Blanks...

Hey All,

I work with composites quite a lot and was planning on shaping my own board at some point...I have got myself a bit of a design together using BoardCad and plan to make something. I have a vac pump (a proper one not a vacuum cleaner) and a shaping shack. I know it being my first board it will be rubbish...I think its well documented that everyone first board is rubbish.

I am having issues trying to select a blank though. There are a few older posts, but well, I would rather be safer than sorry as carbon is pricey...

There seems to be very little info out there really about it. I have done some reading and stumbled across this guide from SP systems. Which I now cannot find a link to now. Anyhow they talk about using Styrofoam IB which is a form of insulation.

If you look on the patrik website for their freestyle board they mention that they use styrofoam for a blank (Core MaterialEPS (Styrofoam):

patrik-windsurf.com/f-style/

I know that homeblown blanks tend to have wooden stringers built into them. But I guess they are more designed for surf boards rather than a windsurf board.

It seems quite simple (and far too easy), but I managed to work out that Jewsons sell something similar to styrofoam:

www.jewson.co.uk/building-materials/thermal-insulation/extruded-polystyrene-insulation/products/ICX2I025/yelofoam-x2i-extruded-polystyrene-2500-x-600-x-25mm/

Its compression strength is actually better than styrofoams I think:

www.dupont.com/building.html

Am I going mad, or is it that simple, could I use the jewsons yelfoam as a blank?!

Thanks in advance for any advice, oh by the way, I am UK based, but there seems to be very little in the way of forums in the UK to ask about this sort of thing...

Sparky Mark.

I gather if you are talking vacuum then you are doing PVC sandwich over foam?
But home blown refers to PU (old surfboard style)? I will assume the former

Any styrofoam supplier of note will be able to supply a selection of EPS grades. Do some googling cos it depends if they talk kg/m3 or lbs or SL grade etc in your neck of the woods. 12-16kg dependent upon your outer sandwich

Forget XPS it is prone to delam unless prepped well and what looks like a cheap option becomes a PITA

Home blown, do actually do EPS as well as PU blanks:

http://www.homeblown.co.uk/product-category/surfboardblanks/epssurfboardblanks/

Did a bit more searching, although I got the compression information for what I was looking at, I didn't get the density. A quick search revealed the following:

www.insulationshop.co/yelofoam_cellecta_75mm_insulation_x2i.html

This quotes the density as being 30kgm3. This sounds a bit overkill??

Yes I was planning on vacing down some corcell or similar. I was thinking something along the lines of 5mm, which sounds pretty beefy now. Guessing I could use something like 3mm foam? The power of the sandwich is not do be underestimated.

I was planning on using a 135g carbon/kevlar twill cloth over the blank to start with, then vacumming the foam on, and lastly finishing with a 300g Biax Carbon weave, and another layer of the 135g carbon/kevlar I had planned on putting some extra re-enforcement around the foot pad areas on the top skin (probably the 135g carbon/kevlar cloth at 45degrees and one at 90).

I think with this type of blank though, I would create a heavy board? One way I was planning on trying to get all the weight down though was the vac everything down, including the laminate and also cooking it in some kind of home made oven.

I was going to finish it using something like SP115 epoxy with some sort of pigment to colour the board. Actually really like the look of the sicomin stuff (shop.matrix-composites.co.uk/surf-clear-evo-resin-kit-160-p.asp)

Anyhow, thanks for the replies, they are greatly appreciated!

Sparky Mark.

I think the problem with thick UK insulation foam is that it's meant to go under the floor to insulate the home from the low ground temperature so it's going to be high density and closed cell.
The home blanks are probably also high density and are only surfboard size.
Over here we can by blocks of foam in several densities and just about any size we want, makes it much easier.
The beauty about extruded styrofoam is that it's closed cell and doesn't need a bung, but yes it is heavy.
The expanded version can be much lighter but does require a bung, as it's open cell.

I guess it depends on how big your board will be. A very small speed board (around 60l) will be OK out of 30kg/m3 as the blank will only weigh 1.8kg. But if you're making a big light wind board the foam density becomes much more relevant. the blank weight for a 120l board will be the same with 15kg/m3.

