Black and brown colored spots on knives

[parunner58]

I have been having this problem for years and have really become curious to why. Being home alone & bored during the week must make your almost 50 year old mind go!!!! LOL August 2008 will be the milstone.

Anyhow. we have two sets of Onieda stainless the we use daily, and with both sets the knives come out of the dishwasher with black or brown spots. SOS does take them off. Over the past 24 years we have had a Kitchen Aid Superba(Dec 1983-Aug 1997), Frigidaire Gallery(Aug 1997-May 2006), and Bosch SHX46(May 2006 - Current) The other pieces come out spotless. I thought it may be the food residue causing the spots (I never pre-rinse) so I did wash the knives before washing in the DW and still got them. I have tried Cascade, Complete powder, W/dawn(my favorite), Liquids, Electrosal gelpacs and powerball. ALl gave the same results. The KA, GE, and Frigidaire repairmen all said never use Liquids only tab style. so I have. Every other dish, pan, or whatever comes out clean and spot free. We do not even have a bad etching problem,some glasses are over 25 years old. I am ready to go buy new silverware. We have a set of Onieda stainless that we got from Betty Crocker coupons with our Initial engraved on them, that we use with our good dishes and that comes out spotless.

I thought maybe a water problem, we have city water, get lots of suds, no limescale, laundry comes out bright white(sometimes too much suds in washer). its very strange, would appreciate any commemt, suggestions. I attached a picture.

Mike

 

[oxydolfan1]

Try a little plain salt, and rub it with one of those Mr. Clean sponges....

 

[whirlcool]

We have the same problem, and it has been with different kinds of dishwashers over the years. I think it has something to do with the mineral content of the water. We know that in some cities the problem is worse than in others.
About twice a month, we just use an SOS pad on each piece that has the spots. Takes only a few moments. And it takes a couple of washings before the problem returns.

 

[bundtboy]

dis-similar metals

If you put any silver plated anything in with stainless steel this will result.
Check to see that you do not have any silver in with the load.

B

 

[danemodsandy]

Sublimation

It looks like you have a sublimation problem. This is a little hard to explain, but basically, it's a situation where rust can be transferred from one item to another, carried by the water and chemicals in the dishwasher.

What usually causes it is rust somewhere in the DW. The likeliest sources are a rusty rack, or rust on chrome-plated utensils ("Dollar Days" spatulas, spoons, etc.). If you can locate the source of the rust and eliminate it, you shouldn't have any more trouble. Almost everyone has an inexpensive chrome utensil or two. You could also have rust stemming from the tub liner in the DW. Look for rust bubbles around the sump down where the wash arm sits, and at the bottom of the door.

I recommend using Cameo stainless steel cleaner to remove the rust from your flatware. Cameo is in most grocery stores, somewhere near the other cleansers like Comet. It will leave the flatware clean without stratching.

I also recommend looking at utensils before you buy them, checking to be sure they're stainless steel. It will say so somewhere if they are- the term "stainless steel" may not be applied to anything not actually made of the stuff.

Your problem will not go away until you locate the source of the rust and eliminate it.

 

[toggleswitch]

~It looks like you have a sublimation problem. This is a little hard to explain, but basically, it's a situation where rust can be transferred from one item to another, carried by the water and chemicals in the dishwasher.

MY HERO!

Of the various sets of knives I have, only one suffers this fate. I thought it may have been inferior SS used for that product.

 

[danemodsandy]

Toggles:

"Of the various sets of knives I have, only one suffers this fate. I thought it may have been inferior SS used for that product."

Actually, that can be a factor. 18/8 stainless is more prone to the problem than the higher-quality 18/10. But getting rid of the rust source usually cures it.

 

[parunner58]

Thanks for all your suggestions.

It can't be silver plated stuff as we don't own any.

The KA had no rust, The ^%^%%*%*% Frigidaire was all plastic, thats why I don't have it anymore, the tub warped and cracked.

The Bosch is new, SS, don't see any rust in it. The sliverware is the only metal that gets washed in the DW, pots are hand washed only. We live in an area that has a high iron ore content in the mountains, could that be the problem? a high iron content in the water, I may call the water company and ask.

 

[danemodsandy]

parunner58:

Yes, iron content in your water could also be the problem. If you care that much, there are filtering systems that can be installed in your house to remove it.

