Anyone ever buy a serious kitchen knife on aliexpress - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 30, 2025, 02:47:47 pm
content: There are a lot of luxurious-looking kitchen knives on there, like Damascus steel, etc1- has anyone ever ordered a kitchen knife of any kind from them?2- was it any good?I just want to splurge a bit and I need a good chef's knife just for various cutting and chopping, I'm not deboning dinosaur shanks or anything.

author: kripton2035
author_rank: Super Contributor
timestamp: May 30, 2025, 03:43:47 pm
content: I just bought this one on ali :https://www.aliexpress.com/item/1005007275507007.htmlit does the job (cutting well) but feels cheap in the hands...and I don't know if it will last ?

author: 5U4GB
author_rank: Super Contributor
timestamp: May 31, 2025, 12:40:47 pm
content: Turwho is a legit Chinese (not Japanese) company who make kitchen knives, but nothing like what's on the Ali link, and nothing like those prices or specs. The closest I could find is thisChef's knifefor USD 146 and with nothing like the claimed specs of the Ali one. So my guess is it's a fake copy of a Chinese copy of a Japanese knife. I'd say the real thing, hand-made, forge-welded, etc, would run to about USD 1,000.Having said that, if you have a thing for the Damascus steel look and it does what you want...

author: Halcyon
author_rank: Unknown
timestamp: June 01, 2025, 05:30:14 am
content: My personal suggestion would be to buy a good, high quality chef's knife, designed by an actual chef.https://shop.brianlagerstrom.com/products/8-lagerstrom-chefs-knifeSomething like this is built well, reasonably priced and as long as you look after it, will last a lifetime.I don't see the point in spending something like $200 for a knife for food, which will do exactly the same job. I have a mate that spent ridiculous amounts on an "authentic Japanese" knife, which he can only use for certain kinds of food, can't go in the dishwasher and must be dried immediately after use. It's all a bit of a wank.

author: IanB
author_rank: Super Contributor
timestamp: June 01, 2025, 05:44:14 am
content: Quote from: Alex Eisenhut on May 30, 2025, 02:47:47 pm"Damascus steel" is a gimmick and irrelevant for practical use.There are so many factors affecting a chef's knife, like balance, handle, bolster, blade profile, grade of steel, hardness, durability, etc.Read/watch reviews, make a shortlist, and buy a good brand. Anything you buy that is unbranded/unreviewed is going to be a lottery.You cannot "splurge" on AliExpress, that would be a contradiction in terms.

author: coppercone2
author_rank: Super Contributor
timestamp: June 01, 2025, 05:44:49 am
content: I got one of the nicer looking 'damascus like' stainless steel knives (blunt tip) and its pretty nice. Did not rust and stays pretty sharp, I think its a powder steelI got the carbon damacus one and its real nice but it will rust and requires carein the 50+ dollar range, made in china but supposedly japanese craftsmanship. they feel hardyThen there is the 12$ one that feels like a cheap piece of shit, super flimsy. I don't know what it is about it. I mean I can't expect someone with low income would not be able to use it but the plating job looks janky and its mad thin for what its supposed to be, or maybe it ends up LOOKING like a shitty electroplate and its just a bad finish. makes me feel poor to use it. Its too light, but that can honestly be a feature for some stuff like cutting melonbut regardless of the price once a year or so I will sharpen all the knives pain stakingly and they all end up working OK lolthose cheap hex clad whatever it is frying pans are also real niceSome of the knives that look better rust more then some that look reallly god damn cheap too (which stay sharp fine)can't blame someone for cutting more expensive food with a lower quality knife because if you get the 300 dollar knife for ham sandwiches its a failI recommend sharpening whatever garbage you have until the hilt fails personally

author: Simmed
author_rank: Frequent Contributor
timestamp: June 01, 2025, 06:25:47 am
content: i bought not a knife but SS tool for mashing thingsit turns out it was not SS

