Dan's Alu fin 2015. Fin base material is HPR5 resin. Great stuff, rubber toughened, never cracks, no fabric reinforcement necessary. About the consistency of honey so it has to be heated to mix and pour which creates its only problem, lots of shrinkage.

Is there anyone out there who has a pinch of Cad skills? I have my fangyfin saved as a .stl file. I have found a company that is interested in casting in pure SiC or titanium. However they want 2D drawings of the fin with the dimensions. The fin was created in Onshape by a third party ( who is away on hols for a while) but I haven't figured out how to produce some scale 2d drawings with dimensions and export them as a pdf. If anyone can give me a hint or help, I would really appreciate it ( you can pm me if you prefer)

A quick update on progress. To get the MkII cast in titanium $2400 and that's in China! To cast it in SiC was much cheaper, but minimum radius was 3mm which makes for a chunky trailing edge. To hard chrome the Aluminium - possible but no one wants to do as it contaminates the baths. I am still looking at some aluminium matrix composite alloys, but it is likely the cost is going to be too much. So , Aus808 had the best solution so far, aging and alloy grade ( possibly with anodizing as well - thanks Elmo) Regardless, the MkII will be cast next week as per the Mk I, and I am getting a couple made so one can be re boxed as a Tuttle for everyone to have a test crash with.

CNC in Alum stupidly expensive??

What size did the fin end up Fangy?

sailquik said...
I will be over there to do my best crash test dummy imitation in November!

Should I pack a few extra cameras

Love ya' work Fangy! Not shy about pushing the limits.

Now I see why you wanted one out of Silicon Carbide, I'm not sure ali is going to cope with that sort of treatment.

YEAH!! Red is back

Bunnings sells barrel nuts?????

fangman said..

keef said..
been exchanging a few emails with Te Hau and convinced glazing is the go, after molding the fin he has two steel plates clamped onto the mold and into a hot box and baked until its as hard as a coffee mug, the advantage is if you wear the leading edge down you build it back up with a toughened resin and stick it back in the mold and bake it

nice keef! I am interested by the glaze idea - what is it made of and how well does it stick? I am thinking along the lines of a vitreous enamel coating applied to the aluminium might be comparable. Being made of glass frit it will be fine for hardness, so as long as the fin is not flexing and cracking the 'glass' it could have potential.

fangy send Te Hau a message he is very obliging and on the money with this stuff, he uses a nuplex epoxy 404 resin and it has a consistency of margarine(similar to araldite ) but will thin out with heat' the down fall is it's very toxic and when heated and very fumy' as for me I cant use it as I'm getting sensitized to the fumes of most of the fgi products , but if you heat the fin and put the resin on with a spatula it will thin and you can use a disposable brush
after its cured you can stick the fin in an oven at around 70deg
I used some exposed basalt fiber on the leading edge of the mxr copy (just to see how the basalt would sand ) and the glazing on the rest of the fin, after baking at 70deg the leading edge was easy to sand but the glazing was hard to sand with anything over 400 wet and dry
the 404 is an epoxy so it has flex and probably have a better chip resistance than g10 even before it has been baked

daffy Bunnings barrel nuts are about $1 each , I wouldn't trust them unless you used some sort of nylon washer underneath , standard brass nuts are $6 each so maybe one of each would be a good combo

I use to cook off my fins in the oven. Just normal resin/carbon etc . Then on one job I left it too long and too hot. Man what a bitch to sand, almost impossible. The surface seemed like glass. So maybe it is just the temperature that does it.

This made interesting reading

www.masterbond.com/q-and-a/how-properly-cure-epoxy-aerospace-industry

Especially the bit about some companies claiming that their epoxy cure fully at room temperature ( e.g. West Systems).

decrepit said..
Gavins just presented me with this.


He's machined the rebate and bent a piece of Basils 20mm X 10mm bar, ready for me to shape the leading edge and fit to an endgrain palm blank, for a 21cm 50deg weedy.
This is a far superior job than I can do with a right angle grinder!!!!

any chance of some pics on the build mike ,

A speedfin is not fast when she is worked in front over the box. Wolfgang

is Wolfgang talking about speed fins the forward boxed 50deg fins the tip of the fin is in the center of effort