removing stain from stainless

Discussion in 'Materials' started by Steve W, Jun 18, 2014.

  1. CDK
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    CDK retired engineer

    Completely wrong! The solution must be reductive, i.e. free the oxygen that has attached to the steel. That is the opposite of corrosive.
    And the intention is just to improve the optical surface quality of stainless steel that is often less stainless than the name implies.
     
  2. jonr
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    jonr Senior Member

    Passivation of stainless steel is more than cosmetic - the high chromium exterior layer that is created actually reduces corrosion.
     
  3. UNCIVILIZED
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    UNCIVILIZED DIY Junkyard MadScientist

    My apologies. It would seem that I didn't quite gather the question well enough, & got in over my head chemistry wise.
     
  4. CloudDiver
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    CloudDiver Senior Member

    Industrial Metal Supply, Heavy Duty Degreaser/Descaler. This is a mild Phosphoric Acid solution. I use it to clean metal (Mild Steel, 304 & 316 SS, Non ferrous) prior to TIG welding. Takes off rust with a scotch brite pad. I also remove the stains (tarnishing) on polished SS exhaust pipes on my motorcycles. You'll find similar products to this at any welding supply store (Praxair, AirGas). Not rocket science, milld acid solution is not enviormentally harmful or dangerous to use, will not weaken your standing rigging. No need to nuke it.
    This is not the MSDS, just an info sheet. Like Hot Sauce, I put that **** on everything.
    https://www.industrialmetalsupply.com/SharedContent/Documents/ProductLiterature/Metal Degreaser.pdf

    BTW, this product is $6 for the spray bottle, $14 a gallon and a little goes a long way. Not harmful to clothing, but do not allow prolonged exposure to skin (wear gloves or rinse off hands as soon as possible). Also, do allow long term exposure to painted surfaces. Please don't get the wrong idea, this stuff does not 'eat' things quickly, including your skin... it is pretty mild.
     
  5. tom kane
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    tom kane Senior Member

    My understanding of chrome in stainless steel and in chrome plating is that it is very porous and that it why in the good old days of beautiful chrome, copper was applied first to reduce it`s porosity and to act as a smoothing surfacing material.
    I am not impressed with modern chrome plating. Or stainless steel.
     
    Last edited: Jul 2, 2014
  6. Steve W
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    Steve W Senior Member

    Many years ago I worked at chrome plating and the items went through 2 different types of copper baths followed by nickel plating before the final chrome plating.

    Steve.
     
  7. UNCIVILIZED
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    UNCIVILIZED DIY Junkyard MadScientist

    Is there any chance that Vinegar (aka Acetic Acid) might work? I've used it in lieu of the pricier, & more (expensive & corrosive) industrial types of acid as a pre-priming/pre-alodyning prep on aluminum, & it worked like a charm. That, & of course vinegar's cheap, & not particularly harmful to one's skin, or favorite work jeans.

    And this one's a touch out there, but please bear with me. To polish silverware, & jewelry which doesn't have inset stones, one can put a piece of aluminum foil into a non electrically conductive bowl, filled with water. And then put in the item to be polished, & buff off the tarnish with a rag.
    It's fairly simple chemistry, as on the periodic table & galvanic scale, aluminum is right next to zinc. So the aluminum acts kind of like the zincs on your prop shaft... Just a thought.

    Perhaps said thoughts will stir someone's thinker enough to help in coming up with a solution.
     
  8. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Vinegar is the prescribed primer wash for galvanized prior to paint primer.
    of all the reductant derust processes I've tried, I really like the molasses water.
    I put the rusty parts to soak and forget about them a couple of weeks. Do the 1001 other tasks I need to. No worry about leaving them too long. For me, it's the easiest and safest. Cheap too, if molasses bought by the gallon size jug from restaurant supply.
     
  9. Yobarnacle
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    Yobarnacle Senior Member holding true course

    High quality drum hardware (musical instrument drums), is at least TRIPLE chrome plated. Top of line super expensive stuff, MORE! I'm ignorant if copper and nickel plating is done first. Probably is.
     
