please critique this construction technique

hello gang,

could use insight to problems in theory (performance), or production of a quiver for myself using materials and techniques of as follows;

  1. starting off with the lightest corecell (3 pound density) 1 1/4 inch sheets = thermoforming rocker into the sheets

  2. shape 1 sheet as deck and 1 sheet as bottom

  3. chamber out nose and last 10 inchs of tail (hallowed space butting up against the solid core in an eliptical shape)

  4. channel chamber some of the middle 2/3rds of board (not centerline or rails)

  5. glue together halves

  6. glass entire board with high temp cure epoxy ,1layer kevlar unidirectional cloth, and 1 layer sacrifical glass veil (to sand)

i am not a board builder so i have no idea how this sounds…what i do know is i like superlight responsive surfboards,but dont like breaking them and repurchasing the same board a hundred times…pls help…i know this is gona cost me but im ready for a better scenario…had a firewire that resisted breakage for a while, but when it finally went and I saw the bead size of the eps core I thaught that may be a reason for the lack of liveleeness. it had flex but maybe a slow recoil? my theory is some energy gets lost in the transfer of energy of the dual density composites, so i am trying to stay away from that construction type…

1 SECIFIC QUESTION ; 1 thing somebody told me is the bubble size of my corecell is gona need to to have microballon filler or else it will leach resin… i am only using corecell because of its superior shear elongation before break…if my cloth is laminated to the bough (microballons) might shearing occur under heavy load?

                                                                               THANKS ALL--JUSTIN

IMHO way too complicated and your basing the structure on 3# corecel which really isn’t structural. Look at the WMD compsand thread. I think that is a superior method … and wayyyy easier and cheaper.

You can have a finished board that would be damn near bullet proof for the same amount of $ the corecell would cost.

Hey Justin

There’s only one way to find out and that’s ’ build it '.

I’m thinking it’s overkill but who knows it may work for you, my current build is loosely based on Greg’s timberflex theory but using corecell for the rails. Make one , ride it and post pics it could be fun.

As far as the sheer strength under heavy loads goes what type of surf is this board for? Heavy enough load and anything can let go.



yea,yea, hundreds of tons of water will break anything…the boards will be at pipe and off the wall alot…but the firewire i had does not come close to how strong something could be made and it handled about 40 sessions at backdoor and off the wall before finally meeting its death over the falls at 6 foot hawaiian log cabins…ive had about 25 normal shortboards goe in 1-10 sessions out there…so for me in the long run i hope to save alot of money…BUT AGAIN I NEED YOUR INPUTS CAUSE I HAVE NO EXPIERIENCE WITH THIS KIND OF THING…ABOUT THE BOUGH??? AND IF GLASSED WITH ONLY UNI LENGTH WISE WHAT ABOUT SPLITTING???

Just replace the center corecel panel with a thick sheet of honeycomb nidacore(Swizzle) and you won’t have to hollow out anything.

It’ll be way stronger and way more expensive…

While you’re at it cover the outside with unidirectional carbonfiber(fiberglast) and the glass the exterior with basalt glass and you have the schnizzle. Just be sure to bag it all togethor as well as the glass with teflon perf release…

LMAO,If I hit the lotto I’ll try that.

this is swaylocks


and ye shall


and receive

and receive

and receive

and receive

and so forth

Hi Justin,

Its an interesting and thoughtful approach, It makes me think…


I’m reminded of the time an interested rep, selling me sheet foam, estimated the cost of a solid HD core for a board shape…

I can’t remember the price, but it was in 4 figures…

Very stiff, very expensive, but it would be very tough, and waterproof.


what i do know is i like superlight responsive surfboards,but dont like breaking them and repurchasing the same board a hundred times

Hi Justin, craftee here. Superlight and break resistant requires some special doing. Board’s strength is divided (unevenly) between the core and the laminate. The lighter the core, the heavier the laminate, the heavier the core the lighter the laminate. Superlight boards are light core with light laminate and not very break resistant, altho some people have pushed this boundary.

Greg’s WMD is a good choice. Dont skimp on glass. A good #2 eps board (marko) either WMD style or with 3 layers of 6 top and 2 layers bottom will be break resistant and not too heavy.

Dont really understand your build so I cant critique effectively. But a sig problem with these foams (dcell, corecell) is pore size and resin usage resulting in semi dry, heavy laminates.

had a firewire that resisted breakage for a while, but when it finally went and I saw the bead size of the eps core I thaught that may be a reason for the lack of liveleeness. it had flex but maybe a slow recoil?

