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Rounding board edges

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lovethepirk
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Rounding board edges

Postby lovethepirk » Sat Sep 24, 2016 8:59 pm

Long story short, I have a SS Glide at 160 x 40.5 and a Cabrinha Tronic at 145 x 43. I love both boards but the glide doesn't carve well at all and can be very sticky to jump on if it isn't really smooth. Oh and by the way...I never read this before, but my Glide sprays me in the face constantly...my other boards I have zero problem with. I'm used to it now, so I can just predict the spray and close my eyes, but for a while it was a pain in the ass.

I figured I'd try to remake the tronic outline in a board that is 155 x 47. This ups the surface area a little bit vs the SS glide, but I'm mainly looking for a little better carve and better jumping.

I'm about ready to either sand the hell out of the edges or use my table router to round them.

Any suggestions on how sharp, and/or how much I should round the edges of the board?
Also, my tronic has about 43mm or rocker and the glide has 23mm. I'm thinking of making this board 25mm so after soaking it a little, should I stress it to about 40mm of rocker and then the springback should get me to about 25mm?

Thanks.

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downunder
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Re: Rounding board edges

Postby downunder » Sun Sep 25, 2016 2:58 am

For me the subtle rounding worked. A touch with a sand paper, not more and a bit of experimenting how much.

So in the middle is your ply wood? HOw thick? It is more like rocker table to 80 mm resulting in 20mm, all depending on what and how doing it. For example, 80mm table, and 4mm ply with 4x220 grams Uni FG on top will give you massive rocker. But 1x220g not so. Same with flex. Double the ply wood with two layers, and you'll get 65-75mm rocker, no FG at all. Triple the ply wood, and have a tank:)

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Re: Rounding board edges

Postby plummet » Sun Sep 25, 2016 8:06 am

Rounded for carving. Sharp for boosting. Somewhere in between for a compromise.

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Re: Rounding board edges

Postby rynhardt » Sun Sep 25, 2016 9:17 am

Personal preference, really. I like round edges which are more forgiving.

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Re: Rounding board edges

Postby NorCalNomad » Sun Sep 25, 2016 5:21 pm

You realize the reason the glide is made strait like that is so that it's gets maximum planing surface for light wind performance.

Also rocker is the curve from tip to tail. Not the curve of the outline.

Also don't round your edges, it will make the glide slower and even more "sticky"

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edt
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Re: Rounding board edges

Postby edt » Sun Sep 25, 2016 5:33 pm

rounded edges create more drag the water don't release as well, sharp edges are faster so you want sharp edges that said my board has the edge completely ground away so it's got no edge left (too many beach starts) and i don't notice a huge amount of drag on my board, I think most of your drag comes from the rocker.

theoretically it seems that if you round the rail right were the water is splashing you create more drag for the water so it won't kick up into your eyes. if you just round it right where the problem is i doubt you see a performance problem. Let us know how it goes.

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Starsky
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Re: Rounding board edges

Postby Starsky » Sun Sep 25, 2016 5:59 pm

Think its fairly standard that boards with rail "shape" are softest in the centre of the rail and transitions to sharp by the time you get the the last 1/4 of the rail at the tip and tail. The rail should be sharp off the ends. Leaves the portion of the board that is normally in the water mostly sharp railed with the softer portion being engaged mostly when you carve.

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lovethepirk
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Re: Rounding board edges

Postby lovethepirk » Mon Sep 26, 2016 10:42 pm

Thanks...I just softly rounded the edges.

Unfortunately, my board is 12mm thick. How long should I soak it in water do you think and how much rocker should I stress on it to get 25mm of rocker as an end result?

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Re: Rounding board edges

Postby downunder » Tue Sep 27, 2016 2:29 am

I wouldn't recommend soaking a plywood, if is a ply.

What you can do as your first project is 2x6mm marine type plywood. That will make a concave and rocker with no need for soaking and risking trapped moisture in a ply voids, which is a guarantied failure.

You'll need to tapper your 12mm tips/rails hard so 6mm ply will fix that and give you more flex on tips.

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Re: Rounding board edges

Postby plummet » Tue Sep 27, 2016 5:55 pm

downunder wrote:I wouldn't recommend soaking a plywood, if is a ply.

What you can do as your first project is 2x6mm marine type plywood. That will make a concave and rocker with no need for soaking and risking trapped moisture in a ply voids, which is a guarantied failure.

You'll need to tapper your 12mm tips/rails hard so 6mm ply will fix that and give you more flex on tips.

D.

Yep that's good advice. I don't recommend soaking either. It also can play havoc with bonding glue in the plies and lead to delamination.

If you are committed to the 12mm sheet then just roll with no rocker for this board. Chalk it up to experience and move on to reducing thickness laminating thinner layers together to achieve a better result.
Note that tip flex is desirable for a smooth ride. To get that you really want 2-3mm core at the tips and glass or carbon to give you a flexible yet strong construction.


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