This concept has been brewing in my head for a while…has anyone explored the ability to customize or change board flex? Seems like there would be a way to make a board where you can change the flex of the board. For example, can you make a board where you can install (or remove) a material to stiffen up the board? Perhaps create “pockets” that run along the board that allow the surfer to install plastic rods of varying stiffness to change the flex? I think about snowboards and the ability of the rider to control the flex and tighten up the radius of the board which in turn can create a tighter turn or create preload before doing an air. There has a to be a way to transfer this control over to a surfboard, right? I know there is a huge difference between a snowboard and surfboard because of the binding interface. But I’m surprised current shapers have not explored this part of board shaping. How come we don’t see more mixed material blanks (i.e. eps / pu blend blanks or some other combo)? Just some thoughts after a couple of drinks.
You go! Fill us in when it matters.
PU foam feels really good.
Other stuff can sometimes be made to feel ok.
PU foam is cheap and easy too.
Adjust the glass schedule to feel the best for you and go from there.
What you suggest is overkill imo.
Seems like PlusOneShaper mentioned a board somebody made or was making that used an air bladder to adjust flex/stiffness.
Snowboards are much thinner.
Seems like it’s definitely possible, but in a situation where you’d want to add/remove those plastic rods, would it just be better to switch to a totally different board/set up?
It might be possible to use some carbon channels or spun carbon rods /p>to alter the flex as well as alter the over all rocker of the Board. Making a board that would fit many different wave situations. for very fast steep waves an insert would put a little more nose rocker and stiffen the board. for weaker waves with flat spots a lower entry cocker and a more flexible tail might be in order. One board a few set of inserts and you could have a one Board quiver for traveling.
Tinkler tails…
Tinkler tail
…I use 4wfs; the best fin system; however do not works commercially because the surfers are too lazy to unscrew 2 screws…go figure with all that combo
Bufo boards use pressurized air inside the board to make them stiffer or softer for variable flex. Years ago, maybe 10 years ago, CMP now BB30 talked about inserting rods in channels to stiffen the board. Lots of work and a hassle compared to Bufo’s method. I think BB30 uses different combinations of woods in the compsands he makes to add more stiffness, it’s not just for the looks.
Greenough uses varying amounts of air in his mats. I think this is probably the best and simplest way to have a variable flex, but may be harder to control where you want the board stiffer and flexier. That may be where rods or other inserts will be worth looking into. You could have slots in different places or inserts with a variable stiffness to make certain places stiffer.
I think with what we’re seeing in multi layer blanks, it’s possible to insert air bladders inside the foam in very specific places to tailor the flex by adding or removing air. Maybe have 2, 3 or 4 bladers. I also think it may create a more durable or longer lasting board than a Bufo because you have insulation between the outer board and the air bladder. You could even use helium or another lighter than air gas to help create asuper light board, or offset all the added weight. I wouldn’t be surprised if someone tries it.
It’s an interesting discussion amongst those who are interested in such things. But if if you are serious; use rods.
Greg loeher, prompte EPS/pu rails blank long time ago here. Surftech make it for their surfboards tech for some years now and dhd with is epoxi core too now, + many other shapers like Clever,…
Hydroflex stringerless with pump have to be use for who want to learn about flex. Sways archive too.
Stoneburner,
Yes I did quite a bit of testing on ADJUSTABLE board flex. By pure dumb luck I had 4 things happen. I saw an old video/movie of an inflatable aircraft (Vietnam era,) I paddled SUP’s with Jim Wier, I met Rouven Brauer (Bufo,) and I got turned on to iFoam. Each of these things contributed to building a variable flex board.
The movie I saw was about Goodyear’s “Inflatoplane” (see on YouTube,) where an entire aircraft was made from air chambers, and pressured up to become stiff, fully functioning flying surfaces. Similarly, Jim Wier, who owns an inflatable SUP company called “ULI” (sic) used pumped air for keeping a giant air bladder/board rigid enough to ride, one day for a laugh he pumped up a 14 footer so rigid that he could stand on it, supported, between a couple of pickleweed bushes, the thing was literally stiff as a board, and that image stuck in my mind.
