galvanic corrosion on alum trailer

[brokeboater]

I have a 1986 aluminum trailer i am trying to get a few more years out of. the spring hangers are made of steel and are bolted to the bottom of the main aluminum I beam. the crevice made between the two pieces have caused a corrosion to form on the aluminum and has caused some pitting in it. this is a salt water used trailer but surprisingly the spring hangers themselves are in good shape except for being somewhat distorted from the build up of corrosion in the crevice, to the point of actually curving them down and away from the I beam (the reason for my work). the pitting concerns me some even though it is not anywhere near half way thru or anything. my question is what shall i do to try and prevent this from happening again? an insulator of some type? should i treat the pitted area with anything or paint? i'm pretty sure the hangers have been replaced before so it hasn't taken 26 years or so to cause this to happen. thanks in advance.

oh yeah, for what its worth, the spring hangers looked to have been painted with "cool seal" like you put on top of mobile homes. the galvanizing under it was still nice and shiny looking. they were in good enough shape i plan to straighten them out and reuse.

 

[Scott Danforth]

Re: galvanic corrosion on alum trailer

galvanic corrosion is an electrical process from dis-similar metals in a salt environment. to prevent it, dont put it in salt water. if you want to live with it, make sure you have a sacrificial anode bolted to the trailer.

as far as the pitted area, would need a pic. if its half-way thru the material, I would look into replacing the trailer. welding is not an option because it takes the temper out of the aluminum.