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Number of shaves on a blade... over 8...why?

"It's not a question of technique, it's a matter of physics and chemistry."
Sig303, Because you mentioned straight razors earlier I will jump in here. Yes straights do need regular stropping. However the first point is that the metals used to make straights is very different which is why a modern stainless DE blade can't be effectively stropped but old carbon DE blades can.

Second the heat/cold quenching treatment of DE blades is very different compared to Straights.

Third depending on the brand a DE may have a coating, see the quote from a patent:

"The specific disclosure provides for a razor blade comprising at least one cutting edge portion defined by two face portions having a narrow included angle there between. At least a portion of each of the face portions has an RF sputtered coating of a hard metal having a thickness of less than about 600 Angstrom units

Fourth, the bevel edge on straights is a single bevel with usually a slightly con-vexed edge (if the blade is stropped on a soft surface such as pasted leather or balsa). DE blades may have up to 3 bevels. Please note I am not saying that DE blades are sharper because although I have rather primitive honing skills I can get a straight as sharp as a mild DE. More experienced straight users would far exceed my abilities. I am just saying that the final bevel angle on a DE may be exceed that compared to a straight which will lead to longer edge life.

Fith: When I found myself getting an increasing number of good shaves from a single blade I doubted my own objectivity. Therefore I put 2 blades into 2 identical razors, one blade had 2 uses, the other had 12 uses. Without knowing which blade was in each razor I could not tell any difference. Of course blade life depends on the brand of blade. I can't get even one satisfactory shave from a mild blade like a Dorco. With a Derby, maybe one barely tolerable shave followed by another one or two very average shaves. On the other hand, after 3 shaves there's little point throwing away a Polsilver, Gillette Yellow, Astra SP, Nacet etc because these blades will still have many more good shaves left.
 
Fatboyming - You make some interesting points and I don't disagree with you regarding them factually, just their import for the question at hand.

We certainly agree that the steels - whether carbon or stainless - used in straights (or knives for that matter) are very different than the stainless or high chromium steels with sputtered coatings used in most modern DE blades. Of course most DE blades have a PTFE coating as well and this has an impact as well.

As regards the quenching and tempering of blades, while there are no doubt differences, I'd only concede that each is probably optimal for the intended use; the difference in response to stropping - i.e., the realignment of micro serrations on the edge - is no doubt a result of this in conjunction with the differences in the steels/sputtered coatings. The main impact of this is simply that a straight's edge is more susceptible to being revived via stropping versus the modern DE blade edge's degradation being more permanent, though it may hold that edge for longer (though it's not clear how much longer if at all).

The difference between bevel setting 1 or 3 bevels is, at least to my mind, largely irrelevant. The fact that many straight shavers/honers set multiple bevels notwithstanding, the whole point of having multiple bevels is to support the cutting edge with more metal leading to a more durable edge and, given DE blades extreme thinness, they benefit more from that than a comparatively very thick straight blade would.

All that said, a blade edge just simply degrades physically and chemically via oxidation over time and, whereas a straight (or knife) can be refreshed, a modern DE blade (more or less) cannot. Indeed, though I can't seem to find the relevant article, I've seen it argued that micro oxidation of the blade edge might even more deleterious to edge performance than the physical deterioration. Regardless. the latest relevant patent I could find is a Gillette patent regarding a process of washing of extraneous PTFE coatings by the use of solvent leading to quicker "sharpening up" of the blade and slower degradation of the edge circa 1996. The salient part of the patent to our present concern is, I believe, this part:

"The following specific examples illustrate the nature of the present invention. The quality of the first shave obtained with blades of each of the following examples is equal to or better than the quality obtained in any subsequent shave; and the decrease in quality with successive shaves in the case of blades of each particular example is equal to or less than the decrease in quality in the case of conventional fluorocarbon polymer-coated blades manufactured without the present solvent treatment step."

In short, after the initial sharpening up the blade, it's all downhill from there. As to how far downhill someone is willing to go, that might be a YMMV thing, but I'm still confident in my original assertion that shave ten is not as good as shave 1 or 2 (allowing for the aforementioned sharpening up).

As to your last point, while I might disagree that shave 12 is the same as shave 2, we have very similar tastes in blades and I can push all of those blades (plus Israeli Personnas) a lot further than most others.
 
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Fatboyming - You make some interesting points and I don't disagree with you regarding them factually, just their import for the question at hand.

We certainly agree that the steels - whether carbon or stainless - used in straights (or knives for that matter) are very different than the stainless or high chromium steels with sputtered coatings used in most modern DE blades. Of course most DE blades have a PTFE coating as well and this has an impact as well.

