UPDATE: 12/2014 - More board designs available at http://sheldrake.net/cardboards/, now under a less restrictive CC-BY license.
Cardboard surfboard core structure assembly. Cut and assemble these parts to form the shaped core structure for a 6'4" surfboard. Fiberglassing instructions on my project website will help you complete the board build.
I've been making and riding cardboard-core surfboards for about three years now. They work. Leaks are not the huge problem you would expect. And they happen to look - what's that old term the surfers used to use - awe..., awes..., awessss..., Bitchin!
These files are also a source of replacement part cut patterns, if you've ordered this board core kit from me or a cutting service. Just search through these files to find any part that's been damaged or gone missing. It shouldn't be too hard to cut one or two pieces by hand, with an x-acto knife.
This set of cut patterns is published under a Creative Commons attribution, share alike, non-commercial license. Derivatives are permitted, but discouraged, since this is not the best format for making changes. But if you do figure out some useful modification, I would be pleased to know about it, share it, and possibly integrate it into my file production pipeline.
The license is non-commercial. The primary purpose of publishing these files is to enable the lowest levels of the board-building ecosystem (where I reside) to experiment with building these boards at the lowest cost. Lots of people have local access to laser cutters, and cardboard is ubiquitous, so widely distributed low-cost production of these core kits is possible.
If you see glowing dollar signs in those translucent hexagons, you'll want to build at least one and surf it before considering whether there's any money to be made. I would be glad to discuss it with you. But I recommend you do a little "non-commercial" research first.
Bottom line: if you really want to build one of these boards, and can't get a core kit from me for whatever reason, here's a way to make your own.
If you build a board from these files, I will be thrilled to see pictures of the results. I'll feature the first response on my project web site.
[Photos on this page: 1.) Nick Yarnes with his very experimental build from one of my router-cut core kits. 2.) A Different Nick, in New South Wales, with his assembled router-cut core. 3.) Finished board by Nick in NSW 4.) A recent laser-cut version of this core.]
1.) See the full kit instructions on the cardboard surfboards project website, to see what's involved in building an entire board, beyond cutting and assembling this core kit. From the project homepage, find the "kit instructions" link on the right side. http://sheldrake.net/cardboards
2.) If you're up for all that, download one of the compressed file sets at the bottom of this page. Get either the EPS or DXF versions - whichever format works best for you.
3.) Get enough cardboard for 21 12" by 24" panels. Thickness is important. You're looking for cardboard that is somewhere around 4mm thick. (3.8 to 4.2 should work) It's a standard dimension called C flute, and it's pretty common. But it's not always easy to find a source for 12" by 24" panels without folds or damage, especially if you're scavenging. I hand-cut most of my panels from 4' by 8' sheets I buy at a packaging and moving supply store in town.
4.) Find a laser engraver/cutter with a 12" by 24" or larger cutting envelope.
5.) Adjust speed and power settings so you get surface marking for the part numbers and the fastest possible cut for the part contours. (Don't worry about kerf offsets. It matters, but I've already included a slight offset that seems to work.)
6.) Cut all the panels. It might take take three hours to cut everything.
7.) Pop out all the parts. Each part has two or four short bridges holding it in the panel. I don't know if these work yet, so let me know if they don't - if they are too hard to break, or if the bridges got burnt away. Also, watch out for the corners on some of the ribs, where notches get too close and cut the corners free. Where this happens, or almost happens, I've added extra bridges and numbers to the corner pieces so they don't get lost, and can be matched up with their "parent" ribs later, after assembly.
8.) Arrange the parts in order.
9.) You now have a core kit ready for assembly. The board building instructions on my project website begin at this point, so go back there for the rest.