How can the service life of disposable razor blades be increased?
Would soaking them in food oil work (to reduce "oxidation in air")
or do those magnetic razor blade things you set your razor onto
actually work?

alias, 

Thanks for an enjoyable question.

A razor blade becomes dull because its sharp cutting edge is
physically worn off. In ordinary shaving, there are two main causes of
dulling:

1. Abrasion of the blade against whiskers or hair. Like an axe on a
tree, these repetitive (tiny) impacts gradually round over the acutely
sharp angle on the blade's leading edge.

2. The blade's steel cutting edge also wears off due to oxidation
(rusting), caused whenever the blade is soaked in water. Small
particles of steel rust and fall off the blade.

These two things occur every time you shave. Over several days, enough
steel is worn off until the blade's cutting edge is blunted and
jagged. The blade can no longer cleanly slice through whiskers or
hair, and tears them off instead. The same thing occurs when you
whittle wood: a sharp knife slices through wood fibers cleanly, but a
dull knife tears them.

You could extend the useful life of a razor blade by protecting the
steel from abrasion and/or rust. To reduce wear and tear on the
cutting edge:

1. If the other people in your life don't mind, shave less (or not
all).

Guys: beards are warmer in winter and always highly intellectual in
appearance. Girls: Well, I won't even go there.

2. Make your whiskers/hair softer and easier to cut by soaking them
thoroughly in warm water before you shave. Use soap or lotion to
lubricate your skin and help carry away bits of cut whisker.

To reduce rusting of the razor blade:

1. If you don't mind, shave without using any water. This is easier on
the environment and will wake you up faster.

2. When you're finished shaving, rinse the blade off thoroughly and
tap it several times against the inside the sink. This will knock off
any excess water sticking to the steel.

3. If you're really determined and have the time, dry the blade off
completely with a hair dryer. Given the cheapness of disposable razor
blades, this is a waste of electricity and time. Make coffee or
pancakes instead.

Immersing a razor blade (providing it's completely dry) in vegetable
oil might keep water from getting to the blade and rusting it.
However, to avoid leaving one's nose on the bathroom floor, you should
clean off that slippery razor with soap and water before shaving.
Doing this merely exposes the razor to yet another water-bath,
re-establishing the chance of rust.

The only ways to restore a dull razor blade to sharpness are as
follows:

1. Sharpen a new edge on the dull razor blade. Grind or file steel off
both sides of the dulled edge until you have a new cutting angle.
Unless you have a file-wielding nano-bot to do this for you, it's
going to be very difficult and time consuming.

Plus, you may reduce the height of the blade too far below the razors'
plastic housing, causing the blade to not shave whiskers or hair at
all.

2. Replace some of the missing steel, then resharpen the edge.
Assuming that you could find a cheap, workable method of adding minute
amounts of steel and sharpening them, this method could maintain the
blade's proper cutting height.

However, you now have a new career with lots of specialized sharpening
tools to buy. While you might gain some unique expertise, you're
losing time and money.

Magnetic or mystical razor blade holders may claim to keep razor
blades sharp, but they simply *don't*. These hands-free "methods"
cannot physically regrind a new edge on the old steel, nor can they
add any new steel to the worn edge. Steel molecules do not magically
appear out of thin air and attach themselves to the blade's cutting
edge.

If these magical methods really worked, we would see them used by
craftsmen who make a living by sharpening things. What a great time
saver! Yet these craftsmen continue to sharpen things in the
time-honored physical way.

For a clean, smooth shave, the fastest, cheapest, and most effective
way to maintain the sharpness of disposable razor blades is to throw
them out and buy new ones.

Hirsutely yours,
huntsman


References -

Did you know that "Men spend an average of 5 months of their lives
shaving"? No wonder my arm is tired:

Shaving Statistics and Facts
http://www.quikshave.com/statfact.htm


Gentlemen! Amaze your friends:

How to Shave Your Head
http://www.headshaver.org/shave_your_head.html

"Shave hair that is softer or lighter first. Shave areas that have
coarser or stiffer hair last (like the back of the head). This gives
the shaving cream more time to soften coarse hair and provides a much
more comfortable shave. "


A discreet reference for the Ladies:
http://hometown.aol.com/bobbiedoll26/shave.html


The basics of sharpening tools:

Archived E-mail Posts
Subject: Tool Sharpening Tips and Techniques
http://carverscompanion.com/Ezine/HelpFiles/SharpeningMessages.html


This custom razor blade manufacturer uses computer-controlled
sharpening tools:

Specialty Blades, Inc.
SBI CNC Sharpening Technology
http://www.specialtyblades.com/technical_info/cnc_technology.html


The art and craftsmanship of the finest blades in the world (sample
pages available):

Samurai Sword: A Handbook
by John M. Yumoto
Charles E Tuttle Co, June 1958
ISBN #: 0804805091
http://www.amazon.com/exec/obidos/tg/stores/detail/-/books/0804805091/slide-show/lib_dp_sp_1/103-7968089-7571826#reader-link


Mystical forces do not sharpen razor blades:

Australian Skeptics
Pyramids, Pyramyths & Pyramidiots
http://www.skeptics.com.au/journal/paramyth.htm

"in the late 1950s, a Czech named Drbal claimed that a razor blade
placed under a cardboard pyramid retained its edge for longer than
would normally be expected."