I doubt the size of the beads is the reason. Slow recoil has to so with a board that flexes too much for the particular rider or conditions.


  • you are not lightweight

  • youre surfing/railing style is very agressive and forcefull (esp bottom turns)

  • the board is too flexible for you

  • waves too powerfull

  • too much rocker

  • all of the above

Push a spring half way and you get only half of the springs potential back. Push it to its limit and no more, you can get full potential response back. Push it beyond its limit and you get only a portion of your input back the rest is wasted. Point being, flex spring back can be tuned or you can just luck out and get it w/o trying. Luckly for you, thousands of boards are built everyday and these things have been sussed out.

Your “chamber” comments concern me. However, Aviso has had good success with them but at a hefty price tag.

FW is 1# foam in the interior. Using 1.5 or 2# will dramatically increase break strength. My HI board this year was T-Flex with 2# interior, 2 oz under the bottom skin, 4 oz under the top skin, 6 oz over both sides. Pretty bullet proof and still light. For even better break strength use 6 oz X-Glass under each side.and 4 oz over. A bit more weight but I suspect this would be nearly break proof … as much as anything.

Warvel for the sheet foam. for the veneers for the X-Glass

Marko for the EPS

Again 3# corecel isn’t really structural … I think you guys are missing that.

BTW, uni doesn’t have as good a break strength as X. X is best because it defuses load best. Uni tends to focus load in boards. In T-Flex the veneer is a uni … a real effective one, equal to about 12 oz of glass. With X under and regular weave over your speading load in eight directions. With uni you spreading in two. Standard is 4. See the diff?

yea greg!!!

, stoked to have your expierience up in here…but im a little slow…whats wrong with my reasoning----i selected the corecell cause sounds like it keeps flexing without shearing, coupled with a cloth kevlar thats supposed to be real flexy…whole theory being to not creatate anything rigid so the whole package is all ABSORB…NO STRINGER AND SUCH

heres another one while we are at it …how come??? rails always get more wrapped, stringer stronger… BUT when boards bearly buckle they crease at stringer and rail…joints… MAHALO!!!

3# corecel isn’t structural which means it’ll breakdown with stress.5# would do what you want but be too heavy. Kevlar isn’t flexy, it’s stiff … high modulus stuff. If you want flexy go with propylene foam or polyethylene.but don’t expect any return. It’s about flex return, not about flex. Wood gives the best flex return you can get, that’s what it does, for their entire exsistance trees flex and return and don’t break down doing it. On balance wood has the best strength to weight charateristics of any material.

Boards crease where they do because that’s where the forces focus. Generally because of geometry but also because of the structral schedule. This has been sussed over a long time … I’ve been working on structural applications for 30 years. I could write you a book on why … but just take my word for it, T-flex will give you what your after.


That X-Glass, in what weight/length is it available in USA?

in europe i only have found heavy stuff, 8 oz or up…

you have any ideas where to find some of that lower weight stuff in this part of the world?


It’s available here through Graphite Master in LA. GM and Seabase do biz so they may have it.

Back in sailboards I used a 9 oz X and it was incredible. I did one sailboard with a 9 and a 6 on the deck and a 9 and a 4 on the bottom. 1# foam in that one and I jumped the hell out of it and never broke it. I broke every other straight laminated board I ever had. Only sandwich construction held up. So I have a lot of confidence in stating that used in conjunction with T-Flex we’re looking at something with very high break strength. Especially on semis, guns and longboards. In particular those that will be ridden in extreme conditions. One of the issues with the X I used in the past was the cosmetics. This new stuff is better but under veneer there’s no issue. I’ll also offer that the 6 oz is kind of overkill but perhaps not on the fore mentiond type of equipment.

Thanks Greg,

Very Helpful !

I’ ll post results of my longboard T-Flex/T-Sand… Which is going to see some massive Guethary this year.


The new board I posted over on the WMD Compsand thread has X under the veneer on the deck. Not that you can tell.

greg, if you need not spare any COST or HASSLE, what would be the materials you would use for the lightest most responsive board that was preety damn strong too???

also was i reading the tech sheet correct when i noticed that pu warvel sheet foam has 50 something percent elongation before shear???

what about using all chamberd warvel with some wood and forget the eps??

has anyone ever done tests on recoil speed of all the different materials ie cores: pu, expanded eps, extruded eps, wood??? and recoil of glass ,carbon, kevlar ,other…???

and what about getting more spring from uni directional fibers compared to fabrics with fill fibers crossing over them.????

youve got an eger mind here…