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Old 29-06-2015, 16:35   #16
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Re: Flexofold vibration

A possibility:

If your engine is a two cylinder one, it is possible that there is some form of resonance between the varying load imparted as the blade tips pass the hull and the power strokes from the engine. The different frequency of blade tip passages from the 3 blade to the 2 blade could interact differently with the natural resonance of the engine on its mounts.

I don't believe the the set screw issue could possibly be the cause, as shown by fstbtm's diagram of the locking pins. I know that mine (three blade) could not behave as Hylite has suggested.

Finally, I suppose that there could be a mismatch between the two blades supplied by FOF, unlikely as that seems. Could be different pitch, or just a mechanical balance issue.

Good luck with it... we're really happy with our FOF after 12 years and 40,000 miles.

Jim
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Old 22-07-2015, 21:04   #17
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Re: Flexofold vibration

I did find with my 2blade flex o fold that they are very susceptible to growth build up.. Just a small amounts causes vibration...much more than fixed proud ?


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Old 29-07-2015, 11:25   #18
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Re: Flexofold vibration

Boat out of water now... Growth in 3 weeks was amazing, barnicals all over... Maybe the extra hot weather in savannah

Anyway... Almost indriveable..

Recommendations for paint on flex-fold props ???

Thanks


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Old 29-07-2015, 16:04   #19
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Re: Flexofold vibration

We've had good results from Prop Speed on our FOF 3 blade. Growth wipes off with a sponge.

We have used etching primer and hard bottom paint, but it comes off the tips of the blades pretty soon.

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Old 30-07-2015, 23:21   #20
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Re: Flexofold vibration

Prop Speed worked great for us too on the flexifold.


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Old 31-07-2015, 11:54   #21
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Re: Flexofold vibration

Quote:
Originally Posted by Gboy View Post
Recommendations for paint on flex-fold props ???
I have acquaintances who have had both good and poor results with Prop Speed - success seems to be very sensitive to honoring the timing of the application steps.

A cheaper DIY alternative has worked very well for me on Volvo props, which I have just applied to my new Flex-O-Fold props, although they have not yet be installed. It's labor intensive and time consuming, but works great:

1. Wire brush/sand the hubs and blades down to bright metal.
2. IMMEDIATELY apply a thin coat of zinc chromate based vinyl butyral washcoat/etching. I used to use Interlux 353/354 Vinyl Lux Primewash until they stopped making it, but Seahawk S-75 is the same stuff and Petit also makes a version. The immediacy of applying this after getting to bright metal is so the metal doesn't have a chance to oxidize which hinders adhesion of the next (primer) step. I usually mix up a batch of etching, then wire brush the hubs/blades and etch them one at a time with essentially zero time to oxidize. There's plenty of pot time available with the two part etching - even with my six blades and two hubs.
3. Within 24 hours of etching, start applying 6 coats of Interlux Primocon by brush. You can overcoat every three hours per the Primocon instructions.
4. Lastly, apply a minimum of three coats of Interlux Trilux 33 by brush. Do not use the spray versions as you can't get it thick enough. 6 hours between coats.

Yes, this is a lot of coats, but it really works and has lasted me for 7 month winter cruises in the tropics. I usually get three treatments out of a quart each of the Primocon and Trilux - that's 6 props worth.

Interestingly, the Primocon can instructions still refer to the 353/354 Vinyl Lux Primewash even though it's no longer available. One year I tried the alternative per the Primocon instructions and primed immediately rather than etching and it failed miserably.

Good luck,
Dave
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