Mysterious grey powder on aluminum boat

polk county

Petty Officer 2nd Class
Joined
Jan 22, 2008
Messages
128
I have an aluminum john boat that is missing a lot of paint from years of use. I noticed that objects such as coolers, gas tank and dry boxes all have grey powder deposits where they slide around on the floor of the bare aluminum. The powder looks like graphite powder being a grayish black in color. It feels very fine and will not come off with soap and water. Is this my aluminum boat shedding metal? Any ideas
Thanks
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Re: Mysterious grey powder on aluminum boat

Aluminum will come off on most anything that rubs against it .
 

shrew

Lieutenant
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Dec 29, 2006
Messages
1,309
Re: Mysterious grey powder on aluminum boat

Aluminum oxidates when exposed. I believe that this creates a protective barrier on the surface of the aluminum.
 

rbh

Fleet Admiral
Joined
Mar 21, 2009
Messages
7,939
Re: Mysterious grey powder on aluminum boat

Aluminum oxidization is usually found under painted areas where the water got in and sat, kinda like aluminum rust, and it begins to pit the aluminum.
I would clean the area till it shines or is clear of the oxidization, then hit it with a aluminum primer to etch the metal then paint over it to seal it if you are not going to leave it bare.
 

Fleetwin

Lieutenant Junior Grade
Joined
Nov 23, 2011
Messages
1,141
Re: Mysterious grey powder on aluminum boat

Aluminum oxidates when exposed. I believe that this creates a protective barrier on the surface of the aluminum.

Correct and completely normal, to a point.
 

H20Rat

Vice Admiral
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Mar 8, 2009
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5,199
Re: Mysterious grey powder on aluminum boat

aluminum rust... entirely normal.
 

acarter92

Petty Officer 2nd Class
Joined
Dec 25, 2011
Messages
198
Re: Mysterious grey powder on aluminum boat

I have an aluminum john boat that is missing a lot of paint from years of use. I noticed that objects such as coolers, gas tank and dry boxes all have grey powder deposits where they slide around on the floor of the bare aluminum. The powder looks like graphite powder being a grayish black in color. It feels very fine and will not come off with soap and water. Is this my aluminum boat shedding metal? Any ideas
Thanks

It's probably a mixture of the aluminum rubbing off and then oxidizing (rusting).

You could put something over it (carpet, rubber, etc...) Or just let it go, I doubt it will really hurt anything...

Austin
 
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