author: the Chris
author_rank: Regular Contributor
timestamp: June 01, 2025, 07:27:53 pm
content: My personal experience is that you cannot rely on the initial sharpness to judge the quality of a knife but rather how nice it behaves when being sharpened and how long it keeps it. I bought a few 30-50€ of those Chinese knifes for friends and one for myself but I didn't have the impression to have gotten a bargain considering their prices. A solid quality knife by e.g. Zwilling will cost the same and will do the job just fine as well plus it seems to improve upon sharpening quicker, often needing just a few pulls over the sharpening stone. I own a Wüsthof knife for breads since several years now which I would not be able to sharpen myself due to the wave profile but it didn't lose any yet despite regular use. That's where I would put my money if I would be in the market for a knife for a lifetime, imho.

author: coppercone2
author_rank: Super Contributor
timestamp: June 01, 2025, 09:57:26 pm
content: Ehh those wave profiles are over rated you just need a cylinder and some time. The reason why most people can't do it is because they don't use optics to figure out what the effect of what they are doing is. Put sharpie on it and do a few strokes and it becomes clear to what is happening under a microscopestop watching videos and other crap and just physically look at the thing on 10x + zoom and then you know what you are doing and what you want to be doing. I think alot of the skill videos they show are a dead end to frustrationi swear with knives sharpening I feel like I am reading about theoretical physicists looking at statistical interpolated data in excel for a process that you can actually see with your eyes for like $10.99aka I figured out how to sharpen my fancy scale tooth bread knife with 20 years experience and $5000 cam based grinding system with telescoping rods and adjustment micrometer and spinning stuffhttps://www.amazon.com/TEKCOPLUS-Hasting-Foldaway-Mini-Magnifier/dp/B0CSD51R31?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A22X0D7RGHGI0Q&gQT=1I like to use the expensive german magnifying hand glass with the light built in for $100 (esenbach or something) but you can get by with that and a flash lightThe only one I aint figure out how to sharpen yet is the steak knife with the reallly fine teeth. I guess you need to use some kind of needle file on this or somethingThat is one of the thing I notice about engineering mad people never use magnification and they always get into some INSANE conversation with some kind of ideas extrapolated from hunches because they don't actually look at the thing they made. Like a bad solder joint on SMT parts. Or stuff with connectors. I get invited to some discussion thats heading for discussing quantum tunneling and a poltergeist then I look with a magnifier and something is obviously wrong. I don't know if its engineers that just think that a magnifier is too cheap to help them or something? needs to be a $1000 tool to be relevant? I am serious they just don't want to do it for some reason. Not kidding, they are ready to hire consultants to trouble shoot these problems because they think its a design flaw because no one looks if the part is floating on edge.........I really start to think its like a total snob thing, that they see its a polystyrene plastic cheap looking thing with a acrylic lens and that there is NO WAY it can be helpful for their expensive problem. Maybe if it was $200k imaging robot system. Or they think they look old using a magnifier (not showing your vigour?). And then I bet they get hit with a $300 doctor appointment to remove a common splinter. Its like bathing a cat for some reason.is there some superstition or phobia about magnifying lens that people tend to have? I am serious (not saying that this forum has it but its what I see iRL)I thought its supposed to be cool. I think of sherlock holmes (and he is still pretty hip for a detective, using cocaine and smoking pipe). Why is using magnifiers so unpopular??

author: coppercone2
author_rank: Super Contributor
timestamp: June 01, 2025, 10:29:49 pm
content: This is what I think starts to be tricky, when the serrations are super close to each other (like 1mm)https://m.media-amazon.com/images/I/51NXPVtIVRL.jpg

author: 5U4GB
author_rank: Super Contributor
timestamp: June 02, 2025, 01:01:37 am
content: That type of knife is great for cutting up cardboard packing, and also for cutting up old carpets, the serrations means they work much better than a standard carpet cutter. Not sure why you'd want to use them in the kitchen though.

