Hi all. Ive been asked to make an SUP for someone. So far my shaping expertise involves making my own 9' longboard.
Finding surfboard blanks seems easy enough but finding PU SUP ones not so much so I'm wondering if anyone can point me in the right direction of a PU 9'8 blank possibly. Looking at a final product being around 9'6x32"x4-41/2"

Reason Im looking at PU is I have spent a lot of time learning ins and outs of PU resin and exactly 0hrs knowing anything about epoxy (plus it's dearer).

Thanks in advance for any info.

Just check the weight of a PU blank and what the board will end up weighing...

I guess your best bet is to decline the order.
PU will be much too heavy for a board this volume, and shaping EPS and glassing epoxy are very different from working with PU and polyester, it is not worth attempting it for a one shot job. For instance expert polyester glassers first epoxy boards are full of pinholes...

Otherwise, I guess you will have to make the foam blank yourself, with some innovative features to keep the weight down such as digging chambers in it, or using an honeycomb core, or... quite an undertaking.

PU Blanks are too heavy for sups, you'll have to get a block of EPS foam and hot wire it.

Ah, well there you go. Thanks for the heads up.

Im not against having a crack. I'll jist have to learn more about epoxy then.

I really appreciate you guys taking the time to reply though.

So on this..... Can anyone point in the direction of where to get EPS Blocks from? I think I'll make a hot wire cutter and shape it myself but not having a lot of luck locating somewhere to buy the foam.

Thanks

Garlic aioli

I disagree that shaping EPS and glassing epoxy are so hard. What you lose in cripsy easy shapability, you gain in not needing a stringer plane and all that ****around. Do it all with a new surform plane and a shapers block with about 120 grade and you can't wreck it.



Try a foam supplier, you don't need a "blank" just a big block and hotwire it out. If the foam suppliers will only do a full block (like 10ft x 6ft x 6ft ish) then try any refrigeration coolroom places, they should do 10ft x 4ft x 6" thick in SL (13kg) for about $150. (with no cladding each side, just EPS)



Epoxy is easier than bloody styrene resins , no changing ratios. Just do it

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Mark _australia said..
I disagree that shaping EPS and glassing epoxy are so hard.

I didn't say that it was harder, just that it was different.

My experience is that expert PU+Poly glassers that just glass epoxy like they glassed polyester are in for big surprizes: pulling epoxy like poly will leave pinholes, sanding will overheat, cure time is not tweakable in the same way, the board will weight a ton because they didn't expect how much an EPS blank absorbs the resin, etc...

People used to polyester, like the original poster, will have first to "unlearn" their habits.

As a customer, I would never order an epoxy board from people used only to PU.

Yes very true.
I guess awareness before starting is the key

www.polyfoam.com.au/materials.php?Expanded-Polystyrene-EPS-1

Used them in Tasmania, cut 2400x1200x1200 block to whatever thinkness I wanted..

Hi. A mate bought a block from A&C Polystyrene 6 Enterprise Pl, Wetherill Park NSW 2164.
Phone
(02) 9756 2512
It is a long way from you but if you can find a similar company in your area that would be the go. They also cut the rocker
in the blank using an Illustrator EPS or a PDF. The might be able cut the shape completely with a digital file.
Also you need to give the shaped blank a light coat of epoxy mixed with a filler to stop the resin soaking in to the blank when you glass it.
Hope this helps

Thanks all. I found a couple of foam suppliers in Geelong and their prices are quite reasonable and will make it to my specs so shaping shouldn't be a problem.

Ive been seeing videos where they're talking about selling the eps with everything from spak filler to paint to reduce the epoxy soaking in. Any thoughts on this?

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bigmc said..

Also you need to give the shaped blank a light coat of epoxy mixed with a filler to stop the resin soaking in to the blank when you glass it.
Hope this helps

I missed your last bit of advice there. Thanks for that tip too :)

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misterbrettc said.. Ive been seeing videos where they're talking about selling the eps with everything from spak filler to paint to reduce the epoxy soaking in. Any thoughts on this?

Yanks love their spak filla coat for some reason, I think its a bit agricultural - invented by somebody when they first started using EPS and somehow caught on.... sure it reduces resin soak in, but it allows for lazy shaping too on a surfboard where you want that perfect foam under the glass. Less applicable on a SUP unless you are going for that look.

The resin and q-cell fill is much much better, I have no idea why they still use "spackle" on everything

I personally would wet out on a table, roll it up on a pvc tube and roll it on like we do building windsurf boards. You'd be amazed how much resin is left out of the cloth. Then with hotcoat and sand you have got down to the absolute min weight without vac bagging.
On a SUP I would vac bag the deck with wood or PVC in standing area though. Glass bottom and rail tape with carbon first so it can't bend in the bag... but still use a rocker spine to be safe.

Many ways to skin a cat though....

Skin the cat the way you want or follow the way that Mark rightly said but I reckon to shape your Eps with a cnc machine would be a good option too.