How many times in the dishwasher before a knife is ruined?

[dag2000]

My wife ruined all my kitchen knives a long time ago by washing and drying them in the dishwasher.

I recently bought a Syderco chef's knife (unfortunately no longer produced) and after the very first time it was used, I found it in the dishwasher, nice and clean. I threw a fit and it won't happen again, but I'm wondering about the nature of the damage that is done to a knife when cleaned in a dishwasher.

Specifically, how many wash and dry cycles does it take to degrade the blade? Is the degradation linear, i.e., a little worse with each wash, or is it discontinuous, changing from working to ruined directly. Finally, what happens to the steel itself? What is the damage?

Thanks in advance.

[uhiforgot]

Welcome to the forums!!!

I say it depends on the steel. Supposedly the drying cycle is hot enough to damage the tempering of the steel. My ATS-55 Rescue has taken more than a few trips through the dishwasher, and still performs well. At one time I touted it as "dishwasher safe" :p It definitely had to be relubed afterward, but I noticed no difference in longevity of edge retention, but then it's hard to tell on a serrated edge that beat-up. Knowing what I know now, I'd never do it to any knife. But then that's not helpful to answer your question...

...there was going to be a point to this, but forgot what it was. :o

-Jeff

[vampyrewolf]

My problem with my knives in the dishwasher is when the family tosses a shaving sharp kitchen knife in with the bowls up top... good bye shaving edge, hello toothpick dull. I yelled enough times that now my kitchen knives get put on the top of the sink and washed by hand. Kinda helped when I refused to sharpen thier butcher knife again until they quit tossing it in loose

If you can keep other stuff from banging into your edge, you solve that problem.

The big reason ppl say not to wash kitchen knives is because of handles. The good old high carbon knives usually had wood handles, and the dishwasher will let em rot over time. With the new nylon or kraton ones, you don't have to worry.

As far as "how many times"... I haven't found a limit yet :p I toss my spydies(closed) into an open cutlery section, and then lube em up after. I prefer washing by hand with HOT tap water simply for speed, but have tossed em through a load for convenience a [i[few[/i] times. Dish soap (the liquid stuff for the sink) is good for your knife. Get your knife wet, get it soapy, rinse it off with hot tap water and shake it dry... lube it up. Dishwasher soap(usually powder) is corrosive in nature and will eventually make a mess of your blades(just look at a drinking glass after 40-50 loads). If you use liquid stuff in your dishwasher it doesn't do that

[Ted]

...Supposedly the drying cycle is hot enough to damage the tempering of the steel...

I've been told that that is not true. Most dishwashers don't go beyond 70 degr. celcius, and that's way below the temperature to affect the tempering of the steel.

Other issues like rust on the edge, or moisture trapped inside or underneath the handles can be a problem of course.

[ghostrider]

I've been told that that is not true. Most dishwashers don't go beyond 70 degr. celcius, and that's way below the temperature to affect the tempering of the steel.

Other issues like rust on the edge, or moisture trapping inside or underneath the handles can be a problem of course.

I gotta agree with Ted on this one. I always thought it was because of the handles, and the fact that they can get dulled by clanking against other items such as vampyrewolf's bowls. Easier to jus wash them by hand seperatly.

[uhiforgot]

I gotta agree with Ted on this one. I always thought it was because of the handles, and the fact that they can get dulled by clanking against other items such as vampyrewolf's bowls. Easier to jus wash them by hand seperatly.

I did not know that... Well, now I've gotta solve the problem of no longer having a dishwasher :p :rolleyes:

-Jeff

[The Deacon]

Aside from possible damage to some handle materials, I believe the worst things for knives in a dishwasher are the detergent and the fact they tend to bang into other items. Dishwasher detergent is considerably more caustic than regular "dish detergent" used for hand washing. It actually "eats" the edge off a knife. Imagine H-1 would be immune, but other stainless steels will lose their edge over time. Some brands may be better, some worse, in this regard, but am fairly sure they all do it to a degree and the progression would, in all cases, be roughly linear.

