What I don’t get is someone using 4 oz total on the deck and then acting like they’re concerned about strength?
You can get 2oz that will work just fine, just make sure it has the correct chemical finish on it for your resin choice. You only see 4 and 6oz becuase that is what the vast majority of the industry has found to be sufficient for essentially all jobs and stocking more glass that would rarely be used is** **inefficient
Each time you double thickness of skin you x8 stiffness of skin. Stiffness of skin is main characteristic for flexural (dent) and buckling (crease, snap) résistance. With your 2 layers you will be slightly thicker so slightly stronger. Don’t expect miracles. Multiaxis fiber allow an isotrope strengh, strengh in all direction not only in fiber direction, better against dent. Innegra fiber is a good candidat for bulck your skin. Increasing élongation to breack of skin increase shear strengh wich give a tough skin against dings, a hard to puncture skin. But most of time what increase élongation to break reduce stiffness so…
Well then you just dont get it. Progression comes from not settling, learning, and doing something better than the status quo. I am here to learn, and quite frankly the concept behind my question applies to all board makers and is a good discussion. I am absolutely concerned about strength, just not at the expense of weight. If I can make something even incrementally better why would I not want to at least try? What I dont get is that your statment makes it seem as if asking a simple question, about a much borader technical topic, is something I should not have done. Lets foster a community of knowledge and encouragement, not put downs and pointless one liners, (of which I have been guilty of myself on here).
This is half the reason I am asking. I am thinking of using 2oz pure innegra, and 2oz E glass on the deck of my next board (which is Innegra’s reccomended schedule). I am only begining to investigate Innegra in the 2oz weight myself. I have read that it can be hard to work with, doesnt wet out clear, and doesnt sand well. You need to use a layer of regular cloth on top to be able to sand it since it is baisically plastic. I am also concerned about its bonding ability to the foam, although with epoxy resin I am not too concerned. It seems to be a better cloth but its so expensive, and ‘‘looks’’ relatively non exotic (hence not much marketing advantage) its no wonder the big names are not using it.
Most people on here think you need at least 2 layers of 4oz on the deck but I am simply not pressure denting that schedule at all (using E glass)…and thats using the second to lightest PU density foam. I plan to go PU foam, epoxy resin, and the innegra cloth.
Thank you Lemat.
Am I understanding correctly that multiaxis fibers are good for dent reduction due to their isotropic properties, but not necessarily so good for complete buckling since they sacrifice total longitudinal strength for a more focused and homogenious local strenght (compared to bi-directional cloth)? If so, that would seem to make sense.
I may not be making a whole lot of theoretical sense with this but if the primary cause of buckling is at some point a detachment of the skin from core, how much of a difference does the ‘3-D’ glassing technique come in to play? Even something as simple as poking a bunch of holes in the surface of the blank prior to laminating? Adding slots on both sides of the stringer and filling with strands of fin rope?
Stiffer is skin more buckling strengh, need more forces to lift from core. It’s comp forces that initiate buckling, in comp stress that’s fiber un axis wich play up to shear of resin. Some fiber off axis can “help” localy resin for shear strengh.
lets just say the blank (core) held all the properties that you want in terms of the amount of flex it can handle before breakage, but. the impact strength (sharp ding punctures, rocks, fin chops etc) was the same as that of your standard ‘chosen’ blank
… Only the ‘impact to weight’ strength ratio is important …
Would I be wrong is thinking ‘Inegra plane weave’ would be a good/great choice?
Best, maybe?
…just found the **bold **button - look out i’ll be yelling at everyone now ha.
If you only want to protect your blank from puncture you want a flexible tough skin so innegra laminate with high elongation to break resin will work well. Other plastic fibers like diolen, xynol etc… too, only limit is resin adhesion, those plastic fiber have poor adhesion with resin, less a problem with flexible resin.
cheers
“Makes it seem” … to who? Just a passing comment, a little tongue in cheek, to make a point.
I kinda think it “makes it seem” like if you want strength on a surfboard deck then go with a little more than 4oz. of fiberglass, just sayin’.
Before you “put down” a post as pointless, might wanna make sure you’re not just missing the point.
By the way, this issue (strength vs weight) has been around for awhile, believe it or not, and has been studied by bigger brains than you and I. I think the most significant strides have been made in the area of lightweight EPS blanks with vacuum bagged composite skins.
The op has stated he wanted to build his surfboard with 2 layers of 2 oz cloth on the deck. You said “do it, it is stronger”. So in your opinion would 2 layers of 2 oz. cloth be strong enough for a surfboard deck?
Yes, its strong enough for a short life, ultra light, pro type shortboard, which is what I am willing to experiment with. ‘‘Strong Enough’’ is purely subjective…like my spelling.
That’s why I asked for an opinion. From Mr. Thrailkill.
2 x 2 oz glass, versus 1 x 4 oz glass, is stronger than the 1 x 4 oz. But IMO is not up to the task of performing as a surfboard deck. But, if you don’t care about rapid breakdown, then sure, it’ll work. For a while. This OP wants to ‘‘experiment’’ with it, as he stated. Very much like re-inventing the wheel, IMO. All this shit has been worked out, by others, years ago. I prefer a board to last for years, not last for weeks or months. All the foregoing is my subjective opinion.
…hello Yorky; I have an opinion about fiberglass but still not have an opinion about innegra. I see it in boards, but I do not use it yet however, I doubt that the resistance/cost ratio could be any good.
Sorry, not too much help.
2 layers will have a higher strength to weight ratio as there is less open space between the weave and less fiber distortion as the warp and weft go over each other. Also it will take less ‘fill’ resin to cover the weave pattern for sanding. In your build I would put 2 Oz on both sides of the innegra.
Well said Bill. Clarified and Qualified… Lowel
IMHO that schedule would be overkill…