Nothing wrong with EPS, properly glassed EPS boards are far more durable than any PU/PE construction as Ray said. If you don’t like the ride however, then that’s a different story. SUP’s have become a bigger resource than boards for many name manufacturers, and this wouldn’t be possible without EPS. Nobody would buy a 40 lb+ flatwater SUP made with a poly blank. Those kooks would just go to Costco and get a 60 lb kayak instead for $400. In any case, most people don’t take care of dings regardless of the board’s materials. I have seen SUP’s with at least 10 lbs of water in them; and many other instances where the only hope was saw in half and then the dumpster. Invariably, the SUP people will say “why didn’t they tell me about this when I paid $2K ?” Well, even if they did these people wouldn’t have listened nor understood anyhow. Can you imagine having all the discussion like in this thread with a typical customer? And they’re insulted when you tell them to get a foam board like a Wave Storm if they don’t want to be conscious of taking care of a real one.
For the rest of us though, if you don’t want a ding to suck water or deal with heat sensistivity, just put a vent in and the problem is solved. Some water will still get in, but not as deep and it will dry much faster. No different than a poly ding.
Also per Ray’s comment on 1.5 lb sold as 2.0 lb EPS, the typical tolerance in density per cubic foot is +/- 0.5 lb. The reason is due to the pressure used in packing those beads together as I said previously. Often the density is higher on the outer layers of the EPS block/form as that’s where the pressure is applied. This force isn’t transmitted evenly towards the center which winds up less dense. So they can have a reasonable acceptance rate, +/- 0.5 lbs variability is used. I’m talking here about the big slabs used for insulation. Most people who mold special forms (like Marko or the others who do shapes for packing material) don’t use this tolerance since they don’t have to comply with a government standard for insulation density. Keep in mind that the beads are made separately and much of the chemical effort for EPS improvement is directed at that rather than how it’s formed. There’s some serious enviromental issues with EPS, just look at what’s mostly in those floating garbage piles in the Pacific. The major bead suppliers are looking for ways to degrade it faster (i.e. water contact).
Hence the old hippie term " I like the vibe…" I’ve studied sound energy, vibration, and resonance for 20+ years and I can tell you that we know very little about it. It can be modeled like an electrical circuit, analyzed by extremely complex differential equations (of which more than 50% of the truth set will be wrong), but we manage to get it to work largely by trial and error engineering. Ancient Chinese scientific philosophers said that everything in the universe was comprised of the same material but each vibrated at a different resonance. Certain Buddhist sects believe that if the whole world is chanting the same phase a resonance happens and then some kind of miracle for the human race. Guys on Swaylocks think that an epoxy board resonates different than a poly one and therefore the ride differs. It’s all speculation and faith, the vibe either resonates with you or not.
Vibration is one of the mechanical i teach, so as you i know we know not so much (but more than in meca flux, Bernouilli stay in peace LOL). Benjamin too but he know more on this speciality and he show a simple way to quantify dynamic flex of board to compare from board to board. As static flex measure don’t work for me, as extensometric gauge inlaid recording deformation while we surf (but intersting to improve strengh), i used is tech, based on a resonating exitation frequencie, to compare my board to improve my build tech behavior.
The ride is different because of the density of the core. You ride EPS is smaller waves, you ride PU in larger stuff and then if your towing in at Mavericks your riding a very high density PU or wood. It’s NOT the flex, it never has been. The most experienced guy at riding boards WITHOUT A DOUBT is KS. Watch what he rides when, refer to the last few sentences and you’ll get why. I’ve measured flex and that’s not it. The foam density makes the rail set different, an advantage for EPS in small/medium, an advantage for PU in larger stuff and an advantage for wood core in really big stuff. Remember multi density, parabolic stringer blanks? What do you think the goal was there? Lighter boards in bigger surf that allowed a PU rail set.
Everyman, your not testing thoroughly and your theorizing on thin data. You’ve only tested one small block of each and only one density of each. Foam varies, A LOT. We use the lightest density foam products you can buy and they are inconsistant by nature, ask anyone whos shaped 10K+. Your also not testing boards, again your theorizing based on one small block of foam from one production run of one manufacturer vs. one small block of foam from one production run from one manufacturer.
BTW, I don’t make blanks so I don’t really care but I’ve shaped plenty of all of them and I’m a fan of all of them. They are all valid depending on what I’m making for what’s being riden and by whom.
If I ding my board I come in and fix it with an epoxy dig repair kit I usually keep with me. If I’m in the middle of nowhere I’ll try and dig up a vinyl sticker. Mind you this has only happened twice in my life (and I’ve been surfing for 28 years. Most dings I’ve procured has been when travelling to and from a surfspot. However that was a cool and informative test. I did a simillar test on the float properties of Q-cell filler. You got to love science experiments!
I have ridden PU, EPS, XPS and surftech. Not ever felt what people refer to as flex/feel/recoil/dampening and all those other words that are being thrown around. Last surf I had was on an XPS board with a half inch solid wood stringer and it surfed just the same as any other board.
The idea that materials in themselves will influence the performance of the average surfer is bullshit. Weight and shape of the board does, materials don`t.
Logically speaking then – if I have never seen the Northern Lights, they don’t exist?
Materials can and do make a difference, as can how those materials are laminated, how they are sanded, and how well matched they are to each other (or not well matched).
Simply because someone hasn’t experienced something yet doesn’t mean that it doesn’t matter.
Then the people that are of the opinion that materials matter should be able state their preference and why. Then be able to pick out that construction among a selection of boards of equal shape and weight in a blindtest. Make all the boards a solid color so you cant see what its made from and have a few surfs on each.
I predict the wine critic special. Praising a bottle of wine not knowing its the cheapest kind with an expensive label slapped on for the occation.
The physics confirm what empirical results have measured.
At least one pro builder at Sways, with impressive credentials, has commented on flex and recoil and its effects on performance.
“Prediction” of subjective perceptions? How quantifiable is the field of psychology?
To compare EPS with PU, foam densities must be identical. A 2.5 pcf EPS core is identical in weight to 2.5 pcf PU core, if both cores have an identical shape/size. Glassing materials, schedules, total resin weight and type used, stringer type (etc) must also be identical for valid comparisons. Controlled Variables.
The variables of wave form (slope, shape, break type, etc.), size, period and velocity would have to be held constant for every wave; the number of waves ridden and the number of “average” surfers participating – with a large enough sample size of waves and “average” surfers – must be controlled for your $10-12/gal jug-wine prediction to hold water…
the unglassed foam is at what the current atmosphere around it is at at that very moment, once you encase foam the internal atmosphere is what ever the barometric pressure was that day. Add in water temperature that is most likely less than the air and you have the ingredients to get the glass job to inhale when broken. As Everysurfer said about the board being compressed, this is most likely to a lesser degree but still a factor to take into account.
I make all my personal perfomance board from EPS, I don’t care how brown it gets, I don’t build them for looks, when I want pretty I used polyurethane. I don’t keep riding one when it gets dinged, which is seldom considering the increased strength from epoxy resin. I put one in the rocks on the Westside several years ago and it broke my heart to not be able to continue the session, the price I pay for light and strong, but not as strong as a boulder
