Need a non-adhesive sealant.

I'm not understanding exactly what the task is, here, that could just be me, though. Depending on the actual duty involved, even linseed oil putty will provide a seal that hardens only very gradually, and is not terribly elastic, or hard to remove, but not knowing what rigours it will be exposed to, we are in the dark.

 

it is a removeable beam with a spacing for silencing; the beam is bolted to the hull internally

We could probably do without sealing, but because of poultice corrosion; seam sealing seems wise

sorry I did not offer more detail; was trying to follow kiss here

 

Watch the first ten second or so of this video. This is to seal the middle beam at the cat hull insides. The beam in the video that slides into glass sockets.

 

If the beam is well painted, poultice corrosion should be avoided. It is going to stay in place when assembled ?

 

there is tight spaces and aluminum and someday saltwater; corrosion recipe

 

Many designers do not get into that level of specificity in designing. Let's not go there. My design covers the structural needs of the vessel. Things like plumbing and bedding compounds, electrical, windows, etc. are for me to determine. The vessel should work out well and I am pleased with the designer's efforts.

The boat is the only one on the planet; so we are also a prototype, so no experience.

A designer might also suggest 'sealant' which does not address the best type.

 

It is a Wood's design and I can ask him, but he has already answered a thousand emails from me. I am not sure how to explain this to you, but I asked you not to bring the designer into it "Let's not go there" and you were not polite in that regard. I asked a question about how to best seal a joint to wit you have offered less than what I asked for and indeed for what I asked not.

To explain to you still further, the beams are not closed on the ends. Any slosh of saltwater that gets into the beams would puddle inside the beam and crystalize; leaving salts sitting on the aluminum. I would prefer to avoid that.

Please contribute to the question or don't respond.

 

Fallguy,

You've been here long enough to know this is an open forum.
Anyone can offer anything they want, good, bad, or off the subject.
Explain the issues or be prepared for what you get.
And taking a snotty tone won't get you much help when you left out the useful info to start with.

How about you seal off the ends, put a drain channel in the socket, and a drain hole in the beam.

You know we are a bunch of amatures, since you paid Woods for his design, why don't you ask him?

 

oh, I well understand the forum

crediting Richard Woods for my question is not desired nor fair; asking him is not desired; I got a great suggestion to use duct seal

perhaps I should ask Richard the paint colors or how to reduce polemics on this forum

What I really don't understand is the purpose for Brendan putting Richard's full name in all caps? It is really just a shot as was his prior post?

And you think me snotty.

Richard has responded timely to perhaps several hundred emails in building this prototype vessel. I wanted to give him a break on one!

 

Fallguy, what do you want to seal, the beams themselfs or the gap between the beam and hull? To solve both problems at once I would put a cap on the outside of the hulls covering the hole and on the inside (meaning the side between the hulls) a rubber boot (like a mast boot) and fill the space with grease. Even if you find some non adhesive sealant, the fact that it does not adhere means there will be a gap between sealant and beam for water to go in (capillary action). I would be more concerned about this scenario then leaving it open so that oxigen can repair the natural oxide coat.

 

If poultice corrosion is the concern, unless there is excessive play inside the beam housings, and the beams clunk around causing continual abrasion, a proper paint job utilising highly waterproof coatings on a suitably etched surface, should do the job.

 

A quick search with wording " aluminum cross beam sealant in a catamaran" went to at least 3 sites, Beachcat, Sailing Catamarans and Build a Catamaran .com,
Within some posts were other links.

I would have concerns, (as does Rumars) that if any water is able to get into either the inside of the mast, which you or someone alluded to this possibility, or into the seam, that if you did not get 100% coverage of the bedded surfaces and introduced salt water into a slight void within the bedding, that you may have more issues with corrosion than leaving it to "breathe/drain"

Perhaps the addition of several anodes might help as well

Painting the outside will inhibit corrosion between the hull and beam and permit draining

 

Brendan, please ! We know the weather has been dreadful down your way, but you can still comport yourself with a sunny disposition !

 

I share similar concerns Brendan.

Fallguy, how about my other suggestion from page one, or is grease banned from your vessel as well?
I don't know what you're trying to seal without an adhesive but if nobody has any suggestions you like
then perhaps you can go back to the designer and ask.
If it were my design, I think I'd want the best outcome possible regardless of who's building it.
Especially if it's the only one on the planet!

 

It even put me in mind of plasticine, a pliable filler that won't stick.