Mast corrosion and bolted tang

[groundtackle]

I’ve been dealing with the results of having my just repainted rig reassembled by a rigging company in Anacortes a few years ago. They failed to properly insulate stainless fittings ( read that as didn’t even try in most cases). I’ve been dealing with the problems as they arise and before they get too severe. It’s been ongoing and I don’t want to go into how annoying it is to pay for a proper job and trust it will be done right then .........
The thing I want now is to arrest the corrosion starting to show at the tangs on the front of my mizzen (jumper stay) and main mast(inner forestry). These are bolted on with the bolt heads inside and without removing the spreaders or drilling new access holes i cant get at the bolt heads.
When I turn the nuts the bolt spins too. There’s about 3/4” of extra bolt protruding. My idea is cut a slot in the bolt end then use a slot screw driver to carefully remove the nut to near the end of the “extra” giving me 1/2 inch of space to work in. From that point, clean , sand, interprotect, paint, insert plastic sheet and sicaflex then tighten nuts again.
I wonder if anyone has a better plan to recommend.
Thanks
Nick

[slug]

Originally Posted by groundtackle

I’ve been dealing with the results of having my just repainted rig reassembled by a rigging company in Anacortes a few years ago. They failed to properly insulate stainless fittings ( read that as didn’t even try in most cases). I’ve been dealing with the problems as they arise and before they get too severe. It’s been ongoing and I don’t want to go into how annoying it is to pay for a proper job and trust it will be done right then .........
The thing I want now is to arrest the corrosion starting to show at the tangs on the front of my mizzen (jumper stay) and main mast(inner forestry). These are bolted on with the bolt heads inside and without removing the spreaders or drilling new access holes i cant get at the bolt heads.
When I turn the nuts the bolt spins too. There’s about 3/4” of extra bolt protruding. My idea is cut a slot in the bolt end then use a slot screw driver to carefully remove the nut to near the end of the “extra” giving me 1/2 inch of space to work in. From that point, clean , sand, interprotect, paint, insert plastic sheet and sicaflex then tighten nuts again.
I wonder if anyone has a better plan to recommend.
Thanks
Nick

Instead of plastic sheet, You can clean up the tang and paint a few coats of epoxy resin on its mating surface
This forms a good insulator and is the way many mast builders do it
Use plenty of sika when you mount the tang... also on the fasteners
100 percent waterproof joint
It shame that the tang is thru bolted , clumsy and very poor workmanship

[Reefmagnet]

Duralac or TefGel makes a very effective barrier. Duralac is easier on the wallet and should be thin enough to paint onto a surface with restricted access.

[Don C L]

Seems your plan is a good one, though the plastic may get eaten away in UV light, tefgel and duralac probably better... but, I may be missing something obvious, but how did they mount those with the bolt heads on the inside?

[groundtackle]

Originally Posted by Don C L

Seems your plan is a good one, though the plastic may get eaten away in UV light, tefgel and duralac probably better... but, I may be missing something obvious, but how did they mount those with the bolt heads on the inside?

When the rig was down I imagine there’s a hole under the spreader, which is very close, that allowed them to put the bolts through from the inside

[roverhi]

Butyl or any caulk would probably work to insulate the fitting. You came up with a creative way to loosen and retighten the bolts without access to heads on the inside.

[macman4190]

The bolts don’t go all the way through the mast and protrude out the opposite side? Mine do.

[s/v michaela]

Black PVC Pipe wrap tape to isolate fittings.. super simple....then Tef gel/Ducolac on all the SS screws/bolts, Monel rivets, and you should be good to go. If you run into a spot where you cant slot the bolt, you can always tig/tack on a little piece of Allen wrench or double nutted all thread....

[Cheechako]

Originally Posted by groundtackle

I’ve been dealing with the results of having my just repainted rig reassembled by a rigging company in Anacortes a few years ago. They failed to properly insulate stainless fittings ( read that as didn’t even try in most cases). I’ve been dealing with the problems as they arise and before they get too severe. It’s been ongoing and I don’t want to go into how annoying it is to pay for a proper job and trust it will be done right then .........
The thing I want now is to arrest the corrosion starting to show at the tangs on the front of my mizzen (jumper stay) and main mast(inner forestry). These are bolted on with the bolt heads inside and without removing the spreaders or drilling new access holes i cant get at the bolt heads.
When I turn the nuts the bolt spins too. There’s about 3/4” of extra bolt protruding. My idea is cut a slot in the bolt end then use a slot screw driver to carefully remove the nut to near the end of the “extra” giving me 1/2 inch of space to work in. From that point, clean , sand, interprotect, paint, insert plastic sheet and sicaflex then tighten nuts again.
I wonder if anyone has a better plan to recommend.
Thanks
Nick

Your plan is basically good, but I think you can do it without making slots etc. See if you can grip the end thread and start those nuts loose. Those don't look like nylok nuts fortunately. Make sure the plastic is UV resistant. I would likely just use some Lanolin.
Here's your problem, not matter if you insulate the plate, the bolts are still going to cause corrosion unless you can insulate those too. That's difficult to do.
I had a big mast completely rebuilt, painted etc in Annapolis. New rigging complete. In less than a year the lower 6 ft of the mast was bubbling a lot of places. Aluminum and SS or bronze just do not mix and are very difficult to islolate.

