On Blades, Coatings, etc.

I've been working on writing a book on shaving lately, which may or may not ever get finished, let alone published. But I thought the initial rough draft of this particular chapter would be of interest to the wet shaving community, so here it is.

Chapter 23: On blades and Coatings

Before we start this section, let me preface it by saying the relative price of a disposable blade might be high, but the absolute price is not prohibitive. A 100 blade pack, of whatever brand, is seldom beyond the financial means of the hobbyist wet shaver. Blades are perhaps the most personal choice of all for a shaver, as each blade will react to your skin and hair type differently than others.

Still, for the most part, the average wet shaver puts way too much thought and consideration into razor blade choice. Most razor blades sold for shaving, are in fact, suitable for shaving. The budding wet shaver often finds joy in substituting one blade for another, to gain an infinitesimal improvement in the quality of the shave. Some people use dice as counters, to keep track of the number of shaves on a blade, some people mark the blade with a permanent marker. Some people only use a blade once or twice before discarding it. I use a blade until it becomes tuggy, and immediately swap it out mid shave, if necessary. I couldn't say how many shaves I get from a blade. More than seven and less than fourteen for most blades, I suppose. Tracking shaves like that is good for perfecting your shaves. For me personally, it lessens my enjoyment and adds one more thing to the "too do" list. That's a fancy way of saying "I'm lazy," isn't it? Ah well.

There is no set number of shaves you should get from a razor blade. There are too many factors that make that number highly personal. A person with stiff, wiry hair will dull blades faster than a teenager shaving peach fuzz. A person who does a four pass shave will dull a blade sooner than a person who does only one pass and touch-ups.

The rare carbon blade user falls into one of two categories, he or she will use the blade once, then bin it, or they will go to outlandish lengths to maintain the edge using vintage sharpening machines for that purpose. To be fair, most do work fairly well on carbon blades, and a person can reasonably expect to get 20-40 shaves from a blade thus maintained. The vast majority of wet shavers are disinclined to deal with the special care requirements of carbon blades.

It is the same problem faced by millions of cooks and chefs. Carbon chef knives are easier to sharpen than stainless knives, and arguably hold a better edge, but walk into most stores that sell kitchen knives, and you won't see many carbon blades for sale, only stainless. Very few people are willing to keep using a knife that must be wiped down constantly to keep it from rusting, no matter how keen the edge may be.

Generally, the thicker the blade, the longer the shaving edge will last, and a person who shaves with GEM, injector, or Artist Club blades will usually get double or triple the shaves per blade compared to a double edge blade user. These blades are also more expensive, so perhaps overall, it's a bit of a wash in the money savings department.

We have William Nickerson to thank for the invention of the double edge blade. Gillette's idea would have gone nowhere if not for this gifted metallurgist, who figured out how to make thin, flexible, sharp, and durable blades. We now call small cuts "nicks" in his honor. (That's totally not true, the last name is just an odd coincidence). The modern "butterfly" blade was actually developed by Henry Gaisman of Autostrop for his Probak razor, and the patents on the blade forced the Gillette Company to merge with Autostrop in 1930. This merger left Gaisman in total control of Gillette for the next eight years until his retirement in 1938, and his shrewd executive ability turned the then struggling company into an economic powerhouse.

DE blades come in two types, stainless and carbon. Carbon blades have their fans, and those fans have a tiny pool of modern blades to choose from. Vintage carbons are usually not usable due to micro-pitting and rust, but if found in usable condition (verified under a 10x or stronger loupe, everyone really should own at least one) can offer an excellent shave. After shaving, dipping a carbon blade in rubbing alcohol (to dispel the water) and then in mineral oil will keep the blade from rusting between shaves. Another excellent use for carbon blades is to utilize some of the many unique contraptions and razors that were made to re-sharpen carbon blades between 1910 and the 1950's. None of them work on modern stainless blades, which is what the other 99% of wet shavers use. If you try to use them with stainless blades, you will most likely wind up with a rolled edge or other form of edge degradation. At best, you won't improve your shave, and at worst, you will be left with a shave you'll never forget (and not for the good, happy reasons).

