Mast Collar Cavity/Corrosion

[theway]

I have what seems to be relatively small cavity on my collar. The rest of the collar seems pretty strong when I jab at it with a screwdriver. Any suggestions from the attached pictures?
(It goes through to the wedges)

I'm not really in a position to replace the collar. I was thinking about filling the cavity with JB Steelstick or Waterweld, or perhaps just some silicon to prevent any water leaking in.

Does the collar do much structural support or is it mostly an interface for the mast and deck and alignment for mast wedges?

Thanks!

[Sailmonkey]

Suggestions?

Pull the mast and check it for the same corrosion that is plaguing the collar.

And stop covering everything with silicone caulk!! ;-)

[theway]

Originally Posted by Sailmonkey

Suggestions?

Pull the mast and check it for the same corrosion that is plaguing the collar.

And stop covering everything with silicone caulk!! ;-)

The mast was out about 6 years ago and appeared strong. The collar at that time probably should have been replaced as it was showing signs or wear. (Hind sight)

I covered the wedges with silicone as an extra layer of leak protection to fill the larger gaps. Neoprene Collar wasn't 100% leakproof.

[UNCIVILIZED]

From the pics all I can discern is that you have s large example of galvanic corrosion in aluminum. But as to what it formerly was, repeat, was, I've no idea. And it appears to have been dead & buried for a few decades.

[Suijin]

Dear lord. That's a cluster-$*^# of issues.

Wedges help to stabilize the mast but don't really provide any meaningful structural support.

As for the silicone, you've made a bad situation worse. Ideally you'd remove it all and wet sand every surface it was on (silicone is a sealant and has poor adhesive qualities; when it breaks seal and/or comes off it leaves silicon residue and nothing will stick to that surface...not even more silicone) and use a proper marine adhesive sealant.

Silicone sucks in your bathtub. It sucks even worse on a boat. It's next to useless.

As for JB weld, you'd have to grind down to good aluminum to get a good bond. You'd have to do that for anything you try and patch it with.

[Stumble]

I... just... good lord...

First silicone is acidic, guess what the major weakness of aluminium is? It's to acids. So all that silicone sealant you have applied over the years is causing, in part, your mast corrosion.

Second, wedges are massive structural elements of the rig. They provide substantial support to the mast. It is litterly the reason why keel stepped masts can be lighter than Deck stepped masts.

Third, did I mention that silicone is a terrible sealant on boats? The first time the mast shifts, possibly because the wedges were incorrectly installed, the almost zero binding strength of the silicone probably failed and water intrusion started again.


To fix this... remove all the silicone, fix the collar, then pour spartite to fix this permanently. Finally remove all silicone from the boat, there is simply no place on a boat where it is the right tool.

[theway]

I'm mainly concerned with the collar and if it's going to cause me trouble over the next year and 23,000 miles around the globe. It made it from California to Hawaii with no problem. I leave for Tahiti in a month and noticed it when I took off the cover to stop the leaks.

The silicone was just put on today, but is now coming off. Didn't know it was acidic (I'm learning). I'm not sure what was used before to seal things, but it was used only on the seems, so the corrosion would seem to be from something else.

I'll check out sparetite.

Thanks.

[Suijin]

Originally Posted by theway

I'll check out sparetite.

Thanks.

Spartite is expensive and molds to the mast and collar, so you're going to want to repair/replace the collar before you even bother with it.

At the very least, pull the collar and get down to good metal. If it developed that hole who knows how bad the rest of it is under all that corrosion.

[theway]

Thanks for your continued feedback on this...

I'd love to pull it all but I'm not sure I have the time or capacity right now. Most of the collar corrosion seems to be on the surface when I jab around with the screw driver it's quite solid. Also a view from inside it appears that the wedges are also supported by the fiberglass too, which is not aluminum nor corroding
(See pic below)

Also how acidic is the silicone? Am I screwed because it was on there for a couple hours, and do I need to get every small bit of it off the aluminum. Over what period of time are we talking about for acid corrosion from the silicone. The mast happens to be painted so I hope that fends of anything that isn't left long term.

[UNCIVILIZED]

Note(s):
- Spartite doesn't form a watertight seal around the mast/mast collar. It's a synthetic, 2-part, pour in place polymer which takes the place of wooden or composite mast wedges.

- There are a host of threads here on CF about how to remove Silicone. Including the super slippery film that it leaves behind.

