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.
I have always settled on six bottom, six and four deck. Sometimes six, six, six. The four only goes to the rail apex so not much strength there. But double six is fairly strong.
May I venture to say that you need to match your bottom lam to the rail lam with at least 8 oz. do a double 4Oz bottom with full laps onto double 4oz deck with a 4 oz patch to make it 12 for the feet on standard eps.
I have built boards with 18 on rails, 6 on bottom, rails stayed intact upon impact, then where the 6 met the 18 it failed.
the main thing is to surf empty breaks wit lots of tubes and prevent rail damages that way
Yes when you impact strong rails, bottom lam delam on the flat near rail. Good reason for staggered laps from deck lam on bottom and/or add reinforcement bend on flat around rail when lam bottom.
"the main thing is to surf empty breaks" since covid it became crazy where I live, south French coast, so much guys come and stop here for surfing. All breaks are saturated even before and after sun lighten waves... Became impossible to surf without danger, all mates asked me bigger boards to be able to take waves and stronger one to resist other boards impacts. Many guys start successful ding doctor business and surf schools. A nightmare. Some "older guys", like me, move to other sports.
I do double layers on the bottom and up to 3 on the deck with my stringerless EPS boards. My latest has double 6 on the bottom and double 6 on the deck with a 1/8" Balsa skin. I also do the lams with a single layer of glass, so I do 4 lams. Bottom, then deck, then add Balsa then another layer of glass, then a layer of glass on the bottom over the boxes. Overkill and heavy, but very strong, and should last many years. I've done double 8 oz cloth before. If I had 4 oz cloth I'd mix it up, but right now I just have a roll of 6 oz. Without the second bottom lam, the board is not heavy, but I feel better knowing the boxes have glass over them. I've left the second bottom lam textured (no fill coat) on several boards. Those were an experiment to see if having the textured bottom helps or not. One of my favorite boards is like that.
So a 6&6 gives me 12oz. At the rail. A little more on the deck with the layer of4oz. Cut at the deck. If I remember right Loehr's DVD Glassing 101 was all 4oz multiple layers. What we sometimes fail to consider is the size of the strands in the weave.