and what kind, and why… Weight thoughts, flex thoughts, strength thoughts…
As I wrote, I haven’t noticed any negatives from 4x6oz full rail wrap, and I love the “toughness” - scratches v. full on dings. But, of course, that’s just me…
I don't know why you're using 6oz at all. I thought you generally used Epoxy resin
Hey Taylor I~m a big 6oz fan at least on the bottom. but I did a 4x4x4+ a full 4oz patch lately that was super tuff against the thumb test. Rails were plain out just hard. Board came out 2.6kg with Glass Quads from shapers.
Ah mcding… I figured I could count on you to have something to say.
Colorup - I’m a big fan of the roll of 6oz I got for free… Once it’s gone I’ll go back to 4 oz, and I’ll probably go with 6 full wrap layers. As I wrote, plus I kook out a bit…, I prefer scratches to full on holes after the board meets the reef… Again -this is just me.
Anyone have observations on flex/weight issues?
I do a 4X4 on top with a single 4 on the bottom. Maybe thats crazy, but this combination on EPS foam with RR Epoxy has given me boards that have lasted surprisingly long. My most recent shape has this layup, and even with surfing it about 4-5 Days a week it has held up unbelievably. Also, I love light boards, my most recent one wieghs about 4Lbs.
On another note, if I do too light of a glass job and the board breaks, Iguess that means i have to shape another! 
I’ve had 3 stringerless EPS/epoxy done by a good laminator (because my laminating sucks) with 2x4oz full wrap rails and bamboo top deck. Snapped em all*. One I’ve snapped 3 times, another twice. Crap cloth? Maybe. But I’ll be sticking to Sways advice in future to put at least 12 oz over the rails
- of course, them being 2" thick, with 1" rails (at 1" in), 23" wide and limited deck doming may have something to do with it - or maybe I should quit making those free fall takeoffs
You are talking about a total equation that doesn’t break down well into small increments.
The lamination, normal rail wrap, glassing schedule, stringer thickness, resin quality, sander expertise, etc. It all figures in to the equation. Cosidering most of the deck lap is sanded away during sanding/edge set, maybe one layer of 2oz heavier cloth can work for you. But to answer your question, you need to identify where the weakness is, then correct from there.
Hi Taylor -
One thing I've noticed is that the shape influences flex. A lot. A board with thin rails and a scooped out tail deck will have increased flex over thick rails and a domed deck. Of course rail wraps (particularly) along with top and bottom laminates will have an effect but a domed deck will be comparatively stiff even with a light glass job.
I'm wondering what would happen if we took a tip from ski and snowboard makers - shape a flat top and bottom and just glass the flats separately... no wraps - just leave a gap along the edge that could be filled with some sort of flexible goo?
You are right about a domed deck. Flat vs. domed = substantial difference. I have tried that. (No further comment.) But it’s also thickness vs. rail thickness. It’s a complicated equation. Flexible goo on the rails? I don’t know. It sounds like snap city. Cool if somebody wanted to try and wanted to share the results.
Those free rolls of 6oz are a winner. Are you counting both rails when you say 6 full wraps---- fair enough —but is that 6x6 on the bottom and 6x6x6x6 on the deck---------- it~ll be good for busting through chop but it~ll need a bigger wave to get going. That could end up being around 5-7kgs that´s the same as a lot of wood board constructions. You wont have to worry about flex if this is the schedule but I think I have misinterpreted something you said here.
I~m pursuing a few ´flex´ builds at the moment. Keahana and carbon rail models and I ride a tiny firewire every now and then. I~m only an average surfer but so far I prefer stiff boards that have direct drive. You turn em and they go there. The firewire is great for making late drops but it leaves you hanging til the last second when your arcing around sections and back up to the lip, it felt kind a saggy. But In the baz and off a lip it was amazing but anywhere you had to skirt a section or cutback-pretty average., it was like ´where~s the go button´
For average guys like me, I reckon a nice solid board that´s right for the day and not to much fancy stuff. With 3 laps over a carbon rail, I don~t think much flex is coming in to my builds but I´ll keep you posted if I notice something
For epoxy, 6x6/4 is “standard” strength. Thicker is usually for overall strength, but it is overly weight heavy. Everything, including the glassing schedule effects the flex. The “same performance” with better snap resistance either comes down to small changes (in stringer width for example), exotic materials, or knowning your process well enough to make a big difference-making mod with minimal weight change. Something like that is so specific it is builder dependant.
I hope you can withdraw something of value from my comments.
Hey all - Thanks for the input.
To try and be clear, what I’m doing now is RR epoxy w/two full length layers of 6oz, top and bottom, which both wrap the full rail, the top layer a bit further so. I lam the bottom first, hit the high spots on the lap w/sander/surform if (I catch it at the right time), and putty the lip smooth. I put @ 1/3 legth tail patch on the bottom at a 45/45 degree orientation, and a 2/3 length deck patch at 45/45 too - these do not wrap the rail. On my long gun I put three full length layers and a patch.
I hear ya John - One thing for sure, my boards have a flat-to-concave deck from the tail to about 1/3 leangth from nose, then some fun convolutions on the nose for compound curve and a little bit of floatation adjustment.
Hey Redboards , I know you like shaping boards but , would you ask that guy to put a carbon rail outside the bamboo and let us know how that goes.