As regards the quenching and tempering of blades, while there are no doubt differences, I'd only concede that each is probably optimal for the intended use; the difference in response to stropping - i.e., the realignment of micro serrations on the edge - is no doubt a result of this in conjunction with the differences in the steels/sputtered coatings. The main impact of this is simply that a straight's edge is more susceptible to being revived via stropping versus the modern DE blade edge's degradation being more permanent, though it may hold that edge for longer (though it's not clear how much longer if at all).

The difference between bevel setting 1 or 3 bevels is, at least to my mind, largely irrelevant. The fact that many straight shavers/honers set multiple bevels notwithstanding, the whole point of having multiple bevels is to support the cutting edge with more metal leading to a more durable edge and, given DE blades extreme thinness, they benefit more from that than a comparatively very thick straight blade would.

All that said, a blade edge just simply degrades physically and chemically via oxidation over time and, whereas a straight (or knife) can be refreshed, a modern DE blade (more or less) cannot. Indeed, though I can't seem to find the relevant article, I've seen it argued that micro oxidation of the blade edge might even more deleterious to edge performance than the physical deterioration. Regardless. the latest relevant patent I could find is a Gillette patent regarding a process of washing of extraneous PTFE coatings by the use of solvent leading to quicker "sharpening up" of the blade and slower degradation of the edge circa 1996. The salient part of the patent to our present concern is, I believe, this part:

"The following specific examples illustrate the nature of the present invention. The quality of the first shave obtained with blades of each of the following examples is equal to or better than the quality obtained in any subsequent shave; and the decrease in quality with successive shaves in the case of blades of each particular example is equal to or less than the decrease in quality in the case of conventional fluorocarbon polymer-coated blades manufactured without the present solvent treatment step."

In short, after the initial sharpening up the blade, it's all downhill from there. As to how far downhill someone is willing to go, that might be a YMMV thing, but I'm still confident in my original assertion that shave ten is not as good as shave 1 or 2 (allowing for the aforementioned sharpening up).

As to your last point, while I might disagree that shave 12 is the same as shave 2, we have very similar tastes in blades and I can push all of those blades (plus Israeli Personnas) a lot further than most others.

You referenced an initial patent application from 1964. I suspect technology has advanced a bit since then.
 
Fatboyming - You make some interesting points and I don't disagree with you regarding them factually, just their import for the question at hand.

We certainly agree that the steels - whether carbon or stainless - used in straights (or knives for that matter) are very different than the stainless or high chromium steels with sputtered coatings used in most modern DE blades. Of course most DE blades have a PTFE coating as well and this has an impact as well.

As regards the quenching and tempering of blades, while there are no doubt differences, I'd only concede that each is probably optimal for the intended use; the difference in response to stropping - i.e., the realignment of micro serrations on the edge - is no doubt a result of this in conjunction with the differences in the steels/sputtered coatings. The main impact of this is simply that a straight's edge is more susceptible to being revived via stropping versus the modern DE blade edge's degradation being more permanent, though it may hold that edge for longer (though it's not clear how much longer if at all).

The difference between bevel setting 1 or 3 bevels is, at least to my mind, largely irrelevant. The fact that many straight shavers/honers set multiple bevels notwithstanding, the whole point of having multiple bevels is to support the cutting edge with more metal leading to a more durable edge and, given DE blades extreme thinness, they benefit more from that than a comparatively very thick straight blade would.

All that said, a blade edge just simply degrades physically and chemically via oxidation over time and, whereas a straight (or knife) can be refreshed, a modern DE blade (more or less) cannot. Indeed, though I can't seem to find the relevant article, I've seen it argued that micro oxidation of the blade edge might even more deleterious to edge performance than the physical deterioration. Regardless. the latest relevant patent I could find is a Gillette patent regarding a process of washing of extraneous PTFE coatings by the use of solvent leading to quicker "sharpening up" of the blade and slower degradation of the edge circa 1996. The salient part of the patent to our present concern is, I believe, this part:

"The following specific examples illustrate the nature of the present invention. The quality of the first shave obtained with blades of each of the following examples is equal to or better than the quality obtained in any subsequent shave; and the decrease in quality with successive shaves in the case of blades of each particular example is equal to or less than the decrease in quality in the case of conventional fluorocarbon polymer-coated blades manufactured without the present solvent treatment step."

In short, after the initial sharpening up the blade, it's all downhill from there. As to how far downhill someone is willing to go, that might be a YMMV thing, but I'm still confident in my original assertion that shave ten is not as good as shave 1 or 2 (allowing for the aforementioned sharpening up).