author: coppercone2
author_rank: Super Contributor
timestamp: June 02, 2025, 02:10:46 am
content: its used for bread but usually reasonable bread knives have much larger serations that can sharpen easily on a small rodThe tiny serrations seem to be for cheap steak knivesmaybe the idea is that you saw through thick bacon or steak crust,. and perhaps it can facilitate butter spreading on table butter

author: bitwelder
author_rank: Super Contributor
timestamp: June 02, 2025, 09:16:41 am
content: Quote from: IanB on June 01, 2025, 05:44:14 amI'd second IanB's opinion.I would also add that after having done some market research it would be important to TRY the 'candidate' knife' in your own hand:not all hands are made equal, and not all hands are equally skilled to keep a knife.So maybe a certain model could be even highly appreciated by professional chefs, but it's a bit bulky and in small hands it could be even uncomfortable to hold,which affects not only its efficiency during usage, but also its safety.(And so no, I wouldn't recommend to buy a serious kitchen knife on AE).

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 03, 2025, 03:44:17 pm
content: Thanks all. The 8 inch chef's knife I have now I got at Dollarama about 20 years ago for one Canadian dollar. It's actually really good.The handle is starting to loosen, that's the only thing wrong physically. (They don't sell stuff like this at Dollarama anymore, and I still don't know how something this good was sold at a dollar store.) It's just that things stick to it, especially my sushi rolls.After googling for knives, OF COURSE youtube immediately served me up ads for various fancy knives presented as "hand made" with fake sounding names, so I checked aliexpress right away to see what they actually are, you know?Yup the Damascus steel is cladded on each side and the sharp bit is just the regular steel in the middle.I also enjoy Brian Lagerstrom's content, him, Chef John and Sip and Feast are my go-tos for actual realizable recipes.I'll think more about what knife to buy.

author: Halcyon
author_rank: Unknown
timestamp: June 06, 2025, 09:08:41 am
content: Well, this happened just now...I was preparing dinner and generally I'll use the flat side of the knife to crush cloves of garlic, before slicing/dicing them. It seems like Ikea 365 knives aren't that flexible since it completely snapped under a moderate amount of pressure.This one was made of X50CrMoV15 (Stainless steel with 0.5% Carbon, 15% Chromium, with a small amount of Molybdenum and Vanadium tossed in).

author: Marco
author_rank: Super Contributor
timestamp: June 06, 2025, 11:19:55 am
content: Problem with Damascus is all the well known brands, including now Japanese, restrict it to their highest priced ranges.But it is pretty.

author: IanB
author_rank: Super Contributor
timestamp: June 06, 2025, 05:22:53 pm
content: Quote from: Halcyon on June 06, 2025, 09:08:41 amWell, gosh, how on Earth did you do that?To crush garlic, one should lay the flat of the blade on the garlic, parallel to the chopping board. No part of the blade should be touching the board. Then, one should use the heel of the palm, or a hammer fist, to smack down on the knife, right above the garlic. At no point should the blade experience any bending forces.Basically, like in the video below (jump to 42:30):https://youtu.be/QjZ1LFqNWRM?t=2550