Much of the following information comes from an article written by Herbert Shuldiner for Popular Science magazine in February 1970, pgs. 60-61, called "Science Gives You a New Edge on Shaving;" catchy title, isn't it?

Stainless blades come in a near infinite variety, and from every corner of the earth. They almost all have some form of PTFE coating, and the blade edges may also be coated in chromium, platinum, ceramic, titanium or tungsten, or combinations of any of those five coatings. The coatings are applied through physical vapor deposition (PVD), and are very thin, measured in angstroms. The coating, or combination of coatings, is about 300 angstroms thick (one angstrom is a little bigger than a millionth of an inch). PVD coating on razor blades is a bit different than the rest of the industry, as they use a low temperature process, which avoids the teardrop effect on the cutting edge, improving the edge quality. Platinum is the most popular coating, despite the added expense (and yes, they use real platinum). It adds durability and smoothness to the blade. Chromium is a little shinier, and a little smoother than platinum, and is usually the base layer for any additional layers, The chrome reproduces the stainless-steel edge, and even fills in some of the voids created by the original grinding. This adds considerable strength to the edge. it's also far more resistant to corrosion than the base layer of stainless steel. It is also far cleaner than the base metal, so it provides a superior surface for PTFE coatings. Ceramic functions similarly to chromium coatings. Tungsten adds strength and longevity, as does titanium. The Teflon coating is completely gone from the blade edge by the end of your first pass (confirmed by observing the blade edge under an electron microscope), so don't get overly wound up in PTFE blade coating hype.

Does the coating make a perceptible difference to the shave? Yes. A measurable, quantifiable difference? Most wet shavers will get about 20% more shaves from a chrome or platinum-chromium coated blade, but at the end of the day, it's mostly there to keep the blade in perfect condition until first use, and to keep the blade edge from deteriorating as long as possible after first use, and that is the job these coatings excel at. Gillette, among others, did lots of study groups in the 70's, and determined that people generally suck at being able to detect minute differences in sharpness, but they can tell a difference in smoothness. That was really the turning point for blade coatings as Gillette focused on smoothness over sharpness.

Let me detour for a moment. If the razor blade manufacturers really wanted to create a long lasting blade, they could, and have. In the 1970's, Personna produced the fabled 74's, the new (DE and injector) razor blade made from tungsten steel and coated with titanium. The name came from the atomic number for Tungsten, 74. They discontinued it after only a few years of production, as it broke the 'razor and blade' business model. These blades lasted up to 10 times longer than a regular stainless blade. If one pack of blades will last someone half a year, they won't sell as many blades to that person. It's a pity, as they were exceptionally fine razor blades.

Back on the subject at hand, what is far more important than the coatings is how that razor blade is sharpened and heat treated. The starting thickness of a modern DE razor blade is 0.004 inches. Grinding, honing, and stropping produce an edge that is 20 millionths of an inch thick.

In Machinery and Production Engineering (London), vol. 53 no. 1357 (1938, p33-38), They describe the process of manufacturing Gillette Blue Blades, which I have transcribed here, with a few small edits to improve readability:

The Manufacture of Blades

Some of the most interesting machines installed in the factory are used in connection with the manufacture of blades. The blades are not made singly but are produced end-to-end in one long ribbon of steel, the parting-off operation being actually the last performed before final inspection, and being done after hardening, sharpening, and stropping. We may consider here the manufacture of safety blades of the Gillette type. These are made in a variety of designs to suit razors of different patterns, and are usually produced from 1.25 percent carbon steel which includes about 0.3 per cent of chromium. As is well known, ineffective drying of a blade after shaving is the chief cause of the edges losing their keenness. When moisture is allowed to remain on the edges, corrosion sets in very rapidly, with the result that the initial sharpness of the blade is soon destroyed. To offset this, a special brand of Gillette blade is made from stainless steel, and with these blades drying after shaving is unnecessary. Generally speaking a stainless steel blade may be expected to retain the keenness of its edges for a much longer period than a blade of ordinary steel.

