Stainless Prop Film

csukraw

Seaman Apprentice
Joined
Sep 20, 2022
Messages
31
Prop looked shiny last year. Now all of a sudden it looks super dull. Wondering if it’s galvanic corrosion. One thought, I replaced the plug assembly last year and wasn’t able to get a bolt through to reattach he ground wire inside the bilge. Figured I don’t store in water so wasn’t a huge deal. Fresh water use only. Not sure if that would cause this. Or maybe my anodes are bad. Pics below of the prop last year, the prop this year and the anodes. Any advice?
 

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Deepdiversplit

Recruit
Joined
Jul 13, 2023
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5
Hmm, I'd say it looks like SS from China? I have had similiar results on some SS accesories that I bought for my rig after washing it and the parts where made in China. :-(
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,967
Looks like a non-Polished SS Alloy that was Nickel/Chrome Plated. Boating in a Lake/River with a low PH Level(acidic), may have stripped the Plating off
 

csukraw

Seaman Apprentice
Joined
Sep 20, 2022
Messages
31
UPDATE: A little scrubbing with CLR and it came back. Not sure what the issue was exactly but it’s looking like it did before now.
 

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dingbat

Supreme Mariner
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Nov 20, 2001
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UPDATE: A little scrubbing with CLR and it came back. Not sure what the issue was exactly but it’s looking like it did before now.
Combination of hot exhaust and minerals in the water.

Check to make sure you don't have a cooling problem with your motor.
 

jimmbo

Supreme Mariner
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Combination of hot exhaust and minerals in the water.

Check to make sure you don't have a cooling problem with your motor.
Perhaps it had been run in an Alkaline Lake, but there the Aluminium usually takes a Beating
 

QBhoy

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Mar 10, 2016
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Surely you’re kidding us on here ! That’s got to be two different props pictured there.
 

csukraw

Seaman Apprentice
Joined
Sep 20, 2022
Messages
31
Nope! Same prop. I had to give it a good scrubbing but the CLR took whatever coating was off it. I’ve followed up with a little bit of polishing, but that’s it.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,503
Perhaps it had been run in an Alkaline Lake, but there the Aluminium usually takes a Beating
Stainless has very good resistance to alkaline attack. Would require polishing to restore the shine.

Seeing it came off with CLR, I'm guessing calcium or lime buildup depending on what part of the country he is in.
 

csukraw

Seaman Apprentice
Joined
Sep 20, 2022
Messages
31
Southern California. Just got back from Lake Mohave so maybe it happened there. I remember it being shiny before that trip.
 

jimmbo

Supreme Mariner
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Stainless has very good resistance to alkaline attack. Would require polishing to restore the shine.

Seeing it came off with CLR, I'm guessing calcium or lime buildup depending on what part of the country he is in.
Which is why a few posts back, I thought Low PH.
I guess it could be Brackish Water.
The water in Lake Mohave is a Chemical Stew, and is quite Brackish.
 
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QBhoy

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Often guilty of over thinking things, when it comes to odd things like this. But thought I’d mention what’s in my head anyway…just in case…I think I’d be tempted to have a look at the gear oil. Just to put mind at rest. Make sure all is well and no black looking, burnt smelling oil is present in there. Rule out it being as a result of rather serious levels of heat transfer. Looks very unusual to me, I must say. One of the pictures even looks like it has a lovely professional painted finish. The picture most recently shown after you cleaned her up..perhaps shows some colour in the stainless finish. This can be common on props in the budget end of the market…but can also be a sign of thermal transfer.
Just make certain there are no signs of arcing, caused by a circuit seeking its way to earth or ground. Looks like there are a number of bonding earth wires meeting there.
Anyway. Voice of doom here..sorry about that..but got it off my mind..you can do what you wish with it. All the best.
 
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JimS123

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Jul 27, 2007
Messages
7,993
I had the same problem. The prop was shiny, then after a week moored at a campsite dock it was all dull. It polished out, but boy was i pissed.

I contacted the marina and they said they were having electrical problems on that dock after some repairs and the electrician was working on it.
 

csukraw

Seaman Apprentice
Joined
Sep 20, 2022
Messages
31
Yeah actually I saw a sign in the marina at Mohave that mentioned potential electrical currents in the water. So that’s likely what it was. Frustrating.
 

jimmbo

Supreme Mariner
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May 24, 2004
Messages
12,967
I really don't like People learning about the Shocking Truth of Electricity, anywhere near Water. I know that any Power to a Dock would have to be on an Isolation Circuit, and should be safe, but there shouldn't be any Stray Currents. I suspect the Marina cut some Corners somewhere and the Wiring isn't to Code
 
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