. I cannot vouch for varnishing the doorknob since it was less work to just get a new one, but neither method will survive weapon vs. weapon training unscathed. Speaking of D Guards, if you have a steel guard on a Butterfly Sword it will require constant thorough maintenance since you touch it every practice.
I am happy to share my knowledge and experience, and pass on the experience of others, but neither the I nor Modell Design LLC assume any responsibility whatsoever, under any circumstances, to anyone or entity who follows or fails to follow techniques described above (use or abuse at your own risk), including but not limited to discovering that you can cut yourself when cleaning a sword and that it is a bad idea to let it drop on your finger or toe. Be very careful of the pointy tip of a dull-edged sword during cleaning as it may sneak up on you when you are no longer on alert.
Modell Design LLC