QUALITATIVE ANALYSIS OF THE EDGE CHARACTERISTICS OF

SHAVING RAZOR BLADES AS A FUNCTION OF CONTINUED USE

Sad_Scientist

Argon National Laboratory (USDOE);

Whisker Hall, University of Elements, USA

Keywords: Blade Sharpness, Shaving, Blade Degradation, Razor Quality

Abstract

This research focuses on depicting the degradation of a shaving razor blade throughout the

blade’s entire shaving cycle. Various SEM micrographs were taken from multiple angles of

seven razor blade edges, including an edge-on view, a side view, and a cross sectional view of

every single blade. Micrographs were taken after each of the first through fifth shaving cycles for

five different blades, along with a new razor blade and two control blades. For this research, the

razor blades were Feather Hi-Stainless Platinum Double Edge. Qualitative analysis results and

discussion are included in this paper.

Introduction

The sharpness and edge characteristics of cutting utensils and their affects on various materials

have been the focus of many studies, anywhere from slicing watermelons to slashing human

flesh1,2,3,4,5,6,7

. However, the scientific research has not yet pierced the shaving community. Post-

pubescent males and females who are familiar with the wet shaving technique have no doubt

noticed that the periodicity of nicks, cuts and irritation increase as the used blade life increases8,9

.

This is also generally accompanied by a decrease in shave quality. There are many potential

causes for such poor performance of the razor blades over continued use, including but not

limited to corrosion10,11

, plastic deformation12,13,14,15

, bending flow16

, chip formation17

, and burr

formation16,18

. These defects in the razor blade can result from many parameters, possibly

including but not limited to whisker thickness, shaving cream lubricant, mineral content of the

water, number of consecutive shaves, shaving technique, and storage humidity.

Before reading the rest of the paper, it would be best to get caught up on terminology used in the

shaving community, as well as basic processing steps and their consequences in the world of

razor blade manufacturing. Figure 1 shows a schematic cross sectional view of razor blade edges.

The dashed line shows what a perfect, ideal tip of a razor blade would look like after sharpening.

In real life, “debris deposit” occurs during the grinding and polishing process which gives rise to

the solid black line. During the polishing step, tiny abrasive particles move along the surface,

either towards or away from the edge tip, pushing scraped up metal and debris in front of and

behind the abrasive particles. This is responsible for the rounding of razor blade tips that are

fresh from the manufacturer. Figure 2 shows another schematic which points out the direction of

the polishing media, as well as parts of the blade that will be referred to throughout the rest of the

paper.

Figure 1 - Cross section view of razor blades, showing the debris deposit at the top of the picture which is responsible for

the curved, solid line. An ideal edge is shown as the dashed line for comparison. Image from J. Verhoeven16.

Figure 2 - Schematic showing parts of a blade and polishing abrasive direction. The ride line shows a possible direction of

abrasive particles during the sharpening step, the other direction being downward.

In this experiment the author attempts to control or possibly even avoid many of the parameters

that are considered to affect the edge quality of razor blades and focus on only one variable, the

number of consecutive shaves before switching to a new razor blade. The idea is to qualitatively

educate the shaving community in the mechanical behavior of a typical razor blade as it is used

over time.

Bevel face

Tip

Experimental

For this study, an experienced shaver (experimenter) consistently took a hot shower before each

nightly shave at approximately the same time of evening after the same amount of sleep the night

before. Exfoliation was performed with Clean & Clear Oil Free facial cleanser on a typical wash

cloth with firm pressure. This ensured both consistent whisker growth and a properly soaked

beard. After the hot shower, the experimenter dried off the body without drying off the face to

allow the moisture to continue to soak the beard. Hot water then filled the sink and the badger fur

brush (DOVO Satin Silvertip Shave Brush), along with the glycol based shaving soap and soap

dish, were allowed to soak and come up to temperature. A hot wash cloth at approximately the

same temperature was simultaneously pressed against the experimenter’s face while the brush

and soap were soaking. After approximately 3 minutes of soaking time, the experimenter

produced a rich lather using the brush and soap. Care was taken to produce a consistent viscosity

of lather throughout the experiment, but no rheological measurements were performed to prove

such consistency.

