Different curved patterns for fins of different thickness.
The lengths of the red tubes are for measuring the required length of carbon tubes and will not actually be printed with the hollow fins for resin filling.
I've tried to create a curved line rather than a straight line through the tips of the rods, I believe it makes it less likely for the fin tip to snap off along that line.
For the thinner 20mm wide version the line is concave, for thicker fins it's convex.
Test surf with printed fin WF2SLEF2226HRx30x0p8mm_UTFB3018infill5pc_X3DtPPLA0p15mm_20170424.gcode went well at Greenmount today.
That is the fin with 5% infill, 6 carbon arrow shafts, and no epoxy resin fill.
It's the one on the left side in the photo. The one in the middle is the fat one I filled yesterday, it will be next in the surf.
Head high barreling waves, sometimes a bit overhead, the usual crowds (potentially including ex-world champions, current world champions and always many wannabe world champions) made it hard for fellas like me to test a fin all that well. I only got 3 waves in other words.
But, the fin did what fins are supposed to do. I practically only surf 8ft McCoy SIngle Fin Nuggets, with some sort of Gullwing Fin in it. This fin is not spectacularly different from other Gullwing fins, but that's all I can tell. The level of competition for waves is so intense, that I, who refuses to drop in, gets too few waves.
So, the fin did not hinder my surfing at all; and 'cause I made it myself it was the bees' knees etc.
It did not come out of the box one bit, not even when I proned it onto the gently sloping sand bank at considerable speed several times;
and it's weight increased from 213g to 218g, so I assume 5ml of water got in. I could not see any water levels in the spaces between infill during a quick inspection after the surf.
The 40mm fat smooth fin worked well in it's first surf at Kirra.
I got 2 nice waves in 45min and that's a good result considering the skilled competition in the near perfect conditions.
The fin did not cause any trouble until it got ripped out of the box and the string attaching it to the fishing swivel snapped. After 10min of searching I found it again, floating around. Inconsistent swell helped finding it, and luck. It's not a reliable method trying to use the buoyancy of the fin alone to get it back.
The way it got ripped out of the box was such: I found myself caught inside after catching a wave, with a surfer on a head-high wave trying to get barrelled on the wave breaking toward me. A surfer on my left and another on my right less than 5m away were also paddling out toward the breaking wave. I had to turn my board parallel to the wave and jump off, to make space for the surfer on the wave. I could not paddle left or right because of the other surfers on each side. I dove down feet first and let the board cop a KIrra lip broadside. Then the fin was gone and I got another lesson in finless surfing. I'm starting to get the hang of it....
I'll try stronger string for the next run.
Too many new ideas emerged while trying to write this up, so here is the short version:
Printing the Universal Tough Fin Base at the same time as the fin, from PLA.
Not tested in the surf yet, but feels sturdy in the vise.
Another small improvement to the Universal Tough Fin Base (UTFB):
Recessed screw hole and markers for removing forward section if use with screw is desired.
Due to success printing solid fins (pending more testing in the surf to determine if they snap off), no carbon rods or fill port for resin filling is required, so that I could move the forward ball spring plungers back a bit to make more room for a cutout section.
This fin base can be used in three ways:
1) With ball spring plungers (BSPs) only, to maximise safety as the fin will come out when hit from fore or aft.
2) With ball spring plungers and brass pin in front, to prevent accidental knocking out by seaweed. This also reduces the risk of accidental loss of the fin.
3) Remove marked forward section and insert brass pin aft, to allow the fin to be screwed in as 'traditionally'. BSPs may help stabilise the fin laterally in some fin boxes, or could maybe be removed altogether if using this method.
Another Sunday spent mostly on this sacred pursuit......
And now I have a few fins ready to be tested by others, for pesky little problems, like:
- do they fit any fin boxes other than the ones in my boards?
- do they snap off when used by competent surfers in substantial waves?
- are they any good in general, for use in a surfboard?
The blue one is a solid PLA print, I had to sand the surface a bit because the perimeter printing parameters are not quite perfect yet. I think I'll send that one to wrcsixeight when I also have a solid BLEF version ready to accompany it (soon I hope).
Surffoils can take his pick between the red and the purple fin, and the last one is for a local guy.
Oh wow !
I'd be stoked to ride one of your fins and I've got plenty of boards with boxes to test. I've got this old McCoy Zap...
That purple ones got my name all over it please !
I'll PM you now about postage but I can certainly pay for a Priority Postbag to my door.
Thanks very much Mr Mik.
A package is in the mail for Surffoils.
I have put together a set of three fins of similar print settings for you.
This way, you can compare apples with apples, and more importantly, you can taste all the fruit during one feeding frenzy. That's if you can find a mate or two who are interested in swapping fins in the surf.
All three fins have been printed from PLA with a solid 'UTFB' and infill of 10% (cubic) above the UTFB.
I have only surfed one of them so far (the red one with winglets), and only once, in weak waves at Burleigh Heads, up to shoulder height, they were not sucky at all.
So there is a chance that the mechanical strength is just not sufficient, and they might snap off. It could also be that the material weakens over time, maybe they break after a certain number of stress events, who knows. It's all experimental, so use them at your own risk and try to surf them on a few waves away from crowded conditions, at first, just in case they don't last.
I had to sand off the support system after printing the fins, and their surfaces needed sanding a bit, too. So cosmetically they are anything but perfect, and you might find they need more fine sanding attention to detail, in case they hum or whistle dixie or something.
All three fins have the same "Universal Tough Fin Base" configuration. Hopefully it will fit snugly into most single fin boxes. It is not the latest version but essentially the same.
These three fins all sink, so they should be tied into the fin box by screwing a screw and plate with a fishing swivel into one end of the fin box, then attach the fin to the swivel via the stretchy rubber string. I meant to include some more string in the parcel, but just found that I still have it in my pocket...sorry!
So, if you want to use the fins far aft in the box, then attach some sturdy string to the front (through the vertical screw hole) and put the screw and plate in forward in the box.
If the fin is getting knocked out by impact from the front too often (e.g. seaweed), then put a pin in the front horizontal hole.
If you want to screw it in, e.g. once you have found the optimal position, then file off part of the tab fore. You will probably have to remove the fore ball spring plunger for this, but it would contribute very little in this scenario, anyway.
I hope you get some joyful rides with these fins.
Please let me know how they hold up, and don't be too polite, I want to know what's wrong so I can maybe make them better.
Hi Mik, I am grateful for your generosity and I will test all the fins and post the results here if you like ?
Here's 3 girls of mine waiting for testing....
Wow! Nice boards!
And yes, post results for everyone to see.
The amount of plastic debris that I have produced (in my attempt to avoid sanding back that first fin composite wood/fibre/epoxy laminate) can only be justified if it helps a lot of others to avoid the same mistakes.
So point out the mistakes, please.