Recommend barrier between stainless steel spreader/boom brackets and mast?

[Reefmagnet]

I totally removed all fittings from my mast in order to give it a new coat of paint. The spreader and boom brackets had caused some not too serious pitting corrosion where they were in contact with the mast. Even though the mast is totally painted, I'd like to add an additional barrier if possible. It seems the original barrier was just some kind of zinc chromate paste/paint, but I don't think this is available anymore. Could also have had some kind of silastic or polyurethane goop used fill the gaps as well (placed between the barrier and stainless bracket). I'll probably use some sika 291 to seal the gaps, but wonder if there's some readily available material I can use to form an isolation barrier that won't interfere with the integrity of the bracket's attachment.

Any suggestions, or am I just overthinking things here?

[Alan Mighty]

A sheet of robust polymer material - such as P.V.C., or nylon - usually does the trick.

Which you use may depends on the exact physical configuration.


Electrical tape is adequate in some cases. It's inexpensive. But when rotational torque is applied, electrical tape can squirm and distort.


Nylon washers work in many applications. Sunlight can damage them. And they are thick (in contrast to electrical tape).


I don't think overthinking is a thing. Overthinking beats careless mindlessness every time.

[wrwakefield]

Reefmagnet,

Along with the methods you mention, Duralac [Barium Chromate Paste] can also be used to isolate SS and aluminum surfaces upon assembly, and Tef-Gel on all SS fasteners mating with aluminum.

Both seem to last indefinitely, and both seem expensive, but you don't need much so the tubes also seem to last forever...

Cheers!

Bill

PS: On Edit- it looks like Whitworths carries Duralac.

[Rhapsody-NS27]

I'm in the process of removing the hardware off my mast for a full repaint. I have had several others tell me to use Tefgel or duralac when reattaching the hardware later.

As I remove some pieces, I have found the manufacturer had used electrical tape between the mast/boom and hardware. Saw it on blocks, winches, and cleats.

Are you doing a full repaint or more of a touch up?

[roverhi]

Have used vinyl window material like that used in dodgers and/or electrical tape.

[barnakiel]

I paint both surfaces with a flexible paint (say a polyurethane paint), then use heaps of Lanocote or Boeing or Duralac on the fasteners. Then mind to punch out the cores, if you are riveting.

Cheers,
b.

[Wainui]

Alan at Seatek in Long Beach painted my mast
He uses Plumbers Tape between all fittings

2 in. x 50 ft. 20 Mil Pipe Wrap Tape-53550 - The Home Depot

Works great

[Reefmagnet]

Thanks guys, some good ideas. I already use TefGel, but there's just too much surface areas to apply the stuff for this application. It would send me broke(r) buying enough! I use it for all the rivets and screw holes. I'm soon to install 25 or so mast steps so that should see a fair bit required at least. I like the thin film idea. In fact I would (and will) use clear fruit juice container PET plastic made into gaskets for the smaller stuff. The boom and spreader brackets that I removed had what was either a slight amount of polyurethane or even a thin sheet of nitrile rubber installed. I'm not a fan of nitrile rubber for gaskets in this application because I've had problems with it "creeping" in the past on similar jobs and that would make me worry about having the rivets loosing tension. I like the idea of the plastic tape. Cheep and should work.

Rhapsody, I did a full repaint. First time ever. There's a couple of things I would do different if I did another one. The big one is that I would totally remove all the old paint. I spent more time trying to smooth over the divots left where I'd gone back to bare metal to remove oxide (which of course only reveal themselves after the primer has gone on) then I would have if I'd just taken all the paint off to start with. I used a 7" sander/polisher with a poly strip disk for most of this job. Paint was epoxy hi build primer with a polyurethane top coat.

[tkeithlu]

If you decide that you do want zinc chromate, it's available in aerosol and paint cans for the aviation market - they use it to prevent corrosion on all kinds of aluminum surfaces.

[belizesailor]

Originally Posted by roverhi

Have used vinyl window material like that used in dodgers and/or electrical tape.

Ive used plastic sheet material to separate compoments and TefGel on connectors before. Lasted for many years.

Plastic was cut from vaccum molded packing material. Lasts forever in a land fill and held up well in this application.

[Reefmagnet]

Thanks tkeithlu, I should have mentioned my enthusiasm for using zinc chromate waned when I found out about the carcinogenic properties of the chemical. I discovered that even the home build airplane guys have generally moved over to epoxy primers these days because of it's toxicity.

[MarkJ]

TefGel. $14 per tube, if memory is correct.

[Jim Cate]

For the larger areas, any thin, tough plastic will work. I often use bits cut from one of the el cheapo plastic "cutting boards" sold in dollar shops, etc. These are not the rigid polyethylene types, but thin (~.015") flexible ones. Often sold in sets of 4, in different colours for a buck or two. being flat, they are easier to work with than scraps from bottles, etc.

Jim

[Reefmagnet]

Originally Posted by Jim Cate

For the larger areas, any thin, tough plastic will work. I often use bits cut from one of the el cheapo plastic "cutting boards" sold in dollar shops, etc. These are not the rigid polyethylene types, but thin (~.015") flexible ones. Often sold in sets of 4, in different colours for a buck or two. being flat, they are easier to work with than scraps from bottles, etc.

Jim

Excellent. We are using these at the moment (as cutting boards) and the thought had crossed my mind. Problem solved!

Sent from my SM-G900I using Cruisers Sailing Forum mobile app

[Rhapsody-NS27]

Originally Posted by Reefmagnet

Rhapsody, I did a full repaint. First time ever. There's a couple of things I would do different if I did another one. The big one is that I would totally remove all the old paint. I spent more time trying to smooth over the divots left where I'd gone back to bare metal to remove oxide (which of course only reveal themselves after the primer has gone on) then I would have if I'd just taken all the paint off to start with. I used a 7" sander/polisher with a poly strip disk for most of this job. Paint was epoxy hi build primer with a polyurethane top coat.

Thanks, I've been looking at stripping down my mast. I've seen others who only sanded down the bad spots and even saw that recommended by others that if the paint is still adhered well on the mast, to leave it. But, I've been looking to strip it all down to bare metal.

While I've seen recommendations for Zinc Chromate primer, and I do have 3 rattle cans of it, I'm thinking to not use it. I'm looking at using Awlgrip products on this mast and they have a chromate-free primer, Wash Primer CF that I'm looking to use instead, after the alumiprep and alodine steps. The Wash Primer is still supposed to etch into the metal and provide a good base for the next layers of Primer/top coat.

Maybe the Wash Primer is something that could work for anyone not wanting to use zinc chromate.