Coils of blank strip are received at the works stores, the average weight of a coil being about 33 lb., and each pound of strip material will produce approximately 400 blades. The thickness of the strip for Gillette type blades is 0.0061-inch, and the tolerance permitted is plus or minus 0.0002-inch. In the case of Valet blades the strip is nominally 0.010-inch thick, the tolerance in this case being plus or minus 0.0003-inch.

The first operation on the steel strip consists of blanking and perforating, and is done on high-speed presses. The strip passes to the dies through guide rollers, and two blades are formed at each stroke, the output from each press being 500 blades per minute. The rolls are used to flatten the strip after the press operation.

It will be noted that they are loaded by means of a [counter] weight, and a system of levers, and the strip, after leaving the rolls, is coiled automatically on the drum. The rolls remove any burrs or slight distortions which may have been caused by the presses. Simple combination press tools are used for perforating the strip, and the waste material falls through holes in the base of the dies to a suitable receptacle.

After coiling, following blanking and rolling, the strip is treated in an Imperial Chemical Industries trichloroethylene degreaser, to remove all traces of oil and dirt. Four coils are operated upon simultaneously in the same machine, the material passing through the treatment chamber and being re-coiled again automatically following the actual cleaning part of the operation.

Hardening and Tempering

Particular interest attaches to the operation of hardening and tempering the strip after the degreasing process. The heat-treatment is done in electrically-operated furnaces, the hardening and tempering furnaces being placed end to end, so that after the strip passes through the hardening furnace, it is quenched and then passed directly into the tempering furnace. A reducing atmosphere is provided in the hardening and tempering furnaces to prevent oxidation.

The formed strip is drawn from the coil by rolls, and passes first through the hardening furnace, the temperature of which is maintained automatically. Leaving the hardening furnace the strip passes through water-cooled metal quenching boxes.

The tempering furnace is also electrically heated, the temperature being automatically controlled to within a few degrees of that specified for the treatment.

An interesting item of the heat-treatment equipment is the end tempering furnace. While the edges of the blades are tempered to give the most suitable results for shaving, the centers are of a somewhat different temper, to ensure the flexibility essential to prevent breakage when the blade takes up its correct curve as held in the razor. In the end tempering furnace, therefore, the strip passes between copper terminals, and current is thus passed continually along that portion which is between them. This current does not affect the edges of the blades, but it heats up the centre portions, which will later form the ends of the blades, and in this way provides additional tempering. [author's footnote: These processes were covered by British Patent No. 401366, or GB401366A, application 1932.]

In the case of Blue Gillette blades, the characteristic blue color is imparted to the material by the provision of a special gas mixture in the hardening furnace. Depending upon the material concerned, the speed of the strip when passing through the line of furnaces varies between 250 and 350 blades per minute. On leaving the end-tempering furnace, the strip passes between a pair of pull-through rolls, and is then coiled on the drum.

Marking and Lacquering

Acid-etching machines are used to mark the safety blades with the trade-mark and other lettering. The coil is fed to the printing device by rolls, and the inscription is printed on the blades by rubber stamps, each being of sufficient length to print two blades on both sides simultaneously. In operation, the rubber stamps first rest on fabric pads, which are level with the strip, and then move over to print the blades. The machine operates very rapidly, and actually stamps and etches 400 blades per minute.

Leaving the printing device, the strip passes through a neutralizing bath of alkaline solution, which kills the acid, and then moves between air jets, which blow upon it to remove the liquid. Next, the strip passes through a heating chamber, which dries it thoroughly, and finally between two rotating mops, which wipe it on both sides before it is coiled ready for the lacquering operation.

One set of lacquering equipment accommodates six coils of printed strip material simultaneously. The strip is drawn from the coils, over rollers, and down into the lacquer bath. Leaving the bath, the steel is passed upwards through the preheating oven. It then passes to the stoving oven, through which it travels before being wound again on the coils.

The speed of the strip on its way through the bath and ovens is 80 blades per minute for each of the six coils. The pre-heating oven, and the stoving oven, are both electrically heated, the actual temperatures being controlled automatically.

