I've been making some fins lately

As part of my finfoil project, I decided to do some more hands on work to test and improve the software.

I thought I’d share some pictures, who doesn’t like pictures?

There’s more on my instagram page: https://www.instagram.com/finfoil/

Functional works of art. One day I’ll make some fins as nice as these.

Those are incredible; great job!

I’ve been trying to figure out how you made the ones with the gold or blue cutouts.  At first I thought maybe you laminated a colored resin panel between wood, which would give a colored halo, but that wouldn’t give the cutouts in the middle of the fin.  So before you used the cnc to cut the foil, did you use it to cutout the designs, fill the cutouts with colored resin, and then use the cnc to foil the fin?  With the fin with the gold cutouts and halo, I wonder if you did something similar to get the gold halo?  So before you used the cnc to foil the fin, did you have the cnc cut a path around the outline of the fin, fill that with resin, and then foil it?  

I had the same questions about the “inlays”.

After study the finfoil instagram for longer than I should admit, I believe he cuts the inlay portions and outline out as a pocket. Then fills the pockets with a colored resin. Then finally cuts out the foils. I’ve been trying to mimic his process the last couple weeks or so, but I don’t have a lot of spare time to mess with my cnc.

Congrats, you figured it out!

I’m not the first to cut halos this way, jrandy and others have been doing similar things.

Some cut a slot for mechanical bond, but I found this unneeded with epoxy (never tried poly for this). I fear the slot even introduces airbubbles.

The tricky part is to realign the stock on the CNC, but it’s the same process as double sided machining, so once you figured that out, you’re good to go.

There are some other pitfalls, especially with the colored resin or using cheap plywood, but I’ll leave those for the brave to figure out.

BTW all fins are done with the same process, no differences with the gold or blue one, only the IPCOS one does not have a halo.

 

Hans, I think I asked this before, but I am a slow learner sometimes. When you are making a fin with a base, like the futures in the first pictures, why do you route the wood between the fin and base? I drew some crude arrows on your picture to point out the place I am talking about. Are you not worried about the strength? I always thought the base where the fin meets the box is where all the forces combined and would need the most strength. I do remember you saying that you do the halo all the way around to protect the wood, but is the little bit between the fin and base part of the protective halo? Honestly, whatever the reason it does look cool. Like your fin is floating just off of the board. Thanks again for sharing and caring.

To Hans’ comments above, I was inspired by Dave Town to try halos and old school templates from Bill Thrailkill and by Ricky to try them on the CNC, featuring software from finFoil and OpenSCAD.

 

No, I’m not worried about strength, why would a wood core be stronger than a resin core?

The strength is in the fiberglass laminate over it, not in the core. Also I’m using epoxy resin, not polyester, I’m quite certain it’s even stronger than a wood core (also heavier).

It’s not needed to have the base core disconnected from the fin core. But it has some advantages. This area is much more likely to require some shaping to make it fit. Shaping the wood shows in it’s layers, while the resin masks it better. Other than that, the disconnect helps to visualize where the base ends and the fin starts, very handy when casting on bases like with the windsurf fins.

Makes sense when you put it like that. I forgot that you use epoxy and it is more forgiving than poly which can be quite brittle depending how it is catalyzed.

I already posted these in the show us your homemade fins thread, but since Hans has been gracious enough to help me out I’ll post some pictures here also.



How will you fill the grooves without distorting the foil shape?

Honestly, I didn’t put too much thought into its performance. It is filled with a little of resin. I am not even close to a good enough surfer to be able to tell you if it will noticeably affect performance or not.