Had to reinforce the Tuttle box in an old Starboard Formula 161 so that it can take the loads of a windfoil.
I was intrigued by the laminates on the bottom, and wonder if anyone knows the exact layup of these boards.
Above the EPS, there appears to be:
1. yellow coloured foam - is this PVC foam or expanding epoxy resin ?
2. thin layer of carbon
3. brown coloured foam - PVC like Divinycell?
4. thicker layer of carbon
5. the white skin, which also appears to consist of three layers - does anyone know what products are used for this skin ?
The layup on this old Formula board also appears superior to my 2017 Starboard Phantom raceboard.
While considering what material to use for reinforcing the Tuttle box, I found this link comparing XPS and PVC foam.
www.trinardo.com/y.a.t-yetanothertrinadofoamcompare3
I had some XPS and PVC in the shed so did my own comparison test.
The compression strength of the XPS foam appears to be about 20-30% of the PVC.
Therefore I suggest XPS foam is not suitable for high compression loads like foil box reinforcing.
Select to expand quote
Well that depends on the density of each surely?
Although I haven't seen xps with density as high as vinyl gets.
The sandwich above appears quite sophisticated, I'm just taking a guess here, but it could be the inner foam is a lower density than the outer, maybe 60kg/m>3 for the light yellow stuff and 80kg/m>3 for the dark brown. I've no idea what the very outer layer is, I'll take another guess and say it's impact resistant to protect the vulnerable carbon.
The starboard site says this of the current formula contruction "Both deck and bottom are wrapped in 45 degree biaxial glass fiber wetted out with an expanding foam epoxy cured under high pressure. The biaxial glass gives a crisp, stiff feel with flex for choppy conditions. The foam epoxy creates a 2mm skin thickness for a microsandwich effect: tough and strong"
So that may be what the outer layer is.
I have an older starboard formula board which I modified for learners and taking the dog for a spin .
I added two side fin boxes so I can use 3 , 30 cm fins for shallow water .
When cutting holes I was surprised to only see , from foam up,
Eps , 3 mm divinicell , one layer carbon then wood .
That's it
Wood was drying out and cracking . Lucky to have a super thin layer of varnish or spray resin to seal.
There was no sandwich construction , just layers .
I would have thought a layer of carbon or glass over the eps or over the wood .
Select to expand quoteyoyo said..
The starboard site says this of the current formula contruction "Both deck and bottomto happen in a moulds are wrapped in 45 degree biaxial glass fiber wetted out with an expanding foam epoxy cured under high pressure. The biaxial glass gives a crisp, stiff feel with flex for choppy conditions. The foam epoxy creates a 2mm skin thickness for a microsandwich effect: tough and strong
That's interesting and makes me wonder .
With controll this has to happen in a mould . Like they did in the old days.
If it wasnt and they relied on a even expanding amount ...... well it won't be , even in a vac bag . The amount of filler and sanding needed would not make sense.
I would love a tour of that factory , but it won't happen , not one vid or even a pic ????
Call me old and grumpy , but the bull...t were fed about construction techniques cobra use is a load of crock.
Sounds great , works good , cheap. Eviromentally friendly , not even close.
I feel better now.
Select to expand quoteImax1 said..
I have an older starboard formula board which I modified for learners and taking the dog for a spin .
I added two side fin boxes so I can use 3 , 30 cm fins for shallow water .
When cutting holes I was surprised to only see , from foam up,
Eps , 3 mm divinicell , one layer carbon then wood .
That's it
Wood was drying out and cracking . Lucky to have a super thin layer of varnish or spray resin to seal.
There was no sandwich construction , just layers .
I would have thought a layer of carbon or glass over the eps or over the wood .
Yes, this one is wood on top as well. The wood drying and cracking seems to be a common issue too.
I will probably sand back and add layer of light eglass/epoxy to seal it.
Am not too worried about weight as it's just a windfoil trainer.
Select to expand quoteazuli said..
Yes, this one is wood on top as well. The wood drying and cracking seems to be a common issue too.
I will probably sand back and add layer of light eglass/epoxy to seal it.
Am not too worried about weight as it's just a windfoil trainer.
If you are doing that, give the nose some extra love - it'll need it. 
Select to expand quoteazuli said..
Had to reinforce the Tuttle box in an old Starboard Formula 161 so that it can take the loads of a windfoil.
I was intrigued by the laminates on the bottom, and wonder if anyone knows the exact layup of these boards.
Above the EPS, there appears to be:
1. yellow coloured foam - is this PVC foam or expanding epoxy resin ?
2. thin layer of carbon
3. brown coloured foam - PVC like Divinycell?
4. thicker layer of carbon
5. the white skin, which also appears to consist of three layers - does anyone know what products are used for this skin ?
The layup on this old Formula board also appears superior to my 2017 Starboard Phantom raceboard.
While considering what material to use for reinforcing the Tuttle box, I found this link comparing XPS and PVC foam.
www.trinardo.com/y.a.t-yetanothertrinadofoamcompare3
I had some XPS and PVC in the shed so did my own comparison test.
The compression strength of the XPS foam appears to be about 20-30% of the PVC.
Therefore I suggest XPS foam is not suitable for high compression loads like foil box reinforcing.
Hi there, when you say "had to reinforce" you meant you want to prevent damage or the box was already having issues?
Select to expand quoteWillyWind said..Hi there, when you say "had to reinforce" you meant you want to prevent damage or the box was already having issues?
There was evidence of stress, so decided to strengthen before it suffered major damage or took in water.
Sorry imax I meant the 3mm pvc foam wood and one carbon. That's pretty good for a board that won't be jumped.
wood seems to be strongest construction I've seen. Shame that starboard didn't seal it well enough so most degraded but easy fix
Select to expand quoteyoyo said..
The starboard site says this of the current formula contruction "Both deck and bottom are wrapped in 45 degree biaxial glass fiber wetted out with an expanding foam epoxy cured under high pressure. The biaxial glass gives a crisp, stiff feel with flex for choppy conditions. The foam epoxy creates a 2mm skin thickness for a microsandwich effect: tough and strong"
So that may be what the outer layer is.
Foaming resin I believe.