Before the grinding, honing, and stropping operations on the strip, several coils of standard size are spot-welded together to form one large coil. This avoids any unnecessary reloading and re-setting of the machines, and at the same time affords an opportunity of inspecting the blade strip for cracks and other flaws. An automatic machine is employed through which the strip is passed at high speed. When a flaw or a crack is encountered, the machine stops automatically, while a red light warns the operator that something is wrong. The defective section is then cut from the band, and the two ends are joined together by welding. In the same way, when the end of the blade band is reached, the machine stops automatically to enable the operator to weld the end of the next coil to it.

Specially designed machines are used for grinding, honing, and stropping, these three operations being done on what is virtually one long machine. The coil is placed on a horizontal table, and is drawn through the machine across the various grinding and honing wheels with the cutting edges of the strip in the same vertical plane. Each individual blade passes through the entire sequence of sharpening operations in about 30 seconds. The first two of the units in the line provide for grinding the rough angles on the edge of the blades, each of the two units grinding one upper and one lower edge. The next unit bevels the angles, a finer grade of wheel being used for this operation, after which the strip passes through the various honing units, which carry wheels of still finer grade. Stropping is done by means of leather wheels about 1/4-inch wide, several of these being mounted on a single spindle with spacing collars between them.

At the end of the machine, after leaving the stropping wheels, the blades are cut off one by one at very high speed.

The band is indexed to the cropping shears by the crank and a connecting rod and slide, location being taken from the holes pierced in the centres of the blades. A slide, operating at right angles to the direction of travel of the strip, holds the cropping tool, and the parted-off blades are stacked on to the pins of a holder or carrier. [Author's note: these "carriers" sometimes went home with employees, and occasionally show up on online auction sites. The blades contained within, still covered in oil, are as close to perfectly preserved as any blade can be.]

Each holder accommodates about 900 blades. Normally, cutting-off is done at the rate of 350 blades per minute. The loaded holders are inspected as they are taken from the sharpening machine, and any defective blades are removed. Special mercury vapor lamps are used to illuminate the benches where these charged holders are inspected, and blades which are not sharpened properly reflect light differently from satisfactorily sharpened blades when the charger is held at certain angles, and can thus be readily detected. Various blades are selected for individual testing, and are checked with precision measuring instruments. In any blade, the two edges must be at a certain distance from the centre line, and the maximum tolerance for this distance for each of the two edges is not more than 0.002-inch, while the tolerance for the overall dimension of the distance between the two cutting edges is ± 0.004-inch.

Wrapping and Packing

Special machines are installed for wrapping and packing the finished blades. Each blade has an outer printed wrapper, and an inner waxed paper wrapper which prevents moisture from reaching it. One automatic wrapping machines is capable of wrapping as many as 40,000 blades per day. The printed outer wrappers are held in a cage, while the waxed paper is drawn from a coil and the printed wrapper is drawn from the magazine and placed in a pocket on the table.

As the table rotates, the waxed paper is cut from the roll by a shaped knife, and is placed on the printed wrapper ready to be folded round the blade. As the table rotates still further, the blade is slipped from the lower end of the charger and placed in position on the two wrappers, and the metal fingers then close the wrappers over on to the blade. These fingers work in pairs, the waxed paper being first closed over the blade before the outer wrapper is folded into position. At the last station, the package is pushed by a plunger into the vertical guide tube, from which batches of the wrapped blades are taken as they accumulate.

The packing of wrapped blades into cartons of five, six, or ten, is also carried out by automatic machines. Batches of paper are placed in a number of vertical channels, and from the channels are fed in batches of five, six, or ten to pockets in an endless chain which moves along the front of the machine. The cartons are fed into pockets of a second endless chain which runs parallel to the first chain, and during their travel are opened ready to receive the blades.

