As far as core goes, if I would say I have the construction finalised, I would be lying.
What I noticed is that 90° layer helps alot to hold the concave shape, which contributes to the stiffness (and of course grip, upwind,...)
45° or 30° layers improve torsional strength on the other hand reduces stiffness. I must keep attention which layer and in which phase to taper, otherwise I get assimetric flex (left:right) at tip and tail, although small difference, however noticable (at least for me
I already decided next time to go with middle
90°- 1,4 mm veneer
30°- 1,4 mm
-30°- 1,4 mm
90°- 1,4 mm
where a 2 mm 0° sheet will be replaced with 2 x 1,4 mm under 30°, so adding 0,8 of thickness and hopefully some torsional strength.
I am not saying this will be final
I think main change on my last build was implementing ash veneer to improve hardness of the core, because since finless I ride extreme shallows and hit a lot of rock (if there is just sand, I can find a rock
)- I will post a photo of dented bottom. Of course material properties are different, thats why I went down with the thickness of the middle.
I used it, loved it, but couldn't source it anymore for like one year, so I went with p-tex topsheet. It is transparent, however matt, so carbon inlay and wood grain are not so clear as with TPU which had smooth, shiny surface. I can not comment on scratch resistance yet.
As far as edge goes, I chose boat varnish because it is single component, and I made like 6 layers. It was scratch proof.
From what I see when sanding layers, epoxy soaks in like no more than 0,5 mm (excluding pores).
Like Downunder suggested, my intention with p-tex edges is to protect the board from impact damage (droping it, hitting stuff,...). I did have to revarnish the edge 4 times in one seasson + one bigger repair, when I hit the edge so hard it split a little.
It does not take much more work compared to varnishing and sanding. I made another smaller template to cut out core and one to make the edge. I made chamfers to one edge of veneer and rail and used hot glue along the groove to bond them.
@Downunder: we can sure meet somewhere in the middle, between LJ and ZG!?
So approximately where I live. I am kidding, however wouldn't mind if you actually decide to visit me! We should definitely stay in contact through PM and see how it goes.
Edit: LOL, I spelled "would grain"