Yes sir! As I said; “I am impressed”.
Finished board with balsa deck and wax grip from Viskus. Rode it yesterday, and It’s doing what I hoped it would. Going to play with a variety of fins for a couple of sessions.
I’m pondering and EPA build, maybe… I want a nice blue or green tint (not a pigment) but I know well that the blank has to be really clean for a good result. Long ago I helped a kid do his first epoxy lam on his first EPS blank, seemed that clear board could be expected to come out nicely.
Was your blank skimcoated (spackle or whatever) then sanded smooth before glassing?
Is the apparent blotchiness of the bottom the best that can be expected from EPS?
Thanks
I use a lightweight spackle to fill in the beads and any tear outs, then sand until I see foam.
The bottom lam would be a ittle nicer if I sanded it better and buffed it. It has a rattle can clear coat and it’s not a good job. Because this blank is made from so many pieces, a tint doesn’t look good.
I have other boards with a light pigment, looks like a tint, that are OK. One thing that becomes an issue with tints is having the footballs under the boxes. Those always come out darker.
I’m sure I have mentioned this before; On Maui Kenny Tilton use to pick his blanks up after the bottom had been lammed. He would take them home and vacum bag a veneer onto the deck. Then back to the glasser for the deck lam. The glasser at the time (Moonshine??) wasn’t set up to vacuum bag. Especially veneer. If you do a clean lap, whether free-lap or cut on a clear it’s no sweat. Doesn’t matter where the lap is because the veneer covers it. Even on a pigmented bottom, a good paper backed veneer cannot be seen through.
Here’s a pic of my first cut. It was taken before I did the last contour pass, so the edges are not very pretty, but overall I’m happy with how everything worked out. Need to fix the design a bit and cut another.
Amazing that you built the machine yourself. I wouldn’t worry about having a perfectly finished shape. Most shaping machines leave a bit to finish by hand, especially the rails. If you get the rocker and profile dialed in, you are set.
Well, it was quite a journey, I started around July I think. A lot of things didn’t work as I planned. On the other hand a lot of things did and now the machine works. It is not an industrial CNC, but I think I can cut one board in less than 2 hours. With some upgrades I will probably fit into 1:15 or so. For personal use, it’s not bad. Plus the CNC was cheaper than the board I was copying hehe )
Now I will need to learn how to laminate it : /
The profile and the rocker I copied from a board that I bought some years ago. It was a really nice shape and I loved how it felt on the water, but it delaminated too quickly, so I decided to do my own 
I still haven’t decided what to do about the stringer. Usually kite surfboards don’t have them, or have it made from foam wrapped in carbon fiber. I have to build a few different boards and see how they feel.
I have a question about the bottom edge. In the 3D model I have the entire bottom edge sharp ATM. I will probably need to round the front part and keep the tail sharp. The question is: how much should be left sharp? Only the fin area? 25-30% of the board? What happens if I leave like half of the board sharp?
Most tints and even opaques tend to come out splotchy in Epoxy. Partially the spackled foam, but often because of the pigments used when combined with Epoxy Resin.
It’s obious that the “beady” nature of EPS, even after spackling and sanding, will leave areas which are more open-cell than others, so a tint will produce poor results compared to a foam with an even surface texture and porosity.
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Long ago I was listening to Ted Wilson (Fiberglass Hawaii owner) state that tints and opaques had the same base or vehicle (a glycol of some sort, I’m no chemist) and were somehow thus compatible with both polyester resin and epoxy (at least he implied they were compatible with the products he sold). It’s also known and confirmed by Ted that the more effective (and hazardous) components that were once used, are no longer in the formulation, so pigments especially lack the color saturation they once had. This is particularly tellling in the darker pigments like red and blue, less so in yellow. McDing are you suggesting that the vehicle in pigments is/are not completely compatible with epoxy?
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Further on potentially incompatible vehicle, is it suggested that dry powder pigments (which would lack a vehicle) would have better results?
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Avoiding tint or pigment, would the best solution for a colored EPS board then be a spray, using a vehicle that overcomes the hydrophobic nature of EPS? Maybe an alcohol or a similar compatible solvent or wetting agent that doesn’t dissolve EPS?
Not a kiteboarder myself so take it with a grain of salt. I’ve watched a lot of kites ripping up my local at Diamond Head, Kahala, and so on, Robbie Naish in his day, waves double to almost triple overhead. Impressive stuff but a real pain in the arse when three kites get a rotation going and no surfer gets any waves after that.
Think of the water flowing off the board… at first glance you’d want clean release from the wide point of the board to the back. There are those in the surfboard community that hold differently and it’s almost a religious contention, but in kiteboarding you probably never have a lack of power, so wasted energy is assumed an issue.
Going farther, turning a kiteboard is a wholly different than turning a surfboard for any number of reasons. One, your driving energy comes from the sail, transmitted strongly dowward to the board through the soles of your feet, rather than gravity and/or the different accelerations of water vs board angle of attack in different parts of the wave. Next, a kiteboard has one rail nearly completely immersed (a simplification) when going in a straight line, while a surfboard has more equal (left/right) immersion. This might suggest that the sharp/dull rail question is not relevant at all. Three, surfboards have a much shorter turning radius and body language than a kiteboard, so (for turning anyway) the considerations for one may be completely irrelevant for the other. You can briefly use a kiteboard as you would a surfboard, but you’ll very quickly miss the driving energy and grab the sail pretty soon… you’ll have to, slack lines to the kite mean no drive and no control, and you’ll bog. Four, and again a result of all the available drive, kiteboards can be shorter and still work well. They (almost) don’t even have to float, so volume is a non-issue… it’s a lot about surface area (again, minimized because of the drive available).
The more I think of it, the kiteboard vs surfboard comparisons grow farther and farther apart. All together, a kiteboard has such a surplus of driving energy, why would it matter at all?
Blend it and call it good: leave the front half blunt-edged, the back half sharp, and blend between the two as you see fit. Sharper rails ding more easily.
Wind toys, windsurf and kite, have always tuck under (sharp) rails all the way. They need first water release for planing. For flat water, they have 0 (race) to minimal (slalom) entry of bottom rail. Those boards need first to plane straight fast with reduce agility/control in speed turns. For waves they have more entry of bottom rails but sharp like Maurice Cole or Greg Griffin surfboards rails.