author: coppercone2
author_rank: Super Contributor
timestamp: June 06, 2025, 09:55:45 pm
content: use a mini kitchen mallet, the head should be around 1x1x1.5 inches.Good knives can crack at the hilt too, there is often a weld there that looks ultra premium and robust but none the less its a weldI wanna know the hidden statistic that shows how many people had to visit the ER because they tried to smash a slippery garlic with a knife, or struck a knife that brokeIf you do some research on powder steels there is always a chance it can break because of a defect. IMO its just not good to strike hardened objects. It flexesWAYmore then it ever would cutting. All the factory does is put a defect limit on a x-ray if you even get that. Like volume of defects. I doubt they even try to classify the defect to think about how it can propagate.if you put a paper towel on it you won't even really need to clean the malletAll of these super alloy non dulling tough knives are powder steel. They don't like forge them after like old knives (forging crushes defects, but can also cause defects), and the forgable alloy does not have the spectacular specifications of powder steel. That's why you get such a good knife for the price, their basically ez-bake oven + modern chemistry. While the apparatus is expensive, there is little skill required (cheaper employee, popular job with lower stress). I think its way more of a 'desk job' at that point where you need very specific information, tables, chemical analysis but not so much the trade skills of traditional knife making, other then sharpening. btw even with a simple arc weld, the process of peening it a little after its done is very weak forging practiceMechanical stuff really took off with powder metalurgy. I think its how you can get hard drive quality (dimensional) parts inside of cheap gadgets now. Casting was the same idea but other then expensive die casting you could never get the tolerances dialed in like you could with powder / press tech. Especially with gears, now low slop is cheaper. Weak complicated mechanisms with some slack are feasible now at a way lower price then setting up a machining center to shape up cheap castings. It's like ready for final dimensional grinding on critical surfaces (near the last step) when it comes out of the oven. And its all open mold without pistons, and you have no liquid seal requirements like you do with plastic molding, since its powder. And you don't have a hard flash to deal with, only a very soft flash that is eliminated before it gets hard to deal with, with plastic your flash is at final strength at the end of the cycle.... I see in many cases they just vibrate it a little and any mold flash is gone, if there even is any at all.I am not certain, but I am pretty sure the reason why you can get cheap damascus is because its a powder steel mix. Its not made like those youtube videos that show you nuts and bolts being forged. Its more like ceramicThis is what the better (cheap) knives might start with.https://damasteel.se/knowledge-hub/our-steel/process-of-making-damasteelYou get a sintered blank that you grind into a knife. Mass production might make it way more of a knife shape then a blank, which then just needs to be sharpened somewhat and maybe get some special heat treatment. I doubt they 'fold' it. its like cookie dough vs pizza dough. Ideally they would want to sell you a knife that is ready out of the mold and just needs a tiny tiny bit of grinding to sharpen the edge.

author: Halcyon
author_rank: Unknown
timestamp: June 07, 2025, 03:46:41 am
content: Quote from: IanB on June 06, 2025, 05:22:53 pmThat's exactly what I did, mind you holding onto the handle with my other hand, the knife would have experienced some flexing, but only slight.

author: IanB
author_rank: Super Contributor
timestamp: June 07, 2025, 03:54:11 am
content: Quote from: Halcyon on June 07, 2025, 03:46:41 amAnd the handle was clear of the edge of the cutting board, not overlapping an any way?

author: Halcyon
author_rank: Unknown
timestamp: June 07, 2025, 06:43:19 am
content: Quote from: IanB on June 07, 2025, 03:54:11 amCorrect. I've done it the same way hundreds of times. (EDIT: Admittedly, not with this particular knife, since this wasn't my knife.)

author: Marco
author_rank: Super Contributor
timestamp: June 07, 2025, 11:35:20 am
content: Quote from: coppercone2 on June 06, 2025, 09:55:45 pmMaking the billet is hardly relevant to the cost of the knife. It's purely marketing which decides large brands like Zwilling only put it on their 300$ knives, the cheapest of the cheap could put it on a 10$ knife.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 07, 2025, 02:53:14 pm
content: IKEA quality has been in freefall lately. I avoid the place now.I think they peaked about 20 years ago.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 07, 2025, 03:18:16 pm
content: Quote from: IanB on June 01, 2025, 05:44:14 amit's also a label -- the knives were labeled "Damascus" -- for a Walmart brand (attached). The etching pattern was identical on the few knives I checked. The price was <$10, so I suspect it was not hand made in China.