As to your last point, while I might disagree that shave 12 is the same as shave 2, we have very similar tastes in blades and I can push all of those blades (plus Israeli Personnas) a lot further than most others.
Regret to intrude on your little science debate, but...
Gillette (and others) test their blades replicating what they determine to be the most common or average use patterns. To wit:
You shave with a blade using shaving cream, you rinse the blade off, you leave the razor and blade to dry. You repeat it all to-morrow.
Many of our ilk deviate from such norms. We rinse the blade off with scalding hot or ice-cold water, depending on our belief systems. Some take the blade out. Some wipe it off (though many think that this action is counter-productive). Some pat it dry. It's reported that some even dry their blade off immediately with a hair dryer, to stop oxidation before it starts. Some rest their blade for a day or more. Consequently, many of us report significantly longer blade life than average, or expected.
I too, have read that oxidation, in the form of corrosion or rust, is a significant, possibly even primary cause of blade deterioration, i.e. greater than the wear occasioned from cutting hair. If this process can be slowed, or arrested, blade life will inevitably be lengthened. Some blade coatings or treatments (as noted by you above) are designed to inhibit oxidation despite the expected neglect of the average user. In the hands of one of us, these blades can last much longer than intended.
I, for one, find it hard to believe that any of us so-called wet-shaving "enthusiasts" would willingly suffer the discomfort of a dull blade, so I tend to believe our members' reports of "number" of good shaves from a blade.
In the late 60's Schick ran a TV ad touting that one blade shaved 17 barbers with no noticeable deterioration, even showing a magnified comparison of the used edge with a new one. Of course, the barbers were shaved one after the other, so the blade had no time to sit and oxidise. It serves to show how many shaves a blade can perform with no noticeable loss of sharpness, when oxidation is taken out of the equation.
Straight razor users are advised to strop their blades after shaving, not merely to re-set the edge for the next time, but to remove any residual moisture from the blade edge so as to prevent oxidation from forming.
Modern disposable blades are not amenable to stropping not only because they are too thin to benefit from it, but due to the alloys they are composed of and the coatings applied to them.
This was not always the case. Before the introduction of the modern thin blade, disposable blades were significantly thicker and there were systems on the market for stropping them and thereby extending their life.
Some blades, like those of the Valet Auto-strop, were an interesting sort. They were thick enough to strop (and meant to be), but too thin to hone, so one would use the blade only as long as the edge could be maintained by stropping. After that, it would be replaced with a new one. So Valet sold replacement blades to its users, but at a much, much slower rate than the Gillette system.
I'm not disputing your general premise that disposable blades suffer an inexorable decline through use, just that the rate of decline can vary drastically, depending on the blade (its alloy, coating and manufacturing process), and the user's maintenance habits.
In other words, to use your example, while it might be true that shave 12 could not possibly be exactly the same as shave 2, the difference could be "imperceptible" to some, under the right conditions and maintenance protocols.
 
To answer the original question with another question, why toss a blade that is still providing acceptable shaves? They don't get dull that fast. It could be three shaves, it could be ten, it depends on the brand and the individual blade, but I'll toss it when it's time, not before.
 
I'm not going to make many friends with this comment so let me set the stage, I'll be short. I used to rent a big house with a good friend who was also a barber and half owner of a shop. He persuaded me to let him give me a straight shave, something that makes me very nervous. First he asked me about my beard. I told him heavy and coarse. I let him shave me twice then I asked for his honest opinion. He told me I have just an average beard . He shaved a lot of wealthy men at his shop, most everyday. They all described their beards as heavy, he never contradicted them, but he told me they're all average. I hope I made my point because I can't hunt and peck anymore.
Average is called average for a reason.
 
A couple salient points here:

First, most of the coatings on modern blades are to reduce friction of the hair as it's cut, resulting in more comfortable shaves. This is entirely separate from the issue of edge sharpness or cutting ability -- bare stainless blades drag much, much more than coated ones. Coatings in this category include PTFE, chromiun, platinum, and the various ceramics used. Anti-friction is the point.

Second, the stainless steel used in modern blades isn't going to show even micro-corrosion over any reasonable time frame unless it's left covered with something corrosive. Hard soap scum holding the edge above the skin is probably more responsible for "edge degradation" than any corrosion. This is NOT true for carbon steel, it will degrade very rapidly in contact with soap (hence the suggestions to remove from the razor and pat dry between uses). Chrome, platinum, and diamond like carbon coating will reduce corrosion so long as they are present, but their main purpose is friction reduction.

Third, diamond like carbon coatings DO greatly extend life for the simple reason that they are both friction reducing AND very, very hard, hence resisting actual wear. This coating may or may not be advertized (Blue Diamond blades from SuperMax, but who knows what Gillette puts on theirs).

