Pitting on my blade:(
- Thread starter UW Mitch
- Start date
'cause Mayo's already making me a TNT!
well, actually he's not making it yet, but hopefully he'll get to it soon.
~Mitch
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My Hobby Page
well, actually he's not making it yet, but hopefully he'll get to it soon.
~Mitch
------------------
My Hobby Page
- Joined
- Mar 15, 2000
- Messages
- 3,208
Mitch:
I think that when you get your TNT you will forget about the pitting on the blade of your Sebenza. By your description, the knife has had 5 owners and it is a ATS 34 blade which means it is an older knife. It might be worth it to put on a new blade but by that time you will have you TNT and it won't matter because I think that will be the knife you will carry. That left hand Elishewitz sure is tempting! But then again the small plain is a nice little knife. I'm waiting for a small wood inlay and also a small apogee which was sent last Monday and I hope I get it today. I will post my reaction in the custom section of the forums.
[This message has been edited by Scott Dog (edited 10-19-2000).]
I think that when you get your TNT you will forget about the pitting on the blade of your Sebenza. By your description, the knife has had 5 owners and it is a ATS 34 blade which means it is an older knife. It might be worth it to put on a new blade but by that time you will have you TNT and it won't matter because I think that will be the knife you will carry. That left hand Elishewitz sure is tempting! But then again the small plain is a nice little knife. I'm waiting for a small wood inlay and also a small apogee which was sent last Monday and I hope I get it today. I will post my reaction in the custom section of the forums.
[This message has been edited by Scott Dog (edited 10-19-2000).]
- Joined
- Jan 11, 1999
- Messages
- 669
Sorry to have taken so long to give a response on this one. I needed to talk to Chris on your second email, Mitch, and he was out of town for part of last week.
We can well understand your concern, especially when the knife had already been returned to us. Rust is a difficult thing to deal with but, if you go back to the beginning and how it starts, it might help you understand what is going on.
The piece posted by GigOne on 10/09/00 is interesting and informative, even if the technicalities are a bit hard to follow! To expand on the information there, the corrosion starts at the point where there is dirt in the steel. The dirt is in microscopic inclusions and it cannot be removed. You can polish over it, disguise it for a period but you can't permanently remove it. The dirt inclusions are randomly found in the steel and, until such time as they show as rust, are invisible. The corrosion or rust spots slowly grow as they are exposed to moisture and/or acids, which can be everyday things like tomatoes, apples, oranges, blood, finger oils but are sometimes more exotic substances. There is no way of knowing what the previous owners used the knife for, or for what period of time the knife might have been left dirty. The hinge area can be a trap for dirt (which is why we supply the wrench to allow you to strip down the knife and keep it clean!)
The dirt inclusions in ATS 34 was one of the main reasons we change from using it. It took us a long time to get to the point where we could change to BG42 - it took 18 months of negotiating with Latrobe Steel to get them to roll it in the flat bar that we needed! BG42, ATS 34 and other regularly used knife steels are on the lower end of the stainless steel category because they have carbon in them - and it is necessary to have the carbon for the hardening process. The only way to get around the presence of carbon is to go with titanium or talonite - neither of which does Chris feel are up to the abilities of BG42 in general purpose edge retention. This is an area that has been discussed extensively in prior posts and we don't want to go there again!
I hope this helps everyone understand - there has to be compromise in the manufacturing of anything - perfect does not exist! We use the best possible combination of things to make our knives the best we can. Where there is an area that we can improve things, we will make a change. This does not mean that what we did before was bad, it just means that what we change to is an improvement!
Anne
[This message has been edited by Chris Reeve Knives (edited 10-24-2000).]
We can well understand your concern, especially when the knife had already been returned to us. Rust is a difficult thing to deal with but, if you go back to the beginning and how it starts, it might help you understand what is going on.
The piece posted by GigOne on 10/09/00 is interesting and informative, even if the technicalities are a bit hard to follow! To expand on the information there, the corrosion starts at the point where there is dirt in the steel. The dirt is in microscopic inclusions and it cannot be removed. You can polish over it, disguise it for a period but you can't permanently remove it. The dirt inclusions are randomly found in the steel and, until such time as they show as rust, are invisible. The corrosion or rust spots slowly grow as they are exposed to moisture and/or acids, which can be everyday things like tomatoes, apples, oranges, blood, finger oils but are sometimes more exotic substances. There is no way of knowing what the previous owners used the knife for, or for what period of time the knife might have been left dirty. The hinge area can be a trap for dirt (which is why we supply the wrench to allow you to strip down the knife and keep it clean!)
