I'm no expert.. but I say that it should work.

btw.. I felt my friends PSH board yesterday while it was sitting in the hot sun and the board felt cool.. the deck pad felt warm.. and the black circle on the deck where the PSH logo is was almost too hot to touch.. I was amazed.

I've been thinking about spraying one of my Kilaoa paddles with a thin white spray to see how that effects the heating up in the sun... Jeez they get hot after just a few minutes left in the sun.

DJ

I used to have a white gelcoated racing ski that was carbon.
It used to get way to hot if I left it in direct sunlight for too long.
So i would always try put it under shade.
But my Glass ski could stay in the sun all day no probs ( as long as the bung was out )
I think a white tinted carbon lay up would still draw some heat.
But I aint know expert.

One thing to keep in mind when pigmenting epoxy, is the fact that the more pigment that is used the more it will degrade the phisical properties of the laminate.
To make a carbon laminate white would require a high pecentage of pigment & a thick white pigmented filler coat to get a good opaque white surface.
Painting with good tough marine polyurithane & a gortex vent is by far the most reliable way to minimise heat related delamination.
Regarding that theory of carbon under a white surface getting hotter....I just tried it foor you....most of my long boards have a 100mm wide carbon uni down the center....there is no noticible difference in temp in this area & the glass next to it.
The one on the left has been sanded, the other undercoated.

LSD said...

One thing to keep in mind when pigmenting epoxy, is the fact that the more pigment that is used the more it will degrade the phisical properties of the laminate.
To make a carbon laminate white would require a high pecentage of pigment & a thick white pigmented filler coat to get a good opaque white surface.
Painting with good tough marine polyurithane & a gortex vent is by far the most reliable way to minimise heat related delamination.
Regarding that theory of carbon under a white surface getting hotter....I just tried it foor you....most of my long boards have a 100mm wide carbon uni down the center....there is no noticible difference in temp in this area & the glass next to it.
The one on the left has been sanded, the other undercoated.

thats interesting guys. i was thinking of a white tint, not overtly, to the carbon, but still painting the board. lsd, it looks like you have slight tint in there. that was the sort of thing i was thinking of
cheers

CMC said...

Hey LSD, do you find the marine poly paint adds much weight?

I read that with ski's etc that any colour at all adds weight to the carbon other than clear. Ie Black is lightest.

Have you ever measured the before and afters? They were saying some colours were also heavier than others.

Yeah...thats right any paint will add weight, the better the paint job... usualy the more weight needs to be added. The preparation for the top coat adds weight, high build primers etc
Also colours or particular types of paint are not as opaque as others, so more coats are needed to give good depth of colour.
The 12'6 boards in the shot would have roughly taken about 1.5 kg of paint.
These being proto's I have done them with a bit of carbon uni to stiffen & a glass layup.
Clear coating is the way I save weight with my wave boards, I think the last one weighed 4.8kg with no fin.

DavidJohn said...

I'm no expert.. but I say that it should work.

btw.. I felt my friends PSH board yesterday while it was sitting in the hot sun and the board felt cool.. the deck pad felt warm.. and the black circle on the deck where the PSH logo is was almost too hot to touch.. I was amazed.

I've been thinking about spraying one of my Kilaoa paddles with a thin white spray to see how that effects the heating up in the sun... Jeez they get hot after just a few minutes left in the sun.

DJ

Simple physics....
The colour makes (practically) zero difference in how the heat from the surrounds transfers into the board. Eg placing it on hot sand, or leaving it in a hot car, it won't make any difference. (this is convection and conduction at work). If your board is black all the way through or white all the way through - no difference in core temperature if you stuck it in a dark hot room for the same amount of time.

The big difference is in RADIATION, eg the transfer of energy (heat) across space (and thru the air!). White and lighter colours reflect (or don't absorb) as much light and so don't heat up as much. Dark colours absorb a lot more energy and so get hot quickly. So a black surface (paint, or black carbon fibres under clearcoat) in the sun can heat up to a much higher temperature than the surrounding air for example, provided they are in the light. (and once this outer layer is hot this heat is transferred to the layers underneath).

The simple way to keep carbon fibre (or anything) cool is to paint/gelcoat it white or metallic - you don't want to try to colour the composite's resin (as it'll affect strength).

For carbon paddle poles and blades I can't see what the fuss is about personally, other than they get hot to touch. I have a black carbon fibre bicycle, wheels etc etc and they don't go floppy in the sun....

(the only concern is the foam core in boards, which can overheat)