I have some 1/4" Meranti marine ply, super strong stuff. Looking to make a longboard fin, after foiling how many layers of glass should I layup?
Keel fin out of birch ply. First set I’ve made. If I’m glassing on should I layup fiberglass patches on first and then add the other when glassing on? I see it done all different ways…
not quite made from scratch but heres my fins , how to get two sets out of one large glass on:)
some leading twinzer fins, glass on and one tabbers.
Birch ply is awesome until it gets the tinyest bit of moisture in it. Then it swells like crazy, delaminates and turns to mush. Murati, Okume or plain old exterior ply is best for anything near water.
thats great work pico, how’d they go…?
Hi, the foil of your fin is not good! Fin foiling is more than beveling the leading and trailing edge.
Try my finFoil application to get an idea how your glue lines should look.
Don’t get me wrong, you did a nice job with the template and you have nice fluent glue lines. But your foil is far from efficient.
cheers Bazza , very nice !
can you let us know how they go , please ?
and , what back fin do you use with those ?
warrior ,
N I C E !
....NOTHING beats a homemade present , I reckon !
cheers , guys !
ben
I’m done foiling but I still need to glass them. Aircraft ply + fiberglass. The sidebites have about 40oz of cloth on the flat side and the center fin has a 1/16th G-10 + another 20oz of cloth for the spine. The center is also 1/2 thick at the base, the base being routed down so I can glass on a G-10 facing and extension for the screw. I doubt any of these fins will ever break.
...BEAUTIFUL !
Can you please take a shot or two , of when they are glassed ,
and
also , when they are in the board , if it's not too much trouble , please , gdaddy ?
cheers !
ben
good so far surf foils, definetly a different feel. need a few more surfs and then I’ll post a better response. Much looser feel for sure. which is good because Ive not been enjoying the drawn out turns on my fish (formerly with rasta keel) for my area.
Made some fins for the 4WFS (four way adjustable fin system).
I used 6 layers of 1mm birch ply (EDIT: i just read that it’s called aircraft ply), and putting some glass and epoxy between each layer and several layers of glass at the flat side of the fin. So i get an 8mm plate that is also the thickness of the fin base for 4wfs-fins. Then i foiled them. At the end I just put 2 layers of epoxy, no glass, on the fin and sanded/polished. It feels really solid, nice finish, not too flexy, i think it will hold up well. Already had one session at the Eisbach river wave with it. I think those are faster and easier to make than the ones with normal ply and glassed / hotcoated.
Great work gdaddy and florian!
I like your technique and foiling work.
and ...
....can we see your fins now , please , hans ?
cheers mate !
ben
They are still under construction. I’ll take some pictures of the current state and post them tomorrow.
Don’t expect too much from them 
I’m an amateur that happens to have programming skills and knowledge of aero/hydrodynamics.
My home made boards are ugly, but they ride great.
Oh yeah, I also work extremely slow. I build 4 boards the last 9 years and still have yet to finish my first set of fins.
I eagerly await....
cheers hans !
ben
Ok as promised the last pictures:
Unfoiled
Semi-foiled (not finished)
Here a pic of my RO sander. I love this guy! Has a nice handle and is variable speed.
A recap of pictures poster earlier:
cheers , Hans !
so ,
that is going to end up as a quad set ? [ with "speed diallers" for the back pair , yes ?]
will they be glassed on , or plugged ?
what size board are they for ? [a fish ?]
last questions ... HOW did you 'attach ' the wood layers to the glass panel beneath them , and how many layers of glass IS that ?
that is an interesting way to do things ... it is always good to see new approaches to the way people make fins , here at "Sways" ...it's all a learning curve , for me !
cheers for sharing , mate !
ben