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On the Measurement of Croap Durometer: A New Methodology

AimlessWanderer

Contributor
Let's not overthink this.

Throw it at a wall. Does it stick? Croap.
My mind was heading in a similar direction

Firstly though...

What "hardness" are you trying to identify? Deformation under load, or brush loading speed... which are not necessarily directly proportional.

If deformation under load, draw four incrementally sized concentric circles of a known size on a wall, much like an archery target. Firing a measured amount of soap, gouged out by a melon baller for example, into the centre of that target from a known distance with a catapult, will result in a different sized splat according to the hardness of the product.

The hardness of any product splat staying withint the innermost circle would be 5, and any that splats right out to the outer circle would be a 2. Cream like products with a hardness of 1 would fail to travel to the wall, as it would not have the structural integrity to withstand the initial accelleration, and the splat would be on the tester themselves.

The beauty of this test is that it's quite cheap, and needs just a simple clean down after the test. That clean down can be avoided altogether, by drawing the circles on a neighbours wall.

Brush loading is more complex, as that's a cumulative effect of both wear resistance and self-lubricating properties. This is muddied further by variations in brush choice, brush variations themselves, and water chemistry blurring the data on the self-lubricating properties. Wear resistance is therefore the easiest to measure, and can be achieved with a loudness meter and a stopwatch, both of which can be found as smartphone applications. A cheese grater would also be required.

Wear resistance of the product sample, again using the melon baller as a dosing tool, can then be graded according to how long it takes to injure yourself by trying to grate that sample, and the volume of profanities emitted.

For soft creams that should be nigh on instantaneous, and loud enough to worry the neighbours... assuming this test is done instead of firing soap at their house... in which case they'll be cheering instead. At the other end of the scale, Mitchell's will take an eternity to grate, and the grater will be blunt by the time skin makes contact.
 
Two words. Water content. If that isn’t the determining factor, I’ll be shocked. And if it is, than can you weigh it, cook the water off, and then weigh it again? The ratio of water let’s us know where it is between ages triple mill like MdC and a cream?

Seems like cooking it off and weighing it can be achieved with household goods, probably a digital kitchen scale and a double boiler rig?


Sent from my iPhone using Tapatalk
 
Two words. Water content. If that isn’t the determining factor, I’ll be shocked. And if it is, than can you weigh it, cook the water off, and then weigh it again? The ratio of water let’s us know where it is between ages triple mill like MdC and a cream?

Seems like cooking it off and weighing it can be achieved with household goods, probably a digital kitchen scale and a double boiler rig?


Sent from my iPhone using Tapatalk
I belive you are right and water content is a decisive factor. Although, it will cost more than 1$ to test this. And more importantly...the process will irreparably damage the observed soap. I think this is not a desired outcome of a test
 

BigJ

Ambassador
To meet the annual continuing education requirements of my BOSC membership, it is necessary for me to either:

1. Advance the science of shaving in some extraordinary or dubious way
2. Provide evidence of unrepentant indulgence in one or more acquisition disorders.

Unfortunately, my spouse has recently discovered the 10'x10' storage unit I've been renting for my shaving necessities, so the latter is not an option at present. Therefore, it must be science.

One problem that I think worthy of study is the firmness of various cremes, croaps, and soaps. Some cremes are firmer than croaps, and some croaps are harder than soaps. Mitchells Wool Fat soap is the only known material harder than diamond. It's gets downright confusing. This would not be an issue if no one cared, but studies show that 0.03% of shavers have a strong preference for a specific degree of firmness in their soaps. Shamefully, manufacturers offer little to no information on this key parameter. It would be helpful therefore to have an easy, repeatable way to measure the firmness of soaps, such that any hobbyist soap hoarder can measure the firmness of soap/croap for the purposes of posting more edifying reviews to this message board.

It's a vexing problem, but fortunately we may stand on the shoulders of giants; the rubber and plastics industry has devised such a tool, which is called a durometer. I have used these devices myself, and find them indispensable. It is a simple tool, that consists of a "needle" affixed to a spring. The tool is pressed down on the material to be measured, and the shore durometer is displayed on a dial indicator. The OOO Scale Durometer would be perfect for this purpose, but sadly many wet shavers do not have this tool in their shaving den.



