just noticed some corrosion on my mast where one of the fittings is attached. Crack in paint and a spreading bubble of corrosion. Its fore spar and five years old. Apparently there was an issue in the past re corrosion of masts in bcd’s. Any comments and how is this best dealt with, cos it ain’t going away?..
This is a common and inevitable problem not only with BCC masts, but with all aluminum masts with stainless fitings and fasteners. Do an internet search on “bi-metallic corossion” and you will find more than you want to know about this unhappy process. Best practice is to do as good a job as possible of protecting the two metals from direct contact – easier said than done. I alwas use a slather of Tef-Gel on fasteners and between mast and fittings when mounting hardware or removing and replacing fittings. To guote the Jamestown marine supplies catalog, “Ultra Tef-Gel is a fastener lubricant used to prevent corrosion and seizing. Developed using aerospace industry experience, properly applied Tef Gel eliminates the blistering, corrosion, rust, galling, and seizing of hardware commonly experienced in corrosive environments and with dissimilar metals. It can be used in all weather conditions. The amazing composition is derived from a specially formulated PTFE paste. Syringe tube design for easy application. Whether it swivels, slips or slides, Tef-Gel will protect and ensure the painless future removal of assembled hardware.”
Expensive, and worth every penny. A little goes a long way in minimizing (but probably not “eliminating”) future problems
I haven’t tried Tef-Gel, but I can highly recommend pure lanolin extracted from sheep’s wool, which also comes in the form of a thick gel.
This was recommended by John Purins - the previous owner of Adventure.
It is incredibly durable, and has been used for all the screws and fittings on Adventure’s spars.
Screws dipped in lanolin before being driven into the aluminium hold well, and are very easy to remove months or even years later.
Ahoy Stewart , similar questions were asked and answered on the Brion Toss Rigging Forum “Spar Talk” http://briontoss.com/spartalk/forumdisplay.php?s=&f=1&page=1&pp&sort=lastpost&order=desc&daysprune=7
I too wanted a remedy to stop the spread of that white powder corrosion lump or blister.
My first step was to clean out all the white powder, best as I could , then apply a caustic soda solution , I mixed up a batch of Lye and used that.
Wash with fresh water, dry , then coat with zinc chromate primer, then re-paint.
Some boaters use Alodine (sp-?) as an etch , then re-paint .
After doing some search , I read that adhesive silicon neutral cure is also a good insulator like Tef-Gel and older corroded parts that were bedded in silicon were more easy to remove .
Good Luck , and please report back to this forum, on your method and results .
West System sells a kit for aluminum repair which includes an etch, Alodine
I think, and aluminum powder to thicken the mix. I used it for mast step
renovation and it works well.
On Fri, May 2, 2014 at 12:19 PM, BCC Forums bccforums@samlmorse.com wrote:
As stated the West System kit is a good product. I would remove the fitting, repair the corrosion and install the fitting using either Tef-Gel or anhydrous lanolin. Anhydrous Lanolin is hydrophobic and dielectric, i.e. is does not mix with water and is an electrical insulator. Anhydrous lanolin is available online for about $20 (USD) for 1 pound. Drug store may have stock it but you will need to ask.
I use anhydrous lanolin on fastenings, turnbuckles, and to coat the plates on mast fittings. It’s an old remedy handed down from the days of sail.
Don’t forget we are in a fundraising drive.
Rod
Just catching up with email now back from 3 months sailing boohoo. Talked to forespar the maker and they are now out of making masts! They are sending someone out to do the repair at their expense, but I suspect the show ain’t over cos there will likely be more happening elsewhere. It is obviously galvanic as it only happens where different metals meet . There are dinks elsewhere where the paint chipped but no corrosion.