Corrosion on mast fittings

Silver Fox

Growing old, not up
Hello all

Been lurking for a while, first time posting and I hope someone can help / advise me. I just bought a Laser with a hull number of 149xxx which puts it in the 25 or so years old range. I believe the spars are probably of the same vintage; on the mast at the gooseneck and vang plate (?) there is some corrosion due to stainless steel and aluminium being dis-similar metals. The mast is quite pitted at the corners of the fittings and I can't say what it looks like underneath them.

My question is should I drill out the rivets and replace the fittings directly opposite where they were originally ? (i.e. spin the mast 180 degrees ?) Depending on the damage, can I treat and fill the corrosion also ? What brands of fillers/treatments/rivets should I look for ?

Thanks in advance for your help.

BL
 
should I drill out the rivets and replace the fittings directly opposite where they were originally ? (i.e. spin the mast 180 degrees ?)
No, you should NOT. That would double the number of screw holes at a given cross-section, which would seriously weaken the mast at those points (having holes on the tensioned edge of a spar is extra bad).

You might want to drill out the gooseneck and vang tang to see what the damage really looks like. You could even post a few pictures here. If it's really bad then the solution is to spin the mast 180° around its fore-and-aft axis, that is, "end-for-end" it. For that you need a new bottom plug and a relatively hard-to-find countersunk rivet, too.

_
 
If you are already going to the trouble of drilling everything out, I would through-bolt the fittings when putting everything back together instead of re-riveting.
 
My 2-cents worth.... corrosion of the rivet holes beneath the Vang tang on the mast caused the whole thing to break off. At an inconvenient time & place. Outgoing tide under the Golden Gate bridge. I got rescued OK, but since then when I see corrosion like that anywhere on a spar, I am replacing it.
 
Thanks LaLi, torrid and Eyeper for your input. Might save the pennies and buy new spars, given that they may be getting on 25 years old......
 
They may not be worth saving. For your next sections there is an anti-corrosion paste you can get and put a layer between the dissimilar metals before riveting them together. Other than that just make sure to wash everything down with fresh water after every salt water dip.
 

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