author: Halcyon
author_rank: Unknown
timestamp: June 08, 2025, 01:26:26 am
content: Quote from: Alex Eisenhut on June 07, 2025, 02:53:14 pmI generally agree. There are still some pretty decent products in their range, but mostly, it's cheap flimsy crap. I do like their range of electronics products though. Their Sonos/Symfonisk products are quite good, as are their batteries, USB mains power supplies, LED globes (for the price).I also have a bunch of kitchen stuff which have no "performance expectations" at all, like everyday cutlery, stainless steel bowls, drinking glasses, that sort of thing.

author: Psi
author_rank: Super Contributor
timestamp: June 08, 2025, 05:10:26 am
content: Any recommendation for a sharp knife that can go into the dishwasher without getting rust spots?I don't mind if i have to sharpen it often due to the corrosive chemicals in the dishwasher, that is totally fine, I just don't want rust spots.I was thinking maybe ceramic as that wont rust, but not sure about sharpening them.Do they make knifes out of high grade stainless that absolutely wont rust? Seems like it's always low grade stainless.

author: coppercone2
author_rank: Super Contributor
timestamp: June 08, 2025, 05:54:46 am
content: I think their stingy with passivation. I had stainless knives that after a few years started to rust from dish washing. The key was to passivate them in warm citric acid for a few hours. The water turns brown, the rust comes off, and you should get a clear ceramic layer on top of the knife.The solution you make is about 20-30% citric acid (this is pretty strong, you need like 1lb of citric acid to do a bunch, its like 300 grams per liter). I recommend a ceramic baking dish filled with knives, covered the solution (1 inch over the knives) and then keep it on low in the oven for a few hours.While some stainless does rust more, a good deal of it should be fine if you passivate it right. Proper passivation does not agree with cheap factories because it takes a while and is a invisible feature. In industrial terms citric acid is considered expensive, and nitric acid is a disposal problem in pickling bath quantitiesOr if you don't want to mix chemicals or think there is a magic ingrediant, you can buy a gallon of citri-surf passivator that is pretty much the same thingimagine you fill a bucket with green and red marbles, then you carefully take all the red marbles off the surface so it looks like its all green marbles. this is what the citric acid does'after sharpening, you theoretically need to do this again, because the edge is no longer passivated. Citri surf gel how how you would passivate the edges after sharpening without a dipits just how stainless steel is. It gets light resistance from just being in air for a while, but its not the same as doing a iron strip off the surface. There is also more advanced chelating agents that can be used for this proboboly instead of acids

author: Psi
author_rank: Super Contributor
timestamp: June 08, 2025, 07:26:00 am
content: Quote from: coppercone2 on June 08, 2025, 05:54:46 amInteresting! will give it a go. Thanks

author: coppercone2
author_rank: Super Contributor
timestamp: June 08, 2025, 08:05:16 am
content: yeah its crazy I got in a big arguement with someone that kept saying the steel is shit and it was fine for 1 year despite daily dish washing. I did have to re-do it once on some stuff so I recommend getting a empty 1gal container to keep the acid in just in case, you can actually also use it after to clean out a dish washer or clean up things like water kettle, pottery, etc.Biggest mistake is not heating it, it should be moderately warm, its temperature sensitive. if its working it turns brown orange like iron waterthe other thing too for knives is if you dish washer them, if you can make arrangement to keep it on top rather then on bottom it ttakes less thermal shock and beating, sensitive items should go on top, the washing container is on the bottom (non ideal design)I notice another thing that kills knives is doing a cup dip, they get band of corrosion near the water air interface. same for passivation or rust removal, the interface is bad, needs full submersion.all the kitchen ware that people put in cups gets rusty even in soap water, there is something particularly corrosive about the water line. big secret to all these chemical and electrochemical processes is full submersion. you need the right tank its critical. I think there is tiny bubbles that pull in air as they bust out of water and put highly oxygenated fluid on the very edge of the part, like a symphon. or something with air batteries ?for rust removal the same thing, too cheap to get the right container and partial submersion in some weak chelating agent like evaporust = corrosion line on the water line. same for electroplating, electropolishing, chemical cleaning, pasivation, etc

author: jpanhalt
author_rank: Super Contributor
timestamp: June 08, 2025, 10:32:16 am
content: It must be West Coast water.My mom (in SoCal) put knives in the dishwasher daily and there was never rust on the blades, but there was some rust staining from the handle. She put dinnerware knives that were all stainless in the washer blade up. Handles were hollow. I suggested blade down, and the problem disappeared. I left California in 1962 and have never had rust on any knife blade, dishwasher or not.I do not put carving knives in the dishwasher. Paring knives maybe.