The lather was then applied to the experimenter’s face, first in a “circular” motion to fluff up and

massage all sides of the whiskers with shaving soap, then in a “sweeping” motion to even out the

thickness of the lather19

. Lather time is approximately 90 seconds total. Once fully lathered, the

razor (Merkur "Barber Pole" Hefty Long Handled Classic) and razor blade (Feather Hi-Stainless

Platinum Double Edge) were dipped in the hot water to bring up to a comfortable shaving

temperature. Two complete passes of shaving were carried out, with a quick soak and full lather

of the face in between passes. For each pass, care was taken not to overlap the razor blade with a

previously shaved path that was missing lather. Both passes were swiped in the same direction as

the grain of the beard. Since each razor blade was double edged, either of the two edges were

alternated for each swipe ensuring a consistent wear on each edge.

After the first nightly shave, the razor blade was returned to its original wax paper wrapper and

then stored in a makeshift desiccator made from a Pyrex® container with anhydrous calcium

sulphate to prevent further oxidation, corrosion, or damage to the blade’s edge. Razor blade #2

was used the following night with the same procedures, only this razor was used for 2

consecutive shaves (4 passes, total). Razor blade #3 was used for 3 consecutive shaves, and so

on, until 5 razor blades were used. For all blades that were used for more than one night, the

razor was forcefully tapped dry at the end of each shave. In between each nightly shave, the

Feather razor blades were stored while attached to the Merkur razor as this is common practice in

the shaving community20

. The storage area was well ventilated at approximately 40% relative

humidity. After each blade cycle was completed, the blades were dried with pressurized air

before being placed in the desiccator. For control blades, a brand new razor blade was rinsed

with tap water and left to air dry for 5 days, and another razor was used once for shaving and left

to air dry for 5 days. This allowed us to account for any corrosion that took place throughout the

experiment.

At the end of the shaving stage of the experiment, all of the razors were simultaneously taken out

of the desiccator and prepared for analysis. The razor blades were sectioned so they could be

viewed from an edge-on direction (i.e. the tip of the blade is at a right angle to the line of sight of

the image), a side profile, and a cross sectional view. Gold sputtering was needed for the cross

sectional view. Micrographs were obtained with a JEOL 59101LV scanning electron microscope

(SEM) with energy dispersive x-ray spectroscopy (EDS) capabilities for elemental analysis.

Results and Discussion

SEM micrographs using secondary electron imaging mode can be seen in Figure 3, where the

razor blades were imaged edge-on. Some of the razor blades were unfortunately tilted away from

perpendicular to the beam making it difficult to discern the very tip of the blade, therefore

guidelines were inserted in the picture to clarify where the tips reside. The micrographs clearly

show a pattern of increased wear as the number of consecutive shaves increase. Starting with the

brand new razor blade in figures 1 and 2, a clean tip can be viewed from top to bottom of both

micrographs. This was typical throughout the entire razor blade. Small ridges and imperfections

on each face of the bevel appear to be 1-3 μm in size towards the very tip, but texture from

sharpening can be seen behind that portion. This region towards the tip is due to debris deposit,

or plastic deformation towards the very tip of the razor blade that occurred during the sharpening

process.

Now continuing with the edge of razor blade #1, it can be seen that this supposed bending flow

region is no longer present. Instead, this immediate region appears to have smoothed out, with no

visible deformation to the very tip of the razor where the two faces meet. This was typical

throughout the entire length of this sample’s tip. The blemishes and imperfections that can be

seen on #1 were completely on one face or the other, never overlapping the very edge. These

blemishes are approximately 5 μm in size, and were typically seen in intervals of a few hundred

microns apart. The edge appears quite sharp as there is neither blunting nor deformation that is

visible at this magnification. It appears as if the debris deposit portion of the blade was rubbed

away during the first shave.

With razor blade #2 we start to see significant deterioration of the blade. There are many more

visible blemishes along each face of the bevel. One thing to note is the blemishes tend to be

textured in a direction parallel with the blade edge. That is to say, each of the blemishes tends to

be longer along the vertical axis of the image. This is due to the textured microstructure that was

present in the razor blade due to the rolling process during manufacturing. A thin strip of metal

with the basic internal composition of the final product is made with a cold rolling process,

which turns the equiaxed grains into elongated, textured grains. These textured grains remain

throughout the rest of the processing until the final polishing step. During the shaving process, it

is likely that a whole grain is dislodged from the surrounding microstructure, which would create

imperfections of the same shape we see in our micrographs. The very edge of the razor, where

the two faces of each bevel meet, appears to be somewhat damaged as well. The grinding texture

on either face of the bevel from the sharpening process is much more pronounced in this

micrograph, but this is only due to increasing the contrast in the photo software.