The dirt inclusions in ATS 34 was one of the main reasons we change from using it. It took us a long time to get to the point where we could change to BG42 - it took 18 months of negotiating with Latrobe Steel to get them to roll it in the flat bar that we needed! BG42, ATS 34 and other regularly used knife steels are on the lower end of the stainless steel category because they have carbon in them - and it is necessary to have the carbon for the hardening process. The only way to get around the presence of carbon is to go with titanium or talonite - neither of which does Chris feel are up to the abilities of BG42 in general purpose edge retention. This is an area that has been discussed extensively in prior posts and we don't want to go there again!
I hope this helps everyone understand - there has to be compromise in the manufacturing of anything - perfect does not exist! We use the best possible combination of things to make our knives the best we can. Where there is an area that we can improve things, we will make a change. This does not mean that what we did before was bad, it just means that what we change to is an improvement!
Anne
[This message has been edited by Chris Reeve Knives (edited 10-24-2000).]
Anne,
I totally understand. I know that as the fifth owner of this knife, I cannot know what this knife has been through. It was probably, used, abused, cared for, and loved. Perhaps at some point I will go for the blade change, but for the past six or seven months, it has been my daily carry, and I will not part with it.
Thanks,
Mitch
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My Hobby Page
I totally understand. I know that as the fifth owner of this knife, I cannot know what this knife has been through. It was probably, used, abused, cared for, and loved. Perhaps at some point I will go for the blade change, but for the past six or seven months, it has been my daily carry, and I will not part with it.
Thanks,
Mitch
------------------
My Hobby Page
Mitch,
Maybe this is your lucky day! Just received an email from Tom saying that he won't be at the NYC show. He's staying home to get caught up on orders!!! Maybe your TNT is on the list and you can stop worring about rust!!
Michael
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He who has smelt the smoke is never free again...
Maybe this is your lucky day! Just received an email from Tom saying that he won't be at the NYC show. He's staying home to get caught up on orders!!! Maybe your TNT is on the list and you can stop worring about rust!!
Michael
------------------
He who has smelt the smoke is never free again...
C4,
I've been emailing with Tom. My knife won't get started until probably late Nov or early Dec. Hopefully I'll be able to pick it up when I try to go home for vacation.
~Mitch
------------------
My Hobby Page
I've been emailing with Tom. My knife won't get started until probably late Nov or early Dec. Hopefully I'll be able to pick it up when I try to go home for vacation.
~Mitch
------------------
My Hobby Page
- Joined
- Oct 7, 1998
- Messages
- 1,838
U W Mitch; stainless steel is just what it says: it stains LESS. It is not stain or rust PROOF.
There is nothing wrong with your blade, other than what is normally wrong: the carbon inclusions (which Anne calls 'dirt,' rightly enough, as they are more often slag than pure carbon) which permeate the steel. Latrobe BG-42 steel is a Bearing Grade steel, and is manufactured using the expensive VIM-VAR (Vacuum Induction Melted, Vacuum Arc Remelted) process. This guarantees a very clean, albeit expensive, steel. Even 154-CM steel, which is now made by a argon - oxyen decarburization process is cleaner than ATS-34.
So what if you have carbon inclusions, you say? What is the problem? Well, edgehopper, the problem is this. In the presence of water, carbon will react and form carbonic acid; this will attack the steel. If you have the chloride ion present (such as from the salt in your sweat), the H+ from the carbonic acid will be delighted to meet the Cl- and form hydrochloric acid; further attacking the steel and causing pitting. The chloride ion also facilitates the electric current present in what is now a miniature galvanic cell, and disrupts the formation of a protective oxide coating (for a discussion of this, see): http://www.corrosionsource.com/discuss2/ubb/Forum4/HTML/000218.html
This concept is put forth clearly here: http://www.corrosionsource.com/discuss2/ubb/Forum4/HTML/000140.html
Now the above paragraph refers to all stainless steels, but knives of quality are generally made from martensitic stainless; the addition of Ni would obviously make the stainless austinitic, such as the typical 18-8 (18% Cr, 8% Ni) of stainless flatware, so we can't add Ni to improve our knife grade stainless steel. If you don't know about stainless steel types, go here: http://www.ssina.com/student.html
Please note, however, that one method of increasing corrosion resistance suggested above, the addition of Mo, is not only feasible, but has been done; the main elemental difference between ATS-34 and BG-42 is the 4% Mo in the BG-42; the Mo serves well as a corrosion inhibitor, as well as having other well known favorable effects on the steel. Thus BG-42 is superior in corrosion resistance both from its' lack of carbon inclusions, and the presence of Mo.