Galvanised water pipes could also be involved, if you have any.

I'd just clean the knife blades periodically; that's much the cheapest solution, if you have no other problems with rust, like bad-tasting water.

 

[whirlcool]

I examined our dishwasher and found that on the lower rack a couple of spines are broken off revealing the metal rack below the rubbery finish.
So I looked at repairclinic.com, they want almost $100.00(!) for that replacement rack. Heck, the dishwasher itself is only about $179.00 new!
They sure are proud of those racks! The top one was even more expensive!

 

[chromacolor]

hummm... not sure, but when I bough new flatware years ago, there was a notice in the box that said NOT to use any diswashing detergent with Lemon. It didn't say why, but I don't buy any with lemon in it.

 

[tomturbomatic]

Instead of a new rack use one of the rack repair kits or mix up some two part epoxy and cover the rust.

Often lower grade alloys of stainless will not have enough chrome and nickel to keep the steel in the alloy from oxidizing in high moisture or salty air environments. Any acid stainless steel/copper cleaner will take care of the discoloration, but will not be a permanent solution. The variables are many between water quality & temperature, type of detergent, whether or not a rinse fluid is used to help eliminate drops of water staying on the stainless ware as it dries and if fast heated dry is used or no heat dry. If you clean them up, you might find that with the old stains gone, the new ones will not be as objectionable and can be taken care of quickly so that they won't build up and really mar the appearance of your flatware.

 

[frigilux]

I've always wondered why that happened to my flatware. Thanks for the explanation and the tips for preventing it.

 

[parunner58]

Thanks for all the advice. I will just do like I have been doing and SOS them every so often. What is funny is it's just the knives, the rest of the pieces are fine.

Mike

 

[gansky1]

Great explananation! There are heads in dishwashers all over the world this week, looking for rusty racks!

The sad parts is, rusty racks will likely be the culprit and a majority of machines suffer this fate. The nylon coated racks are a bit more durable than plain vinyl coatings but care is still needed not to nick them with utensils or bend them too far. I saw an LG dishwasher on clearance at Breast Buy a short while ago that had all the nylon scraped off one of the top-rack supports where the height adjustment mechanism was. Some unsuspecting buyer will have a huge rust problem as soon as they run it the first time!

 

[danemodsandy]

parunner58:

Mike:

The reason it's just the knives is that their blades are probably a different stainless from their handles or the other pieces of the set. Blade stainless is often somewhat higher in carbon so the blades will take an edge, even if it's just a serrated one. Even if your set was touted as being 18/10 stainless, the knife blades are probably not. There is 18/10 flatware out there with one-piece knives (Dansk comes to mind), but it tends to be the more expensive stuff.

 

[roto204]

Greg!!

"Breast Buy"

ROTF

If I had a modern dishwasher, I'd go hunting. Because I don't, and my racks are pretty-good-but-mostly-so-so, I figure it's my own fault.

Praise the Lord, and pass the SOS pads...

 

[sudsmaster]

I have a set of Oneida flat ware that does much the same thing. I agree with the dual alloy hypothesis.

I would recommend against using salt on the knives - chloride is the enemy of stainless steel. But a cut lemon or lime rubbed on the surface will eliminate most if not all of the discoloration.

An alternative is to wash the knifes by hand. I do this with cutting knives already.

 

[whirlcool]

We are trying an experiment.
We have two sets of dinnerware. One is an ancient wood handled set we bought from JC Penny back in the early 80's. We use Mineral Oil on the handles to keep them nice and shiny.
The other set we have is an Onieda set, that actually was pretty pricy (18/10).
When we run the dishwasher, we haven't been segragating the two different sets. So this COULD be a a major contributing factor. So now we are going to separate the two different types into different sections of the fork/knife basket in the dishwasher and see it it makes a difference.
It's threads like this that make being a member of this site all worth the while!

 

[tomturbomatic]

SOS pads do not have the acid that you need to remove the oxidation from the stainless steel knife blades. Remember that to remove an oxide, you need to set up a reduction reaction. The acid will break the bond between the iron and oxygen amd make the stains disappear. One thing that might be making the staining worse is a chlorinated dishwasher detergent or a lot of chlorine in your water since chlorine in solution with water releases oxygen making more oxygen available for bonding with the iron in your knife blades. It's like if you have iron in your water or rust in your washer and when you use chlorine bleach you get little rust spots on the white clothes. Then you have to treat them with Qwink or a similar acid product to remove the rust stain.