Lastly, I met Rouven, who owned the now defunct HydroFlex glassing company. His concept was to pressurize EPS boards to keep them from skin-buckling, and therefore breaking and pressure denting.
At the time I was working on optimizing SUP’s for surfing, but most were too rigid, even with minimal glassing, because they were so thick (4"+) and pretty wide (28") and not too long 8 to 8’6".
John Dahl (owner of Sticky Bumps and other ventures,) had me shape some iFoam boards, basically it’s a ball/bead foam used for “boogie boards.” It is very elastic/plastic, it squeezes but then pops back to shape. The main user (INT corp) was making boards with iFoam cores and EVA skins, which are very flexible. They also were starting to glass boards with iFoam cores. These boards had stringers, and sometimes load strips, to get them in the rideable range.
Bufo was using Schrader valves to keep the air in his boards (think car tire valves.)
That’s when the light went on, I built a surf type SUP which had TOO MUCH board flex built in, on purpose. It was iFoam, with one layer of 4e bottom, double 4e top, and NO stringer. It was weird just shaping it, imagine it flexing on the racks. I consigned HydroFlex to glass this and install the Schrader valve on the deck/nose area.
The final mystery was gas flow. Bufo showed me, using pressure gauges all over a shortboard, how quickly a pump (small bicycle hand pump) would “fill” a board with air. It did so, ALL OVER the board, INSTANTLY. BUT this was for EPS. I had already put the SUP in for glassing and didn’t know if the board would “air up” in a decent amount of time, or even at all! Much to my relief, the iFoam also flowed air, I already knew it did not flow liquids, kind of like Gortex.
What I did was a series of tests, pressurizing the hull until the board was much too rigid. Then, whilst still in the water, I would let some air out, and so on, and felt the board’s ride change. High pressure was too rigid, I likened it to a the early SurfTech boards which were skinned-sandwich monocoque constructions. If you rode these you know they felt odd at times to say the least. Later, the company worked the “bugs” out. Low pressure was almost unrideable (picture trying to sit up on a deflated swimming pool air matress.) Well, to put it simply there was a pressure that “felt” right, not only that but I was quite shocked by the amount of change the ride characteristics that happened with change in hull pressure. I was surprised how lively and springy a board would feel in a particular “octave” and a little pressure either way would start to dull things down. I found the sweet spot (for THAT particular construction/size) to be around 6 psi.
I had a lot of fun changing the feel of the boards. Funny, eventually it got to the point that I just wanted to “get the board right” and leave it. Which ironically led me to constructing a NON-pressurized board that had the same spring constant. For the SUP it was iFoam and one of Rob Green’s “PowerLinez” composite stringers and a very light glass job using top grade glass. *this is kind of like the hotrod guys who have “air bagged” suspension then finally settle on the “right” rake, and swap out the bags for coils, which seems to be happening more.
In summary, there is a LOT to be learned when playing with variable/controlled flex, and board flex in general.
I am working on this push once again on a couple other projects right now, learning which areas are receptive to body flex and which are not…
Hope this helps!
Best regards,
George
(here’s a follow-on project I did with Tak and Ekstrom from a few years ago:)
Hi George, how are you doing? Are you still making the asyms?
http://www.swaylocks.com/comment/520889#comment-520889
Nice post PlusOne. It is an interesting progression of research and development. So you were pressurizing the actual foam core with an air valve via the existing interconnecting air passages within the foam itself. I never would have thought to try that: I like it. Cool way to evaluate a specific variable.
I have been thinking about methods to create different flex for various sections within the same surfboard (variable flex?) over that past several months. Have you ever done research in that area?
Thanks for the input provided in your post.
Bill
That was a pleasure to read, I missed it first time around (why do I have to search for new post, here there and everywhere).
