Does anyone know wheather l can change the length of my fin without making too stiff or taking away the twist of the foil lm only talking about 5 cm.the fin is a goldwing 44 cm .slalom thanks let me know before l go ahead.
as long as you maintain the thinning toward the tip - so after you cut it you'll need to take quite a lot of thickness out of the last 5-6cm.
that will mean re-foiling that last bit too, so take note where the max thickness is (as it is a percentage of chord so is not say 20mm from the leading edge all the way down.
I've had it done with several fins, but do not touch the tip, just remove the old box and make a new box! That way you can even re-rake a fin if you need or want to!
Marko
I've done quite a number of fins, exactly the way Mark describes and for the life of me can't understand why the red thumbs?!
If you follow the chord ratio, why not??
I want to know how re-boxing makes it shorter?
Sure you can cut the base off and re-box .....but then you just have a shorter fin - it will be stiffer and thus not twist as much.
If that effect is what you want to achieve then fine..... but if he cuts 5cm off the base of a 44cm goldwing and reboxes it he will not have the same thing as a 39cm goldwing.
I assumed it had tip dmage anyway...?
HA HA, yes of coarse it will be stiffer,
but it will be less stiff if you cut the bottom rather than the top, Excluding any sanding you may do later.
And truely the stiffness will be identical on the shorter ruler you will just have less leverage to bend it with.
Timewise, I can sand a fin down and maintain the chord ratio in about 1-2 hours. To rebox it will take about a day, allowing for the resin to cure properly. Then it's a matter of drilling and fixing the barrel nuts.
What I'm reading into Gavn's original question is can it be done without having to rebox it.
the best way to refoil it is too sand both sides along the thickest part of the foil, flat, when you have both side exactly the same roll the corners off to the leading edge, then repeat the other side , then sand the to the trailing edge, if you try too foil one side at a time its hard to keep it symmetrical
I'd recommend rebasing. You're not going be anywhere near as accurate re-foiling the tip as the original CNC machine.
You dont have to cut off the entire head, just grind off the base front and sides so that a new base can be re-molded onto it at whichever length you desire. Of course you'll cut off any unsed length from the base.
Thank you all for your opinions l have decided to take 5 cm from the bottom & do what Mark suggests. I dont think by doing this it will have any adverce effect of changing the characteristics of my tectonics fin!
^^ but Chris how you refute my argument also refutes yours.... cutting the base off has the same effect - as you still have a fin that is thicker in draft compared to it's length either way you do it.
My issue was with Dunk0's question "which will be stiffer?" and I propose that is irrelevant to this discussion as nobody would cut the fin like in #3 and then go use it.
I maintain the best way to shorten is to cut the tip off and reshape as you can take thickness out as far up as you desire..... whereas just cutting at the base and reboxing makes it stiffer and introduces errors (is it now perpendicular? is it in line with the board? etc etc)
I think l will keep the 44 cm fin as it is& buy a talon tectonics 39 cm these fins are made by professional people as I dont want to stuff it up
Haha great idea. Then you have 2 fins to choose from. I'm sure the debate will continue regardless [}:)]
I can see the merits of both methods.
If you're unsure of your hand foiling abilities reboxing, ensures the original foil.
If you're good at hand foiling, as Pepe says, cutting the fin down is quicker.
We have very abrasive weed here, so refoiling and reboxing happen on a regular basis.
With the help of a tilers profile gauge it's possible to get the foil almost as close as top quality CNCd fins.
I use a small angle grinder with sanding pad to do most of the rough work, (Pepe uses a belt sander). If I take a bit too much I bog the hollow with qcell and paint with automotive spray cans.
chris, thankyou for shedding a bit of logic.
mark, the tip is the thin flexible bit why would you chop it off? sure you could sand a new fin out of the chunk of fin you have left but why would you not just thin down the top if you desired more flex.
personally both ways sounds like waytoo much work
i have a quad with 14 and 10's
i want 13 qnd 9's
should i rebox them or sand them down.
