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PostPosted: Mon May 14, 2012 2:16 pm 
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Here's what I've come up with:

I had replaced the original rivets on my aka knuckle once or twice already using the same 3/16ths stainless steel rivets that Hobie used. By the second time however, I noticed the rivet holes were becoming larger, almost 1/4" in dia. Weather this was due to movement, corrosion, dissimilar metals or a combination of all three, the holes that the rivets go into were no longer 3/16th's they were getting bigger.

I found the jay-cee sales & rivet inc. online store and had a long conversation with one of their very helpful engineers. I explained exactly what I was trying to do ie:
A boat in salt water, movement in a round joint between two aluminium fittings, the total wall thickness of the aka and knuckle joint combined and the diameter of the aka etc. This is what he suggested I use.
http://www.rivetsonline.com/rivets-en/b ... ivets.html
Specifically the 1/4" Gesipa Bulb-tite Blind aluminium rivets Part# RV6604-8-06 They're sold in packages of 100 @ $41.36, plus tax or about 51 cents ea. and must be installed using a pneumatic air hydraulic rivet gun.

This is what they look like compared to the original s.s. rivets on the right:
Image

This was on a test piece of aluminium plate about the same thickness as a aka and knuckle joint combined:
Image

Close up view of what it might look like inside the knuckle joint:
Image

Installed on my aka:
Image

I only did this a month ago to the one knuckle that was in the worst shape at that time. I've been out sailing 3 or 4 times since, but so far I'm not seeing any movement in the joint area at all. For the time being I'm very satisfied with this arrangement. They're tight as heck and there's no more corrosion around the rivet from dissimilar metals. As the remaining s.s rivets become loose I plan on replacing them using these 1/4" aluminium rivets.

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Ezra Appel
Palm City, Florida
2014 Tandem Island


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PostPosted: Mon May 14, 2012 2:30 pm 
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Awesome. No glue on your repair, Sun E?


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PostPosted: Mon May 14, 2012 2:56 pm 
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NOHUHU,

Correct, no glue.

I'm in agreement with Mikereddy on this this point. If I ever had to replace just the aka, it would be near impossible to remove it from the knuckle if it were a glued joint. This is probably one of the reasons why Hobie made these two parts separately.

I just wish I had more "sailing hours" on these 1/4" aluminium rivets. I don't post my ideas until I've thoroughly tested them in the real world. This is one exception and obviously I will be keeping an eye on how the fair in the future. In the mean time I think this might be a viable solution until someone comes up with something better.

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Ezra Appel
Palm City, Florida
2014 Tandem Island


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PostPosted: Mon May 14, 2012 2:59 pm 
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Well I'm interested in Cliff's reply. But from my own experience, 5200 applied on a properly scaled and cleaned surface is permanent and waterproof. So I would want to coat the whole of the aka tube where it inserts into the socket, not just put beads of the caulk around certain parts. We always joked about 5200 being "bulletproof."

It will be a messy insertion job, with a lot of squeeze-out. So care and careful masking are important. Plus you must carefully remove the masking tape before the 5200 cures. Or else perhaps cut along the socket rim after the cure with a box knife before peeling the tape off. The point is, 5200 sticks to everything and is hard to get off, even uncured.

Corrosion of aluminum inside the tubing as a result of salt water's effect on aluminum (not necessarily electrolysis) is another kind of issue. I haven't looked at how many places water can enter. If I store the boat assembled, the idea of hanging up akas to let them drain is also not attractive. I just don't have time in my life, and arrange everything to get max time on the water for minimum time in travel, setup and take down.


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PostPosted: Mon May 14, 2012 3:56 pm 
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Thanks for the research and fix sEs! 8)
It will be interesting to see how the aluminium holds up long term compared to the stainless rivets.

Hobie- this post should be moved to the repairs/problems section.


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PostPosted: Mon May 14, 2012 5:21 pm 
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I second that,...

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PostPosted: Mon May 14, 2012 6:26 pm 
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I agree, but I wish I had know that could be done a couple of hours ago before I asked folks to direct their future comments to this thread instead. :roll:
Looks like I might need to put a few of those new rivets in my own head to tighten up my brain! :o

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Ezra Appel
Palm City, Florida
2014 Tandem Island


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PostPosted: Mon May 14, 2012 8:25 pm 
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My company specializes in repairs of aluminum cars, Jaguar, BMW, Aston Martin, Audi and so on. Every brand utilizes bonding (2 part adhesives) and mechanical fastening together. Welding of aluminum components is also used but much less than you would expect in an automobile. The mechanical fastening is always done with aluminum or boron rivets, blind, self piercing, friction. Never have I seen the use SS rivets. Jaguar and BMW engineers have both taught us that the bonding is the real strength in the union of two or more components, the mechanical fastening's first job is to make the union stable during the curing process, second it provides redundant fastening however the bonding is primary. I am speaking of the structural components of a vehicle and would consider the aka a structural component of the AI / TI. Personally I would bond and rivet and would not be that concerned about ever getting it apart, although that can be done with heat as long you use the proper 2 part bonding agent.