It sounds like you had a lot of fun expermenting, and at the end of the day the journey paid off. The surf where you were letting out air would have been a real trip.
The Tech, you were involved with must have been a real eye opener. (I wouldn’t know where to start, to create a shell like that).
Q how did you measure the flex of the air board, so you could apply it there after?
Thanks,
Adryan
Toally, I hate changing fins when the waves are one, having to deal with 3 little screws.
… A board that flexes, gets to a point and stops so it won’t snap. That’s flex control.
This is hydroflex super charger tech principle.
The Hydroflex Supercharger is very interesting technology.
To accurately get the desired pressure/flex, you would have to pump the board when it cooled to and matched ambient water temperature. Would be critical to open the valve when you get out of the water and put it in the hot sun (car racks and/or beach).
Here’s a funny story, just to add to the flex control concept. I made quite a few of the pressurized hulls, mostly for SUP where the hulls were almost always inherently too rigid (so I was making them TOO SOFT, not just standard.) Things got to the point where I was not fully explaining the “airing up, then airing down to suit” idea when boards got picked up. One particular customer, had me build a longer/slender “ranging” board to paddle distances to access more remote spots in our area for surfing, etc. A regular customer, I usually get a message back on how the newest boards went. This time- silence. Couple weeks later we cross paths and I have to ask, he’s looking down, hesitant to say probably what he really felt, “Honestly George, the board BOGS, feels like it’s pushing water, hard to paddle and hard to catch waves, maybe it’s me, but…” then I ask, “Well what pressure are you running?” “Pressure?”
He had not pumped the hull up AT ALL “I wondered when I would need to use this (holding bike pump,) I thought after I got some pressure dents or something…” A third party confirmed, that when he stood in the middle of the board and paddled, that the board was “hinging” where he stood. Now you’ve got to realize, this was NOT just a SuperCharger glass job, but a very “loose” glass job, where I laid the cloth “off axis” about 10 degrees (this makes the straight bending exaggerated, REALLY BENDY.) It was Winter and I imagine, as Bill alluded to, that the cold water nullified any chance at even a tiny bit of pressure to help support the board! Picture that Swimming Pool Air Mattress sadly “bent” in the middle as someone sits straddled on it…
In the end, he started really getting into the pressure thing, “Hey, what you running today?” It was around this time that I realized it a good idea to “fix” the spring rate of the board as it gets rid of a bit of the “overthinking” that can happen when a choice of something not well-understood is given. (Adjustability is not for everyone, but great for some!)
Another thought, I found the “magic” pressure was the same in many different conditions, and all different sizes of waves. So, either a particular board has a resonance that we can exploit, or pressure/flex is just one component to the bigger flex/rebound picture.
To respond to the comment about using different foams, materials, in a controlled manner- I’m doing that right now with a couple really experienced builders in my area. So rather than overall (or Global) bending we are addressing specific zones (or Local) bending within the board (and more the rebound than the down stroke.)
To answer Yorky, I did a VERY crude measurement of the Linear Bending Spring Constant, (K sub L,) using 200 pounds of weight, and two simple supports (saw horses, padded,) at a pre (and self) determined distance from the weight. Deflection was measured on the “good” pressured board, and on the first try using a composite stringer (allows control of spring constant with laminations,) got a board built that was quite close to the “good” board. The guy I worked with on the stringers had two SUPs with different flex stringers in them and measuring these helped me “bracket” where I wanted to be…
…I’ve given this a bit of thought, the SHAPE of the board affects flex, things like thickness and rail shape, but staying with the basic combination I came up with has resulted in some great/fun boards. I can only conclude that I don’t completely know what part of the bending (or rebound) feels so right. Maybe it gets the board “in the ballpark” and the details are overshadowed? I kind of think that this is true with High Performance thin shortboards, where a lot of guys still either like PU/PE, or use it as a reference point against newer construction schedules.
Good stuff!
George