Fourth, the original Gillette three hole blade was 0.006" according to the patent. I have quite a few three hole blades I got with an old Bakelite slant, some probably dating from before WWII, and most of them are 0.004". While that is a big difference in percentage, in actual use I doubt anyone could tell the difference other than that the 0.006" blades sometimes feel stiffer, although not always.

Fifth, all DE blades are polished with diamond dust on automated machinery, and have been since 1920 when Gillette developed the equipment. With modern automated equipment with computer controls, I'd expect DE blades to all have very fine, clean edges unless there is a QC failure, and they will indeed be both sharper and "slicker" than any hand honed straight. That is not to say the straight with a "duller" or less perfect edge won't shave better, but my experience over my graduate school career was that off the shelf utility knives were far sharper than any microtome blades I sharpened, and I spent a huge amount of time on it using equipment designed for the task. I have not tried "The Method" using diamond paste on balsa yet, but that may get close if done carefully. Better shaves from a straight razor have a lot to do with the dynamics of a thin vs thick blade and vibration damping rather than edge acuity I think.

Sixth, sensation of sharpness and actual edge condition are not linearly related. A very fine edge without coatings will be much more "uncomfortable" for most people that a mediocre edge coated with PTFE because the bare steel pulls the hairs a lot more. If you ignore that sensation (and the "I need both hands to shave with this Derby"), the actual shave will be the same. I'm finding that with the Derby Premium I'm using -- definitely feels "like a Derby" -- but I'm getting close, long lasting shaves. Just feels different than a fresh GSB. This is a common misconception, and I think many people discard blades as soon as the initial PTFE coating wears off. I'm too frugal to do that, but if you wish, there is nothing wrong with it. A dip on PTFE solution would "restore" the blade though...

Seventh, DE blades are very brittle because they are quite hard. Poor angle control and heavy beard can result in actual edge fractures and an actual dull blade. You can see this by reflecting light off the edge itself, just like knives. An intact, fully formed edge is so fine it will not reflect, but dents and chips show up as bright spots along the edge. A razor blade isn't going to dent, so bright spots are chips. If you routinely chip blades, I'd suggest adjusting your technique until you don't chip the edges, you will get far better blade life and much comfortable shaves, the latter being much more important I think.
 
One time I got 3 full comfortable shaves from a blade. I'll never forget that day. I'll forever cherish it in my heart.
 
To answer the original question with another question, why toss a blade that is still providing acceptable shaves? They don't get dull that fast. It could be three shaves, it could be ten, it depends on the brand and the individual blade, but I'll toss it when it's time, not before.
+1
 
A couple salient points here:
...the original Gillette three hole blade was 0.006" according to the patent. I have quite a few three hole blades I got with an old Bakelite slant, some probably dating from before WWII, and most of them are 0.004". While that is a big difference in percentage, in actual use I doubt anyone could tell the difference other than that the 0.006" blades sometimes feel stiffer, although not always...
Great write-up. Excellent information.
I would only add that in my experience, I can always tell the difference between the old, thicker Gillette 3-hole blades and the thinner styles that succeeded them. Also, I believe Gillette abandoned the 3-hole style in 1929 and thereafter made blades that contained a slot (later an elongated slot), and diamond cut-outs to accommodate other brands' razors. Thus, if the blades with your bakelite razor are Gillette, they must be from 1929 or earlier, according to my information.
 
Seems a little hypocritical to spend $80 - $100 on a razor (which works out to 4000 shaves or 11 years of shaving blades) . Reading all the responses I still don't get, even using a blade more than 3 times ...[when the same people will buy after shave for $24 that might last 4 to 6 weeks!}

This thread sparked what turned into a "blade-tossing" meditation:

I don't think I've ever spent more than $25 on a razor or brush, or more than $5 on aftershave or soap. If I ever do, it probably won't be in this life. I got into DE shaving because the cost of cartridges was becoming obscene. Since then I've come to enjoy shaving much more than I had enjoyed it previously. But frugality, if you must call it that, remains a big part of the equation for me, and clearly for many others as well.

For me, it's really just practical. I don't consider myself cheap at all. I do pay a bit more for premium blades that give me the best shaving experience and that demonstrate longevity, all of which translates into value. I keep using them -- duh! -- as long as they shave well. (E.g. Polsilvers and Bolzanos bought in bulk cost me around $.16 - $.18 per blade and easily go 7 or 8 shaves and often longer. Tossing them after 3 or 4 shaves is exactly like throwing away nickels and dimes, or like drinking half a beer, dumping the rest, and popping a new one. I really don't understand why anyone would do this. It seems perverse.)