At one point the blades are traversed into the cartons by means of a simple finger movement, and the loaded packets then move on further mechanical fingers sealing them before they reach the table, where they are checked and finally wrapped automatically in cellophane paper to exclude damp. Special interconnected devices are used on the packing machines, which reject any packet that does not contain the requisite number of blades.​

There is very little difference between modern production and what was happening here in 1938. The machines are smaller. Now lasers etch the blade brands onto blades, and high tech coatings are applied, digital readouts are used, and there is more automation, but the core process remains largely unchanged. The same production line described here may still be in use elsewhere in the world, albeit modernized. Some of the finest blades in the world are made on machines that were originally built and used by Gillette in Boston, before being shipped off to developing nations, to be shipped off yet again to third world countries, or countries with ties to third world countries, like Russia. Wizamet PolSilver blades were once made by Wizamet in Poland on an antique belt driven machine that used to churn out blades for Gillette in the early 1900's. That production line got sold to ZAO International, who moved it to St. Petersburg before merging with Gillette to form PPI. That production line makes the Russian made Polsilver Super Iridium blades. The Wizamet name was trademarked by Gillette in Morocco, who makes the Wizamet Iridium Super, also in Russia. Neither blade is the original long discontinued Polish made PolSilver, but both of the newer blades are comparable to the older Polsilver blades. This isn't even an unusual occurrence, as other old brands have also been shuffled from place to place. Nacet blades, common in Africa and the Middle East, was once a U.K. blade brand. All it takes to stir up a storm of controversy is for a manufacturer to slightly change the packaging or blade etching, and the cries of "counterfeit" and "the quality has gone downhill," ring from all corners of the internet until someone talks to the manufacturer and confirms the change. The huge number and types of DE blades produced at PPI St. Petersburg all come from only four blade production lines, with a fifth inactive line as backup. That places a lot more credence to the idea that blade coatings matter, doesn't it?

There has been a rumor going around for decades now, that many blades produced at these plants are the exact same blades, priced and packaged differently, depending on that blade's particular export market. Can I prove it? No. Is it likely to be true? Probably. The Gillette Rubie Platinum Plus and the Rapira Platinum Lux are two blades that many people swear are identical, but we'll never really know.

This isn't the only factory move in recent years. Personna moved all their Israeli made blade manufacturing to Germany due to the continuing tensions between Israel and Palestine, and the wider conflicts continuing in the Middle East. There used to be hundreds, if not thousands, of blade manufacturers. As the companies failed or merged with larger corporations, the equipment became concentrated. The vast majority of the world's supply of razor blades is made by a small handful of companies, who are all very secretive about their production processes.

In 2019, Czech Blades S.R.O. introduced the Tiger and Tatra brands. This is the company that originally manufactured Astra blades, before selling the brand to Gillette. Included in that deal was a non-compete clause, which has now expired. Fans say these new blades are better than the well regarded Russian made Astra Superior Platinums.

Here's a list of some of the more well known factories:

PPI in St. Petersburg, Russia
Mostochlegmash in Moscow, Russia
Vidyut in Bombay, India
Gillette in Manuas, Brazil
Gillette in Shanghai, China
Lord in Alexandria, Egypt
Treet Group in Lahore, Pakistan
Kai in Oyana and Senbiki, Japan
Feather in Seki and Mino, Japan
Feintechnik Eisfeld in Solingen, Germany
(These guys do a lot of private label production. Starting your own razor company? Want your own brand of blades? These are the guys to talk to. If you see "eisgehärtet" or "ice tempered" on the package, it was definitely made by these guys. Personna also does private label, though they require a very large order, so most private label stuff comes out of Fientechnik Eisfeld.)

This is not a comprehensive list, as Gillette and Personna have factories all over the world, but this covers the main suppliers of DE blades.

Side note: Vendors typically purchase blades in 'Master Packs' of 10,000 blades, so they usually have a lot of blades in inventory. Reputable vendors don't carry counterfeit blades. You wouldn't think something as cheap as a razor blade would be counterfeited, and you would be wrong. The easiest way to avoid counterfeit blades is to not order blades from Chinese sellers. That isn't to say all Chinese made blades are bad. The Chinese made (not counterfeit) Schick injector blades are considered some of the best ever made. As far as DE blades go, the Chinese made Wilkinson Sword blades for the Indian market are considered decent.

