Mast corrosion

[Tom Hinrichs]

I'm currently re-fitting and paintingmy mast. The only real corrosion issueis the area under the spreader bases.There was no bedding or barrier usedin the original installation and Ifound extinsive corrosion betweenthe stainless and the mast. I contacteda local rigging shop and they suggestedputting plates of aluminum between the mast and the spreader bases before re-installation. Comments?

 

[Allan Hadad]

Corrosion Protection

When I repainted my mast and replaced all of the rigging I made sure that there was minimal contact between the dissimilar metals. I coated each fastener liberally with a plumbers compound you can find in hardware stores. It provides for antisieze and dries to a rubbery consistency. Look for a small blue and white plastic tube. The second thing I did was to install plastic washers under every single stainless steel bolt head and nut and between tunbuckle tangs and the mast. This prevents scoring of the painted surface when tightening these fasteners together. That way the stainless steel and aluminium contact is quite minimum. After 3 years, I have not seen any blistering up of the paint, that would suggest galvanic corrosion is re-occuring.Good Luck,Allan HadadH34 "Alchemie"SF Bay

 

[Tom Hinrichs]

More details

I guess I should have been more specificabout the "Plates". the rigging shopmade it sound like common practice topop-rivet plates over the pitted areaand have new compression tubes madethat are long enough to take the loadfrom the new outer plates

 

[Harry Asbury]

Same problem & my fix

Tom, I had the same problem last year on my '27. I was installing a new roller furling system and took down my mast to check wiring, standing rigging, etc.. Found corrosion at each fitting. My fix was after removing everything from the mast I sand blasted the entire mast down to bare metal. Made very sure I removed all corrosion from the pitted areas. I then filled all pits with JB Weld. When hard I sanded and smoothed the filled areas. Painted the mast with three coats of epoxy paint and let set for several days to cure. While waiting I bead blasted all stainless parts and buffed bright again. I also did my spreader arms, mast cap, all rollers(sheaves) and pins. I then borrowed an industrial air pop rivet gun and put everything back together. I live in north Florida so I sail all year long, right after install the furling and putting the mast back on the boat we took a two week sailing vacation down the west coast of FL and back across the Gulf. So far no problems at all with the mast. Oh, I also did the boom while I was at it. I checked it pretty close last weekend, no signs at all of returning corrosion, so I guess it worked. Harry Asbury on Dolly Phynne

 

[TOM M.]

DON'T RIVET WELD

Your mast can easily be repaired with plate that is rolled to fit the contour, then heli-arced welded, the area mus be ground to fit the plate, riveting is not strong enough, welding enhances the strength of the mast, also if there is any small corrosion areas on the mast, these too can be ground down to the bare metal and filled welded then blended, then all repaired areas can be alodined, zinc chromate primered and painted white, and the mast will be as good as new.