I thought I had pushed the fair go rule far enough hijacking Macroscien's thread, so I will start afresh. This is the first Fangy fin in Aluminium complete to a smooth finish. 55 degree rake to handle thick weed and burgs. I now need to try it out against some weed and see how the leading edge fares. If it's looking promising and holding up better than G10, the Mk II will be cast and I will see how that behaves...stay tuned :-)

The Mark I above ready for crash testing. The Mark II below will follow if all goes according to plan.

anodizing would help with wear resistance

I like the cutout of the MkII. Keen to hear how they go... a video would be even better :)

The Windsurfing Shed said..
Looks great.

From memory Dunkerbeck experimented with Aluminium fins (pointers though) at some stage but all failed unfortunately (fatigue failure?)...

I am hoping that the thickness off the base and the short overall height, will guard against fatigue. The Mark II are thicker again and filleted to try and distribute the stress more evenly across the base area. But time will tell if I got that right...

fangman said..

The Windsurfing Shed said..
Looks great.

From memory Dunkerbeck experimented with Aluminium fins (pointers though) at some stage but all failed unfortunately (fatigue failure?)...

I am hoping that the thickness off the base and the short overall height, will guard against fatigue. The Mark II are thicker again and filleted to try and distribute the stress more evenly across the base area. But time will tell if I got that right...

Mal Wright built some aluminium slalom and speeds fins way back in the late 80's or very early '90's. As I understand it, Ian Fox has one or two, and I have a couple in my speedsailing museum, a 20cm deep US box assy speed fin (first fin I did 40 knots on! ) and a symmetrical slalom pointer at about 32cm deep. They were actually machined with a CNC machine and hand finished to remove the machining marks. AFAIK, he didn't have any failures with them. I think modern CNC machinery could do a far better job of them, Mal had the TM series fin moulds machined from aluminium blocks in the early 2000's and they only required very fine surface finishing before use. G10 fins are made with CNC machining, and it is my understanding that they usually require very little final finishing.

I'm not sure which one this is, but it is an early one. I think it is the TM-26 Alpha fin, but it could be the TM-V6 assy speed.



But sand castings can also be made with quite a fine finish from my experience with casting skateboard (WindWheeler) trucks.

great ally mold sailquick and ahead of its time late 80's but it looks to good to be true

keef said..
great ally mold sailquick and ahead of its time late 80's but it looks to good to be true

I think you misread the post Keef. The late '80's fins were CNC machined. I will post some pics when I get a chance to take them.

The moulds for the Carbon TM range of fins was made from about 2005 to 2010. The pic shows one of the first CNC moulds.

Edit. I just found the original Time Machine website links are still up. Here are pics of a TM45 mould (TM-V7 or V8):

http://www.intellimass.com/TM45/TM45_Mould.htm

sorry daffy but I was mainly looking at the pic of the mold , perfect fin in the mold with no spillage

Hey Fang, you should be making alloy dentures

Jokes aside great work mate, good onya
Peter Clifford in FNQ used to make and market aluminium fins moons ago, I think they were hollow and I don't remember ever seeing any break. He's still using alloy fins, just saying

Firie - I will leave the alloy fangs to Wazzatoothfairy.
Aus 808- thank you for the help (again:-). I didnt specify any alloy this time, I wasn't even sure whether it could even be done and it was hard to find a foundry that would do such a small job.. If the first fin works ok, I will have to look at the costs to use a better alloy and heat treat. Thanks again for the info.

Christian Bornemann and Franz Grabner ( Austria) made with the new B+F in Rake 30° a good speed. No Cut out and no concaves.and 8mm thin
or thick. For Lüderitz is the left side 3mm thinner. I worked now in such a fin diagonal concaves in, must she work a little thicker,good 9mm. And no
joke,she is 2knots faster.She is tested by Klaus Küppenbender. He was 15 years ago one of the fastes speeder in Germany. The next fin is
rake 30° assym. diagonal concaves and the cut out. Wolfgang

so good to read a thread that is not about GPS units.
Fangy that first one looks a lot like a shark fin. As far as hyrodynamics goes, anything that follows nature has to be on the right track.
...and if it doesn't work you can always strap it to your back and go swimming at Cottesloe to scare the life out of the other swimmers

My handmade Aluminum 21/25. Seems to work fine. Have had 35+knots in less than ideal conditions. Wears well through the mud compared to G10 or carbon

Yep, great looking Job Dan

Dan133: It seems to be a fin for one way, the most worked leewards flat like now. They used right and left fins. But a concave is faster. Concaves
on both sides from base to tip do not work. Only diagonal 60% concave from the base and on the other side 40% concave from the tip. that works
tour and retour, no spin outs. Air bubbles from the bottum comes to the fin ,we go in an angle of good 10° leewards , so water and bubbles goes in
this angle from leewards to the other side through the cut out and jump horizontal out. Bubbles cannot go down at the end of the fin. Wolfgang

Fangy said..
I thought I had pushed the fair go rule far enough hijacking Macroscien's thread, so I will start afresh. This is the first Fangy fin in Aluminium complete to a smooth finish.

Lessacher said..
Dan133: It seems to be a fin for one way, the most worked leewards flat like now. They used right and left fins. But a concave is faster. Concaves
on both sides from base to tip do not work. Only diagonal 60% concave from the base and on the other side 40% concave from the tip. that works
tour and retour, no spin outs. Air bubbles from the bottum comes to the fin ,we go in an angle of good 10° leewards , so water and bubbles goes in
this angle from leewards to the other side through the cut out and jump horizontal out. Bubbles cannot go down at the end of the fin. Wolfgang

Don't think you should worry too much about thread hijacking Fangy, seems par for the course here