Rusting Gas Caps?

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Bill3558

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C Dory Year
2006
C Dory Model
22 Cruiser
Vessel Name
Pluto
On my boat the stainless gas caps have a light rust on the surface. I have cleaned and polished them but it always comes back in a day or so. The water cap on the other hand is perfect.

The boat is kept in the water with shore power plugged in. I wonder if its some kind of weird electrolysis or something.

Any thoughts would be appreciated.


Bill, Beth and Pluto
 
Bill3558":2t1xmz8q said:
On my boat the stainless gas caps have a light rust on the surface. I have cleaned and polished them but it always comes back in a day or so. The water cap on the other hand is perfect.

The boat is kept in the water with shore power plugged in. I wonder if its some kind of weird electrolysis or something.

Any thoughts would be appreciated.


Bill, Beth and Pluto
Click to expand...

Bill-

What are you polishing them with?

The Bartender's Friend (like Bon Ami or Comet, but about 1/2 way in between in abrasiveness) works great.

Wax the stainless after polishing for added protection.

Steel wool will destroy the molecular/alloy structure of stainless steel that enables it to be stainless (non-rustable). It's friction creates millions of miniscule welds that then break off, leaving "loose" iron atoms galore on the surface that then rust.

Are you moored in salt water? Is there a ground wire attached to the underside of the gas fill fitting?

On the other hand, you might just have a cheap form of stainless that isn't rust-proof ! (Hopefully less likely!)

Joe. :teeth
 
Check out THIS THREAD

I went to Worst Marine to get some Flitz but when there they talked me into a more expensive German product designed for stainless passivation. I can't find the product in their online site, though. But what you need is a passivation product.

Warren
 
I hate to say it, but: Cheap Chinese fittings and SS. OK, its not so cheap. This is what they got. I am living with it--and cleaning. There is really no excuse for this. I have had boats crossing oceans, with zero rust on the SS after 15 to 20 days at sea and coated with salt...So it depends on the quality of the SS and the way that it is treaded in the -manufacturing process.
 
Thank you all for your thoughts. The thing thats weirding me out is why the gas caps would rust but the water tank cap doesnt. They are both exposed to the same external environment.
Yes the boat is moored in (mostly) salt water on the Ogeechee river.

Joe, when you say do I have a "ground wire" attached to the cap. Do you mean the beaded safety wire? Thats all that is attached. Should I have more than that?

Thanks again.
 
I will post pictures in my album so you can see what I'm talking about.
 
My gas caps don't rust, but my water and head pumpout do.

Dunno what that means.

Warren
 
Bill3558":33amrky9 said:
Joe, when you say do I have a "ground wire" attached to the cap. Do you mean the beaded safety wire? Thats all that is attached. Should I have more than that?

Thanks again.
Click to expand...

Bill, I think Joe was referring to the ground wire attached under the deck that is there to prevent a static discharge when you touch the gas nozzle to the deck fitting. It can't be seen unless you look underneath. It's not the beaded safety chain that prevents you from losing the cap, although with rust appearing, that might not be so bad. My 1994 fittings are still pristine and I have never done anything but wash them.

Charlie
 
Bill3558":2w14c9et said:
Thank you all for your thoughts. The thing thats weirding me out is why the gas caps would rust but the water tank cap doesnt. They are both exposed to the same external environment.
Yes the boat is moored in (mostly) salt water on the Ogeechee river.

Joe, when you say do I have a "ground wire" attached to the cap. Do you mean the beaded safety wire? Thats all that is attached. Should I have more than that?

Thanks again.
Click to expand...

What I was thinking about the grounding wire was that the gas cap is grounded whereas the waterfill is not, and that could be the difference in why one rusts and the other doesn't.

Joe.
 
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