How and why...

General Discussion
1

I have really enjoyed lurking and learning around here.

Here’s where I am coming from: I really enjoy sculpting

curvy things, wood carvings in the '80’s and wood

boats in the 90’s 'til the present.

I live a mile from a surfing beach, in Pacifica, CA,

and am getting the urge to do some surfing.

Although I could buy a board, I want to make

some boards just for the fun of making some

boards. Surfboards are beautiful dynamic things,

like boats, they seem worth making just because.

One thing I have learned from you guys

is that most of the art of designing surfboards is

the learning the needs and style of the surfer and

their surf and prescribing a design that meets that

need. Kind of like a doctor might study the

symptoms of a patient to find a cure.

Regarding the use of machines to mass produce

surfboards, yes it can be done. But machines

will never design the perfect surfboard to

fit the needs of individual surfers and their surf.

A few observations:

  1. I don’t understand why some of you guys

still use polyester resin. On the boatbuilding

side, we nearly all have switched to the use of

epoxy resin now that its price has dropped.

Polyester is worth avoiding for the brain cell

loss from the stink if for no other reason!

I buy epoxy from www.raka.com for about

$43 a gallon delivered!

  1. As impact resistance is important on the

deck of a surfboard, why don’t you guys use

Xynole cloth? It drapes great, and wets out

nice, doesn’t itch, and is not anywhere as

brittle as fiberglass.

  1. I don’t get it (yet), why buying a blank from

Clark Foam is ‘the way to go’. Lofting up a

shape, like you would do with a boat, cutting

a stringer(s), and sculpting some polystyrene

seems straight forward enough and gives you

more control. Maybe I will eat my words later,

we’ll see.

2

interesting comments, welcome to “non-lurker mode”. I’m sure there’s lots to learn out there from boat builders, sculptors, the home-built airplane crowd and others.

Xynole cloth – I’ve had an aversion to polyester cloth ever since the 70s & disco. Just kidding! you might be onto something there… perhaps a combo layup of fiberglass & Xynole might work well, too.

You should make a board, try your ideas out, post pictures of it…

3

For what it is worth, 4 ounce Xynole cloth has a lock stitch weave

kind of like a T-shirt, but much looser. It really soaks up the

resin, filling perhaps like a 10 ounce fiberglass. It has perhaps

double or triple the elasticity of fiberglass cloth, which gives it

excellent impact resistance and resiliance. Because of the lock

stitch weave, it drapes over curves much better than a traditional

fiberglass cloth.

Yes, I am planning on building some boards, [and I will post photos].

Deciding on which is the problem.

I want one for my 100 pound 12 year old

daughter, who is athletic, but somewhat timid of surf but

wants to learn. We presently have lots of fun with Boogie

boards.

Surf where I live [Linda Mar Beach] in Pacifica is often waist

high, and less in the Summer.

I want one (actually several) for myself. I don’t know yet

how to surf, am 200 lbs and not very athletic. I am leaning

towards high buoyacy board, a tanker, like the Sid Madden

9’3" in the Clark Foam catalogue. And, perhaps a Funboard

like an 8’5"S. Actually, I want to try them all.

I also want a board for my 140 lb 5’7" non-surfing girlfriend.

Advice would be appreciated.

A long tandem board would be fun to try.

4

Good points Bruce. Much of the answers lie in the fact that many surfers are weary of change…they know and like PU/PE boards. The shapers like them because they are easy and cheap to make…point #3, many if not most Clark blanks are already nicely pre-shaped so its easier for the entry/intermediate level shapers to get started.

Just about any board you’ll make will work based on skills you already posses. If you stray too far from the acceptable standards you may get less than desirable performance. You can always correct things later (Im now experimenting with reshaping fully glassed/finished boards…just a new challenge for me.)

good luck!

5

…i think the use of this types of fibers (xylone, etc)is not popular in standard board building cause you dont obtain a transparent lam…

6

Yes, Xylone cloth gives a milky transparancy. Being able

to see the wood stringer is cool, I agree. In boat building,

I am fond of adding glass micro ballons to the epoxy to get

improved ‘sand-ability’. Micro-ballons make epoxy

milky in color too. Transparent epoxy is prone to UV

discoloration. How do surfboard makers control the

UV damage, with UV resistant varnish? [like boat

builders use] Adding pigment to epoxy also can be

used to help control UV damage.

7

Xynole cloth is white and reasonably wets out to nearly clear, although I wouldn’t put an air brush under it. You should use a more flexible epoxy (2020) with that fabric and usually a layer of 4 oz fiberglass over. You need the fiberglass because a Xynole laminate without glass makes a very flexible finished board. Perhaps I should say too flexible. Also Xynole tends to get fuzzy when you hit it with sandpaper so the glass over top helps with this. The Xynole I’ve worked with is kind of fuzzy in comparison to glass and the bond to the blank is much better so board breakage is less. Again the 2020 probably helps with this as well. When your laminating with Xynole be sure to control resin content to an extent. That stuff can soak up heaps if you let it.

I’m not very familiar with the particular epoxy you mentioned (I have heard of them) but surfboard epoxies do have some parameters that make them different than boat epoxies. The prices of surfboard epoxies are still in the range you mentioned though.

EPS foam is widely used in the surf and sailboard industies although urethane still dominates the surf industry. For use with Xynol, I’ve always used a 1.5 lb blank. I’ve also found that Xynol bonds to EPS better than fiberglass so a stringer is not nessasary.

Hope this helps.

8

GregLoehr wrote:

You should use a more flexible epoxy (2020)

Googling “2020 epoxy” doesn’t reveal much.

Where can I read tech data about this epoxy?

…and/or where do you buy it?

Thanks in advance!

9

It’s Resin Research epoxy which just happens to be where I work. 2020 was originally developed especially for Xynol Polyester fabric. You can contact me direct at for any specifics and purchacing.

10

2020 is a product from resin research which was actually originally developed for Xynol fabrics. For specific info you can contact me directly at .

11

I am trying to comprehend the engineering of this;

are you saying that with surfboards, you’re concern

is that Xynol has a lower modulus of elasticity than

fiberglass, and that therefore you recommend an

epoxy with a lower modulus of elasticity? IE your 2020?

…to take the dent of your foot as the Xynol

stretches without stress cracking in epoxy?

If that was the case, wouldn’t a higher tensile

strength layer below the Xynol also be effective?

[Giving extreme fiber tensile strength were it

is needed to prevent denting?]

Also I noticed that your epoxy formulations

have a UV inhibitor, I have not heard of that before.

12

With polyester cloth the elongation is greater than most standard epoxy resins. This is especially a problem over a soft substraight like low density foam. In any composite all the materials involved partner with each other to give a total yield strength. A partner not carrying its share of the load, forces one of the other partners to carry it’s share. In the case of xynol, if your resin is high modulus then your resin elongation is going to be less than the fabric. The resin will then carry most the load and crack before the fabric. On the other end of the spectrum, carbon can use a very stiff, high modulus resin. And if you don’t then the carbon will carry too much of the load and fail sooner than it should. As for xynol on the exterior, this is fine, but it does present some problems with finishing. Xynol, under or over, is not going to solve denting. Carbon is used for this.

UV stability is something surfboard epoxies have had for over 20 years. If you’d like more info you can e-mail me directly at