Rigidity vs strength in wakesurf board design

We are going to take a look at the concept of strength as it relates to wakesurf board construction. We’ve mentioned in the past that we changed our epoxy formulation because we tested the stiffness of some of the popular surfboard epoxies and they are really flexible. We wanted something stiffer. Furthering that investigation we will be doing some work with resin infusion and using Vinyl Ester resin. Most likely you’ve never heard of Vinyl Ester resin and we’ve read a bunch of CRAP about epoxy that is being espoused as knowledge by wakesurf folks whose ego is the only thing supporting that nonsense. You may have heard silly things like fiberglass boards vs epoxy boards and from supposed industry experts! It will be confusing to folks as we start showing you the various tests, but we’ll try to be as clear as possible, because we know there will be a LOT of information that we’ll present that will undo just truckloads of the misinformation that is out there.

We’re going to start with a short video and all we want to do is demonstrate the concept of elasticity. You most likely understand it, you have elastic in your underwear or some place that you can stretch and that is the concept of elasticity. We refer to something that is relatively unelastic as rigid. So here is that video we couldn’t find a way to adequately demonstrate the elasticty of the rubber band.

So we all probably get the idea of rigidity vs elasticity, actually it’s all elasticity, rigidity is a measure of the elastic properties of an object, or the lack thereof. We introduced a new variable in there, this idea of strength. Now we looked at the stir stick and it was rigid, or didn’t have lots of elasticity and the rubber band had LOTS of elasticty and we saw it’s got virtually zero rigidity. In the video we state that the rubber band was stronger than the stir stick. What we mean is that the rubber band can handle more force than the stir stick before failure. Was that clear? Normally we associate strength with a LACK of elasticity. So imagine your coffee table, it supports your feet and books and stands on it’s own. What is it’s measure of elasticity? Probably pretty minimal, we’re sure it has some, but it’s not very much. We also know that if we had all of our buddies over and we all stood on the coffee table, what would happen? It would break and look really stupid with all those folks on it! Does that make it strong?

Well it certainly has some strength and some rigidity, but what if the entire thing was made of rubber? Far more elastic than the wooden coffee table, is it stronger? Could it support all of our buddies before breaking? It would definately bend, but once it touched the ground, nothing would happen. Now that concept of elasticity is what resin manufacturers and surfboard builders talk about when they reference epoxy as being stronger than polyester. Basically that using epoxy resin, which is more “bendy” or “flexy” or what we termed more elastic than other comparable resins. We’ll demonstrate that in some pictures and posts to follow, but we want to clear up one potential area of confusion. That is this lingering question that stiffer is always less strong? No, if we took something like Titanium, it has almost no elasticity but in comparision to rubber, it’s much stronger.

Imagine a one cubic foot block of Titanium and natural rubber, and somehow we attached hooks to two sides of those blocks, and then attached them to lets say locomotives (because it’s spectacular ) and then sent the locomotives in opposite directions, which would break first? Yeah we don’t know either, but we suspect that the titanium wouldn’t stretch or break at all and whichever locomotive had the most power would just pull the other locomotive away The rubber cube, would stretch and then eventually fail by ripping in half.

So whats the take away from that discussion? Stiffer isn’t always stronger, it can be, but isn’t always. When it comes to wakesurf board resins, when an advertising claim says epoxy is stronger, what they are saying is that it’s more flexible, like a rubber band. Huh, six times stronger than polyester means it can BEND 6 times the distance that polyester can, before failure. Not that it can withstand 6 times the forces BEFORE bending, stiffness isn’t really even part of that equation. Is that what you thought? Probably not and that isn’t your fault! Advertisers are crazy spammy with those claims and heck folks IN the industry telling you that fiberglass and epoxy are two different style of boards (later in the week we’ll tell you why that is the HALLMARK of someone that probably doesn’t know what they are talking about!!! )

Did we make that clear? Spammers suck Stronger isn’t always stiffer and in wakesurf board resin claims, STRONGER means it’s more elastic, like a rubber band.

Thanks so much for following along, this concept of wakesurf board resins is going to be a tough one, but we think you’ll walk away, at the end, knowing a LOT more and you’ll be able to use that to make more informed decisions. You’ll also be able to spot yahoo’s that don’t know what they’re talking about (and wind up misleading so many in the wakesurf community). We’ll also be introducing you to Vinyl Ester resin for use in wakesurf board manufacturing and we want to make sure that you folks, our loyal readers have a BUNCH of information! We really hate all the hype that surrounds wakesurf boards and wakesurfing. We don’t want anyone to get the impression that vinyl Ester is the biggest, best most amazing ever! We’re sure that crap sells boats, boards and all manner of  stuff, but we like sleeping at night! It’s a good resin and has it’s place in wakesurf boards and their construction.

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