Tell Me If I'm Crazy

General Discussion
1

I’m sure this idea is in no ways original and has most likely been rejected or tried with poor results. But why not try again.

My main concern with the light weight of expanded polystyrene foam is the loss of strength and durability in the foam. I thought that somehow, some way, the creative minds of the Swayloholics could make this design work in theory. It seems logical to me to eliminate the damage to the deck of an EPS board by gluing a denser piece of foam (1/2" thick) on the top of the blank. The heavier deck seems more logical than sacrificing weight by using an entire blank of heavier foam.

I haven’t thought of another process to create the dual-density blank without vacuum-bagging the blank, if not the entire board. Although, you would run into some trouble when the nose and tail are foiled to extremely thin thicknesses. I doubt I’d run into this problem, as I don’t ride thrusters.

Please criticize, support, rearrange, or completely rule out my idea.

2
Quote:

I’m sure this idea is in no ways original and has most likely been rejected or tried with poor results. But why not try again.

My main concern with the light weight of expanded polystyrene foam is the loss of strength and durability in the foam. I thought that somehow, some way, the creative minds of the Swayloholics could make this design work in theory. It seems logical to me to eliminate the damage to the deck of an EPS board by gluing a denser piece of foam (1/2" thick) on the top of the blank. The heavier deck seems more logical than sacrificing weight by using an entire blank of heavier foam.

I haven’t thought of another process to create the dual-density blank without vacuum-bagging the blank, if not the entire board. Although, you would run into some trouble when the nose and tail are foiled to extremely thin thicknesses. I doubt I’d run into this problem, as I don’t ride thrusters.

Please criticize, support, rearrange, or completely rule out my idea.

You’re crazy…

But seriously. The logical terminal to that train of thought (one that has been traveled by many on many occasions) is to use a vacuum bagging system to attach a thinner (say, 1/8") shell of higher-density foam to the low density core. Bert Burger’s “vacuum forming and construction” thread is a wonderful start to this process, and really tells you all you need to know if you look hard enough.

3
Quote:

My main concern with the light weight of expanded polystyrene foam is the loss of strength and durability in the foam. I thought that somehow, some way, the creative minds of the Swayloholics could make this design work in theory. It seems logical to me to eliminate the damage to the deck of an EPS board by gluing a denser piece of foam (1/2" thick) on the top of the blank. The heavier deck seems more logical than sacrificing weight by using an entire blank of heavier foam.

Go read some of Greg’s and Bert’s comments on the reasoning behind 1lb EPS cores.

the theory is that super light EPS allows you to use more layers of glass to build your sandwich of resin glass foam glass and resin. You can use fillers like syntex or alter the orientation of the glass layers to increase strength and none of this requires the uses of vacuum forming technology. Just standard surfboard methods using different materials and a different mindset. It’s not that difficult and you don’t have to get that fancy to build a much stronger board around the same weight as a poly. Prior to using EPS CMP was epoxing balsa skins to regular clark foam blanks. Sure they came out a tad heavier than a normal heavily glassed board but also pretty damn indestructable with the glass wood glass epoxy shell in place of just a couple layers of heavy volan or S cloth.

The process is very straight forward

4

I forgot about Bert Burger, but I was hoping for something a bit more simple than his process. The problem I have with light foam, heavy glass is the flex patterns, for now at least. I know that epoxy flex can be manipulated to your liking, I’ve just never heard how.

5

Hi,

I’m very new to sandwich construction, but i’m super amping on it at the moment, so i’m compelled to comment!

I know you said you didn’t want to get as technical as Berts system, but consider it, it’s so fun…

oneula is dead right about buiding a great board with simple EPS and glass - light and strong.

Flex? questionable, the arguments are still not dying down…

Even though Bert is way ahead most of us, I’m sure he would be the first to say that the surface has only just been scratched with compsands.

I think the potential lies in the number of changeable variables in the construction of a board.

For example, PU/PE, not much you can change, a few weights of blanks, glassing schedules, shaping techniques, a few other factors.

But that didn’t matter, the formula was and still is great! I love them, always will, I just don’t want a monogamous relationship with one! I’ll always think their beautiful…

Then, take EPS just plainly glassed - same deal as PU/PE in terms of options - theres just not that many diffferent ways you can make them.

Now look at composite sandwich construction.

The very fact that the system is complex, means there are virtually limitless combinations of the materials.

It also means that the “right” formula is hard to find… but now there is the potential to make many “right” formulas, maybe one for each different person even?

May take years to unlock the potential.

The fact that you’re thinking about the construction and ways of getting benefits though different combinations makes me think you’re a perfect candidate for starting vac bagging…

You may find the holy grail of Flex…

Kit

6

This is the stuff that inspires us here, different ideas, different thinking…

Set’s us apart from the rest I think…

I’ve been thinking about using a flat deck wide wooden stringer with rocker set into it countersunk into the deck of the board…

Is that crazy talk or something to think about???

7

Of course i’m gunna say go for it, give it a try!

I don’t feel qualified to discuss the finer points of the engineering of it…

But im back at uni studying something like it, so maybe in a couple of years i’ll have the tech speak.

So for now, I just take my limited budget and go for the trial and error method!

Thats what i’d do with that if it was my idea… sounds cool.

Would definitely look different, and that seems to be in vogue at the mo.

Kit

8

okay you wanna go cheap and low tech…

here’s a recipe

go to hard ware store and buy

One 4’x8’x2" sheet of cheap insulfoam roof insulation (~$15 USD)

One roll of plastic shrink wrapping tape (~$12 USD)

One 4’x8’x1mm sheet of Silompan woven bamboo panel covering (~$30 USD)

One bottle of PU glue or Roo glue (~$30)

take the fins off you favorite board

cut the foam sheet in half

cut the outline on both sheets

spread some glue on the sheets

use 1/2 the plastic wrap to attach the foam to the bottom of the board

wait 24 hours

Now remove the “blank” and hand shape it with a 2’x2"x4" with 36 grit belt sander paper and some drywall screens

now draw a line 1"-2" from the rail and cut this just slightly to support the 1mm bamboo

cut out this outline from the bamboo with tin snips or a sharp box cutter

using the PU/Roo glue glue the cut bamboo sheet into the deck inet using the rest of the plastic tape to hold it in place

Now finish sanding and glass it normally like any EPS of that weight

the deck will be indestructable

the bottom will flex

use glasss on fins

low tech

state of the art

9

Your original inquiry is quite vague.

EPS comes in various densities and each has its own application.

The simplest and most rewarding route is to buy a #2 blank (Marko foam being an excellent choice), shape it and glass it using Greg’s proven methods.

As you go down in density, its gets much harder to achieve good consistent results…its more labor intensive and, expensive (my God, is it expensive). But if youre a gearhead with a phat bank account, lots of spare time on your hands, thats ok…shoot for the moon.