One interesting but so far unused (in the knife industry) method of corrosion inhibition is the 'passivation' of stainless steel. This is generally considered to be the removal of any carbon steel from the surface of stainless steel (usually using an acidic solution). This is now a topic of some dispute; you may read of this here: http://www.finishing.com/faqs/sstpass.html
I read with interest and much appreciation the post of GigOne; I agree with what he had to say, save one item. He said:
While I hesitate to disagree with such an obviously experienced and erudite poster, may I respectfully refer him to the general corrosion forum, from which samples have been taken above; he will find there many problems with corrosion of even austenitic stainless steel. Here is the URL: http://www.corrosionsource.com/cgi-bin/ubbcgi/forumdisplay.cgi?action=topics&forum=General+Corrosion&number=4&DaysPrune=1000&LastLogin=
In short, edgehopper, your stainless steel has behaved exactly as expected in our oxygen rich, moisture laden, C02 ridden and chloride contaminated environment.
Prevention, in the form of an ounce of good rust preventive (Tuf-Cloth for one) is worth a pound of cure. Just remember, it is the same for all of us: 'Corrosion; it's the pits!'
(groans from audience gratefully acknowledged)
Gently replacing my Sebenzas in my humidity controlled, inert gas filled, chloride free, Tuf-Glide spray equipped sock drawer,
I remain,
Sincerely, Walt Welch
There is nothing wrong with your blade, other than what is normally wrong: the carbon inclusions (which Anne calls 'dirt,' rightly enough, as they are more often slag than pure carbon) which permeate the steel. Latrobe BG-42 steel is a Bearing Grade steel, and is manufactured using the expensive VIM-VAR (Vacuum Induction Melted, Vacuum Arc Remelted) process. This guarantees a very clean, albeit expensive, steel. Even 154-CM steel, which is now made by a argon - oxyen decarburization process is cleaner than ATS-34.
So what if you have carbon inclusions, you say? What is the problem? Well, edgehopper, the problem is this. In the presence of water, carbon will react and form carbonic acid; this will attack the steel. If you have the chloride ion present (such as from the salt in your sweat), the H+ from the carbonic acid will be delighted to meet the Cl- and form hydrochloric acid; further attacking the steel and causing pitting. The chloride ion also facilitates the electric current present in what is now a miniature galvanic cell, and disrupts the formation of a protective oxide coating (for a discussion of this, see): http://www.corrosionsource.com/discuss2/ubb/Forum4/HTML/000218.html
This concept is put forth clearly here: http://www.corrosionsource.com/discuss2/ubb/Forum4/HTML/000140.html
Now the above paragraph refers to all stainless steels, but knives of quality are generally made from martensitic stainless; the addition of Ni would obviously make the stainless austinitic, such as the typical 18-8 (18% Cr, 8% Ni) of stainless flatware, so we can't add Ni to improve our knife grade stainless steel. If you don't know about stainless steel types, go here: http://www.ssina.com/student.html
Please note, however, that one method of increasing corrosion resistance suggested above, the addition of Mo, is not only feasible, but has been done; the main elemental difference between ATS-34 and BG-42 is the 4% Mo in the BG-42; the Mo serves well as a corrosion inhibitor, as well as having other well known favorable effects on the steel. Thus BG-42 is superior in corrosion resistance both from its' lack of carbon inclusions, and the presence of Mo.
One interesting but so far unused (in the knife industry) method of corrosion inhibition is the 'passivation' of stainless steel. This is generally considered to be the removal of any carbon steel from the surface of stainless steel (usually using an acidic solution). This is now a topic of some dispute; you may read of this here: http://www.finishing.com/faqs/sstpass.html
I read with interest and much appreciation the post of GigOne; I agree with what he had to say, save one item. He said:
While I hesitate to disagree with such an obviously experienced and erudite poster, may I respectfully refer him to the general corrosion forum, from which samples have been taken above; he will find there many problems with corrosion of even austenitic stainless steel. Here is the URL: http://www.corrosionsource.com/cgi-bin/ubbcgi/forumdisplay.cgi?action=topics&forum=General+Corrosion&number=4&DaysPrune=1000&LastLogin=
In short, edgehopper, your stainless steel has behaved exactly as expected in our oxygen rich, moisture laden, C02 ridden and chloride contaminated environment.
Prevention, in the form of an ounce of good rust preventive (Tuf-Cloth for one) is worth a pound of cure. Just remember, it is the same for all of us: 'Corrosion; it's the pits!'
Gently replacing my Sebenzas in my humidity controlled, inert gas filled, chloride free, Tuf-Glide spray equipped sock drawer,
I remain,
Sincerely, Walt Welch