Also 23" wide? is that a knee board? How long is it? I noticed, back when the swell was up here, that the longboards were breaking a lot. All sorts of builds, Surftechs, Clear epoxies, name brands…Maybe that’s why yours is 23"?
Swannys boards sound sick
Ah ha, these boards are definitly glassed to last, super strong. I wouldn’t imagine you break any. The 45degree patch thing is a winner. Are you using EPS or PU?
Also,when and how much Add’v F do you use. I’m on the 1% for lam and 3% hotcoat. but i’m still having a tough time getting the gloss coat minting.
Hey Colourup - I’m using 2# eps, and I’d have to look to remember how much Add-F… What ever Greg said. I use the same lam and other wise. I’m not one for a perfect gloss finish, so I can’t help ya there…
I’ve broken a couple, but they seem to hold up pretty darn well… One of those things, hard to say not seeing other “regular” boards in the same situations. Like I wrote, I’m always stoked to see only scratches, where I use to find dings, after getting washed up on the reef. One thing I’ve found to be good for that type thing - I try to make sure I get as much cloth layed up on the nose/tail, and fill/coat with Cab-o-sil/superfine fumed silica and epoxy putty - this makes a putty that doesn’t tend to run/droop/drip, and it is supper hard. Make sure to get it how you want it so you don’t have to sand, as it’s harder to sand than straight up epoxy.
All other things being equal - anyone tried more or less rail wrap with the same glass schedule and notice a difference in flex?
I am curious, as I seem to be so dull to minor board flex.
Hey TaylorO,
sounds like your surfing Mavs, that’s a feat to break a board with 4 laps. Are you going stringerless?
I was fortunate enough to surf from Baha to SF one fall to winter and I definitely saw some top to bottom board snapping drainers.
I like to build up the nose and tail too. That’s where boards chip and crack the most, I just use some extra patches of glass as it stays clear. Is that Cab-o-sil/superfine fumed silica and epoxy putty filler coat like q-cell? Does it go white? If it does you could just use q-cell with some chopped up strand, which also goes white, stays firm, but is easy to sand.
Cheers
A glue line or a PVC stringer will still give you a lite board with good flex if that's what you are after. Less prone to failure. But any board can be snapped no matter the construction. The cut-off from a Poly blank can also be added to an EPS core in the form of perimeter rail stringers.
Colourup,
Without hijacking TaylorO’s thread. The boards are 6’0" - 6’2" kneeboards with glued on rails (tried perimeter stringers but they were a mission).
I have no belief in Carbon nor wood on the rails after watching others experiment with these.
But it’s not the width. I’ve kneeboarded for close to 40 years on boards mostly 23" or so wide and only snapped a few. The past two years has been a record that I put down to sub 5lb boards thinner and less domed than I’ve ever had (to take advantage of the superior flotation offered by EPS). I love the flex, responsiveness and liveliness of the light boards - but I can’t afford the snappage.
My laminator is just getting into infusion and 45 degree layups. We’ll see how that turns out, but I’ll still be putting 12-18oz on the rails
Hey Colourup -
No Mav action, just some Oregon juice… Ha! (Don’t tell 'em over at MagicSeaWeed, I mentioned the state that should not be mentioned… Ha!)
One of the boards I snapped twice had a 7/16" cedar stringer, but I’d desined to much of an angle where the deck belly transitioned to the tail., the other heavy glass board that buckled is stringerless, but it had a 5" round delam on the deck - it’s an xps experiment, in the sense that, it got a bubble while in Mex, and I popped it, and left it (testing the foams hydrophobic nature) and learnd that too much deck delam right in the middle can lead to catastrophic (near anyway) failure.
The Cab-o-sil mix is an off white opaque - Qcell and chopped/milled glass fiber is probably similar - the more Qcell thouhgh, the “softer” the putty will be.
Redboards - do you think it may be the lightness of the foam itself, which leads to better flex characteristics? Maybe even with heavey glas on the rails, the lighter foam allows for mor flex. Still not sure I’ve flet it.
When i design an industrial composit parts, i start from load: make skin that resist to load and put foam to keep them in their place. More skins need to be stiff, less foam need to be strong. If i want a flexible part, i make flexible skins and use an even more flexible foam.
Surfboards are not well design parts because you can’t play wiith geometry, for stiffness purpose, and you want it light. But more skins are stiff less foam play for something, for flex. You just need a foam with appropriate “elastic” characteristics.
A sandwich panel should never need a vertical stringer from skin to skin because of stress concentration. If you have to insert this stringer, your skins and your foam are too flexible or your panel too thin. But stronger skins and appropriate foam are heavy.
Fiber on rails acts like a stringer, more fiber = more stringer effect= more stiffness.
Two way to go:
1: strong skins top and bottom and flex rails that allow skins to move each others for global panel flex.Theorically the best way for strenght/weight ratio. It’s the compsand rules.
2: Lighter skins and stringers: in the middle and/or on rails. Easier to make, standard way, but less durable because lighter skins wears out quickly. Good for buisness if customer accept.
Then you can go with success every where between those two ways.
For me it’s better to put more fiber on rails than stringer in center because: less stress concentration and stronger rails against dings (exposed place of surfboards for water inlet that kill them)
I use not less than 20oz of multiaxial fiber (glass/polymer) for rails of shortboards in my epoflex tech.
Sorry for my frenglish