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Broken Aka Brace-Aka Connection-Now a matched pair
http://www.hobie.com/au/en/forums/viewtopic.php?f=71&t=58881		 Page 1 of 1
Author:  rhyolken [ Mon Aug 22, 2016 8:31 am ]
Post subject:  Broken Aka Brace-Aka Connection-Now a matched pair
I have had the bolt which connects the aka brace to the aka break off on both the left and right rear akas. It looks to me like some sort of glue is getting dissolved. Any suggestions as to how to avoid this?

I tired to glue it back in but was not successful so I have wound up ordering new rear aka arms. Can someone let me know how to attach the plastic connector on the aka arm to the aka brace?

Thank you all for your help.

http://imageshack.com/a/img922/7396/NKAqTz.png
Author:  fusioneng [ Mon Aug 22, 2016 11:33 am ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
There is no glue involved in Hobies manufacturing process to attach the tang (the lug that the aka nylon bolt goes thru) to a thin wall (1/16" thick aluminum tube). The tang is welded onto the AKA bar via TIG welding (tungsten inert gas welding).
The break I see in not repairable and the entire AKA bar has to be replaced.

One thing I noticed in your pic is a tremendous amount of calcium on the inner surface of the AKA bar, under normal use that calcium should not be there (the metal should be clean bare aluminum on the inside of the bar. I recently cut the AKA bars on my 3yr old TI after 3 yrs of extreme use in salt water, and the insides of my AKA bars (all 4 bars) were nice clean bare aluminum (no corrosion), just a strange curiosity I noticed from your pic.
That calciom powder is the result of galvanic corrosion of the aluminum itself, and yes it does dissolve aluminum, if what looks like happened, indeed happened, the TIG welds dissolved. This should not happen.
However that joint is exposed to extreme stress, for example if the designed in nylon sheer bolt were replaced with a steel bolt, and you hit something, the resultant damage would be exactly what is seen in your pic.
I'm not accusing anyone of anything here, but if my aka failed because I had a SS bolt in there, I would put the plastic one back in before filing a warranty claim, then declare, it just happened, don't know why (just sayin that's what I would be doin thats all).
FE
Author:  rhyolken [ Mon Aug 22, 2016 11:50 am ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
Thank you for your message and suggestions.

When the first one went I was advised by the shop from where I purchased to TI to be careful about washing out the inside of the AKA with fresh water after each use in our brackish water, which I did religiously. However this did not seem to help.

I do use the nylon pins and have not substituted steel ones. However I noticed that the nut on the pin was close to the opening rather than on the bottom leaving a relatively small space between the bottom of the aka brace and the nut.. Might this results in too much pressure on the part that broke?

Also, the weekend before I had the TI moored in the water and they were fairly high winds causing the boat to pitch back and forth. Could this have resulted in stress to the welded piece?

Thanks x 2 for the suggestions and comments.
Author:  fusioneng [ Mon Aug 22, 2016 1:23 pm ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
Actually that is another valuable clue. The type of stresses you are discribing from the boat tied up and the waves pounding repetedly on the AKA bars is likely the culprit here.
Think about it you go out sailing for a couple hours, the AKA bars may take a slight hit from a wave once in a while, lets say a good number being 10 light hits per outing, at that rate the joint will last many years (and they do), yours is the first I have heard of breaking.
Now fast forward to being moored in chop, that same joint could be taking ten light hits per minute, thats 600 hits per hr.
Fe
Author:  rhyolken [ Thu Aug 25, 2016 10:12 am ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
When I store the boat in the water I disengage the brace and keep the Akas bungeed in. Would this still put pressure on the AKAs or braces to the point that this type of break might occur?
Author:  tonystott [ Thu Aug 25, 2016 1:27 pm ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
Absolutely not. Your storage method is not the cause of the problem, which is the only example I recall seeing on the forum... A very rare situation.
Author:  fusioneng [ Thu Aug 25, 2016 2:36 pm ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
Yea this is the only case any of us have seen, a fluke thing, I wouldn't change anything you normally do, I know I'm not planning any changes to any of my procedures.
FE
Author:  INSAYN [ Fri Sep 09, 2016 7:55 pm ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
He may have had an incomplete TIG weld with a pin hole or more, and the salt water worked it's way behind the joint over time slowly eating away at the raw aluminum back there until it broke off. Impossible to rinse out especially if you don't even know salt water is getting back there.
Author:  fusioneng [ Fri Sep 09, 2016 10:35 pm ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
You typically don't see pin holes in tig, but if they had a new operator that day and they didn't pre-heat the piece, or just had bad welds that day, thats more likely. Bad welds are easy to spot, just look for a white line around the weld area, sea water getting into a bad weld will definately do it.
FE
Author:  tonystott [ Sat Sep 10, 2016 3:42 am ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
New akas under warranty - see your dealer
Author:  PeteCress [ Sun Sep 18, 2016 10:25 am ]
Post subject:  Re: Broken Aka Brace-Aka Connection-Now a matched pair
rhyolken wrote:
...to be careful about washing out the inside of the AKA with fresh water after each use in our brackish water....
I hose off the knuckles on my AI-2, but the aka seems like a closed system with the plastic locater nub pop-riveted on to the ama end and the knuckle assembly pop-riveted on to the X-bar end.

Am I missing something?
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