Thanks for all you replies all, its great that you guys have such a good community over there! Sorry for my tardiness in replying, I spent my weekend teaching people how to sail in sailing dinghies :/

Anyway. You guys are quite right, that yelofoam stuff is wayy too heavy.

The problem I have in the UK with the blank, is that well, if I buy mail order, I think that the postage is almost as much as the actual foam. That said I think I have a line on something local:

www.jablite.co.uk/application/jabfloor/

I can get the 100 version which is 20kg m3.

Some interesting points. So my plan was to make a 95l (ish) freestyle board....my old chili is die-ing. Its got a pure glass bottom but a carbon kevlar skinned top. Its got soft deck syndrome, and well, is just on its way out. Dings really easily, sucks in water like a student sucks beer and well just keeps breaking all the time...

I managed to measure a 2012 flare and a 2013 skate. The companies have made life a lot easier by actually photographing the outline and rockers for their latest boards (JP, Starboard and Finatic). So I have incorporated this into my design (you can place a jpeg over your current board in board cad and pretty much copy the shapes). I am guessing that my rail lines will probably need to be changed a little, but doubt that things have really changed that much with these boards. Still got a few things to work out though.

When I say it will probably be a rubbish board, I doubt it will technically, but as I am not an expert shaper or designer, I am not sure exactly how it will turn out. But reading between the lines of whats been written about the newer boards released I don't think I will be far off (mostly as designs in boardcad pretty much match the specs of the production boards, in terms of volume, length etc...)

The laminate specs I was planning to use where to try and make it fairly bomb proof, as I expect to be stacking it quite a lot. I guess I could drop the carbon kevlar out of the first skin, however, understanding a little bit about the sandwich, I wanted to use it there as I figured it would help to reduce repairs requiring a re-skin of this layer (which can be problematic to do - exotherm, and do you ever the get all the water out?! Are hollow boards the way forward?! see the Steve Allen Interview: windsurfing.tv/video/pwa-ulsan-korea-2017-day-3/).

I figured the Biax cloth is fairly bullet proof too, anti twist, and hopefully would help to keep the board stiff and a layer of carbon kevlar on top = fairly bomb proof no? I hear what you are saying about kevlar when re-finishing it. When you sand it it fluffs up. Had to do several repairs to all kevlar sailing dinghy hulls before now. Less than ideal to work with, but I think fairly possibly. Although I am guessing that the Partik boards which the cobra factory makes are all made using moulds.

I hear what your saying about making a board entirely with glass and doing it cheap. But I figure since I have gone to all the trouble trying to get a half decent design, why make something that I may end up having to throw away in a few years time? Also is it really that much more expensive to make with carbon?

I think I have come across some cheap cloths:

www.ecfibreglasssupplies.co.uk/product/carbonaramid-hybrid-160g-twill-weave-1-mt-wide

I already bought 5m of this biax cloth:

www.ecfibreglasssupplies.co.uk/product/clearance-biaxial-carbon-fibre-cloth-300g-45-1520mm-wide

Quite a few different ways that I could go I guess. But I think making a board with a sandwich would be worth doing for what I am trying to produce. Don't want to make anything too heavy really (the production boards are about 6kgs I think). Also, I think I have the skills and the ability to be able to actually make it.

Anyway, thanks again for the all replies, I really appreciate them! You guys seem to make a lot of your own stuff over there, not sure that really happens in the Uk, apart from maybe Moocustom who is actually only down the road from me. Not sure I would get much advice from him though, as I am sure he would rather sell me a board. But anyone who can make a board that does 50 knots must know his stuff...

...thanks again though guys, and any thoughts welcomed!

SparkyMark.

50mm is not very thick, you are going to have to join several sheets together. and that effects shaping, the glue line will be a different density and be very hard to get smooth. And probably stuff up hot wireing completely

Do yourself a favour and forget aboutwasting money on Carbon.

Fiberglass will make an ever so slightly heavier board, but it has much better impact strength. The board with be plenty stiff enough with a sandwich PVC foam construction.

See the other thread her on why not to use Carbon:
www.seabreeze.com.au/forums/Windsurfing/General/Myths-about-adding-carbon-to-strengthen-fiberglass?page=1#7

www.polystyreneps.com/polystyrene-sheets-insulation.php