APPARENT RUST STREAKS

[Guest]

APPARENT RUST STREAKS

I have a 70' foot wooden boat built in 1961.
I believe it has the original stainless steel rub rails.
THE PROBLEM:
After a rain or running through salt water, there is a rusty looking substance that runs out from
underneath the rail, and stains the hull. I have removed one section of rail; on thehull, the area around
all the screws appeared to be rusty or corroded.
I am looking for a way to solve this problem and eliminate the rust marks running down the hull.

Sincerely,

Richard A. Sales, Captain
EMAIL: Captainsales@cs.com

 

[Guest]

Stainless steel is only corrosion resistant in the presence of oxygen. It is not effective if immersed. It looks as though your wood is saturated and is causing the screws to corrode.

Dry out and West System your wood and use new 17/4 or higher grade stainless screws, or use brass screws.

In your previous posting you said you had a 70 foot fibreglass boat - do you have two 70 footers?!!!!!

 

[Guest]

Stainless steel screws going rusty is not uncommon. The reason is that during the turning or forming process, the surfaces of screws pick up tool steel, which gets imbedded in the surface. Tool steels, which are carbon steels will rust very well. Decent manufacturers of external equipment, demand that stainless fixing screws are passivated by pickling the screws in acid to remove these tool steel residues. On no account use brass screws on stainless steel. They will dissapear even faster. Always use the same steel as the object you are fixing. This reduces galvanic corrosion.