Customising Surf Fins for 3D Printing

Early followers of this blog may be familiar with several projects to 3D print kiteboard and stand up paddle (SUP) board fins, including some fins you can freely download if you’re into kitesurfing. It’s been a little while between posts on this topic, however, I have been busy in the background producing a system to help people with no CAD experience design and customise their own fins ready for 3D printing. The full details have just been published in the Computer-Aided Design and Applications Journal.

Quite a few people have used 3D printing to produce surf fins – after all, it’s very cheap and means you can produce just about any geometry you like. Researchers have looked at the strength of different materials and 3D printing technologies for this application, as well as the performance (fluid dynamics) of different geometries. However, if you are not a relatively advanced CAD user, it is unlikely you will be able to design the fin of your dreams, no matter how awesome the research suggests 3D printing can be! This is what I was interested in solving.

Using Rhinoceros and Grasshopper, the complexity of a fin was condensed down to a series of limited controls that allowed for freeform experimentation. The above image is the interface that allows surfers to customise a fin design in real-time. It is based on a handful of common fin properties such as the fin system, fin position on the board, cant, fin depth, sweep, base length, base foil profile, tip sharpness and tip thickness, all of which can be modified using some simple sliders or dropdown menus. Feedback is also provided in the form of overall dimensions and volume. From the image at the top of the page, you can get a sense for the wide variation in designs possible from this simple interface.

Once you’re happy with the design it can be exported ready for 3D printing. I’ve 3D printed a couple of different designs for testing on my SUP board, the smaller white fin in the image above being 3D printed using FDM, while the larger fin was 3D printed using selective laser sintering (SLS). Both worked well in flat water paddling, although I’m sure some carbon fibre would give me a bit more confidence heading into the surf.

Hopefully some more to come soon as spring and summer approach.

– Posted by James Novak

Giant 3D Printed SUP Fin

Behind the scenes I’ve been working on a Stand Up Paddle (SUP) fin project for quite a while now, 3D printing many prototypes, and more often than not, failing! There is more to this project than meets the eye, but for now the details are under wraps. However I thought it might be interesting to share some of the 3D prints in case anyone feels inspired to give it a go themselves.

The design pictured above is the first one that worked successfully without breaking or having other technical issues. Printed in 4 pieces on my Cocoon Create due to the size, it required a bit of gluing, and as you can see from the pink highlight, a bit of gap filling with a 3Doodler Pen (if you want to know more about using a 3D printing pen as a gap filler, check out one of my previous posts all about it). As a result the fin is about 400mm long, huge compared to the fin that came with the board (which for any SUP fans out there is a Slingshot G-Whiz 9’4″)

These images show some of the breakages I’ve had due to layer delamination – unfortunately the optimal way to print the 4 pieces in terms of minimising support material and warping is vertical, however the optimal orientation for strength is laying down on the flat sides (similar to the image on the right). A bit of an oversight on my part I’ll admit, however I was genuinely surprised how much force the flat water put on the fin. Another issue may be the minimal infill, which was also beefed up in my later prints to add internal strength. There is always a delicate balance between print orientation, layer strength and infill in 3D printing, to name just a few!

The main thing is that the fin prototype now works, and I may have a more advanced version being printed using Selective Laser Sintering (SLS) as I write this… If you keep an eye on my blog by subscribing below, you may just get to see where this project is going 🙂

– Posted by James Novak

3D Printed Action Camera Floaty

Most people when they get an action camera head straight out and start filming crazy things – not me!

I’ve just bought a Garmin Virb X action camera, choosing to avoid the popular GoPro’s for a number of reasons (I’ll spare you the details!) – suffice to say that the Garmin not only records great video, but has a range of built-in sensors allowing you to overlay data on top of video. If you’re curious to see what I mean, check out their promo video.

Since many of my interests are on the water (Kitesurfing and Stand Up Paddling) I needed to add the floaty  – I lost a GoPro a few years ago in Hawaii by not having one, expensive mistake! Sure I could fork out the $27 for the Garmin floaty, but I already had a GoPro floaty as part of a kit, so why not make my own attachment?