Thus a new methodology must be devised. I believe that this new methodology should have the following characteristics:
  1. Measurement should be on an interval scale (not ordinal or nominal)
  2. It must use only household materials costing in total no more than $1.00
  3. It should be possible to make the measurement apparatus in less than 5 minutes
  4. Individual measurement should take no more than 10 seconds
  5. Accuracy must be +/- 13.7%
Sadly, I have no such methodology, nor do I have any good ideas on how it might possibly be done. Please help.
FABULOUS POST!!

This concept meets goal #1. ’...advancing the science of shaving in some ...dubious way!’

I say you qualify for another year!! :punk: :punk: :punk: :punk:
 

BigJ

Ambassador
My mind was heading in a similar direction

Firstly though...

What "hardness" are you trying to identify? Deformation under load, or brush loading speed... which are not necessarily directly proportional.

If deformation under load, draw four incrementally sized concentric circles of a known size on a wall, much like an archery target. Firing a measured amount of soap, gouged out by a melon baller for example, into the centre of that target from a known distance with a catapult, will result in a different sized splat according to the hardness of the product.

The hardness of any product splat staying withint the innermost circle would be 5, and any that splats right out to the outer circle would be a 2. Cream like products with a hardness of 1 would fail to travel to the wall, as it would not have the structural integrity to withstand the initial accelleration, and the splat would be on the tester themselves.

The beauty of this test is that it's quite cheap, and needs just a simple clean down after the test. That clean down can be avoided altogether, by drawing the circles on a neighbours wall.

Brush loading is more complex, as that's a cumulative effect of both wear resistance and self-lubricating properties. This is muddied further by variations in brush choice, brush variations themselves, and water chemistry blurring the data on the self-lubricating properties. Wear resistance is therefore the easiest to measure, and can be achieved with a loudness meter and a stopwatch, both of which can be found as smartphone applications. A cheese grater would also be required.

Wear resistance of the product sample, again using the melon baller as a dosing tool, can then be graded according to how long it takes to injure yourself by trying to grate that sample, and the volume of profanities emitted.

For soft creams that should be nigh on instantaneous, and loud enough to worry the neighbours... assuming this test is done instead of firing soap at their house... in which case they'll be cheering instead. At the other end of the scale, Mitchell's will take an eternity to grate, and the grater will be blunt by the time skin makes contact.

Where can I get a catapult?? :a29:
 
What "hardness" are you trying to identify? Deformation under load, or brush loading speed... which are not necessarily directly proportional.

If deformation under load, draw four incrementally sized concentric circles of a known size on a wall, much like an archery target. Firing a measured amount of soap, gouged out by a melon baller for example, into the centre of that target from a known distance with a catapult, will result in a different sized splat according to the hardness of the product.
Deformation under load.

The splat approach is a lovely idea, simple, inexpensive, and fun. I liked it enough to throw 3 croap balls at my neighbors garage. I noticed two problems. First, it's hard to throw with the same amount of force. Valuable soap is lost in the process.

I think the best solution will be non-destructive, and will not include acceleration of either the soap or the testing mechanism.
 
Two words. Water content. If that isn’t the determining factor, I’ll be shocked. And if it is, than can you weigh it, cook the water off, and then weigh it again? The ratio of water let’s us know where it is between ages triple mill like MdC and a cream?

Seems like cooking it off and weighing it can be achieved with household goods, probably a digital kitchen scale and a double boiler rig?


Sent from my iPhone using Tapatalk
I really like this idea a lot. The variable that drives the firmness of soap is primarily water content. This is would absolutely work!

@samhain666 has pointed out some shortcomings though, the cost of the scale, and the cost of the destroyed soap. The latter could be overcome by using a highly accurate scale that measures in .001g, so that very little soap could be used for the testing. The cheapest scale I could find that would do the job is $12.00. Still though, this is a great idea, and it's the first one proposed that would actually work!

