# Kohler Stainless Steel Sink Pitting/Rusting



## RegeSullivan (Dec 8, 2006)

First let me say my experience with Kolher has always been good in the past and their customer service is top notch. About a year ago I recommended a Kohler sink for a kitchen remodel to a customer of mine. This was not a high end remodel so for the homeowner purchasing a Kohler sink, strainer and faucet was a good bit of their budget. A few weeks ago I did some work in that home and I innocently asked how the kitchen was holding up. The lady of the house said everything was great except for the black spots in the kitchen sink. Hmmm… stainless steel rusting/pitting. Little black spots on the bottom of the sink when rubbed with a white rag made rust colored streaks on the rag. I took a magnet off the refrigerator and it stuck to the bottom and side but not the top. I don't know if the sound deading material is magnetic but I know stainless is not??? Has anyone else had this problem with Kohler or any other stainless steel sink?

Rege


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## RippySkippy (Feb 9, 2007)

I'd call Kohler (1-800-456-4537) and inquire with them....they 'll have the answer you're looking for. As a side note I was in a newly remodeled office building lately, and their SS sink had the same thing...don't recall the brand though...


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## RegeSullivan (Dec 8, 2006)

I didn't want to make the post so long it would not get read but I should have mentioned I did speak to Kohler. They offered to replace the sink but suggested the sink be cleaned with Navel Jelly first. They could not tell me why a magnet would stick to the bottom and sides of the sink but I suspect it is the sound deadening material.


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## RippySkippy (Feb 9, 2007)

If they were so willing to replace it...there may be something going on that they're not telling you. I believe I'd take them up on the offer...I would think at least your customer would appreciate the extra effort....


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## Maintenance 6 (Feb 26, 2008)

Certain stainless steel alloys ARE magnetic. Could be that it's not a true stainless sink. Could be chrome or nickel/chrome plated and has a bad spot in the finish.


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## time29 (May 30, 2009)

I've tried using a new brand, it's working pretty good considering the different circumstances that it was used. By the way, this is where I got the sink. Hope it helps.


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## Ron6519 (Mar 28, 2007)

time29 said:


> I've tried using a new brand, it's working pretty good considering the different circumstances that it was used. By the way, this is where I got the sink. Hope it helps.


What is this post in reference to?
Why would you post the place you bought it and not the brand that was used?
Kohler is willing to give him another one. Why would he need your source of an unnamed sink?
What does this mean," it's working pretty good considering the different circumstances that it was used."?
Sounds like a stealth shill.
Ron


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## Daniel Holzman (Mar 10, 2009)

Maintenance 6 is absolutely correct, some stainless steel can be magnetized, although generally not as strongly as standard carbon steel, therefore testing "stainless" with a magnet is not a test to determine if the steel is stainless. There are over 100 commercially manufactured varieties of stainless steel, and interestingly, some of them are not particularly resistant to corrosion. 

The term stainless steel refers to the presence of chromium in the steel at a concentration of not less than 11 percent by weight. Different varieties of stainless steel (also called Inox) incorporate metals like vanadium, rhodium and tungsten, depending on the specific properties desired.

All that said, the specific metal selected for a sink should be resistant to corrosion, it sounds to me like the specific sink you got was not up to metal spec for the application. This is not uncommon, see for example the problem with Zurn brass Pex fittings made with an inferior grade of brass that corroded. Since Kohler is apparently standing by the sink, and will replace it, that is a plus mark for Kohler in my book.


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## wong (Jan 10, 2013)

*Rusted Blanco Stainless sink*

I got a new 18/8 Blanco stainless steel sink from Rona recently and it start rust as soon as the water is connected. But I had installed another Blanco sink 5 years ago was purchase from Homedepot do not rust at all. Then I did magnet test, guess what the magnet stick to the new one not the old one.... I contact Blano they ask me to buy metal restor/rust remover and blame the water contents iron. The life time warranty is a lie. I guess now day you could not trust any brand.... If you need a new stainless steel sink my sugguestion is please do not install it before you test it out with magnet and water ensure it does not rust.... :furious:


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## danpik (Sep 11, 2011)

wong on 1-9-13 said:


> I got a new 18/8 Blanco stainless steel sink from Rona recently and it start rust as soon as the water is connected. But I had installed another Blanco sink 5 years ago was purchase from Homedepot do not rust at all. Then I did magnet test, guess what the magnet stick to the new one not the old one.... I contact Blano they ask me to buy metal restor/rust remover and blame the water contents iron. The life time warranty is a lie. I guess now day you could not trust any brand.... If you need a new stainless steel sink my sugguestion is please do not install it before you test it out with magnet and water ensure it does not rust.... :furious:


The term “18-8″ is often used to designate products made from 300 series stainless. This “18-8″ call out is referring to the 18% chromium/8% nickel alloy mixture of the steel. “18-8″ is not an actual specification, as it only refers to two different alloys in the steel and their min amounts. While all 300 series stainless steels share this 18/8 mix, slight differences in chemical composition between the different grades of the 300 series do make certain grades more resistant than others against particular types of corrosion. In the fastener industry the term “18-8″ is often used as a designation for a bolt, nut, or washer manufactured from 300 series stainless steel material that has the 18% chromium/8% nickel alloy mixture. However, a fastener manufactured from stainless material that meets the 18/8 alloy mix does not necessarily meet the other slight differences in chemistry required to certify it as Type 304 stainless. Type 304 is by far the most popular of the 300 series stainless steels.

Working as an engineer in the Kitchen Cutlery industry, I had the ability a few years ago to tour a plant in Wisconsin where a lot of Kohlers stainless parts are made. We had an interesting discussion on the quality and availablity of high quality 300 and 400 series stainless steels. In my industry we primarily use 400 series where as in theirs they use the 300 series. While it is true that 300 series stainless steels are non magnetic, it is not true about all stainless. 400 series have a high magnetic charactaristic. This is due to the carbides present in the mix. It is also true that 300 series are more stain resistant than the 400 series but, not stain proof. The demand for lower cost parts has driven the need for lower cost steel. This has opened up a flood of inferior steels coming from the asian market. 

Testing with a magnet to determine steel grade is not the best method. Work hardening of 300 series stainless can impart some magnetic charactaristics. This work hardening comes from the deep drawing process used to form these sinks and can vary depending on the grade of steel used


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## PoleCat (Sep 2, 2009)

Leaving a sink full of water with steel items in it soaking is usually what causes the problems. No real cure for that.


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## NestHI (Jan 11, 2013)

I have found Kohler very good at replacing defective items. Just last year they replaced a 4 year old kitchen faucet for me.


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## 123pugsy (Oct 6, 2012)

danpik said:


> Testing with a magnet to determine steel grade is not the best method. Work hardening of 300 series stainless can impart some magnetic charactaristics. This work hardening comes from the deep drawing process used to form these sinks and can vary depending on the grade of steel used


Some magnetic characteristics is correct. But, the magnet will not stick well at all to 300 series stainless which has been machined. To check, have a piece of something made from mild steel handy. Stick the magnet to the mild steel sample and then to the sink. If the magnet sticks with the same force, I guarantee the sink is 400 series stainless.


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