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PostPosted: Tue May 14, 2013 6:06 am 
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Location: Cape Coral, FL
mingle wrote:
One other question I have (for those who've replaced the rivets with aluminium ones) is don't most (all?) ally pop-rivets have mild-steel pin/mandrel running down the centre?

Wouldn't this cause corrosions issues too?

Or should I be looking for marine-specific aluminium rivets?

Cheers,

Mike.


Mike,
You are correct, the majority of aluminum rivets will have steel mandrels. It's also difficult to find 1/4 rivets. All aluminium rivets are available online but I found them locally at Fastenal.

J

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PostPosted: Tue May 14, 2013 7:49 am 
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Location: Sarasota,Key West FL
I'm on my third TI now, and have learned quite a bit about how to make things work better and last longer on TI's. One thing I do when I get a new boat is clear coat all the metal with Krylon clear spray paint. I soak all the rivets and joints. This seems to help on the galvanic corrosion.

Always rinse everything off well with fresh water when you get home to get all the salt off of everything. I use WD 40 on moving metal parts (ie... mirage drives, etc), and ArmorAll (or that Hobie recommended spray) on all the plastics, and make sure to put everything away dry. (note: It's probably not a good idea to try and lubricate the rudder with anything, just make sure it's clear of sand and junk by rinsing it well with clean water)

If anyone has an older TI (without the glued AKA joints), and the rivets are coming loose I'm suggesting (strongly) to get the Hobie kit to fix the rivet joints, and use the adhesive. Just the rivets alone whether aluminum or stainless, will not fix the design flaw, the glue is necessary. (rivets are not designed to hold that type of joint (without the adhesive))
my 2 cents
Bob


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PostPosted: Wed May 22, 2013 4:05 am 
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Location: Western NC & South FL
sun E sailor wrote:
sun E sailor wrote:
Conclusion: Aluminum structural rivets are better in combination with epoxy or 3M-5200. Interestingly enough, after Matt's posting I replaced all the rivets on a friends TI using 5200 and his are still solid as a rock. I'm fairly confident now that this method is the right way to go. As a bonus, it comes in black now which blends in better too.


SunE, any chance I could get you to help me with this upgrade? Should I buy the Hobie kit or source parts individually?
Travis


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PostPosted: Wed May 22, 2013 6:42 am 
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Location: Palm City, Florida
Hi Travis,
Sure thing, anytime I'll be glad to help you. When you're back in FL, put a call into the Island Clinic and ask for the Doktor Mon . :)

I still prefer using the 1/4" structural all aluminium rivets from http://www.rivetsonline.com/rivets-en/b ... ivets.html
over a 3/16th's stainless. Fortunately I own a pneumatic Pop-Rivet gun, which makes this repair much easier. I've done a few now on other TI's and they're all holding up quite well, no slipping or movement in the aka joint anymore. Check with Mark K. He sails his TI about as hard as our friends in Hawaii and Down Under, and his are still tight :wink: .

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PostPosted: Wed May 22, 2013 7:36 am 
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Thanks. I'll call you when I'm back down. Both for that and to sail. I don't have the tools to do that riveting.


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PostPosted: Wed May 22, 2013 11:01 pm 
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Location: Mt Kuring-Gai, NSW, Australia
Quote:
(note: It's probably not a good idea to try and lubricate the rudder with anything, just make sure it's clear of sand and junk by rinsing it well with clean water)


Could you elaborate ?

I've used INOX on my mirage drives, and recently sprayed the rudder and PIN with it too,
since it made everything smoother (once I'd removed the sand etc).


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PostPosted: Thu May 23, 2013 4:01 am 
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Location: Melbourne, Australia
Hi there,

I've just pulled apart one of my loose AKA/knuckle joints - no corrosion or paint-loss and minimal enlarging of the rivet holes (about 0.2mm?).

Do you recommend any surface-prep, prior to the glueing process (other than to clean away any grease or debris)?

Is 3m 5200 epoxy the way to go for adhesive?

<edit> Do you insert the rivets before the epoxy is set, of just line-up the holes, let the glue dry and then rivet?

And finally - what length 1/4" rivets did you use?

Cheers,

Mike.

sun E sailor wrote:
Hi Travis,
Sure thing, anytime I'll be glad to help you. When you're back in FL, put a call into the Island Clinic and ask for the Doktor Mon . :)

I still prefer using the 1/4" structural all aluminium rivets from http://www.rivetsonline.com/rivets-en/b ... ivets.html
over a 3/16th's stainless. Fortunately I own a pneumatic Pop-Rivet gun, which makes this repair much easier. I've done a few now on other TI's and they're all holding up quite well, no slipping or movement in the aka joint anymore. Check with Mark K. He sails his TI about as hard as our friends in Hawaii and Down Under, and his are still tight :wink: .


Last edited by mingle on Thu May 23, 2013 7:20 am, edited 1 time in total.

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PostPosted: Thu May 23, 2013 5:07 am 
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Location: Sarasota,Key West FL
Ocean moves:
I'm only going from memory here but I remember reading in the manual that came with my Hobie kayaks with the twist and stow rudders that they prefer you not to use any lubricant on their rudder systems , just wash them with water and try to keep the sand out.
I was just assuming this applies to the TI also.
Perhaps Hobie can advise further on the TI rudder.
Bob


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PostPosted: Thu May 23, 2013 11:55 am 
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Location: Kailua 96734
Prior to storage, I lube my rudder parts and coat with aero 303 or other UV blocker. No big deal.

