I have this Hugh, horrible weed fin and I'm thinking of cutting it down to make it a shorter non raked fin, where I'm cutting it there's enough fin to make almost fill the box so I wouldn't have to build it up much at all., probably just wrap a few layers of glass around it then sand it to fit the box. So is this a good or bad idea and is there a better way to build up around the fin to make the new head?

The easiest way is to mould it. If you use a finbox, make sure you have a very good release agent, unless it's in a throwaway board. You can just use bog to build up leading and trailing edges, you'd only need glass to support the barrel nuts, looks like the fin is thick enough at the front, so maybe only need glass for the rear nut.

Most of the people i know who've done it re mould the head (pour moulding material into a fin head mould around the butt of the fin). But you have to have/make a jig to hold the fin in position precisely while it sets.

hand tooling raw glass into a precise shape can be an extremely painful process. Its doable, but it can take hours to get it right, and you can f&@k it up in a split second when you decide to pull out the grinder in a moment of frustration. Not too mention fibreglass splinters everywhere.

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Subsonic said..>>hand tooling raw glass into a precise shape can be an extremely painful process. Its doable, but it can take hours to get it right, and you can f&@k it up in a split second when you decide to pull out the grinder in a moment of frustration. Not too mention fibreglass splinters everywhere.

That's why It's better to use bog and hand sand. I'd never try to shape a fin head with a grinder. If the fin blade is too thick for hand sanding, (and I don't think this is likely) be very careful with the grinder, and bog up where you've gone under

One take on how to approach it.



Edit and from 12:24 onwards on this one

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decrepit said..

Subsonic said..>>hand tooling raw glass into a precise shape can be an extremely painful process. Its doable, but it can take hours to get it right, and you can f&@k it up in a split second when you decide to pull out the grinder in a moment of frustration. Not too mention fibreglass splinters everywhere.

That's why It's better to use bog and hand sand. I'd never try to shape a fin head with a grinder. If the fin blade is too thick for hand sanding, (and I don't think this is likely) be very careful with the grinder, and bog up where you've gone under

Yep, i wouldn't go near it with a grinder either, but i know some people who've found out the hard way

i'll stick with the old block sanding thanks

Anyone worried about correct vertical foil? Fins are meant to perform at a specific angle, it may affect top end performance, spinouts, etc. I may be overthinking it, just some thoughts :)

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Manuel7 said..
Anyone worried about correct vertical foil? Fins are meant to perform at a specific angle, it may affect top end performance, spinouts, etc. I may be overthinking it, just some thoughts :)

Yeah i was thinking about that too. A weed fin will have a longer profile presented horizontally, and it'll be shaped to suit that. turning it upright might turn a functional fin into a piece of junk (or alternatively, it might turn it into a great fin)

The other and much easier modification is to convert it to a shallow-water weed fin similar to the ones made by Egli/Black Project. You'd cut it horizontally at your preferred depth, then make a vertical cut down the trailing edge to meet that horizontal cut and sand everything fair - no molding or epoxy needed. I did this with a very similar and similarly useless "Formula-Weed" and it worked quite well - slow but lifty and suitable for 6.5-7.5. Use a Dremel or other rotary tool for cutting, then a grinder with a Bear-Tex wheel or just a sander for blending the foil at the trailing edge and for rounding off the bottom.

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Subsonic said..

Manuel7 said..
Anyone worried about correct vertical foil? Fins are meant to perform at a specific angle, it may affect top end performance, spinouts, etc. I may be overthinking it, just some thoughts :)

Yeah i was thinking about that too. A weed fin will have a longer profile presented horizontally, and it'll be shaped to suit that. turning it upright might turn a functional fin into a piece of junk (or alternatively, it might turn it into a great fin)

I don't think there's anything thing I could do to that fin to make it worse, it's truly terrible. The guy who gave it to me said it made his board feel like a soggy banana towing a parachute which I couldn't imagine until I tried it.

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Paducah said..
One take on how to approach it.

Edit and from 12:24 onwards on this one

Yep seen those, think I'm going to copy the top video

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Ben1973 said..>>>> I don't think there's anything thing I could do to that fin to make it worse, it's truly terrible. The guy who gave it to me said it made his board feel like a soggy banana towing a parachute which I couldn't imagine until I tried it.

In that case I bet it was a vertical fin boxed as a weedy, and has plenty of flex. Putting it upright should make a huge difference.

Subsonic, just because you buy a weedfin, doesn't mean it was designed as one. A lot of fin companies just make a standard blade and box them at the required angle. This is what's given weed fins such a bad name. It's even worse if it's got any flex, flex isn't a big issue with an upright but it's a huge negative on a raked fin.
I bet a layer of carbon on that fin would improve it no end as a weedy.

That's a Santa Barbara Weed fin - slightly more upright than a standard weeder but definitely designed as a weed-specific fin, but for Formula boards. If you're not running something 10m or bigger it's going to feel just awful. You'd use that fin only where you'd otherwise be using something 65-70cm and very powered up on a formula-style wide board.

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Awalkspoiled said..
That's a Santa Barbara Weed fin - slightly more upright than a standard weeder but definitely designed as a weed-specific fin, but for Formula boards. If you're not running something 10m or bigger it's going to feel just awful. You'd use that fin only where you'd otherwise be using something 65-70cm and very powered up on a formula-style wide board.

OK I stand corrected

I always shape fins with a grinder- speed but fine abrasive is the go

Still, avoid it as much as possible I'm sick of itching lol

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Ben1973 said..
I have this Hugh, horrible weed fin and I'm thinking of cutting it down to make it a shorter non raked fin, where I'm cutting it there's enough fin to make almost fill the box so I wouldn't have to build it up much at all., probably just wrap a few layers of glass around it then sand it to fit the box. So is this a good or bad idea and is there a better way to build up around the fin to make the new head?

To make it easier go down to the beach hold the fin from the tip and throw like a boomerang, if it comes back go ahead and rebox/

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Mark _australia said..
I always shape fins with a grinder- speed but fine abrasive is the go

Still, avoid it as much as possible I'm sick of itching lol

I also always shape fin foils with a grinder, but getting the head to thickness is a different matter. Talking small fractions of a mm here

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Awalkspoiled said..
That's a Santa Barbara Weed fin - slightly more upright than a standard weeder but definitely designed as a weed-specific fin, but for Formula boards. If you're not running something 10m or bigger it's going to feel just awful. You'd use that fin only where you'd otherwise be using something 65-70cm and very powered up on a formula-style wide board.

Yep put it in my ultrasonic on a day where my 60cm race fin felt great with a 9.6. Still felt terrible.

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Ben1973 said..

Awalkspoiled said..
That's a Santa Barbara Weed fin - slightly more upright than a standard weeder but definitely designed as a weed-specific fin, but for Formula boards. If you're not running something 10m or bigger it's going to feel just awful. You'd use that fin only where you'd otherwise be using something 65-70cm and very powered up on a formula-style wide board.

Yep put it in my ultrasonic on a day where my 60cm race fin felt great with a 9.6. Still felt terrible.

Ah, bummer. I have the slightly smaller and sleeker 47 TA weeder and while it's nothing like the Kashy 62 XXS I prefer to run, there are days when the weeds are so bad that it's either a weeder or nothing, so I make do. I agree that the 50 you have is basically a keel.