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Nomad's concave molding technique

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board dude
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Nomad's concave molding technique

Postby board dude » Thu Mar 29, 2018 3:11 pm

Quick photo of the vacuum bag process , the black plates with the paper tape around has the kiteboard inside. The plates are 5mm thick and are 152x45 , we use 2 plates , one on top of the kiteboard and one below.
The black plates are to keep the lamination on the kiteboard perfectly flat whilst being held on the mold , the plates are waxed to avoid bonding to the actual kiteboard or to the mold. The process removes all the air from the laminations.
The mold as seen from the end has the kiteboard positioned to the far left, this is too maximize the hook type concave , for a rider with less weight the kiteboard can be positioned to the right molding less concave on to the actual kiteboard . A rider with less weight does not need so much lift generated by a larger concave.
The molds are created on our cnc machine , the mold in the photo is 150 x 54. The vacumm bag is the pink flexible type used widely in F1.
www,nomadkiteboarding.com
Attachments
IMAG4020.jpg
Large concave to the left , drive edge , concave flattens out to the right , toeside.
IMAG4019.jpg

thewindego
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Re: Nomad's concave molding technique

Postby thewindego » Thu Mar 29, 2018 4:48 pm

Do you precure your skins before this final step?

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rynhardt
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Re: Nomad's concave molding technique

Postby rynhardt » Thu Mar 29, 2018 9:30 pm

Nice setup, dude. Basically a progressive concave across the width of the board? Cool!

Most boards have concave in the center which helps to stiffen the centre. How does the concave at the tips affect the flex? Do you need to go extra thin to keep the tips flexible?

I'm guessing you do a saturated wet layup on the bottom plate and then place the top plate on last before bagging the whole lot? Do you not have any issues with bubbles migrating to the middle of the top plate?

Sorry, lots of questions but I always wonder how you get such great results! :thumb:

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downunder
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Re: Nomad's concave molding technique

Postby downunder » Fri Mar 30, 2018 3:05 am

board dude wrote:
Thu Mar 29, 2018 3:11 pm
Quick photo of the vacuum bag process , the black plates with the paper tape around has the kiteboard inside. The plates are 5mm thick and are 152x45 , we use 2 plates , one on top of the kiteboard and one below.
The black plates are to keep the lamination on the kiteboard perfectly flat whilst being held on the mold , the plates are waxed to avoid bonding to the actual kiteboard or to the mold. The process removes all the air from the laminations.
The mold as seen from the end has the kiteboard positioned to the far left, this is too maximize the hook type concave , for a rider with less weight the kiteboard can be positioned to the right molding less concave on to the actual kiteboard . A rider with less weight does not need so much lift generated by a larger concave.
The molds are created on our cnc machine , the mold in the photo is 150 x 54. The vacumm bag is the pink flexible type used widely in F1.
www,nomadkiteboarding.com
Dude, thanks for posting but you did not really show much to be fascinated about ;)

Let's see, my own pickup for reusable rails mold:

http://boardbuilders-forum.1077691.n5.n ... d1315.html

How's that?

NorCalNomad
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Re: Nomad's concave molding technique

Postby NorCalNomad » Fri Mar 30, 2018 4:09 am

Are those saw horses "the same process used to build F1 cars" as your website claims? The manufacturing photo you just posted is less tech than some of the sketchy carbon knock off frames from China. Also working with people who have professionally worked with Mclaren, I can tell you that's not how Mclaren does F1.

Not paying 2k+ USD for something made on an XPS mold held up by sawhorses.

You guys might make a decent product but there is so much marketing BS it's coming out of your ears.