Razor blade #3 has a more deformed tip running along the entire edge of the sample. Dark

blemishes that run along the tip of the razor are becoming visible, occurring at a greater

frequency than the previous two razors. The blemishes also appear to be slightly larger than the

previous razors, on average.

Razor blade #4 shows very long, continuous blemishes running along the entire edge of the

blade. These blemishes were typically 100 microns in length, and about 5 to 10 microns in

perceived width, expanding much further into each face of the bevel.

Razor blade #5 shows more tip deformation than any other razor. Large gouges can be seen at

the edge of the blade. These are further pointed out in Figure 4, with a side profile of razor blade

#5. For convenience, Figure 5 shows the side by side comparison of razor blade #5 with a brand

new razor blade.

Figure 3 - Edge-on view of razor blade tips. Red guidelines that highlight the tip for razors #3 and #5 are in red.

Figure 4 - Side profile view of razor blade #5. Notice the two 20 μm gouges on the edge of the blade, along with the 150 μm

crack running down the bevel face. These types of defects are partially responsible for nicks and cuts.

Figure 5 - Comparison of a brand new blade on the left, to blade #5 on the right. The texture from the polishing abrasives

can be seen clearly on the new razor blade, whereas blade #5 seems to have been smoothed out.

Figures 6 and 7 show cross sectional views of a new razor blade and razor blade #5, respectively.

This shows the increase in razor tip radius as a function of continued use. It can be seen that a

fresh razor blade has a tip radius of approximately 0.25 μm, whereas razor #5 has a tip radius of

approximately 0.5 μm. There is a larger error in the tip radius for razor blade #5 due to the

unknown foreign matter on the vary tip of the blade.

Figure 6 - Cross sectional view of a brand new razor blade. The tip radius was measured to be approximately 0.25 μm.

Figure 7 - Cross sectional view of razor blade #5. The tip radius was measured to be approximately 0.5 μm. Foreign

debris on the tip that was likely introduced in sample preparation makes it difficult to measure.

EDS measurements were performed on the brand new blade, as well as blade #5. Both blades

showed approximately the same amount of Cr which is to be expected, around 14 at%. The only

other alloying metal detected was Mn, at approximately 2 at% in each blade. However, only the

brand new blade showed any traces of Pt. This leads the author to believe that the Pt has been

sputtered onto the razor at the end of processing, only to provide a minimal cover of the blade to

prevent corrosion during the razor blade shelf life, as well as marketing reasons. This thin layer

of Pt would be easily removed during a single shaving pass, as the layer is likely nanometers in

thickness.

The control blades were was also examined with SEM for this experiment. There was no

discernable difference between the control blade that was only rinsed with water, and a brand

new razor blade. The control blade that was used once for shaving, then left out in the normal

environment (as opposed to a desiccator) appeared to be in the same condition as razor blade #1,

indicating that corrosion did not play a significant role in the edge characteristics of a razor blade

with continued use with these stainless steel blades. Micrographs for these control blades, as well

as other micrographs both included and not included in this document, can all be viewed online

in high resolution.

Conclusion

It has been qualitatively shown that the edge characteristics of stainless steel razor blades edges

deteriorate over continued use. This deterioration is a function of the number of shaves, not a

function of corrosion due to humidity. Grains on the faces of either side of the bevel are shown

to pull out with continued use, leaving behind a textured surface that might be responsible for

nicks and cuts. Portions of the very tip are also fractured off as seen from the side profile view

which may also lead to nicks and cuts. The edge tip radius of the razor blade has also been

shown to increase with continued use, which will hinder the ability of the razor blade to shear

through whiskers given the greater surface area. The razor blades were likely sputtered with a

very thin layer of Pt only for protection of the blade during the shelf life, or possibly marketing.

It should be stated that this experiment has a very small sample size of razor blades, and all of

the shaving was performed by one individual. Any inconsistencies with the experimenter would

lead to inaccurate results. More testing shaves would be needed with various razor blades,

performed by various people, in order to get better quantitative results.

Acknowledgments

I would like to thank mantic59 and the Sharpologist.com shaving community for their input

regarding this experiment.

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