Is one layer of 6 oz enough on the rails?
I guess you can't edit the first post.
How about 2 layers of 4oz?
3 layers of 4 is a light glass schedule over foam rails.
That's pretty light.
3- 4 oz ( 2 deck, 1 bottom ) is minimum. Corecell parabolic is bomb proof. A rail band of 6 oz nylon is almost bomb proof.
This board had corecell parabolic rails, and years later, not a ding.
Everysurfer on that board what are the virtical lines, glue?
Twaron roving. It's a black aramid like Kevlar.
On 1.5 eps foam I use, 3x4oz + 10oz biaxial glass, in fact all layers from top and bottom skin laps rails, no more guys come back from dings repair saying "I don't know what happened I touch nothing"... Carbon rail band increase rails bending stiffness so good against board buckling but not so much against impact dings, need glass over and under. For dings theorically better to use "plastic" reinforcement, I try Kevlar and pet(diolen), on sup rails, nice for strengh not easy to work with. I bet Inegra could be a good candidat for that too but some glass band, easy to find, to work with, cheap do the job effectively.
I like the idea of using biax , cause it brings the fiber orientation into the equation.
If you want to use less fiber on the rail you will have to think about how to make it the most effective.
Thats for tensile strength.
Prevailing wisdom on Sways years ago was 12oz over rails.
I snapped a few stringerless composites with 12oz rails.
I push towards 16oz if I can. ( I use 5.5 oz so 2+1 gets me there)
Surfboards snap from the rail to the stringer, I broke one paddling out at Sunset, it snapped clean in two and had second break about 4" away that ran half way to the center stick.
every buckle has a rail crack with the center stick still intact
True. And if you repair them they are never the same board afterwards. The three or four that I have personally snapped or buckled and many that I have seen all seemed to follow the curve(rocker). Impact was usually on the deck side and the board folded towards the deck. Just an observation, not a rule of thumb. Any board can be snapped or buckled given the right conditions. Snapped the nose off of one of my favorite noseriders duck diving a five or six foot close out at the Pier once. One of the nicest John Mel boards he ever shaped for me. The lip hit the front third of the deck and the force of the wave peeled it back over my shoulder.
That which can be assorted without evidence was read in an illegal magazine.