I think the winning solution will be non-destructive, and will use household items that everyone already has.
 
@ShavingByTheNumbers

This problem seems like it would be right up your alley. Any ideas on how to accurately measure the firmness of croap in a repeatable way? Here are the requirements:

  1. Measurement should be on an interval scale (not ordinal or nominal)
  2. It must use only household materials costing in total no more than $1.00
  3. It should be possible to make the measurement apparatus in less than 5 minutes
  4. Individual measurement should take no more than 10 seconds
  5. Accuracy must be +/- 13.7%
 
Last edited:
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The splat approach is a lovely idea, simple, inexpensive, and fun. I liked it enough to throw 3 croap balls at my neighbors garage. I noticed two problems. First, it's hard to throw with the same amount of force. Valuable soap is lost in the process. . ...
Problem: Consistent sample acceleration
Solution: Gravitational acceleration (aka "Drop Test")
Parameters to be Defined:
1. Consistent sample weight (e.g. 150 grams)​
2. Consistent altitude (e.g. one kilometer)​
3. Consistent impact surface (e.g. reinforced concrete, annoying child)​
Observe/Plot: Deformation/splatter characteristics
Step Three: Profit
 
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Here's an idea. Thumbtack or pushpin with a plastic shot glass glued to the top of it. Stick it in the soap about 2mm, fill slowly with water until it penetrates the croap. Weigh the water on a kicthen scale.
 
Here's an idea. Thumbtack or pushpin with a plastic shot glass glued to the top of it. Stick it in the soap about 2mm, fill slowly with water until it penetrates the croap. Weigh the water on a kicthen scale.
That is an elegant and very simple solution.

The pushpin or tack along with the shot glass would have to be leveled in order to penetrate vertically for every single subject tested.

Maybe a small level like those that hang on chalk cords glued to the shot glass? Should be fairly inexpensive but probably not $1
 
The pushpin or tack along with the shot glass would have to be leveled in order to penetrate vertically for every single subject tested
Just eyeballing it should be good enough. A deviation of a few degrees wouldn't change the force required very much I don't think.
 

cryhavoc

Contributor
To meet the annual continuing education requirements of my BOSC membership, it is necessary for me to either:

1. Advance the science of shaving in some extraordinary or dubious way
2. Provide evidence of unrepentant indulgence in one or more acquisition disorders.

Unfortunately, my spouse has recently discovered the 10'x10' storage unit I've been renting for my shaving necessities, so the latter is not an option at present. Therefore, it must be science.

One problem that I think worthy of study is the firmness of various cremes, croaps, and soaps. Some cremes are firmer than croaps, and some croaps are harder than soaps. Mitchells Wool Fat soap is the only known material harder than diamond. It's gets downright confusing. This would not be an issue if no one cared, but studies show that 0.03% of shavers have a strong preference for a specific degree of firmness in their soaps. Shamefully, manufacturers offer little to no information on this key parameter. It would be helpful therefore to have an easy, repeatable way to measure the firmness of soaps, such that any hobbyist soap hoarder can measure the firmness of soap/croap for the purposes of posting more edifying reviews to this message board.

It's a vexing problem, but fortunately we may stand on the shoulders of giants; the rubber and plastics industry has devised such a tool, which is called a durometer. I have used these devices myself, and find them indispensable. It is a simple tool, that consists of a "needle" affixed to a spring. The tool is pressed down on the material to be measured, and the shore durometer is displayed on a dial indicator. The OOO Scale Durometer would be perfect for this purpose, but sadly many wet shavers do not have this tool in their shaving den.



Thus a new methodology must be devised. I believe that this new methodology should have the following characteristics:
  1. Measurement should be on an interval scale (not ordinal or nominal)
  2. It must use only household materials costing in total no more than $1.00
  3. It should be possible to make the measurement apparatus in less than 5 minutes
  4. Individual measurement should take no more than 10 seconds
  5. Accuracy must be +/- 13.7%
Sadly, I have no such methodology, nor do I have any good ideas on how it might possibly be done. Please help.
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