  10. Steve W
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    Steve W Senior Member

    Im not sure about the triple chrome plating, that may actually be referring to the 3 steps of ,copper, nickel, chrome, which as Tom suggested, is the hallmark of a quality chrome plated job. Incidently, during my testing here, I accidently stripped the chrome from a turnbuckle body revealing the copper layer.

    Steve.
     
  11. rxcomposite
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    rxcomposite Senior Member

    Could be the tri-chrome plating process he is referring to. A much better process than hexa chrome plating whose chemicals are carcinogen.

    Not to be confused with triple chrome plating used for decorative process where the base metal is plated first with copper, then nickel, then chrome. Copper is self levelling and hides minor imperfection in the base metal. Nickel and then chrome has something to do with adhesion and color, nickel being yellowish, chrome being bluish.

    I have heard that automotive chrome finish has the highest standards applied in chrome plating with more than 1 layer of nickel and chrome applied.

    The industrial type of chrome plating is both hard chrome and porous chrome. Not meant for decorative chrome.

    I am not an expert in plating. The info I have is what I learned when I was in the semiconductor industry and part of the process was the plating shop where we have chemist. My interest then was to chrome plate any part of the car I can think of (I am a car nut) so I ask questions.
     
  12. Yobarnacle
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    Yobarnacle Senior Member holding true course

    I have drum sets 40 and 50 years old. It's easy to tell the quality hardware from the single layered chrome plating, at that age. The hardware that still looks new after a bit of cleaning and polishing. The single plate stuff is pitted and rough no matter how much you polish.
     
  13. CloudDiver
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    CloudDiver Senior Member

    I have no idea how this thread got onto the topic of chrome since the OP is asking about Stainless Steel, but let me clear the air about chrome because it seems like there are too many urban legends out there;
    Triple chrome plating (as mentioned above) is not 3 layers of Chrome, it is Copper followed by Nickle and then Chrome. The purpose of the copper layer is to create a conductive surface for the Nickle to adhere to. This is not always used anymore because advances in thecnology (process controls, better liquid solution chemistry, current controls) allow the Nickle layer to stick very well to various base metals without the copper. Austenitic Stainless (non-magnetic) and aluminum parts still need the copper layer as far as I know, but mild steel or CroMoly does not. All of the 'Shine' comes from the Nickle, not the chrome. Most of the color, some of the anti-corrosive properties, and all of the reflection you see is the Nickle. The Chrome layer itself is much thinner and has a much greater Rockwell Hardness than Nickle, it is also virtually transperent. Color wise a polished nickle surface has a warm, goldish hue in the reflection. Once chromed that hue becomes 'blueish'. The greatest anti-corrosion propertites come from the chrome.
    Also, as mentioned above, the Hexa Chrome process is very enviromentally unfriendly, unsatisfactory for anti-corrosion purposed, and primarily used by cheap and dishonest overseas factories who do not follow enviromental protection laws. This process is used primarily on non-conductive substrates like plastics which is why it is called 'decorative chrome'.
    Hard Chrome is an industrial term for additional layers of Chrome (longer dipping for a thicker outer layer), where a very high Rockwell Hardness, corrosion resistance, and wear resistance must be achieved. Nickle is still used as the base layer but they do not typically worry about polishing it prior to the chrome bath. Copper is not used much as a base conductive layer for reasons of thechnology advancements mentioned above. This process is typically used on Hydraulic Cylinder Shafts and the like.
    Now, the reasons for failures in chrome plating over time are many, but I'll point out a few common ones. Enviromental protection laws have made it very difficult and expensive for chrome shops to operate in the U.S. so lots of stuff is outsourced overseas and to Mexico. Poor quality control is the first problem, base metals must be extremely clean. Also, due to expense or just plain being cheap they won't dip the metal into the baths as long resulting in thinner layers. It was mentioned above that chrome is porous... Not true. The base metal is porous, very porous. It is the job of the Nickle to fill and smooth allowing the Chrome a fine surface to lay on and grab. If they cheap out on the Nickle bath soak time you get thinner application of Nickle and a crappy chrome job that will pit on you eventually. In short, good prep work = clean metal. Longer baths = thicker layers of Nickle and Chrome = superior chrome job.