- It'll be tough to see how big your problem is or isn't until all of the aluminum oxide is removed. Meaning getting things down to good, bare metal, with regards to the bits that look super fugly in the pics.

- If there's no corrosion, or issues with the paint on your mast tube now, it should be fine. But see about removing the silicone when you can.

- Isolate dissimilar metals. Aluminum, & Stainless mostly, in this case. It's a recipe for a high dollar battery (repair).

- Fix any serious, & or potentially structural problems prior to leaving port & civilization. Fixing such things mid-ocean bites!

- Most well sealed masts are sealed in layers. Meaning that they have several independent "seals". Sometimes to include.
1) A rubber boot (or neoprene). Often as not glued on/glued to itself instead of having a seam, so that it's nigh on as watertight as the neck seal on a diver's drysuit.
2) A canvas boot. Again, with a sealed seam.
3) Duct tape. Often a whole role... per seal. Though not directly on top of more fragile seal types like rubber boots.
4) "Other". Such as stitched, sealed, & oiled leather. Though oil is bad for rubber, so...
5) Prayer & sacrifices to Neptune

Fortunately there's no shortage of knowledge on this topic out there, so it should be solvable. But make sure that the mast & partners, including your wedges (or Spartite) are structurally stable, & in the right place, prior to going nuts making things watertight again. For obvious reasons.

Ah, & there are lots of options for coating aluminum that can help to mitigate corrosion over time, & or with immersion. Though even with them, things need to be regularly inspected for maintenance.

[theway]

Originally Posted by UNCIVILIZED

Note(s):
- Spartite doesn't form a watertight seal
....

Thanks for the info. I removed as much of the silicone as I can for now and will look up how to do it more thoroughly soon. It's kind of in the cracks a bit now but it looks pretty good, I'm not sure how much it takes to do damage.

And yes, layers is what I have been using. Neoprene first and then sunbrella to protect the neoprene from the sun. I think over time the neoprene has broken down and stops less of the rain. I put a few layers of duct tape under the neoprene for now and will open it up soon to clean and inspect again.

The wedges and mast are pretty damn tight and strong as I mentioned and have been for 6 yrs. if the silicone doesn't rapidly eat aluminum, then I think I'll be good for some time.

[Stumble]

If the silicone has only been on for a few hours, or even a few days then it isn't much of an issue. It just needs to be removed but it won't do long term damage, I thought originally it had been there for a while not just a day or so.

Spartite if applied properly won't bond to the collar. It's not supposed to. The whole advantage of it is that once poured it takes the place of wedges and when you pull the rig in the future it drops back perfectly in place so you never have to mess with it again. As Uncivlized mentioned it's a permanent mast wedge, but actually much better since it is infinitely repeatable.

By itself Spartite isn't a complete seal, but it does about 90% of the work. It leaves a thin sliver around between itself and the collar. Toss a boot over it and that's pretty much the end of the issue.

[theway]

Anybody try wd-40 to remove silicone? Or baking soda and vegetable oil? Baking soda and a brush seems like a good start.

I'm not sure I can get the specialty stuff here in Hawaii.

[mike d.]

Acetone is the only thing I use that works to remove the silicone residue! Even with it, it takes several times, to get it cleaned off! I noticed it the pics, it appears you have a crack, in your gel coat, about middle of the collar. I would be concerned about what is going on underneath, if it is a crack. If that is a hole in the collar, you are getting water into the deck core, if it wasn't sealed, at the factory! You could try vinegar soaked rags on , around the collar to clean the aluminum oxide off! A hardware store should have Aluminum Jelly!

[theway]

Originally Posted by mike d.

Acetone is the only thing I use that works to remove the silicone residue! Even with it, it takes several times, to get it cleaned off! I noticed it the pics, it appears you have a crack, in your gel coat, about middle of the collar. I would be concerned about what is going on underneath, if it is a crack. If that is a hole in the collar, you are getting water into the deck core, if it wasn't sealed, at the factory! You could try vinegar soaked rags on , around the collar to clean the aluminum oxide off! A hardware store should have Aluminum Jelly!

Thanks for the response.

I suppose acetone is a decent place to start.

I noticed that crack too, and the many others on my deck and cockpit. They all seem to be very shallow surface cracks.

There was definitely water getting in, around the mast most likely through the small gaps in the wedges, but it rarely rains hard enough to see the results inside as in water dripping down the mast usually. The duck tape will probably prevent that from happening now. I'll give it time to dry and keep an eye on it. Removing some of the ceiling panels inside for an inspection will happen in the near future.