Author Topic: Removing acid stains from stainless steel  (Read 25253 times)

zahc

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Removing acid stains from stainless steel
« on: November 07, 2011, 03:30:57 PM »
I got hydrochloric acid on my stainless-steel sink and apparently did not rinse it off well enough or quickly enough. Now it has ugly grey/brown acid splash marks on it. Is there any cleaner that will get the marks out? Would it even work if I used fine sandpaper to try to buff the marks off/out of the steel?
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Jim147

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Re: Removing acid stains from stainless steel
« Reply #1 on: November 07, 2011, 04:33:31 PM »
It's going to depend on  how deep it etched it. If it's lite you might be able to use a scotch brite pad going with the grain to clean it up.

I have a supplier that carries something for repairing stainless sinks but I'll have to look it up later.

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AJ Dual

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Re: Removing acid stains from stainless steel
« Reply #2 on: November 07, 2011, 04:42:29 PM »
Either way, it'll require mechanical abrasion to clean it off.

The acid caused a chemical change in the metal and it won't be reversed. It's just a matter of how aggressive the scrubbing needs to be.
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Nick1911

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Re: Removing acid stains from stainless steel
« Reply #3 on: November 07, 2011, 04:57:32 PM »
indeed, this isn't a stain so much as it is accelerated corrosion.

What were you using HCl for, btw?  PCB etching?

might have good luck with some fine diamond valve grinding compound + a cotton rag and elbow grease.

French G.

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Re: Removing acid stains from stainless steel
« Reply #4 on: November 07, 2011, 05:05:35 PM »
I dunno, I'd try some phosphoric or citric acid combined with scotchbrite. Stay with the grain direction to make the stain disappear. If you use more acid, neutralize.
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41magsnub

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Re: Removing acid stains from stainless steel
« Reply #5 on: November 07, 2011, 05:10:08 PM »
probably a meth lab!   >:D

zahc

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Re: Removing acid stains from stainless steel
« Reply #6 on: November 07, 2011, 05:11:37 PM »
I was actually just being stupid and trying to get some deposits out of the bottom of a glass jug I bought at a garage sale. I guess that's what I get for having dangerous chemicals around. I even have a utility sink I could have used.
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Nick1911

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Re: Removing acid stains from stainless steel
« Reply #7 on: November 07, 2011, 05:17:17 PM »
I was actually just being stupid and trying to get some deposits out of the bottom of a glass jug I bought at a garage sale. I guess that's what I get for having dangerous chemicals around. I even have a utility sink I could have used.

Ah, I understand.  In a similar situation, I filled the glass container with solution of hot soapy water saturated with trisodium phosphate, then stuck it in a pot of boiling water for an hour.  (TSP for doing the work, soap for surfactant)  THEN stuck it in the ultrasonic cleaner.   [tinfoil]

RaspberrySurprise

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Re: Removing acid stains from stainless steel
« Reply #8 on: November 07, 2011, 06:50:25 PM »
How did the glass fare in the ultrasonic cleaner?
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Nick1911

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Re: Removing acid stains from stainless steel
« Reply #9 on: November 08, 2011, 11:25:03 AM »
How did the glass fare in the ultrasonic cleaner?

Didn't hurt it.  I was a touch concerned that it would resonate with the glass and shatter it.

zahc

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Re: Removing acid stains from stainless steel
« Reply #10 on: November 08, 2011, 01:18:56 PM »
I tried using Barkeeper's Friend which has oxalic acid, and it didn't help. I think I'm going to have to try sandpaper. Any recommendations on what grit to start with?
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Brad Johnson

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Re: Removing acid stains from stainless steel
« Reply #11 on: November 08, 2011, 01:34:17 PM »
Try a dab of Flitz and use very light pressure.  Don't go too long or you'll end up with a shiny spot that you'll have to rescuff for the finish to match.  IIRC most brushed stainless finishes are obtained with 600-800 grit if you need to scuff it back to the proper texture.

You can also use Bar Keeper's Friend and a scotchbrite pad or brass wool (NO STEEL WOOL!!).  I've used auto polishing compound ((not wax) with some success.

I've heard some people say that Brasso will also get stains off stainless.  I've never tried it personally, though.

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Nick1911

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Re: Removing acid stains from stainless steel
« Reply #12 on: November 08, 2011, 01:46:29 PM »
IMO; 600-800.  Wet/dry as found in the automotive department.  Keep it wet while you're working it.

RaspberrySurprise

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Re: Removing acid stains from stainless steel
« Reply #13 on: November 08, 2011, 03:13:36 PM »
Didn't hurt it.  I was a touch concerned that it would resonate with the glass and shatter it.

Yeah I was expecting that it would shatter glass. Interesting.
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Brad Johnson

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Re: Removing acid stains from stainless steel
« Reply #14 on: November 08, 2011, 03:29:31 PM »
Depends on the resonant frequency of the glass, and that is all over the place depending on glass type, dimensions, etc.  Also, glass is pretty tough stuff in it's own right.  Short of a relatively fragile lead crystal wine glass or champagne flute, I don't see most sonic cleaners as emitting enough energy to do much to a glass object.

Brad
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zxcvbob

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Re: Removing acid stains from stainless steel
« Reply #15 on: November 08, 2011, 11:28:24 PM »
I would try wiping with dilute hydrofluoric acid (Whink rust remover) first to see if that takes the stain out.  You'll still have to scrub it with automotive rubbing compound or chrome cleaner or an abrasive cleanser like Comet.  But the HF might turn the stain colorless.

Wear rubber gloves.  HF causes nasty burns (which can be life threatening) that do not show up right away.  It travels thru the skin to attack the bones and nerves.
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geronimotwo

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Re: Removing acid stains from stainless steel
« Reply #16 on: November 09, 2011, 04:09:09 PM »
once your done, a coarse rotary wire brush will give you the "brushed" finish again.  vary pressure to match the grain.
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