"... to sharpen razor blades requires the ability to add molecules
..."


Search Terms and Google URLs -

- "how to shave"
://www.google.com/search?sourceid=navclient&querytime=IV-FE&q=%22how+to+shave%22

- resharpen razor blades
://www.google.com/search?num=100&hl=en&lr=&safe=off&q=resharpen+razor+blades

- dull razor blade
://www.google.com/search?num=100&hl=en&lr=&safe=off&q=dull+razor+blade&btnG=Google+Search

Thank you for the enjoyable answer. Quite a bit more extensive than I
anticipated; I'm satisfied.

I have an answer for you. Cryogenics! We have a patented process that
we use to treat metals of different types for different reasons. We
will occasionally throw in a couple packs of our disposable razors
because the blades will last longer and they are not as uncompfortable
on the skin as they get dull. the proces does not bother the plastic
handles or packaging. Our process works well on surgical equipment and
knives, it helps the blades edge last longer. You can read about our
process at http://www.coldfire.com , hope this helps!

Further to point (2) above:

Softening your whiskers before shaving not only extends the life of
your blades, it also makes shaving easier and more enjoyable.  I have
a sensitivity to many commercial scents, and so avoided the use of
aftershave.  To reduce the irritation to my skin, I washed my face
first with hot water and soap, then rinsed. THEN I would lather up and
shave, usually one section at a time (in order to prevent the lather
drying up as I worked).  It's the same principle as shampooing twice,
it leaves the hairs softer.

Eventually, however, I tired of this and went with solution (1) (grew
a beard).

chromedome,

[treading softly]

Er, Ah, about your choice of nicknames...?

huntsman ;-)

huntsman-ga's answer is another example of seduction by authoritative
smirking-superior tone, that the less observant believe is good humor.
Note that he provides no facts to support his claim that a magnetic
field has no effect on a blades shaving effectiveness, but merely
calls it "mystical." Yet at the same time, he tries to come off as so
scientifically grounded! Always read between the lines on the
internet, as the quality of information is remarkably horrible but
always put across with great confidence.

A magnetic field adds no metal and grinds away no metal, of course,
just as a leather stropping strap neither adds nor subtracts from a
straight edge. But barbers before the safety razor were not doing
voodoo between sessions with the whetstone that would put a whole new
edge on a razor by subtracting and shaping metal. Long before a blade
needs a new edge, it develops micro distortions which, if eliminated,
would render the blade useful again. Since a safety razor can't be
stropped, the idea is that a long time spent under the power of a
magnetic field would gradually straighten out the kind of distortions
of the edge that result from a change of shape, not a loss of metal.
It's a sound idea, easily verified with a strong magnifying glass or
microscope, but that kind of high tech thinking is beyond huntsman's
patronizing answer.

I have used one of those Razor Mates with Gillette Mach 3 Turbo
cartridges, and I disposed of each cartridge after five weeks of
perfectly good shaving. That's right: 35 close, irritation-free shaves
per cartridge (with shaving oil), and they still have more left in
them. I recently switched to single-blade disposables because I'm
really cheap, and have 13 shaves under my belt so far on the first
one.

No malice, patronization, or seduction of the innocent was intended.
Google Answers users can think for themselves, and tools like Google
give all of us an equal opportunity to check the facts.

A few smirks about shaving were thrown in, but only to entertain the
reader. Certainly no personal jabs or superior attitudes were meant or
implied.

That said, it is undeniable that non-shavers are smarter and more
attractive. We, the willingly hirsute, also have more time to make
coffee and pancakes, and to let our tongues rest in our cheeks. My
answer was clearly non-scientific, but the satisfaction of the Google
Answers patron who posed the question was clear enough.

It is also undeniable that the combined effects of shaving will
physically degrade the cutting edge of a razor, making it duller.
Sooner or later, water and abrasion will take their toll. Here's a
study from the Derma-Safe Company, a manufacturer of disposable
surgical razors:

Prep Shaving Analysis
Warren J. Grosjean, President
http://www.derma-safe.com/Prep-shaving-analysis.htm

"The edge of a new razor blade is of a radius of 3 millionths of an
inch. As this apex is destroyed the ability of the blade edge to
penetrate a hair is diminished and the force required for penetration
is increased."

"Under poor shaving practice conditions, the relationship of skin cut
to hair cut is magnified with increased destructive effects on the
blade edge."