[jhulmer]

Originally Posted by Don C L

Seems your plan is a good one, though the plastic may get eaten away in UV light, tefgel and duralac probably better... but, I may be missing something obvious, but how did they mount those with the bolt heads on the inside?

I have seen this done with the studs/bolts tack welded to a stainless plate and held in place with 5200. Not ideal but strong. We had to tape one to a long stick and work it into the mast and find the hole ... fiddly!


Tho OP can try and turn a nut and see if the bolt turns. They are probably on a plate if done correctly ... that's the question.


Jim

[groundtackle]

Originally Posted by macman4190

The bolts don’t go all the way through the mast and protrude out the opposite side? Mine do.

They don’t go through. I assume I’d need a compression sleeve to do that and there’s no access to put one on.

[groundtackle]

[QUOTE=jhulmer;3112548]I have seen this done with the studs/bolts tack welded to a stainless plate and held in place with 5200. Not ideal but strong. We had to tape one to a long stick and work it into the mast and find the hole ... fiddly!


“Tho OP can try and turn a nut and see if the bolt turns. They are probably on a plate if done correctly ... that's the question.”

They move independently. I’ve now got the tang off and managed to hang on to the bolts but it’s clear they’d fall into the mast if I let them go. Is tefgel going to work better than working some sicaflex around the bolts?
What does the plastic have to be up resistant when its compressed between two pieces of metal where no uv should be?

[Don C L]

Originally Posted by groundtackle

What does the plastic have to be up resistant when its compressed between two pieces of metal where no uv should be?

That was definitely my thinking when I tried it, and I still don't get it, and if it is squashed I STILL would THINK there would be no problem. But where I used it, and I confess I had not trimmed it to exactly match, the plastic started getting crusty and weak on the edges where it was exposed and the weakness, flakiness, had spread in a bit from were it was exposed. It just made me think that next time I'd use something that is more UV resistant out of an abundance of ... caution I guess.

[jhulmer]

[QUOTE=groundtackle;3112641]

Originally Posted by jhulmer

I have seen this done with the studs/bolts tack welded to a stainless plate and held in place with 5200. Not ideal but strong. We had to tape one to a long stick and work it into the mast and find the hole ... fiddly!


“Tho OP can try and turn a nut and see if the bolt turns. They are probably on a plate if done correctly ... that's the question.”

They move independently. I’ve now got the tang off and managed to hang on to the bolts but it’s clear they’d fall into the mast if I let them go. Is tefgel going to work better than working some sicaflex around the bolts?
What does the plastic have to be up resistant when its compressed between two pieces of metal where no uv should be?

I would use a piece of poly hose the correct size the bolt will go through and install in the hole to separate the bolt from the mast. That requires a bigger hole. If that's not a good option then, yes I would use a liberal amount of sika or 4200. (this will help hold them when tightening also)

Put a liberal amount in the hole and try to get it to the head of the bolt. let this cure over night before you draw it all tight so there is still material between metals that want squeeze out. I love Tefgel so I would add this to the threads and plates when installing the nuts also. Tefgel might be enough on its own if that's all you're able to do.
Jim

[groundtackle]

[QUOTE=jhulmer;3112828]

Originally Posted by groundtackle

I would use a piece of poly hose the correct size the bolt will go through and install in the hole to separate the bolt from the mast. That requires a bigger hole. If that's not a good option then, yes I would use a liberal amount of sika or 4200. (this will help hold them when tightening also)

Put a liberal amount in the hole and try to get it to the head of the bolt. let this cure over night before you draw it all tight so there is still material between metals that want squeeze out. I love Tefgel so I would add this to the threads and plates when installing the nuts also. Tefgel might be enough on its own if that's all you're able to do.
Jim

The problem with this is how to make the hole bigger. I can’t remove the bolts, they’ll fall inside the mast then I can’t put in replacements unless I remove the spreaders which is of course a much bigger job. It would be doable without removing the mast but it’s a lot of work I’m trying to avoid. So far I’ve jiggled some sicaflex inside and hope to have enough under the bold head but can’t really say. I’m waiting for the interprotect to cure. Is tefgel really a lot better than coating with sica? Up here tefgel is $40 for a 10ml tube. I’ve got good plastic to insulate the tang so I’m down to just worrying about the bolt itself now. I could drill another hole above these two 3/8 holes to get more of what ever in there or I could put a hole on the side of the mast to access the bolt heads but I don’t know if that would weaken it too much with two holes on the front and one on the side at the same level. The side hole would probably have to be a good 1” to allow me to get a finger in there to do a great job insulating the bolt heads.