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PostPosted: Wed May 16, 2012 1:44 am 
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Location: Kailua 96734
Understood, but isn't that going to promote corrosion?


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PostPosted: Wed May 16, 2012 2:36 am 
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Location: Charlotte, NC
The bonding material, should become your protection from corrosion. Some bonding products do require a primer to be applied first, but this primer does not compromise the bonding strength. There are adhesives that are conductive and non-conductive, not sure that matters much for the aka tube application.


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PostPosted: Wed May 16, 2012 3:26 am 
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Location: Charlotte, NC
Powder coating may be the exception, if the parts are powder coated instead of spray painted I would not have any reservation applying bonding adhesive on top of it. Powder coating is a stronger bond and harder and not that expensive. Last week I had some 19" aluminum wheels powder coated and it cost me $80.00 per wheel, I am not sure but think 4 aka bars maybe $150 -175 total?


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PostPosted: Thu May 17, 2012 6:50 am 
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Location: Canberra, Australia
Can I add my 5 cents worth?

I have been sailing for over 30 years, built many aluminium masts & the problems experienced here are nothing new. The joints are highly stressed & will over time wear, the rivets will stretch, corrosion will set in, etc. With any marine vessel, there will always be some part of the vessel requiring maintenance. (that's why we suffer through winter - to give us time to undertake essential maintenance!)

I have tackled this problem of loose aka joints by drilling out the existing rivets, cleaning all surfaces, applying one wrap of 6 ounce fiberglass tape & metal set to the aka tube that goes into the knuckle & re-riveted the whole lot back together. It's been 5 months & so far so good.

Galvanic corrosion - that's the form of corrosion that occurs between dissimilar metals. There is only one way to slow it up (note I didn't say stop) & that is to electrically separate the two metals. Thankfully, this is not hard to do. A product called Duralac is a fantastic anti-corrosion jointing compound. I have been using this product since I was a nipper & it's always worked! When I first bought my TI, I drilled out all the rivets & re-riveted with stainless steel rivets that had been dipped in Duralac. I don't expect to have to redo this for 4-5 years.

The other essential element for corrosion to occur is moisture. Saltwater is a lovely electrolyte, so as Slaughter has already stated, wash all aluminium parts thoroughly. However, saltwater is also slightly oily, so just using freshwater will not remove all the salt. I use some carwash soap to help breakdown the oily residue. (Do NOT use dish washing soap as some types are very corrosive on bare metals). I also regularly spray the aka joints with a Lanoline spray.

Note, please do not use Clear Sikaflex anywhere near aluminium! It's highly reactive with any bare aluminium surface. If you stick with marine sealants that are designed for harsh environments, then you'll be ok.

These boats have some highly stressed areas, so expect wear & tear and be prepared to undertake winter maintenance.

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2011 Hobie TI


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PostPosted: Thu May 17, 2012 8:57 am 
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Duralac is good stuff - but not easy to find here in the USA - looks like Australia and UK it's obtainable.... but never seen it offered anywhere here for some reason or another - maybe the EPA has an issue with it.


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PostPosted: Thu May 17, 2012 12:39 pm 
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Location: Palm City, Florida
I've been using Tef Gel for years on the trucks I build for my roof cleaning business. Started using it on my TI from the beginning when ever I put s.s. bolts or screws back into aluminium fittings. Great stuff, available on line or at West Marine.
http://www.defender.com/product.jsp?pat ... id=1758237

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Ezra Appel
Palm City, Florida
2014 Tandem Island


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PostPosted: Thu May 17, 2012 2:20 pm 
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Location: Kailua 96734
Teflon? Interesting. Thanks Sunny.


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PostPosted: Thu May 17, 2012 3:50 pm 
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Location: Calga NSW, Australia
Hmm, Teflon. Would Teflon (plumber's) tape be helpful?

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PostPosted: Thu May 17, 2012 3:56 pm 
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Location: Kailua 96734
I was just thinking, "Teflon" ain't that just the opposite of adhesion, which is what we probably need most?

Unless your Slaughter, preparing lunch,...


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PostPosted: Tue May 29, 2012 3:49 am 
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Location: Hilo, Hawaii
Here's a few pics of my fix after a years worth of abuses in Hawaiian conditions:

So far so good with eliminating any looseness at the joints. Despite a few nicks and scrathes, the bond is holding up well.
Image

Closeup of 1 and 2.
Image

Closeup of 3 and 4.
Image

Some corrosion around a few rivets that I plan to brush off and apply Corrosion-X. Integrity of the rivets look intact and here's a pic of the worst one.
Image

shaka \ooo/

c2y


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PostPosted: Tue Jun 05, 2012 8:02 pm 
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Location: Cape Coral, FL
my knuckle joints were pretty loose
so...
after drilling out the old rivets and the sanding joints
ImageImage
Image
holes are drilled out to 1/4" and the akas taped to catch the excess adhesive
ImageImage
I used heavy duty aluminum rivets and lexel for adhesive. I chose lexel over the Hobie recommended epoxy because it adheres well to aluminum and will remain flexible throughout it's lifespan.
Image
so far I've had them out for one sail and I'm very happy with the result!

cheers,

j

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also a more manageable 100 square foot spinny...
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PostPosted: Fri Jun 15, 2012 3:04 am 
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Joined: Tue May 29, 2012 12:22 am
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Location: TI ... Roma ( italy) mediterranean sea
I do not understand the difficulties of the Hobie company, (company leader) to put quickly in practice advice buyers TI and AI on the issue of corrosion from intra-oral, forcing owners to have to intervene with obnoxious, difficult and complicated interventions within a short time after purchase.
I think it's easy to intervene in the industrial stage, replacing screws or metal alloy bars with different materials most suitable for salt water ... also because the money that is raised is investing in the purchase of these special kayak ... and even more so in Europe.
There are many types of industry synthetic even stronger alloys of metal!
I do not understand.

viewtopic.php?f=75&t=42283&hilit=aka+corrosion


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