Blade sharpness is a perception, and is usually offset by smoothness. I like to call sharpness and smoothness a sliding scale, with Feather and Kai at one end, and everyone else somewhere below them on the sharpness scale. Most razor manufacturers are content to grind their blades with a double bevel (also called a double faceted) edge, the initial blade angle, and a micro beveled edge. The Japanese use a triple faceted edge, which adds keenness to the blade edge, at the cost of blade longevity.

For a new wet shaver, a good rule of thumb is to pair sharp blades with mild razors, and smooth blades with aggressive razors. This advice won't work for everyone, but it will for the vast majority of users.

 

The TLDR version.

PTFE adds smoothness.
Chrome adds smoothness.
Platinum adds smoothness.
Ceramic adds smoothness and hardness.
Tungsten adds strength to the blade edge.
Titanium adds strength to the blade edge.

Not mentioned in the chapter (yet) is that Derby usually goes all or nothing. Either only adding no coating, one coating, or throwing the whole kitchen sink at the thing. For example, many of their blades have a Chromium, Ceramic, Platinum, Tungsten and Polymer (PTFE) coating on each blade.

Edit: also not mentioned is what the razor blade manufacturers leave off of the package or blade description. Just because they might use titanium in addition to platinum, doesn't necessarily mean they will advertise that fact.

 

You're welcome.

 

The other Japanese blade.

KAI is an interesting DE blade for a lot of reasons. For one, it doesn't admit to any coatings, and is simply sold as "stainless steel." It's also thicker than the rest of the modern DE blades, more like a vintage blue blade in that respect. It's also a tad bit wider than most other DE blades, leading to more aggressive edge feel. Just as sharp as a Feather blade, with the rare triple bevel grind, it also manages to be a bit smoother and longer lasting than Feathers, according to those who have compared them. I attribute this mostly to the thicker blade, and not any coatings.

That being said, KAI is known for coating their other blades, so I strongly suspect that they use at the very least, a titanium coating on their de blades.

 

I didn't use the word sputtering, but I did talk about PVD coating. Sputtering is the name for the process, and the result is a PVD coating. I'll work it in.

I'll also dig around and see if I can find a more up to date description of the process than 1938, at least for the cryogenic version of PVD for sputtering blades. That technology would have blown their minds in 1938.

Edit: the blade manufacturing section was copied almost word for word from a 1938 publication, so I can't take credit for that. I haven't been able to track down the pictures/diagrams/photos associated with that article, yet, unfortunately. There's pages of them. Part of my editing process was removing references to them.

Also didn't mention that modern blade stropping is done with rubber or leather wheels, and didn't talk about cartridge blades either. It's a very rough first draft.

 

You're right.

Maybe it's Nacet I'm thinking of? Either way, there are hundreds of ways to change a blade slightly, whether it be an extra second of polishing time on the hones, or a double layer of platinum or chrome... Who knows?

I really don't know the difference between a Hi-Platinum or Hi-Chromium blade vs a 'normal' Platinum or Chromium blade.

 

I've been trying out the Indian 7 O'Clock blades this last week, for the first time that I can recall. I'm sure I tried at least one back when I was first getting into wet shaving.

My brother-in-law gave me a tuck each of the greens, yellows and blacks.

So far I've tried the greens and blacks. I preferred the platinum coated blacks. I'm looking forward to trying the yellows. From what I've read, they are one of a handful of blades that don't vary much in sharpness between multiple uses. Voskhod is another of those rare blades, though I don't care for them at all, and find them to feel consistently dull on the first, second, and third use.

Edit: if you are easily offended, feel free to replace the word "dull" with "smooth." In this context, I use them interchangeably.

 

Yes. It is. Lol.

 

I've been doing a substantial re-write of this section, based on all of your observations and questions, and the new info that pulled up. I'll post it up here in a day or two.

Also I remember reading a discussion on Badger & Blade that recounted an interview with someone who helped set up a razor blade production line in St. Petersburg. A link to that discussion would be helpful. I don't much care for second hand info, but I like it better than 3rd or 4th hand, which is all I've been able to dig up. It was about 10-15 years ago, if I recall correctly.