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| New mast question: Why do the two halves need to be epoxied? http://www.hobie.com/au/en/forums/viewtopic.php?f=23&t=58920 |
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| Author: | MITBeta [ Thu Aug 25, 2016 10:55 am ] |
| Post subject: | New mast question: Why do the two halves need to be epoxied? |
My lower mast was dinged by the previous owner and has served me well for the last 3 years, but this past weekend the mast buckled more while I was getting ready to step it. So, I'm ordering a new lower mast today in the hopes I can get more action out of the boat before the cold weather hits... For whatever reason, my old mast was never epoxied together, which worked out well when I got the boat, because my tow vehicle was tall and the mast would have either hit it, or dragged on the ground behind the trailer, so I've been disassembling the halves for trailering. Now I have a new tow vehicle that's a reasonable height and my dealer wants to epoxy the two pieces of mast together. What is the reason for epoxying them together? Is there a disadvantage to not doing this? It's somewhat nice to have the flexibility in being able to disassemble it, plus I'd rather not have to pay my dealer to do this. What do you think? |
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| Author: | tpdavis473 [ Thu Aug 25, 2016 1:05 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
Not to be too cute, but the reason you epoxy stuff together is so it doesn't come apart. I suspect that if you try to trailer it without the epoxy, you could have one piece end up on the road. I am curious about the bottom half buckling while raising. Was there a big side breeze, did it buckle fore/aft? It usually takes a LOT of force to buckle a mast. |
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| Author: | amfoyle [ Thu Aug 25, 2016 1:19 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
Somewhere in these fora, there was a similar question and I seem to recall that the Hobie answer was that it allows a stronger mast unit for the larger sail plans of the Getaways and T2s! (yet the not-much-smaller, but half-the-sail-area, Wave mast doesn't need to be epoxied) |
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| Author: | mmiller [ Thu Aug 25, 2016 1:34 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
The original concept for the Getaway mast was to follow the Wave system and not glue, but due to the larger loads on the Getaway rig... the CompTip was either pulling down into the aluminum or wallowing out and getting looser. Both are bad, so glueing is now the go. |
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| Author: | RobDek [ Thu Aug 25, 2016 3:43 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
What if the comptip was pinned in place which allows for separation as needed. |
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| Author: | mmiller [ Thu Aug 25, 2016 4:30 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
Going to wobble still. |
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| Author: | MITBeta [ Fri Aug 26, 2016 11:13 am ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
tpdavis473 wrote: I am curious about the bottom half buckling while raising. Was there a big side breeze, did it buckle fore/aft? It usually takes a LOT of force to buckle a mast. As I said, the previous owned dinged/dented the mast and I've lived with it for the last 3 years. This past weekend it appeared to buckle even more, so I'm loathe to try to sail with it for a good many reasons... |
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| Author: | MITBeta [ Tue Aug 30, 2016 9:59 am ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
Follow up question: What kind of epoxy is used to glue the halves together? Is there a procedure for this somewhere? |
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| Author: | mmiller [ Tue Aug 30, 2016 1:55 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
I always used automotive bondo. Slathered on the tip and inside the mast. Press together and then support on saw horses aligned / square until hard. |
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| Author: | RobDek [ Wed Aug 31, 2016 1:44 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
I would use G/Flex epoxy from West System. They offer a thickened adhesive product. http://www.westsystem.com/ss/g-flex-epoxy/ |
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| Author: | MITBeta [ Fri Sep 02, 2016 8:50 am ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
Thanks, everyone. Epoxy on order, mast supposedly on truck from California. Hopefully I can get it put together in time for another 1 or 2 days on the water before it gets too cold up these ways... |
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| Author: | randii [ Tue Sep 20, 2016 2:20 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
My 18 had a slight wobble between the comp-tip and aluminum mast extrusion two months ago, and after a great day sailing in heavy air, developed more wobble. It went from barely discernible to worrisome, so I drilled out the rivets, used a heat gun to loosen up the joint, and pulled the pieces apart... they were still pretty well joined, which says a lot for the design -- close mechanical fit even after the rivets were pulled and the adhesive yielded. I found what looks/feels like silicone in the joint, so I'll be cleaning/sanding this away to prepare the surfaces for reunion. I've read here that Bondo is a good adhesive for this task, but I may look into what West Systems recommends. Reassembly looks otherwise pretty straightforward, but I do have a couple questions: - what should I align -- there's slight wobble at the hounds. side-to-side tilt seems obvious to avoid, but is it better to line up the front or back of the mast/tip (or does it really not matter, since it is going to flex)? - the comp tip foam 'absorbed' the spent rivets and casings. is it worth cutting that away, or can I just leave them entombed in there? - any need for silicone on the rivets as they go it, or should I dab with epoxy/bondo? - should I reach in and 'goop' 3M 5200 on the top of the inside plug below the hounds? - is the 2-part foam truly necessary between the comp tip bottom and the top of the inside foam plug? I'll be using 3M 5200 Marine sealant elsewhere on the mast to make sure it is watertight. Any specific suggestions on where to look other than 'for bubbles' in underwater testing? Randii |
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| Author: | randii [ Tue Sep 20, 2016 2:42 pm ] |
| Post subject: | Re: New mast question: Why do the two halves need to be epox |
From another post, Matt said "Installation instructions: http://static.hobiecat.com/digital_asse ... 00CTIP.pdf" Looks like the 2-part foam is optional. |
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