The design of the Garmin Virb X has a range of great little details to snap on to, which is how the USB clips onto the side for charging and data transfer. So I’ve simply used these to create a 3D printed bracket, to which the GoPro floaty can stick. As you can see from the images above, 2 prongs hook around one side, while the snap comes around to the front and secures the bracket around the camera. And gee it makes a good snap sound when is attached! Very secure.

Print orientation is really important for this one, the bracket is printed standing up much like the pictures (you can see the layers in the left image). This means that when force is applied to flex and snap around the camera, the whole thing doesn’t break apart. Also a bit of filing or sanding is needed on the back face to give the floaty sticker a good surface area to stick on to. Otherwise it’s good to go straight off the printer, which took about 100 minutes to print on my Cocoon Create 3D printer. Solid infill, 0.2mm layer height, brim adhere to the platform and a small amount of support material.

If you need this part, it’s all yours for free – just download from your favourite site Thingiverse, Pinshape, 3D File Market or Cults.  Be sure to post a picture when you’re done, I hope it helps you get those awesome videos on or in the water.

– Posted by James Novak

Custom SUP Fin

I’ve recently bought my own Stand Up Paddle (SUP) board, an inflatable version from Flysurfer, which so far is working really well. But this isn’t a product review! My local paddling spots are all very flat, but the fins that came with the board are very surf oriented. This means that when paddling in flat water there is a lot of drag from the 2 outside fins which are angled out from the center line (see the middle photo), and the board doesn’t travel in a straight line – you have to swap hands every few strokes. It’s not a huge deal, but I was curious to see what difference a large single fin would make since most boards I’ve seen use this. Unfortunately Flysurfer don’t sell them, so it was time to get making!

All I did was use my flatbed scanner to capture the original fin shape (the black one in the right photo), trace the top section in Adobe Illustrator since this is the critical detailing to fit with the board, and then add my own shape for the fin based on the shape of some popular fins online. No 3D CAD required. This was laser cut from a piece of clear acrylic, and I used a file and sandpaper to add some shape to the edges. Voila.

Unfortunately I can’t give this particular design 2 thumbs up, it doesn’t perform quite as well as I expected. While it seems a little easier to glide through the water, the fin doesn’t improve the boards ability to hold a straight line – I think it’s a little bit loose in the socket and tilts on an angle in the water. The acrylic might be a little too thin, but it’s a start. I’ll make some tweaks and try again – it’s nice to make something that’s not 3D printed for a change.

If anyone has any experience playing around with different fin configurations or shapes I’d love to hear from you – I’ve read a few interesting articles from SUPguide.com and Neverbored but there’s only so much you can learn by reading, especially when you have to make your own fins because of the limitations of the inflatable board.

– Posted by James Novak

3D Printed SUP Paddle Lock

With plenty of my designs available for you to download and make yourself on Thingiverse and Pinshape, this is officially the first product I’ve created through additive manufacturing for retail sale!

My local surf shop, Surf Connect, approached me with a unique problem: popular Stand Up Paddle (SUP) brand Ozoboard uses a snap-fit locking mechanism to allow for adjustment of the paddle length, but many customers have been losing them into the ocean. While it seems securely locked with the snap details onto the paddle shaft, somehow people just keep knocking them off, I guess because it is close to where people may be gripping the paddle with their hands. This is the grey part pictured in the middle image on the left.

A replacement part costs around $20 to buy, and to make things worse, the company making them is no longer able to supply them. So there are people stuck with paddles they can’t use because of this one small part. Well, as anyone who knows me would say, I’m up for any excuse to 3D print something new!

Some digital calipers, some Solidworks CAD software, and an hour or so of time is all it took to reverse engineer the lock details. The only trick is the metal pin which has been moulded into the original part, and takes all the forces of the 2 paddle shafts when they are locked in place. To do this as simply as possible I just used a screw with a matching diameter (a M6 x 12mm in 316 stainless steel) as shown in the top left image, gluing this with Araldite into place and concealing with a little cap. Other than the extra bulge to accommodate this, the 2 parts are identical.