 

[lightedcontrols]

All you have to do is...

...rinse off any mustard or mayo thats on the tableware and the spots will disappear! Mark

 

[parunner58]

Thanks Tom and Lighted, I do use Mayo and never rinse that off, I will now. Our water does have a lot of chlorine in it also. Is there a DW detergent that would we the best to use with my high clorine condition? I will clean the knives with my stainless steel cleaner and see if that takes off the rest of the marks. Luckily we do not get rust marks on the white laundry.

Mike

 

[sudsmaster]

Tom,

What protects stainless steel from corrosion is that the high chromium content results in a very thin layer of chromium oxide to form over the metal. It's microscopic and invisible, but it prevents oxygen from attacking the iron in the alloy and therefore is is resistant to rusting.

Chlorine atoms, in sufficient concentration, heat, or time, will attack the chromium oxide layer and during the time that it is missing the iron atoms are vulnerable to rusting.

This is the reason why mfg's of stainless cookware suggest that one refrain from adding salt to a pot of water (such as for pasta) until the water is boiling. This dissolves the salt readily and prevents high salt concentrations from forming around grains at the bottom of the pot, which could cause pitting if allowed to form. Pitting is especially bad because it tends to feed on itself. So a highly polished stainless steel surface doesn't only look good, it also helps it resist corrosion.

Various acids are used to clean stainless steel and encourgage the reformation of the thin chromium oxide layer. This is called "passivation". One commercial product uses citric acid - and I've found that a cut lime will remove the rust/stains from knives quite well.

 

[alr2903]

Here too.

That happens here too. we have a KA, and it is the knives and usually right where the handle joins the "blade". I always wondered if it is because the KA dumps the dw powder regardless of brand right down on the silver ware, Then again maybe it is the mayo or mustard and some kind of chemical reaction as Mark stated.

 

[earthling177]

Get some stainless-steel cleaner (Cameo, as suggested before, for example, although some people also recommend Bar Keeper's Friend) and, using a sponge, clean the flatware, rinse well, then run them thru the dishwasher. In my experience, there are a couple of things that cause that: one, it can be that the flatware is not made from the better stainless steel, those tend to react with mustard, mayo, lemons etc; two, even if you have excellent stainless steel, they *will* rust if you clean them with SOS and/or Brillo pads. As a matter of fact, you'd be better off washing all your pots and pans in the dishwasher and laying off the steel wool pads altogether -- if things don't come off the dishwasher clean enough, either run them thru another cycle, or clean them using Cameo. If you must wash them by hand with a cleaning pad, choose something that can't rust, like a stainless steel or brass wool pad, for example, or one of those 3M sponges that have a more aggressive side. I think the SOS pads are leaving small amounts of iron on your flatware that then rust in place.

 

[danemodsandy]

Cameo and 3M Pads

I agree with earthling177 that Cameo and 3M pads are very useful in taking care of stainless. On my Farberware cookware, I use the blue 3M pads (made to be less aggressive than the green, hence no scratching). Cameo and a sponge work very well on flatware.

If something made of stainless has wood or Bakelite handles, it does not belong in the dishwasher, though. The heat and chemicals will dry out wood and loosen the epoxy adhesive usually used to fasten the wood to the stainless. With Bakelite, the problem is that dishwasher detergents (with chlorine or enzymes) attack the material. Bakelite is made by combining phenolic resin with wood flour. Since the wood flour is an organic material, it gets attacked by the detergent exactly as if it was food.

Most Bakelite damage can be attended to by polishing the plastic with Meguiar's or Novus plastic polish, or with Brasso. This will polish the damaged top layer away, exposing undamaged Bakelite underneath.

I'd also like to recommend that cookware in general NOT go in the dishwasher, if you want really good performance out of it. The dishwasher doesn't live that can remove every last trace of cooking film or starch film from pots and pans. They may be clean enough for most people, but they will have a layer of cooking film that will make them prone to sticking and scorching. I have always hand-washed my cookware, and I can count on it not to cause problems. It looks like new, and therefore it cooks like new.