I saw that post too, but we are not talking about fiberglass or finely-tuned racing rudders here.

The right UV coating can only help and will quickly wash off with the friction of sailing.


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PostPosted: Sun Jun 02, 2013 2:28 am 
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Location: Melbourne, Australia
I've done a 'test-fix' on one of the AKAS using 3/16 aluminium rivets and Sika 291i sealant.

The original stainless rivets were a little loose in the holes before I drilled them out, so I did
a quick try-out of the 3/16 ally rivets I bought as a replacement - they gripped very well and
with 4 rivets in-place there was zero movement between the knuckle & aka bar. Although the
rivets are much softer than the stainless ones, so the longevity of them (on their own) would
be a bit questionable.

I removed these 'test' rivets and applied the Sika 291i to the inside of the knuckle 'receptacle'
and the end of the aka bar (after masking off the edges of the joint-area). I put plenty of the
sealant on and there was quite a bit of overflow, which I quickly wiped off. The application of
the sealant for one aka was only around 25-30ml, so the 100ml tube I bought may be just
enough to do all 4 akas.

After 24 hours of curing, the sealant is still quite flexible - more like a traditional silicone - so
I'm a bit unsure whether it'll be as long-lasting as the 3m 5200 (which I have no experience with)
so time will tell, I guess!

Cheers,

Mike.


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PostPosted: Mon Jun 03, 2013 9:36 am 
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Location: Palm City, Florida
Mike,
With silicone I think you'll find that after a while the joints will become loose again. If and when this happens use the black
3-M 5200 and you'll be set for good. At that time you may still be able to use the 3/16th aluminium rivets, as long as the holes have not gotten any larger; if they have than I'd use 1/4".

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Ezra Appel
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2014 Tandem Island


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PostPosted: Mon Jun 03, 2013 10:50 am 
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Location: Sarasota,Key West FL
mingle:
I'm the guy that mentioned the improper design and use of the rivets originally on this forum (long time ago), and my original recommendation was to use silicone as the adhesive. My reasoning was you have so much surface area of silicone there holding the tube from moving that I thought silicone would be sufficient. Plus if it ever had to be re-done the silicone is easily removed. The whole trick with rivets is they are a static holder (no movement stresses are recommended with rivet joints). As long as the silicone limits any rocking motion of the tube in the knuckle you should be golden.
I don't know if you have ever worked with 3M 5200 it's urethane based and bonds tenaciously, even in wet environments (probably one of the best marine adhesives out there). I believe Hobie uses 3M 5200 on the joints, 'because that's what they do', they always design to the highest caliber, using the best materials available.
If it were me, I wouldn't take it all apart and try to redo it, chances are pretty good, that your repair will work fine and give you many years of reliable service.

One other trick that I have learned on the Islands, is if you soak all the rivets with clear coat (something like Krylon or Rust-Oleum clear spray paint), it tends to help keep the salt and moisture out of those joints, and helps slows down the galvanic corrosion.
Bob


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PostPosted: Tue Jun 04, 2013 7:58 am 
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Bob,

I wasn't suggesting that Mike take his (silicone) repaired aka joint apart now, only that (if and when) they become loose again he try using 5200.

It is important to know that Hobie sells the Akas (with the knuckle joint attached) as one unit. I wish they sold them separately, so that if you ever damaged just the tube or knuckle, you could replace them individually; but that's not the case. Other than rivets, (which are not effected by either the use of silicone or 5200) I don't know why one might need to redo something when a new Aka already comes with a knuckle joint.

If as you say:
fusioneng wrote:
The whole trick with rivets is they are a static holder (no movement stresses are recommended with rivet joints).
Then wouldn't 5200 be the better choice of materials in this situation? I highly respect your expertise and in no way am I asking this to be argumentative.

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PostPosted: Tue Jun 04, 2013 4:32 pm 
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Location: Melbourne, Australia
5200 was my first choice (after reading this discussion thread), but seems to be virtually impossible to get (in Melbourne, at least)...

After a few days more curing, the Sika 291i (I have no idea what the "i" signifies!) seems to have set completely. It's still fairly flexible (like silicone), but is far more 'rubbery'. At the moment I've only performed this 'experiment' on one aka.

What I'm going to do on the second aka, is to use the 291 only and leave out the rivets (for now). Once it's cured fully, I'll do a few 'informal' tests to see how secure the bond is and how well it stands up to pulling, twisting and bending. Should be interesting!

Cheers,

Mike.


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PostPosted: Wed Jun 05, 2013 9:20 pm 
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Location: Central Coast NSW Australia
Mike,
I used the same Sikaflex 291 marine adhesive/sealant to fix the very loose knuckles on my 2010 TI back in August 2012. They have had a lot of use since then, with much time spent hiking out on the haka, and they are still rock solid. I used new 3/16 stainless rivets but I did fill the holes with Sikaflex before riveting. No corrosion issues either.


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