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rtz
Joined: 31 Oct 2010 Posts: 296 Location: Oklahoma City
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Posted: Mon Apr 08, 2019 10:49 pm Post subject: PowerBox fin wobble? |
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I've got two boards and the fin on both them rocks side to side. Meaning it has side to side play. Tightening it up doesn't correct the loose fit. Is this common and accepted? |
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GURGLETROUSERS
Joined: 30 Dec 2009 Posts: 2643
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Posted: Tue Apr 09, 2019 12:42 am Post subject: |
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No, it is not acceptable!
An obvious 'fix' for a sloppy fitting fin is to cut a strip of Mylar (or something equivalent) from an old sail, wrap it round the base and up the base sides of the fin, and see how it fits (without forcing it) into the box. It will usually be necessary to cut and adjust to get a 'just so' fit, without any slack or side to side wobble, before tightening it down.
Once you get it right, don't bother changing fins in that board, it won't work loose, so just learn how to get the best out of it! (It's not rocket science.) |
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jingebritsen
Joined: 21 Aug 2002 Posts: 3371
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bred2shred
Joined: 02 May 2000 Posts: 989 Location: Jersey Shore
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Posted: Tue Apr 09, 2019 7:24 am Post subject: |
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Powerbox fin bases taper on both the sides and the ends. If the fin rocks side to side, it means that the tapers on the ends are getting tight before the tapers on the sides. Does the fin fit flush with the bottom of the board? If so, then you need to shim the sides of the base. Use parafin wax or similar to release the inside of the fin box. Then scuff and clean the sides of the fin. Mix up a small batch of marine tex epoxy putty and place a small dab on each side of the fin base. Insert the fin into the board and tighten the screw until the fin base is about 1/32” above the bottom of the board. Wipe off any residual marine tex. Use a square to make sure the fin is perpendicular to the bottom of the board. Let the epoxy cure. Once it’s fully cured, remove the fin from the board and use a flat file to clean off any residual epoxy/flashing. Fin should fit snug with zero side to side movement.
sm |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Tue Apr 09, 2019 9:03 am Post subject: Re: PowerBox fin wobble? |
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rtz wrote: | I've got two boards and the fin on both them rocks side to side. Meaning it has side to side play. Tightening it up doesn't correct the loose fit. Is this common and accepted? |
Fin wiggles on 2 boards, fin is most likely the problem. Not common on powerbox. Should not wiggle, fix it . _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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isobars
Joined: 12 Dec 1999 Posts: 20935
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Posted: Tue Apr 09, 2019 11:23 am Post subject: |
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That's why you're spinning out. A fin MUST be rock solid side to side. At least one of the once-best fin brands (True Ames) has switched their emphasis away from windsurfing and let their WSing fin QC go to hell, leaving it to us to correct their problem (my last TA took an hour of sanding to get it into the finbox, but it beat returning it to the factory because shipping has also suffered).
If the fin is flush with the board but still wiggles, follow Bred's advice to build up the fin. Slightly too small, add some packing tape to the fin to see if that solves the problem before remanufacturing it. If it won't go flush, the fin is too fat and it's time to sand the fin base. Find my previous posts on that problem, probably found by searching the forum for my posts about True Ames.
Sorry, but I just don't have the time to dig it up, and have forgotten what kind of pencil we use to test the fin for high spots. |
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Thu Apr 11, 2019 12:13 pm Post subject: |
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I've had well over 40 Pb boards and ALL were fin solid.
Currently rotate thru 12 Bb boards abd 10 Pb fins, all solid. |
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nw30
Joined: 21 Dec 2008 Posts: 6485 Location: The eye of the universe, Cen. Cal. coast
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Posted: Thu Apr 11, 2019 1:43 pm Post subject: |
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The clear plastic window that comes on all sorts of product packages, makes great fin shims. No need to attach it to the fin base, just place it where you figure out where you need it, cut to size and fit. |
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westender
Joined: 02 Aug 2007 Posts: 1288 Location: Portland / Gorge
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Posted: Thu Apr 11, 2019 2:55 pm Post subject: |
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I saw a guy with a problem once. His fin wouldn't tighten up. The screw was too long. |
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