Rusting Problem Need Help

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artooks
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Rusting Problem Need Help

Post by artooks »

Hi Everyone,

This year strangly many of my Stainless Steel still parts show small rust spots, I did clean them with vinegar and green part of scotch brite, but the main thing that I am wondering is why they rust, could it be the water that I am using to clean these parts, what do you do when you see a rusty spot in SS ?, normally it should not have been happening but it did so what I think is that after I wash the parts and hang them to air dry during this time it could be happening, so at the beginning of the season, should I wash all the SS parts with PBW and them submerge them in 10% citric acid bath for 1 hour for re-passivation ? or what do you recommend ? Not really happy about this outcome. I appreciate the feedback on this matter.

Thanks
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Yummyrum
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Re: Rusting Problem Need Help

Post by Yummyrum »

I work in a Lab ,when ever acid is poured on a stainless sink , it rusts. Constantly scrubbing rust patches off sinks and washing them with soap to neutralise.

So I have to wonder how are your still bits coming into contact with acid ?

Back to stills ,I’ve never had any stainless bits of my still rust …… other than a few spots in my keg which gets a roasting in my gas burner .

BTW . I hate Vinegar .
artooks
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Re: Rusting Problem Need Help

Post by artooks »

Yummyrum wrote: Mon Oct 25, 2021 3:25 am I work in a Lab ,when ever acid is poured on a stainless sink , it rusts. Constantly scrubbing rust patches off sinks and washing them with soap to neutralise.

So I have to wonder how are your still bits coming into contact with acid ?

Back to stills ,I’ve never had any stainless bits of my still rust …… other than a few spots in my keg which gets a roasting in my gas burner .

BTW . I hate Vinegar .
Thanks so what do you suggest ?
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Yummyrum
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Re: Rusting Problem Need Help

Post by Yummyrum »

Well in normal use it should not rust .just a rinse in water should be all thats needed . Don’t put Vinegar , citric acid or any other acidic things near it .

If it has rust spots , you need to physically remove the rust with a scourer … that green scotch brite you are using sounds fine …. But if its deep , a stainless steel scrubber will be more abrasive and effective …. But will scratch your shiny stuff .I prefer to use soap ( a bar of soap ) while scrubbing as soap is Caustic and will help Neutralise any lingering acid .

Then rinse in clean water .
artooks
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Re: Rusting Problem Need Help

Post by artooks »

Yummyrum wrote: Mon Oct 25, 2021 3:53 am Well in normal use it should not rust .just a rinse in water should be all thats needed . Don’t put Vinegar , citric acid or any other acidic things near it .

If it has rust spots , you need to physically remove the rust with a scourer … that green scotch brite you are using sounds fine …. But if its deep , a stainless steel scrubber will be more abrasive and effective …. But will scratch your shiny stuff .I prefer to use soap ( a bar of soap ) while scrubbing as soap is Caustic and will help Neutralise any lingering acid .

Then rinse in clean water .
Maybe the water that I am using to clean has iron parts that gets hold on the parts, I do not know, maybe I shout dry the parts after each use to prevent this, Anyway, thanks for the input. You mentioned to use a scourer or ss scrubber, while I was reading the older posts, it has been said not to use scrubbers or any other metallic parts on SS, to be honest I do not know the reason for that, so if I can use scrubber it will be more easy on my side, for example I am having a very hard time cleaning the tube end os my shot gun condenser, if I were to use a scrubber it will be more effective definitely, so let me ask you this, are you saying that after using a scrubber to clean a rusted patch should I use soap to neutralize it and if so how, do you mean to use the soap during cleaning with scrubber or just afterwards ?

Thanks
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Ben
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Re: Rusting Problem Need Help

Post by Ben »

The reason you don't generally scrub stainless with anything abrasive is that will break up the passivated layer that prevents corrosion, so you have to repassivate with the correct acid solution. Use phosphoric acid for your passivation, it will convert any remaining rust to iron phosphate, which is non reactive. Star-san has enough phosphoric acid content to do what you need, just use the mix ratio for passivation.

What are the parts, and where did you source them from? Not all stainless is created equal. If these rust spots are where welds are its a welding flaw.
:)
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Demy
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Re: Rusting Problem Need Help

Post by Demy »

Generally the stainless steel should not rust under normal conditions. Your water cannot rust the stainless steel. I saw some stainless steel with rust in some cases (my experience): poor quality of the stainless steel in contact with very acidic substances, overheating of parts at very high temperatures, welding, cutting with a previously used disc on the iron, a piece of rusty iron Long contact with stainless steel, glued sparks while cutting iron ..... and others who at the moment escape me.
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Demy
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Re: Rusting Problem Need Help

Post by Demy »

I found an interesting very simple article if someone is interested https://www.rocheindustry.com/does-stai ... teel-rust/
artooks
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Re: Rusting Problem Need Help

Post by artooks »

Ben wrote: Mon Oct 25, 2021 6:44 am The reason you don't generally scrub stainless with anything abrasive is that will break up the passivated layer that prevents corrosion, so you have to repassivate with the correct acid solution. Use phosphoric acid for your passivation, it will convert any remaining rust to iron phosphate, which is non reactive. Star-san has enough phosphoric acid content to do what you need, just use the mix ratio for passivation.

What are the parts, and where did you source them from? Not all stainless is created equal. If these rust spots are where welds are its a welding flaw.
Hi,

I own a CCVM still, it is modular with tri-clamps, I sourced many parts from Still Dragon which is a respectable shop, but I must say the shotgun condenser is not really good the tubes are not smooth and all the time I face with rust problem.
artooks
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Re: Rusting Problem Need Help

Post by artooks »

Demy wrote: Mon Oct 25, 2021 8:27 am I found an interesting very simple article if someone is interested https://www.rocheindustry.com/does-stai ... teel-rust/
Thanks this article is very comprehensive on this matter.
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zed255
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Re: Rusting Problem Need Help

Post by zed255 »

I had a mysterious rusting issue this summer. I discovered that the jug of concentrated hydrochloric acid I had in my chemicals storage area was degrading (the container, not the acid) and a long slow fuming was happening in my work area. Decanted the last litre into a glass chemical container with correct closure and problem solved. Could you have any kind of acid in your environment that is poorly contained? After resolving my containment problem and cleaning all my stainless and copper it all stays clear of corrosion. Even vinegar could be a source of your issue, it doesn't have to be a strong or concentrated acid.
----------
Zed

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If you can't explain it simply, you don't understand it well enough.
artooks
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Re: Rusting Problem Need Help

Post by artooks »

zed255 wrote: Mon Oct 25, 2021 8:59 am I had a mysterious rusting issue this summer. I discovered that the jug of concentrated hydrochloric acid I had in my chemicals storage area was degrading (the container, not the acid) and a long slow fuming was happening in my work area. Decanted the last litre into a glass chemical container with correct closure and problem solved. Could you have any kind of acid in your environment that is poorly contained? After resolving my containment problem and cleaning all my stainless and copper it all stays clear of corrosion. Even vinegar could be a source of your issue, it doesn't have to be a strong or concentrated acid.
Well in my area I have vinegar but all sealed up in a plastic bottle not even opened I have citric acid in salt form I do not know if this could have reach the still and affect it. But I will check again.
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