Both parts were 3D printed on an Up! Plus 2 in about 50 minutes, and as you can see in the top right image, fits perfectly! Even I’m surprised that a) it fits first time, and b) it didn’t snap when popping around the paddle! The only thing yet to be seen is how well it holds up to use out on the water…

I will now be supplying these to Surf Connect exclusively to sell, since there is a genuine demand for them and no other way for people to get them. As a keen kitesurfer (and now SUPer with one of these Ozoboard paddles), I can imagine how annoying it is to be stuck on land when it’s perfect summer weather! If you need one, please get in touch. You can also download the design from Pinshape by clicking here.

– Posted by James Novak

Death of the 3D Printed Fin

The title and image says it all.

I’m amazed the fins have lasted this well being the very first test (approximately 15 hours of use). I don’t actually know how this happened (possibly 1 of my massive stacks!), it wasn’t until I was packing up my gear that I noticed. But as expected the screw holes were the weak point, with the stresses mentioned in a previous post always a concern.

I may look at thickening the profile slightly and taking a small amount of material out of the holes as there was plenty for the screws to bite into. But for now I have a spare printed and ready to go. No time to rest with perfect weather at the moment!

If you download my file from Thingiverse here let me know how it works for you 🙂

– Posted by James Novak

3D Printed Fins Update

With perfect wind conditions lately there has been plenty of kitesurfing – I love summer! But with that my 3D printed fins (check out the full story here) have had a good workout, probably close to 10 hours in the water.

As you can see in the photo the fins are still in top condition, just some grains of sand that have become embedded in the plastic. I have to admit even I’m surprised they haven’t snapped or simply de-laminated when slapping into the water off some huge jumps or being dragged through the sand in shallow conditions.

It’s still probably too soon to call but I’m feeling like this is a success. Remember if you want a lifetime supply for your own kitesurfing adventures, I’ve uploaded the file to Thingiverse for FREE! Just follow the link here.

– Posted by James Novak

Fast and Free!

All I can say is WOOHOO!!!! The fins work perfectly, just like a new set – I have to admit even I’m surprised! Since they work so well I’m giving them away for FREE so anyone can print a set and let me know how they go. Just follow this link to my Thingiverse page.

I might print a few more so I have spares in my kit, but the next step is to try printing some different shapes and sizes so I can really compare what works, which conditions, how fast, how high etc. 1 or 2 top secret ideas as well 😉

Great little 1 week project, if you do print these fins out please let me know how they go.

– Posted by James Novak

Huffing and Puffing

Final update before I test this thing out – The fins screwed onto the board nicely. These were just holes (unlike the real fins which come pre-threaded) as the ‘Up! Plus 2‘ wouldn’t create the detail of a fine screw thread. The only thing I’ve noticed is slight stress marks on the outside surfaces where the screws are, and very slight bulging. Perhaps the next version could be slightly thicker to increase strength around the screw, and maybe even try increasing the diameter of the holes by 0.2mm as there was plenty for the screws to bite into.

Wind forecast: Avg 12.9KT, maximum predicted 17.2KT – Fingers crossed just enough to get out this afternoon, otherwise the next few days are looking pretty dead!

– Posted by James Novak

Fin Printing Success

So far so good – I have printed 2 fins (to use on the heel side of the board where the most force is applied) on the ‘Up! Plus 2‘ printers. I oriented them laying down diagonally on the plate in order to fit the small size (140 x 140 x 135mm), and also for strength of the final product (layer orientation). I’m really impressed with the top surfaces, and only a small amount of cleanup required on the bottom – a bit of acetone or sandpaper should clean this up nicely. All that’s left to do is make sure the screws sufficiently grab into the holes, and then bring on the wind!

– Posted by James Novak