Hollow-core surfboards have always been a little
off the wall, but none has looked as radical as
Mike Sheldrake’s wave vehicles. A Sheldrake board
is stunningly transparent. Its core is a matrix of
ribs running three directions. There’s no foam, just
fiberglass skin over computer-cut cardboard.
In his garage in Orange, Calif., Sheldrake cuts the
ribs from ordinary 4mm corrugated cardboard, using
a Next Wave Automation CNC Shark fitted with a
RotoZip spiral saw. Each cross-section is output
from his own surfboard CAD software, rendered by
his network of Linux, Windows, and Mac machines.
Sheldrake, 34, has surfed since he was 9, but he’d
never made a board — or made anything, really —
until he got fed up with web programming three
years ago. He craved something tangible to show for
his work. He dreamed of creating a wood surfboard,
and told himself, “I’m going to use my programming
skills, but this time I’m going to make something.”
When the last piece is cut, he slots it all together,
and then skins it in fiberglass and epoxy resin.
He’d aced calculus, so he could handle the curve
math. But for the structure? “I thought I’d go a different way from the 90-degree designs most people
do,” he says. “Triangles are stronger.” He sat in a café
sketching, and hit upon a pattern of triangles and
hexagons he calls the quarter isogrid.
Prototype problems are what you’d expect — leaks
and delamination — but Sheldrake says his boards
are standing up to typical abuse in the surf zone. Soon
he hopes to help surfers design their own boards on
his website and then buy pre-cut kits to assemble. But
first he’s investigating better rib materials, Gore-Tex
vents, and other improvements.
After a week of designing, he was convinced it
was doable. Six months later, his cardboard prototypes actually turned out tough enough to surf.
Why go cardboard? It makes lighter longboards,
he says, and leaks can be dried in a day instead of
weakening the board over time. Best of all, instead
of buying $900 boards, he can now make them for
about 150 bucks. —Keith Hammond
Photography by Noah Webb
>> Cardboard Surfboards: sheldrake.net/cardboards
20 Make: Volume 19