"Dry hair has the tensile strength of copper wire. Thoroughly wetted
hair has the tensile strength of wet spaghetti. Cutting inadequately
wetted hair and the resultant cutting of added meat, more rapidly
tears off the edge of a razor blade leaving the blade "dull".  A dull
razor blade penetrates the hair less and less easily cutting more into
the skin and becoming increasingly dull until it will not cut hair and
the patient is a bloody mess."

"When [blade] stroking is against the lay of the hair, the hair is
initially lifted up by the blade and tipped against the skin. This has
the effect of raising the skin behind the hair; when the hair is
penetrated this mound of skin is sheared off - causing increased
damage to the epidermis and dulling the blade."

The study goes on to explain the increased chances of skin infections
from improper pre-surgery shaving. This is probably something to
consider whenever reusing a razor too often.

Blade edges are also degraded by water oxidation. Contrary to popular
belief, stainless steel will rust, as this manufacturer of veterinary
equipment explains:

Suburban Surgical Company, Inc.
Caring for Stainless Steel
http://www.suburbansurgical.com/caringss.html

"Stainless steel is steel that stains less. Stainless steel is defined
as steel alloyed with chromium that is highly resistant to stain, rust
and corrosion. Note to the buyer: THIS DOES NOT MEAN STAINLESS STEEL
WILL NEVER RUST OR CORRODE because current technology has not
developed any steel which is completely stain or corrosion proof."

This is confirmed by a manufacturer of stainless steel stripping used
for razor blades. Their product has "good corrosion resistance" and
"corrosion-preventive oil is applied to the strip before packing", as
noted here:

Sandvik Materials Technology
SANDVIK 13C26 - Stainless strip steel for razor blades
http://www.smt.sandvik.com/sandvik/0140/Internet/se01596.nsf/GenerateFrameset1?readForm&url=http://www.smt.sandvik.com/sandvik/0140/Internet/se01596.nsf/0/737989e5701c57c441256713003a4c44?OpenDocument

Anti-corrosion enhancements would not be necessary if stainless steel
was completely rust-free, but it appears that the more you can add,
the better. Here's a microphotograph of a razor's edge:

http://www.microphotonics.com/images/razor.jpg

It's surprising how rough (and relatively blunt) the edge actually is.
There are obviously many crevices where oxidation could take hold.

In a Wall Street Journal article on the Razor Mate web site, John
Darman, VP of Gillette, emphasizes that corrosion (not blade
distortion) is the primary cause of blade wear:

The Wall Street Journal
To Make Gillette Bristle, Ask About The Razor?s Edge
http://www.razormate.net/In_the_News/Wall_Street_Journal/wall_street_journal.html 

"Gillette's Mr. Darman dismisses this [blade distortion] as fantasy.
The No. 1 reason for blade fatigue, he says, is corrosion, not
bending"

The cutting edge of a brand new razor blade is not a straight line.
The following photographs show how wavy, jagged, and pitted it
actually is:

http://www.csuhayward.edu/sci/sem/whatisit/razor.html
http://epswww.unm.edu/probelab/november.htm

Regular shaving will gradually remove more metal from this edge, and
magnetic devices like Razor Mate cannot make the edge straighter or
sharper by replacing missing metal. It's small magnets are not nearly
powerful enough to pull additional metal out of the body of the blade
and fill in defects on the cutting edge.

Razor Mate's web site <http://www.razormate.net> has many personal
claims and testimonials, but has no physical proof, photographic or
otherwise, of blade straightening. The burden is not upon me to prove
that Razor Mate doesn't work, but for Razor Mate to prove to the
buying public that their "science" works as claimed. A simple set of
before-and-after closeup photographs (showing a magnetically-improved
edge) would help settle things.

Daily use of shaving oil probably extends the perceived usefulness of
disposable razors far more than magnetic sharpening. As chromedome-ga
mentioned, lubricating your skin is a good idea: it softens up your
whiskers for easier shaving and reduces razor burn.

I'll bet my beard that the benefits of magnetic sharpening lie mainly
in the perception of the user, and James Randi (famous debunker and
professional skeptic) would probably bet his chinny-chin also. Here's
his opinion about a similar razor "sharpener":

James Randi Educational Foundation
Commentary - June 8, 2001
http://www.randi.org/jr/06-08-01.html

"Richard J. Milbourn sends us this excerpt from a Sharper Image
catalog, describing a fraud they're currently selling that they say
sharpens razor blades overnight by simply placing the blades on the
small box:

Inside the holder are three linearly sequenced, neodymium rare earth
magnets, each of an unusually powerful 12,000 gauss rating. They are
positioned to envelop the blades in an intense magnetic field aligned
with the linear construction of the blades. The process, called
magnetostriction, aligns the edges by the power of the magnetic field
along the longitudinal axis. Such strong magnetic action is believed
to extend the life of blades . . .

And people will buy it, they'll believe it works, and they'll be
looking for the next farce they can adopt. "Sharper Image"? Their
marketing deception is sharp, I'll agree. But their customers and the
customers' razor blades aren't very sharp...."

Of course, your mileage may vary.

huntsman