Thread: Abrasion pH and luster of the edge, natural hones.

Abrasion pH is a phenomenon where minerals alter
the pH of water when they are ground to a fine powder.

There have been a number of comparisons of man made
and natural hones that comment on the frosty lustre that
shows up on steel after being honed. I am wondering if
abrasion pH and resultant micro etching is involved in frosty
lustre. If so etching might be a serious component in the
generation of a fine edge for shaving.

Reading the John D. Verhoeven paper referenced in another
thread I noted in his discussion on etching steel to visualize
grain structure visible a remark on a frosty lustre associated
with high carbon steels.

In passing I have seen comments about baking soda
being used on hones which might generate the same
result.

I have done this abrasion pH test in the lab 30 years
ago and some minerals are remarkable at this. The
change in pH is both large and easy to measure with
simple pH paper. I do not have any Jnats to try this
but an bit of aquarium pH test kit paper on the slurry
of a hone might be interesting.

Does anyone have any thoughts on this....?

Hi Tom,
If you want I can add slurry in neutral water to see if it is acidic. Given that it is a weak acid, I could if needed further neutralize with a portion of it with some Sodium Hydroxide then remix, take pH and find Ka. That constant could be compared to most likely weak acids salts. Is there not already general mineral composition information on these??
Mike

Originally Posted by Kingfish

Hi Tom,
If you want I can add slurry in neutral water to see if it is acidic. Given that it is a weak acid, I could if needed further neutralize with a portion of it with some Sodium Hydroxide then remix, take pH and find Ka. That constant could be compared to most likely weak acids salts. Is there not already general mineral composition information on these??
Mike

I am not sure the pH change is to a more acidic value.
It can shift the pH to 1 or 12. Etching might take place
at either direction and it need not be that extreme depending
on the chemistry.

This paper has some data points.

http://www.minsocam.org/ammin/AM33/AM33_31.pdf

Originally Posted by niftyshaving

I am not sure the pH change is to a more acidic value.
It can shift the pH to 1 or 12. Etching might take place
at either direction and it need not be that extreme depending
on the chemistry.

This paper has some data points.

http://www.minsocam.org/ammin/AM33/AM33_31.pdf

Nice paper. Will study some more later. According to info here Japan Tool Nakayama's mineral based on CaHPO4. This of course is the salt of a weak acid. I am not sure if that if that helps what you have in mind Tom.
Mike

Originally Posted by Kingfish

Nice paper. Will study some more later. According to info here Japan Tool Nakayama's mineral based on CaHPO4. This of course is the salt of a weak acid. I am not sure if that if that helps what you have in mind Tom.
Mike

Thanks, part of what I am looking for... This might be part of the magic.
Slow and steady I think the secrets will be known...

Originally Posted by niftyshaving

Thanks, part of what I am looking for... This might be part of the magic.
Slow and steady I think the secrets will be known...

One part of me wants to know too, but in some ways I hope know one will ever understand it completly.....

Originally Posted by Kingfish

One part of me wants to know too, but in some ways I hope know one will ever understand it completly.....

OK, like the ending of a good mystery novel.. I will never tell
especially so if I have not read the whole book first.