A suitable sealant for aluminium mast attachments

Hi all!

I have a question: what products have been in the best practice regarding to sealing the attachments like halyard tangs etc.

As I understand that the main issue is about galvanic corrosion between aluminum mast and stainless steel attachments... and some products like some silicons could catalyze this process quite heavily...

So what it would be the smartest choice (and reasonably priced as well) for a sealant? Is it sikaflex, or is it something else?

If I were going to put a tang on I would take electrical tape and tape the area of the mast that the tang sits on. You can find electrical tape that's 3-4"s wide. This insulates the stainless from the aluminum.

Take a razor and poke it through the tape where the holes in the mast are.

Use Tefgel to coat the holes in the mast.

Place the tang and using a pneumatic riveter set the rivets. Do not use a cheap hand riveter.

Carefully trim the excess tape. Don't cut into the aluminum.

Using mineral spirits wipe off any excess tefgel. Then you can use something like shoe goo, or aqua seal to dab over the mandrel holes.

Use the right length rivet.

Wise words

Thanks, Catman for the detail instructions!

Just for confirmation, how about Sikaflex - is it bad choice?

I wouldn't use it for what your talking about. Hobie used to use one of their products between the metals and there were still issues with corrosion. Now there's stuff that pretty much stops it.

A rivet properly installed isn't going to leak. If you want to use it to dab the mandrel holes, fine.

Tefgel . Get it, use it. It comes in a small syringe with a brush. On smaller parts like pad eyes forget the tape and coat all the touching surfaces with it.

My question is mildly related. I'd like to paint the mast on the ARC 22, and I'd like whatever sealant used make the mast water tight, be compatible with paint(silicone is out). This is a fresh water boat, so corrosion is not an issue. Suggestions? Thanks!

Dave

Nobody says it is so here, but... Tef-gel is not a sealer, it's a corrosion inhibitor. I keep seeing ads that seem to compare to sealers.

Plus sometimes that white stuff around aluminum and stainless is just oxidation of aluminum after the paint is scratched off, not galvanic corrosion. So... what davefarmer asks too.

I was led to believe that painting aluminum masts was a bad idea as it promoted corrosion and/or hid corrosion from sight until it was bad...

I think painting aluminum extrusions around salt water doesn't last long, but inland it seems relatively common without serious consequences. So, a sealer that's compatible with paint(probably high quality 2 part automotive paint)? Anyone recommend an acid etch before paint?

Dave

Dave check out awl grip marine paint 545 primer has etching in it

the masts on my boats get a regular coat of wax. Clean em and wax em.

I think you can paint anything (almost) if you prep it right and use the right paint.

If determined to use a sealant use 3M 4200 or 5200.

Thanks Kyle!

Dave