# Stainless steel knives rust in dishwasher!



## DixyDoodle (Nov 15, 2005)

Everytime I put my stainless steel knives in the dishwasher, they come out with rust spots. ARGH! None of my regular flatware gets them, just the stainless steel steak knives. From what I hear, this is a big problem with dishwashers. (Please don't tell me to wash them by hand, lol)

I have been told to try using a dishwashing detergent that doesn't have citrus scent (such as lemon) and to use one that does not have bleach in it. We have hard water, but we use a softener now, so I doubt it is that.

Has anyone tried that with any success? Or maybe some other suggestions? I really hate having to clean dishes "twice".


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## wyld thang (Nov 16, 2005)

wash them by hand, they'll stay sharper. Knives get dull banging around in the diswasher. ALso the handles and fasteners loosen up being soaked in all that water for that long. C'mon, you can handwash a knife can't you?!!


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## Harry Chickpea (Dec 19, 2008)

"Stainless" is a mix of metals. You likely have knives that have carbon (keeps a sharp edge) in them and smaller than normal amounts of nickel.

FWIW, we have serrated stainless steak knives that don't rust in the dishwasher, but our real knives NEVER get washed there. Washing in a dishwasher is, IME, one of the fastest way to dull a knife, ruin wooden handles, and loosen ferrules, like wyld thang pointed out.


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## Oggie (May 29, 2003)

It's a dish washer, not a knife washer.

Knives don't get all that dirty and should be washed by hand if you want to have good knives for a long time.

I keep mine sharp and they don't get washed with anything else. You just don't toss a knife in a sink full of water and expect it not to bite you.


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## SteveD(TX) (May 14, 2002)

Oggie said:


> It's a dish washer, not a knife washer.
> 
> Knives don't get all that dirty and should be washed by hand if you want to have good knives for a long time.
> 
> I keep mine sharp and they don't get washed with anything else. You just don't toss a knife in a sink full of water and expect it not to bite you.


+1
I never ever wash my "good" knives in the dishwasher. They're worth the time to wash separately by hand.


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## foxtrapper (Dec 23, 2003)

Stainless steel comes in many different flavors. Some more stainless than others. Eating knives are usually a very low grade and are prone to rust pitting.


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## chickenmommy (Aug 24, 2004)

Yep. Never ever put a knife in the dishwasher. Even the combination of the detergent and the force of the water can dull them. Seriously. Unless you really don't care about the life of your knives, wash them by hand. Doesn't take much to squirt a little detergent on the dish cloth and give a quick wash while loading the dishwasher. Kills two birds with one stone, the cloth gets somewhat washed out, too, preventing souring.


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## NCLee (Aug 4, 2009)

Ditto all above. Some things just don't belong in a dishwasher. If there's any wood on it, keep it out. Castiron - NEVER. I have some carbon steel butcher knives & paring knives with wooden handles. One trip through the dishwasher would ruin them.

Since, even with a dishwasher some things have to be cleaned up. Counters, pots that don't fit, or even just to wipe down the stove. It only takes a minute to hand wash knives and put them in the dishdrain (handle up BTW) along with doing the rest of the kitchen clean up.

And, stainless doesn't mean rustless. Ever notice those "stainless steel" grills after a couple of years. Most are made of the cheapest SS available. Years ago when I had to order it for a manufacturing process, I had to specify the grade. If memory serves the term then was type 316 for the best. Type 304 would rust. Those terms may not apply today.

Just my 2-cents.
Lee


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## DixyDoodle (Nov 15, 2005)

I have a few bone-handled knives that I wash by hand. The ones that go into the dishwasher are just the cheapo ones with "plastic" handles. But yeah, they do get those rust spots. I just changed the detergent over to regular (no bleach or citrus), so we'll see how it goes. 

I have to say, the more I can get into a dishwasher than into my sink for hand-washing, the better! 

(I do also notice that cooking pans and baking sheets also do not do well in there, so they are also hand-washed).


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## BackfourtyMI. (Sep 3, 2007)

I always wash all my sharp knives of any kind by hand. Someone told me not to put them in the dishwasher so I never do. Didn't know why exactly but I thought it had something to do with the sharpness.


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## NCLee (Aug 4, 2009)

Rust, ruined handles, especially wooden ones, plus water being forced into the joints where the handles and blade meet. (Same applies to letting knives soak in the sink, too.)

Swirling water bangs them around, thus dulling the edge. Everytime that edge strikes another knife, spoon, or what have you that's beside them will help take off that finely honed edge. 

Lee


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## Wis Bang (Feb 20, 2009)

NCLee said:


> And, stainless doesn't mean rustless. Ever notice those "stainless steel" grills after a couple of years. Most are made of the cheapest SS available. Years ago when I had to order it for a manufacturing process, I had to specify the grade. If memory serves the term then was type 316 for the best. Type 304 would rust. Those terms may not apply today.


They do apply, 316 scrap is worth more than 304. Chemical transports are built from 316L [low carbon] to minimize the reactivity. We used to 'passivate' them w/ a mixture of Hydrofluric and Nitric Acids in a mist until the interior looked rusty. Then we would caustic wash the interior. This cleaned and sealed the pores of the metal.

We still had to pick the next load by considering what the last product was even though we had washed the trailer. I've seen solvents be 'off color' after an oil fromthe microscopic remainders in the metal pores despite the caustic and hot water solutions and steam that should expand the surface and let the pores open and clean out...

My best carbon steel knives came w/ instructions to always wash by hand w/ soap and water. The cleaning machines [spinner] we used to clean the chemical tanker provides the same ingredient that a dishwasher uses, 'impingement' by a hot cleaning solution.


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## Paquebot (May 10, 2002)

It's type 430 which will give the appearance of rusting but it's really only stains. It's also magnetic. A standard "tool" for anyone working in the stainless steel metal fabricating trade is a pocket magnet so that 430 isn't used for 304 application and v.v.

Martin


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## Wis Bang (Feb 20, 2009)

Paquebot said:


> It's type 430 which will give the appearance of rusting but it's really only stains. It's also magnetic. A standard "tool" for anyone working in the stainless steel metal fabricating trade is a pocket magnet so that 430 isn't used for 304 application and v.v.
> 
> Martin


I sorrted all the S/S nuts & bolts out of dad's bolt bin w/ a magnet, they all were 316...If it stuck to the magnet it went back in the bolt bin instead of falling in to the bucket for the scrap yard.


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## Paquebot (May 10, 2002)

Wis Bang said:


> I sorrted all the S/S nuts & bolts out of dad's bolt bin w/ a magnet, they all were 316...If it stuck to the magnet it went back in the bolt bin instead of falling in to the bucket for the scrap yard.


If anything stuck to a magnet, it would not have been type 316. Both 304 and 316 are non-magnetic. _416_ would have been magnetic. Nothing in the 300 series would be magnetic.

Bit of worthless or notable information. I'm the only person to have ever operated a Hill-Acme stainless steel sheet polisher in both the US and Denmark. In fact, there is/was only one such sheet polisher in Denmark!

Martin


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