I suppose for some folks, ethos comes into it. Lots of younger people especially are into simplifying, and a no-waste lifestyle is part of it. (Same could be said for old-timers who remember the Depression.) For many, there's a religious dimension -- the less you spend, the more you can give.

My Dad, who raised 6 kids on a teacher's salary, taught me the value of a buck, mostly by example. For decades, he used one Super Speed that he probably bought in his 20's, one brush that he used to lather his preferred Palmolive, and no doubt stretched blades as far as they would comfortably go. While he was probably motivated by practicality, ethos, religion, culture, and who knows what other influences, I doubt he ever thought of it in those terms. In fact, he almost certainly never thought about any of this at all.

I'm also fairly certain that if he ever saw my own very modest shave den, he'd think: "What the ___ do you need all that stuff for?!"
 
Where did you find usable original three hole blades for an Old? Just curious, since they have not been manufactured since the 1930s that I know of (all the slotted blades fit the three hole razors).

None of the blades were Gillette, they were all various German or English blades (Tennis blades, anyone?). The German ones were marked for thickness in mm. I'm guessing they are all pre-WWII but I don't know that. If they are, they are probably pre-1939. Three hole blades were produced for quite a while after Gillette quit making them, especially in Europe I think, and in fact are still made for non-shaving uses. There are even some in 0.006" thickness, but since they are sold for film slitting, I'd not expect them to shave very well.
 
Where did you find usable original three hole blades for an Old? Just curious, since they have not been manufactured since the 1930s that I know of (all the slotted blades fit the three hole razors).

None of the blades were Gillette, they were all various German or English blades (Tennis blades, anyone?). The German ones were marked for thickness in mm. I'm guessing they are all pre-WWII but I don't know that. If they are, they are probably pre-1939. Three hole blades were produced for quite a while after Gillette quit making them, especially in Europe I think, and in fact are still made for non-shaving uses. There are even some in 0.006" thickness, but since they are sold for film slitting, I'd not expect them to shave very well.
Gillette introduced the 3-hole disposable blade around 1904 and maintained that same configuration until around 1929, when they modified it as to the hole (cut-out) pattern and introduced the "tabbed" ends for secure gripping. Shortly after King Gillette's death, they introduced the "Blue Blade," which added a coating to prevent oxidation. Up until that time, shavers were advised (by Gillette) to remove and rinse off the blade, and dry it to prevent rust from forming.
Thus, the only Gillette blades with the 3-hole punch were those manufactured during or before 1929. Other manufacturers may have maintained the 3-hole punch longer, but not Gillette, that I know of.
New-old-stock 3-hole Gillette "Old Style" blades can still be found (though not commonly), on the secondary market. I have some but I have never shaved with them. I should be interested in hearing from those that have as to the quality of the blade.
Until I joined this forum I used to think that old unused blades were degraded, their edges dulled from oxidation and age, and that there was no such thing as a usable or good vintage blade.
Boy, was I wrong!
I now routinely use blades from the 1960's and newer that equal and sometimes surpass brand-new blades. I have no reason to think that unused Gillette Old-style blades would be any different.
 
Stainless blades of any age are probably fine unless exposed to something corrosive -- you may need to remove oxidized oil from them to get them out of the dispenser, but the edges should be fine.

Carbon steel blades I'd be careful with, even with coatings they are very prone to rusting, and it doesn't take much rust on the edge to make them very difficult to shave with.
 
Part of the blade usage, I think, comes from just plain old Yankee thrift: use it til it's used up, then change to the next one.

On average, Russian made Gillette blades that I've used (Astra SP, Polsilver, GSB) shave very well for me for three four-pass-plus-touchups shaves, then degrade very sharply (no pun intended) after that. I get similar mileage, maybe two shaves though, from Rapira and Voskhod. Treet carbons, whether Black Beauty or Falcon, I might get one or two out of. Kai, plain unadorned, uncoated Kai, however, I can easily get 10 shaves from without the least amount of discomfort. I've pushed it to 12, but that's really pushing it - weepers start and I can feel the drag. I could change earlier, yes, but it's a good blade with mileage left, so why would I?

I work with teakettle scalding hot water in a bowl, for brushing into my Cella or MWF soap, or lathering cream directly on my face; I keep that water and use it to wet the razor head before each major stroke. Afterward, I take the razor apart and clean the inside of the baseplate under hot water (with an old toothbrush if it's open comb), and I similarly clean that side of the blade, removing built up soap or cream with my finger very gingerly from the center out to the edge. I don't dry the blade (unless it's carbon), but I do dry the assembled head.
 
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