author: Psi
author_rank: Super Contributor
timestamp: June 08, 2025, 10:39:06 am
content: Quote from: jpanhalt on June 08, 2025, 10:32:16 amIt's more of a problem today than it was in the past.Probably as coppercone2 said, crap quality passivation, where as in the past it was done properly.

author: coppercone2
author_rank: Super Contributor
timestamp: June 08, 2025, 05:01:32 pm
content: well they keep discovering new alloys too every one had trade offs I am saying there is possibly a partial fix to some modern products... and you have powder steel now too, which is alot different then forged or rolled etc steelsI find it invaluable in the kitchen now. Also with formed goods, stainless has a different version that forms easily in dies too I believe. Softer. I.e. a bowl. My sous vide tank gets crap on it after a long cook. In 6 years I probobly passivated it like 4 times. Might be the S30430I have this one old knife that has like never had a spot of rust on it, its magic, but also the handle is cheap shit. its thin too. No name, and it looks crappy, it has this hint of 'aluminum' to it. I believe it might be ridiculously thick passivation that makes it look a little foggy? The ones that never rust sometimes have this look like a hint of 'old/foggy' aluminum.

author: IanB
author_rank: Super Contributor
timestamp: June 08, 2025, 06:14:44 pm
content: I'm scratching my head here.I have always put cutlery (silverware) in the dishwasher: knives, forks, spoons. Not a problem, they always come out shiny.I have never had the inclination to put chef's knives or cutting knives in the dishwasher. Firstly, the care instructions discourage it. Secondly, I want to take care of my nice things.

author: coppercone2
author_rank: Super Contributor
timestamp: June 08, 2025, 06:24:24 pm
content: I think the alloy they use for those is really bad at holding a edge but it never rustsIf you get rid of edge retention as a engineering spec for the alloy I believe it might totally change the game

author: coppercone2
author_rank: Super Contributor
timestamp: June 08, 2025, 06:29:39 pm
content: And why.. I can see why. I end up with 15 knives in the dish washer after 3 meals. That is alot of time to keep washing the knife and using different knives for different foods and sometimes different knives for foods that are separate (i.e. salad that you won't cook and materials that you do cook) for cross contamination reasonsI don't want to use the same knife to cut cheese I put back in the fridge, cut frozen butter, cut a lettuce head I am putting back in the refrigerator, cut meat, cut dirty root vegetables (perhaps room temp potatoes or carrots) or worry about sequencing the knife properly.I won't even use the same knife to cut a lettuce head in half and then to chop the lettuce.You need to have alot of patience to wash knives constantly unless you treat the kitchen like camping

author: coppercone2
author_rank: Super Contributor
timestamp: June 09, 2025, 01:41:47 am
content: also the one thing you can screw up is distilled water, with really bad tap with chlorides you can get like flash smutting (grey black shit), particularly with a water softener water. Some steel does not like tap water. I had it work alot but once it went off on me and I was polishing stuff for a while after (but not knives, this was industrial parts, i think hataloy)... the chloride ions inhibit passivation and you get some weird chalky crap

author: Psi
author_rank: Super Contributor
timestamp: June 09, 2025, 02:43:07 am
content: Quote from: IanB on June 08, 2025, 06:14:44 pmIt's usually sharp knives that have the issue. For me it's the small sharp knives that go into the cutlery basket.I've never had a problem with normal knifes/forks/spoonsThere is also the electrochemical reaction you can get where two items made of different metals touch each other in the cutlery basket in the presents of the alkaline dishwashing water. I try to keep them in their own area of the basket so only the same items touch.

