Alloy Stains Reefing Genoa!s

[Guest]

I have a Cornbrook roller reefing genoa on my achilles Yacht the foil is made up in 3 sections and where the foil is sleeved together this is imparting alloy oxide stains on my genoa.
Without removing the genoa and re hoisting it every time I use it. Can anyone give advice on how to stop the oxidization from the foil?

 

[LORDNELSON]

Are you sure the stains are Alluminium Oxide? If they are why are they only occuring at the joints? Some foils are glued and/or screwed at the joints; is it possible that you have some form of interaction between two different metals/substances at the joint which is producing the stains?

 

[PuffTheMagicDragon]

It is possible that the ends of each section of profile are not anodised since these were probably cut from a long length of extrusion that had already been anodised. The butting ends would grind ever so slightly against each other each time that you use the furler. This would cause minute particles of oxide to accumulate at the joint, ready to be mopped up by the genoa. I would lower the aluminum profiles and then reassemble after smearing the ends with transparent silicone (the kind that is used to stick aquaria together). Wipe away most of what oozes out BUT not all, leaving a little bead all round the joint. I believe that this should keep your genoa off any oxide that might still find its way past the silicone. BTW if you're on a pontoon it helps if you would regularly spray fresh water all over it, especially the lower sections and the drum (Finger-on-end-of-hose type of thing!). OTOH if you get a lot of rain in your part of the world this might not be necessary.

Fair winds!

Wally

 

[Guest]

There is a slight gap maybe 2mm and the foil is riveted onto the adjacent slug it would appear that there are no signs of corrosion from the rivet as it appears to be monal.

 

[Guest]

Thanks Wally I think you may have hit the nail on the head the joint maybe flexing to have taken off the anodising off the ends.
I wonder if there is a way of sealing the ends prior to siliconing the joint. any Idea!s would be welcome

 

[charles_reed]

I'm afraid you may be posing the wrong question.
From my experience the staining is caused not by the oxide, which in hydrated form is white, but by metallic fragments due to the sections working on the joining inserts.

Try tightening up the grubscrews or, if you have the mast down stripping the foil and re-assembling.
I had this problem until I moved up to a heavier section foil and used cyano-acrylic jointing compound in the inserts to prevent any working.
Left too long you'll have so much slop that your only solution will be to replace headfoil and forestay.