    People throw around the term 'TRIPLE' chrome plated because they have no idea what it means but think "3 layers must be better than 1". This is a result of poor quality control standards is various industries (trying to save a buck) producing crap chrome components that pitt, rust, or peel in relativly short order. In the Truck and Motorcycle industry there was a lot of this going on, and nothing pisses off a biker or a trucker (often the same guy) more than having chrome failures on the goodies he buys to dress up his Rig or his Hog. Thats why a good deal of product advertising for Truck and Bike parts throw around the phrase 'Triple Chrome Plated!'
    For Marine use, chrome over Stainless is a waste of time and money. I'm not aware of any standing rigging components that are chrome over stainless; you are begging for heartache. I know there are chrome bits on trim rings, wheels, and Portlights and those are fine. Once chrome pitts tiny holes are always there even if you can't see them, the rust will basically never stop. With Stainless Steel, rust can be removed and the bit can be repolished eliminating the pitts caused by the initial formation of rust.
     
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  14. Yobarnacle
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    Yobarnacle Senior Member holding true course

    good info. learn something new everyday. thanx
     

  15. CloudDiver
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    CloudDiver Senior Member

    For the OP, Steve W, trust me on the product solution I posted earlier, IMS Heavy Duty Degreaser/Descaler. I know you don't have an Industrial Metal Supply in your area, but if you print out that flyer and take it to any welding supply store (AirGas is nation-wide) they will have a near identical product. You mentioned your shrouds are down which is perfect. Coil them and soak them in a Rubbermaid garbage can. You can absolutley dilute the solution with water, you just might need a longer soak time. I use that stuff full strenth all the time and it does not burn my bare hands. If I can find the time I will post a video of how I use it and how fast it works taking the stain and tarnish off my polished 304 Stainless exhaust pipes on my Chopper using only a sponge. You would shat yourself if I could do a video of how quickly and pain free it is to clean a Bronze Prop with this stuff! I wish I had taken pictures of the near black bilge I cleaned with it down to the white paint underneath, looked brand new.
    Don't worry about the acid being too strong, it is not. It can be dumped down the drain after adding water to neutralize it. As a matter of fact you can also try CLR. A good product, however it no longer contains Phosphoric acid. It may be weaker, but it still works.
    For rust prevention on your standing rigging apply Anhydrous Lanolin. I got that trick from legendary Rigger Brion Toss. You can find it at any drug store. Don't use regular lanolin as it has water in the base, Anhydrous mean the water has been processed out and replaced with mineral oil. It's a great thread lube and soaks into the stainless steel. Brion Toss mentions using this on rigging in detail in his book 'The Complete Rigger's Apprentice'. Using this stuff prevents stains and rust and keep your standing rigging looking good and funnctional for decades.
    Also, I don't want to dump on any of the 'home remedies' that were mentioned above but I was in the Navy for 10 years and I can tell you first hand that most of that stuff is a bit over-hyped. Coca Cola has phosphoric acid in it, 'Bug-Juice" has citric acid... Cleaning anything with either makes a bigger mess than you stated with as both also have a ton of sugar. I've had my hands and elbow grease into many Marine enviroment jobs and most of these old-chool remedies do not work or only work to a small degree, plus many of 'formulas' of these products have changed so much that they no longer work as legend would have you believe.
    If you want to go nuts on removing rust I can show you how I used electrolysis to pull the rust of a 20 year old Ford 302 Engine block. All it takes is a big Rubbermaid garbage can, engine-crane, a battery charger, and 2 boxes of Arm & Hammer Washing Soda (not Baking Soda, different stuff by one molecule).
     
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