author: IanB
author_rank: Super Contributor
timestamp: June 09, 2025, 03:03:17 am
content: Quote from: Psi on June 09, 2025, 02:43:07 amI don't even want to risk the issue.There are typically three knives I commonly use: a large chef's knife, a medium utility knife, and a small paring knife. For any of those knives, I just take it from the knife block, use it for meal prep, then rinse the knife under a running tap with a bit of dish soap as needed, dry it, and put it away. It doesn't even see the dishwasher.If you wash the knife immediately after use it doesn't have any dried on food that needs effort to clean. A quick rinse and wipe under running water is all that is required.

author: Psi
author_rank: Super Contributor
timestamp: June 09, 2025, 03:08:46 am
content: Quote from: IanB on June 09, 2025, 03:03:17 amI have around 8 utility knives, 2 chef's knifes and 1 bread knife.The utility knives are the ones that always have the issue

author: Halcyon
author_rank: Unknown
timestamp: June 09, 2025, 05:57:42 am
content: Quote from: Psi on June 08, 2025, 05:10:26 amI've used "Wolfgang Starke" branded knives, almost daily for about 8 years now, and they just get thrown in the dishwasher after every use. No rust spots.For what it's worth, I've only ever used Finish brand dishwasher powder and rinse aid, and the water here is fairly soft (typically around 50 mg/litre of mineral content).

author: coppercone2
author_rank: Super Contributor
timestamp: June 14, 2025, 12:50:47 am
content: Quote from: Psi on June 09, 2025, 02:43:07 amI had citric acid in the ultrasonic cleaner with some brass in there to clean up, I think maybe it was grungy old gas regulator parts.I got a copper plating building up on the side wall of the ultrasonic cleaner where the heater is. I had to refinish it with scotch brite to get rid of the nice looking copper/brass stain on it. Actually a really nice looking plating finish, if it was intentional .It was supposed to be dual purpose, to refinish the tank of the ultrasonic while cleaning the parts. Instead it started.. electroplating? from some battery? Anyway I never really saw this problem from the lab soap. But lab soap does corrode certain alloys, if you put mirror polished brass stuff in there it gets nasty looking after a while (which is a shame because its the best way to get rid of polishing dust from the wheel). However, I need to do the same experiment in a glass jar, I am just not sure if its the basket, side wall, cleaning agent and part interacting, or if its the just the chemical action of the cleaner. And its possible in this case it was also polishing dust doing something.You need to deal with all the little details with chemical and ultrasonic cleaning....And I never saw the problem from the little brass screened 'capsule' containers I use for small parts cleaning (you screw it into a 'ball' shaped screen thing made with brass and stainless so you don't lose tiny parts). There could be something specific about the alloy the gas regulator is made with too, I think their pretty peculiar, at least the brand name ones.My favorite way to clean up brass and copper parts is to put it in vinegar and microwave it in a lab mug lol, it actually works super good.And something I noticed with recent passivation:I have a part that is difficult to polish on the interior. I polished as much as I could and when I did the AAA method of passivation (naoh, citric, naoh) the part that was not polished kept getting smut on it, while the polished part looked brilliant. To me there is something like a possible minimum surface finish requirement going on here, if its too coarse it might some how react negatively. I don't know if I keep doing it, if eventually it will eat all the iron from that rough area, or if its just not working. I will try to electropolish it with stainless electropolish fluid and then do it again, and if it fails I will have to spend a few hours on the rotary tool to polish that bullshitDealing with the inside corner is super whack. But the surface finish is much worse then a knife, think post 200 grit sand paper or so. And it could have something to do with salt, I believe this part was used with salt, which may have some how corrupted the interior surface.But do monitor what you are doing if it turns out those knives are some new fangled shit that does not work lol