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Re: Nomad's concave molding technique

Postby fluidity » Fri Mar 30, 2018 9:53 am

I'm confused, are those pics from Simon's Nomad factory ?
HD EPS is actually fairly rigid anyway. If Simon is CNCing the kiteboard core(not sure if he's doing a wood core or not) then it would already be in the right shape anyway so the mould would only be holding it from warping. If he's using Balsa end grain then it would probably drape with the weight of the composites and resin anyway.
As for moving the layup from one side to the other to get different amounts of concave, if it were me I'd just CAD up a new shape, change some rocker, flex, concave etc. It's not that hard to modify an STL file or if you know what you are doing, to recreate it with fine tuned changes.
But then I haven't made my own CNC table YET... Each of my own concave boards is a new adventure of form frame building and hand laid up and sanded Paulownia strips.
There's a lot more to how a board rides than the factory or the graphics on it!

fluidity
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Re: Nomad's concave molding technique

Postby fluidity » Fri Mar 30, 2018 10:01 am

rynhardt wrote:
Thu Mar 29, 2018 9:30 pm
Nice setup, dude. Basically a progressive concave across the width of the board? Cool!

Most boards have concave in the center which helps to stiffen the centre. How does the concave at the tips affect the flex? Do you need to go extra thin to keep the tips flexible?

I'm guessing you do a saturated wet layup on the bottom plate and then place the top plate on last before bagging the whole lot? Do you not have any issues with bubbles migrating to the middle of the top plate?

Sorry, lots of questions but I always wonder how you get such great results! :thumb:
I don't know how much information Simon wants to give away on his boards :lol:
I've designed and built a couple of high concave boards (15mm+) and they don't flex. I could probably fine tune in some flex by very careful orientation of composite fibre direction though... If you tension the ends up against the centre then the rocker/concave combination will tend to want to curve the sides down to balance the tensions. So if the top only has stiff fibres lengthwise(stretchy fibres sideways) and vice-versa on the bottom then it will flex like above.
That's why my next design experiment is a 5 x channel board, less extreme fibre spot loadings under flex!

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Re: Nomad's concave molding technique

Postby board dude » Sat Apr 07, 2018 7:30 am

Do you precure your skins before this final step?
Thanks for the posts guys , no we don't precure any skins , the kiteboard being built in the above photos is built in 2 vacuum processes , first the top lamination , and then the bottom lamination.
Most boards have concave in the center which helps to stiffen the centre. How does the concave at the tips affect the flex? Do you need to go extra thin to keep the tips flexible?

I'm guessing you do a saturated wet layup on the bottom plate and then place the top plate on last before bagging the whole lot? Do you not have any issues with bubbles migrating to the middle of the top plate?
Yes the tips are thin in core thickness but have extra lamination for good impact resistance , as you know the tips of any twintip take a lot of abuse.
The building technique in the above attached photos uses a core which is perforated , the top lamination is made first allowing any air and extra resin to flow down through the core and sit on the bottom waxed flattening plate.
This technique eliminates any build up of air bubbles trapped in the center of the lamination.
A good wet lamination will provide the perfect resin-weight combination , the laminate is protected with peelply.
HD EPS is actually fairly rigid anyway.
The molds are built from Dow insulation foam , the foam blocks are epoxy bonded to a wooden plate , cnc machined , tested and then an ABS plate is bonded to the shaped top surface to protect it against resin spillage.
The molds are lightweight and can with stand huge vacuum pressures and high temperatures. They are quick to prototype and are continually updated for our advancing shapes.
Attachments
IMAG3996.jpg
Cnc machining foam core mold.

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rynhardt
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Re: Nomad's concave molding technique

Postby rynhardt » Sat Apr 07, 2018 8:46 am

board dude wrote:
Sat Apr 07, 2018 7:30 am

The building technique in the above attached photos uses a core which is perforated , the top lamination is made first allowing any air and extra resin to flow down through the core and sit on the bottom waxed flattening plate.
This technique eliminates any build up of air bubbles trapped in the center of the lamination.
A good wet lamination will provide the perfect resin-weight combination , the laminate is protected with peelply.
So does this mean you turn the entire mould assembly upside down when you do the top laminate?


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