It is currently Tue Oct 21, 2014 9:08 am

All times are UTC



Welcome
Welcome to chefknivestogo

You are currently viewing our boards as a guest, which gives you limited access to view most discussions and access our other features. By joining our free community, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content, and access many other special features. In addition, registered members also see less advertisements. Registration is fast, simple, and absolutely free, so please, join our community today!





 Page 1 of 2 [ 12 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: rust problem
PostPosted: Sun Oct 05, 2014 9:38 pm 

Joined: Sat Oct 04, 2014 8:02 pm
Posts: 7
So I just got into Japanese knives in the past two months or so, and my most recent purchase was a Murata 165mm short slicer/long petty in aogami #1 steel. I was well aware of the care needed for carbon blades when I bought it, but unfortunately there's been an accident. My sister was visiting and used the knife while I wasn't at home, and left it wet in the sink. It has developed what I think is black oxide rust and pitting right along the edge, as well as in a few other areas. There are some photos attached, and my main question is whether these black spots will affect the cutting performance of the knife along the edge, and whether they will continue to corrode the metal. Thank you very much!
Theo

picture 1:Image
picture 2: Image
picture 3: Image
picture 4: Image


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Sun Oct 05, 2014 10:04 pm 

Joined: Thu Jan 02, 2014 6:00 am
Posts: 673
Well first off, there is black oxide and red oxide. Red oxide is rust, hence the red-ish brown colour of rust. Then there is black oxide, which we like to call patina.

It doesn't look too bad, I've seen much worse on the accident end of the spectrum.

I'd pick up some bar keepers friend and go to work trying to remove the oxidation. I really can't tell if the damage is just cosmetic or if the pitting has effected the knife. But judging by the time frame and given the fact your sister probably let the knife air dry, it's probably cosmetic.


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Sun Oct 05, 2014 10:17 pm 

Joined: Wed May 16, 2012 1:49 am
Posts: 314
Location: Amstelveen, The Netherlands
Not sure whether it's rust or patina. Rust is reddish, feels coarse and should be treated. Patina is fine, feels smooth and protects against... rust. I would rinse it with very hot water and see what happens. Probably you will see some colour change, purple or blue. If that's the case it's patina. Leave it. The steel is not that reactive. Anyway, you shouldn't be worried. Even if it's active rust you will easily get rid of it.


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Sun Oct 05, 2014 11:53 pm 

Joined: Sun Aug 26, 2012 5:24 am
Posts: 328
Also it has been reported that Murata knives are lacquered. The oxidation/possible rust can perhaps be due to an uneven wearing of the lacquer.


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Mon Oct 06, 2014 2:30 am 

Joined: Sat Oct 04, 2014 8:02 pm
Posts: 7
Thank you for all the replies, the help is much appreciated. I'm going to run the knife under hot water to see if it's patina, and if not, remove the oxidation with barkeeper's friend. A quick question about the lacquer though, could it negatively affect the initial cutting performance of the knife? I noticed that it was not very sharp at all OOTB, and unfortunately I haven't been able to sharpen it yet (I hope to invest in sharpening soon, but haven't yet done so). Thanks again!


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Mon Oct 06, 2014 2:46 am 

Joined: Thu Jan 02, 2014 6:00 am
Posts: 673
athel16 wrote:Thank you for all the replies, the help is much appreciated. I'm going to run the knife under hot water to see if it's patina, and if not, remove the oxidation with barkeeper's friend. A quick question about the lacquer though, could it negatively affect the initial cutting performance of the knife? I noticed that it was not very sharp at all OOTB, and unfortunately I haven't been able to sharpen it yet (I hope to invest in sharpening soon, but haven't yet done so). Thanks again!



That's OOTB, most blades I've had out of the box are best once they've had a full sharpening session. A lot of japanese makers will purposely not give a damn about the OOTB edge as they know most of their customers will change it anyways.


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Mon Oct 06, 2014 3:41 am 
User avatar

Joined: Wed Aug 07, 2013 12:44 am
Posts: 982
That looks fine from here. No orange spots glaring.



_________________
Only after Winter comes do we know that the pine and the cypress are the last to fade.
Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Mon Oct 06, 2014 1:27 pm 
Forum Moderator

Joined: Tue Feb 05, 2013 6:00 pm
Posts: 2390
The lacquer coating can extend to the cutting edge OOTB. That knife will sincerely benefit from a full sharpening - it will cut like a different knife :-).

Do you know anyone who can sharpen it properly with water stones?


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Mon Oct 06, 2014 4:49 pm 

Joined: Tue Sep 25, 2012 8:37 pm
Posts: 68
Location: Arroyo Grande, California
That blade looks great =)


Offline
 Profile  
 
 Post subject: Re: rust problem
PostPosted: Mon Oct 06, 2014 5:53 pm 

Joined: Mon May 06, 2013 2:34 pm
Posts: 57
I'm actually surprised it's not worse! I'd say leave it alone unless you see red. With normal use through product it will stabilize into a patina. I think that knife has a lacquer over the "kurouchi" finish. If you get too aggressive with cleaning etc, you might lose that.


Offline
 Profile  
 
Display posts from previous:  Sort by  
 Page 1 of 2 [ 12 posts ]  Go to page 1, 2  Next

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

cron

suspicion-preferred