Contact with other items is harder to predict, too many variables involved. But, unless your dishwasher provides a means of completely isolating each knife from contact with anything else - a highly unlikely setup - this type of damage is inevitable. When it occurs, it is more likely to cause inconsistent and localized damage than to dull an entire blade.

[The Mastiff]

A timely topic. My wife just destroyed a forschiner (sp) knife by putting it in the dishwasher numerous times without my seeing her. Between the spray of hot, acidic bleach filled soapy water and the jostleing around it dulled the edge and ruined the wooden handles. It's as if they rotted away down to at least an eigth of an inch on one side of the handle. The blade didn't lose temper though, and it sharpened right up.

I haven't a clue why she did it because she was aware she destroyed our western cutlery knives away like that. I just put it up to that she doesn't care one bit about them. That's how she treats things she doesn't have any interest in.

I just sent off for some Old Hickory 1095 knives. I told her I'd wash them myself.

It makes me glad I didn't buy any expensive japanese hattori knives for her to ruin. Joe L.

[bowarrow2000]

Each has their own ideas about using this or that for cleaning. The dishwasher is the last place I would put a good knife. If you must use some hot water with just a little soap, a toothbrush, pipe cleaner etc. Then dry and blow out with some form of compressed air, Then lightly oil pivot area.
Even the best of stainless doesn't hold up well in the dishwasher after long periods of washing. We never put our good stainless in the dishwasher.

[MojoRising]

... hot, acidic bleach filled soapy water...

Bleach is alkaline not acid. Chlorine bleach is sodium hypochlorite, if you let it sit uncapped out in the sun for a few weeks it turns to plain old salt water. It's an oxidizer and that's what causes the issues with rust.

The mixing of bleach with an acid will produce chlorine gas which can be fatal.

[The Mastiff]

Bleach is alkaline not acid. Chlorine bleach is sodium hypochlorite,

Thanks. I learn something new everyday. Joe L.

[dag2000]

Thanks for the great responses.

[gabo]

My Spins web erased in the laundry

[ronin203]

You should always wash all your kitchen knives by hand. :spyder:

[zenheretic]

My girl quit using my kitchen knives, because I wouldn't let her put them in the dish washer. So now she uses her old, crummy, dull, decaying wood handle knives for kitchen work. She was amazed at how sharp her knifes were when I used a normal kitchen sharpening rod to sharpen her knives.

Are we so automated, that we can't hand wash a few items?

[Zac]

I've been told that that is not true. Most dishwashers don't go beyond 70 degr. celcius, and that's way below the temperature to affect the tempering of the steel.

Other issues like rust on the edge, or moisture trapped inside or underneath the handles can be a problem of course.

Correct. Dishwashers can also only get so hot because plastic melts at a relatively low temp. I do not own good kitchen cutlury but when I use it, I hand wash it simply because it only takes a few seconds. The prime concern is chipping of the blade as it violently bangs into glass and porcelin which is harder than steel on the RHC. The degree obviously depends on the steel but the dishwasher is definately a rather mean element. However, I wash my Manix in it regularly but this is a G10 knife treated with an anti-rust and saltwater coating weekly.

[Davis61381]

Are we so automated, that we can't hand wash a few items?

Personally, I hate dish washers. I've always been a wash by hand kinda guy. It's so much faster. I can hand wash a sink full of dishes way quicker that a dish washer, but then again it's only my grilfriend and me.

[Ted]

You should always wash all your kitchen knives by hand. :spyder:

Hum, I don't agree with that. I think my knives will survive the harsh attack of water & soap.

[Ted]

...Are we so automated, that we can't hand wash a few items?

Well, it's not that I can't, it's that I don't want too. It takes long enough to clean up after having dinner with the kids and having brought them to bed.

And it's not only kitchen knives. There are numerous kitchen items (even pots/pans etc) where the maker advises not the use it in the dishwasher. I try to avoid those items. The only things that don't see the dishwasher now at home is our hand-made Portugal pottery dinnerware which we only use on larger dinners and my wives Swilling & Henckels kitchen knives (who I would't mind tossing in the dishwasher )

[Simple Man]

[quote="Ted"].....wives Swilling & Henckels kitchen knives (who I would't mind tossing in the dishwasher ]

Your wife or the S&H knives............ :D