When you bond aluminum you must have a fresh clean surface, aluminum reacts with the atmosphere and starts building a protective coating almost immediately, sanding of the mating parts is required just prior to bonding. The only rivets you can use in this situation are blind rivets and should be aluminum. Hope this helps.


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PostPosted: Tue May 15, 2012 12:57 am 
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Yakaholic wrote:
On the newer rear aka arms there is a clip that holds the brace onto the aka when you fold in the brace. It is called the "aka brace clip" and is installed at the factory with a rivet. However, if an owner of an older aka arm wants to add the missing clip Hobie has the "Aka Brace Clip Kit" part #79537001. No pop rivet - Hobie sends you the clip and a SS self tapping screw. You just drill the hole the right size and in the right place.

Yakaholic, coincidentally, I am looking to replace the rivet on my aka brace clip with a SS bolt. You don't happen to know the size, do you?

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PostPosted: Tue May 15, 2012 6:28 am 
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Looking at the knuckles on my new 2012 TI, it looks like they are glued in as well as the rivets.
Is it possible that Hobie has tried to resolve this issue in the new version with a glue as well.

Could the Hobie tecnical experts advise what should be done here if this is occuring on relatively new boats that should still be covered by warranty.

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PostPosted: Tue May 15, 2012 7:07 am 
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chrisj wrote:
Yakaholic, coincidentally, I am looking to replace the rivet on my aka brace clip with a SS bolt. You don't happen to know the size, do you?


I recall the SS screw sent to be a rather large sheet metal type self tapping (#10 probable 8031130). I didn't use it. My logic was if I drill a big hole in the ama and the fitting pulls out I will not get a 2nd chance with an even larger hole. So I chose to not use the screw Hobie provided and instead tap the hole with an 8-32 NC thread. Drill used was a #29 9/64" I believe. Figured if that failed I could then use the larger sheet metal screw. BTW 8-32 NC is size used on screws holding down the Harken on my V1 style Xbar.

None of this info may help cause ultimately the screw you end up using depends on the size hole left after you remove the rivet and any corrosion.


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PostPosted: Tue May 15, 2012 7:38 am 
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After doing a more throughout search on the forums, particularly in the repair & problems section, is that the loose rivets problem is over a year old now. The Tandem got the new V2 akas first, so no surprise they would see the problems first.

I like how cliffs2yak fixed the rivets. viewtopic.php?f=75&t=35292&start=30

Not sure if I've seen any definitive response from Hobie yet about their recommended method of fixing the problem. With the exception of this from Matt Miller "In my opinion, field fix should be dis-assembly, coat with 5200 in the casting and re-rivit". Local dealer seemed to think this might be a warranty issue, but boat is over a year old. Dealer was very vocal about any repair or modification to the aka would void the warranty.

Anyway, I'm game for Matt's suggested re-rivit fix if we can get a clearer idea of which rivet type to use. SS, aluminum or ??. I'm hoping the tool necessary is not too expensive.


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PostPosted: Tue May 15, 2012 8:48 am 
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We created a kit for that.

81412001 AKA CASTING GLUE KIT - V2 AKAS
1 GLUE / 16 RIVETS (4 per AKA) $7.99 (USD / Spring 2012)

16 # 8010181 Rivet 3/16 x 1/4 grip length stainless

1 90 second cure epoxy

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PostPosted: Tue May 15, 2012 11:26 am 
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mmiller wrote:
We created a kit for that.

81412001 AKA CASTING GLUE KIT - V2 AKAS
1 GLUE / 16 RIVETS (4 per AKA) $7.99 (USD / Spring 2012)

16 # 8010181 Rivet 3/16 x 1/4 grip length stainless

1 90 second cure epoxy


:D :D :D Brilliant! and Thank You! :D :D :D

All this round and round on how to fix & what to fix it with can now be put to rest. I knew you had to have a solution. Need to post this kit up somewhere as a sticky/FAQ :wink:

Does it come with instructions or is there a PDF? and finally does Hobie sell the rivet gun or at least recommend one?

I think the vast majority of Island owners understand the need to maintain the boat with a little elbow grease given corrosion and normal wear from use. Nice to have the parts, the forum and your valuable help to keep our babies in tip-top shape.

Thanks

Edit: Saw pictures of someone using the "Surebonder" Long Handled Rivet Tool ~ $70 - does 3/16" SS. Hoping that does the trick. Have a mess of boats w/ friends so we can share the tool.


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PostPosted: Tue May 15, 2012 12:52 pm 
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Thanks Hobie and Thanks Matt.
This helps to answer a lot of what we were wondering about... primarily to glue or not to glue; that was the question. :)

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Ezra Appel
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2014 Tandem Island


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