Preferred Spreader End Corrosion Prevention?

[JChorlton]

I have a Spencer 44 with aluminum spars. Apparently I was a little overzealous in my last application of rigging tape on the spreader ends for temporary chafe protection. Water seems to have accumulated inside the tape and when I removed it to sew on some boots there was quite a bit of the white aluminum corrosion products in the groove on the spreader end. Obviously I didn't have enough stuff between the stainless wire and the aluminum spreader end to prevent the galvanic interaction and there was also no place for the water to drain out. My spreader ends are all aluminum and just have one groove for the wire and two small holes inboard for the stainless seizing wire to run through.

My question is: what is the preferred method for insulating the wire from aluminum spreader ends?

I was going to slather on anhydrous lanolin but should I use something like teflon tape to parcel over that? I don't really like the idea of getting too much squishy material in between the wire and spreader end that will compress and loosen later.

[Robbie.g]

i use a small piece of, thin wall tube, held in place on the stay with seizing wire isolating the wire and the spreader. then a leather spreader boot over the top...

[Brian Duff]

I just smear some lanolin on the wire before seizing the tip , then proceed to sewing a leather boot , no padding

[JChorlton]

So ...what kind of tubing do you use Robbie ...polyethylene, vinyl? Do you ever have problems with it slipping or compressing after install?

Brian, do you ever have problems with lanolin liquefying in the tropics and running (or creeping) out of the joint? Have you ever found noticeable corrosion after using only lanolin to isolate the dissimilar metals?

John

[Patrick_Seattle]

In an earlier post (search spreader boot) Brion says he prefers those wheels to boots. I think that makes a lot of sense...

-p

[JChorlton]

Originally Posted by Patrick_Seattle

In an earlier post (search spreader boot) Brion says he prefers those wheels to boots. I think that makes a lot of sense...

-p

Yeah, I thought about using spreader rollers but, in the end, I didn't like the attachment methods for the commercially available products. As I recall, one type even had set screws used to clamp it to the shroud without a backing plate (I could be wrong on that). In any case, I just didn't feel inclined to introduce more failure points in the shroud unnecessarily. I suppose that I could have fabricated my own and held them on with seizings but, again, that's just one more area for the wire to be covered up and start corroding and more rollers means more bits to maintain.

On the advice of my sailmaker, I've decided to try boots that I've made out of shearling sheepskin. Nice and soft on the sails and shouldn't hold the moisture inside the spreader end joint. Sure they'll get dirty and won't last any longer than other alternatives but, as with everything on a boat, it's a trade off.

The only thing that I was curious how others had handled was the isolation of the aluminum spreader end from the stainless wire. Even uncovered, this sort of contact between dissimilar metals will continue to corrode (though not as fast as when it's continually wet). I suppose that the ideal solution would be to fabricate some new spreader ends out of Delrin or similar material but I might have to wait until I take the mast down to do that.

John

[Patrick_Seattle]

These instructions to install the Harken one say to wrap the shroud in electrical tape:
http://www.harken.com/pdf/4438.pdf

They might as well say, cut the wire here... Wire wrapped in electrical tape sounds like a recipe for corrosion to me.

I'm assuming I could have the roller on top of the spreader and put some UHMW tape on the upper surface of my spreader (which is painted with alexseal) to prevent it rubbing the spreader. Wonder if that would work out well.

[Robbie.g]

hi
i use what we buy as 'fender insert'.,it is a white thin-walled tube. We also use it to cover wire, in place of the plastic covered wire for lifelines , as here in nz; nz registered boats looking to go offshore and require cat.1 inspection, are not allowed 'normal' plastic covered wire.....
Not noticed any movement or loss of the isolators, like i said i hold the bits of tube in place with seizing wire over the tubing, and this seems to work.

[JChorlton]

Well, to be perfectly honest, Patrick, the amount of corrosion that could occur under that little of tape might be minimal as it probably would under a small seizing - although there's room for variance with how much tape one applies and how tightly it's taped. I think that I'd be a bit more concerned having a split metal washer sawing around the wire with every spin of the roller. If I had to install a roller I would probably go with small seizings of either stainless seizing wire or some sort of small stuff like tarred seine twine and then make a little split washer out of a bit of plastic to act as a bearing. I'm sure that the professional riggers on this forum probably have other opinions. Whatever you use to hold up the roller, it's still going to require maintenance (which was a consideration for me). Tape sticks for a while but most stuff degrades pretty rapidly with UV exposure.

You might find that the slippery tape works for you on some areas but I haven't tried it on spreader ends. I have found that any tape on spreader ends tends to get quickly worn away by the genoa and that the tape, in turn, tends to not be as gentle on the sail threads as I'd like it to be. Maybe I just don't use enough tact in my tacking.

[JChorlton]

Originally Posted by Robbie.g

hi
i use what we buy as 'fender insert'.,it is a white thin-walled tube. We also use it to cover wire, in place of the plastic covered wire for lifelines , as here in nz; nz registered boats looking to go offshore and require cat.1 inspection, are not allowed 'normal' plastic covered wire.....
Not noticed any movement or loss of the isolators, like i said i hold the bits of tube in place with seizing wire over the tubing, and this seems to work.

That's interesting ...so you're not allowed to use the plastic covered lifeline wire but then it's OK if you add segments of the tubing over the bare wire? The tubing must be a little bit more loose on the wire then ...and like that medium hardness polyethylene maybe.