Re: stringers…Lets say you have a blank without a stringer… Then you make one, with the appropriate rocker and thickness… Then you cut it horizontally, into 1/2" strips…Then you put a thin isolation material (some kind of slippery tape) between the segments, then glue them between the blank halves…This might allow a flexible, yet semi-rigid longitudinal element to the board…Just an idea… I love this thread… Paul http://www.hollowsurfboards.com/Index.htm
Rob, What do you think of routing a percentage off of the stinger at the point that you are looking to increase flex? You could start by shaving off 1/3 of the stringer and replacing it with foam or rubber or…? Would it weaken the board to the point of rapid breakdown? After I saw the marketing strategy of the Disappearing Stringer it made me think about the effectiveness of stringer removal in key areas to increase flex. Then I wondered what would a different stringer material do for the flex — either a blending of wood and ??? (material): perhaps a cork, rubber, surgical tubing with each end sealed to create an air bladder stringer section? I don’t have the resources nor the time to play with it. I am sure the old guard could enlighten us on other stringer materials that have been used in the past and the effect of same on flex, durability etc… Magoo BTW, Read your bio on your website. A very interesting read and a good website. M
Wouldn’t groves stiffen once glassed??? Because of the extra cruve added > to the tail area. Just as a dome deck would be stiffer then a flat?? I think if the grooves were lateral across the tail, it would want to bend lengthwise.
I love this thread, too… Reference: Photo Archive : up to 4ft 11in 1984 Dale Solomonson 3’-6" x 23" x 4", red and white triplane http://www.swaylocks.com/resources/Detailed/228.html The bodyboard shown in the archive photos was one of many that were designed to be modified for flex, post-fabrication. It cant be seen, but the red and white triplane has several deep, diagonally routed relief cuts across the rear half of the deck. They were added AFTER the board had been surfed for an extended time in different conditions, and then simply tracing along the most common lines of flexural stress which began to reveal themselves as permanent creases in the decks LDPE foam lamination. The triplanes which used this design, all had hollow (internal) skeletons that were prepared and positioned to offer flexibility within certain limits. Adding relief cuts in the deck greatly increased the boards tendency to bend in the same ways it had already indicated, but with significantly less resistance from its polyethylene foam core and PVC laminate. Also the hollow ABS skeleton was also able to bend and kick back much quicker/harder with the addition of topside relief cuts. Although this step was an important improvement, as with many other non-rigid designs, these boards still suffered from the riders weight inhibiting overall flex, as well as the deadening effects of polyethylene foam. It was clear that in order for flex to make a meaningful difference in performance, ideally it had to be: more than less, bend and conform in most any direction the wave dictated, and offer instant, resilient response. That was a mean list of attributes to satisfy, and with the creation of each new board, their complexity, labor, toxicity and expense were rapidly increasing… 40+ hours per each was often the norm. I had finally even resorted to planning some of my days off work as nothing more than in-shop building time. Boards and materials were piling up everywhere, with no end in sight… at my place of employment, my apartment, my parent`s home, and in rented storage. Fortunately, my surfmats were also evolving through the same time period. It was truly a sweet epiphany when I finally understood the resolution to so many seemingly contradictory aspects of flexible surfcraft design and construction was right there beside me… in an oddly sophisticated, ephemeral surfcraft, for which all intents and purposes appeared to be nothing more than a crumpled… trashbag! Ha ha!
After posting what I knew about the soft top “pendaflex” boards I had seen, I contacted the guy that showed me. It turns out he doesn’t have all the answers either but it apparently is more complicated than a simple soft top over foam… Re: the Pendoflex, it is a secret proprietary process and he never lets anyone see what is under the pad, or watch his construction methods, but think Greenough spoon. What he does, (I think) is glass the bottom, then scoop out the foam from the flex area on the deck and then glasses the deck, creating a Greenough spoon type flex panel. He then fills the void with the soft, flexible foam pad. I have no idea where he gets the stuff, it’s his closely guarded secret. I have been working with a variant of this idea which is much more simple. Get a “Rusty” 3/4 stringer blank from Clark Foam. They were using this blank for their CJ Hobgood model. I had my friend shape me a 6’5" x 19.5 squashtail from one of these blanks, we used flatter than usual tail roocker, with intent that the ricker could be bent into the board via back foot pressure. We also put extra glass in the area where the stringer tapers to a mere glue line, in order to avoid rumored breakage problems with the Rusty production boards. So far the board has not snapped, or even shown stress cracks, its fast out of the chute and flies in straight (or pumped line) but really changes direction in a hurry. It feels like it is flexing, but then one never knows for sure. All I know is that it is tons of fun to ride.
I’m thinking of getting a few of those rusty blanks but it takes montrhs to get then here thru Fiberglass supply. Thanks>>> After posting what I knew about the soft top “pendaflex” boards > I had seen, I contacted the guy that showed me. It turns out he doesn’t > have all the answers either but it apparently is more complicated than a > simple soft top over foam…>>> Re: the Pendoflex, it is a secret proprietary process and he never lets > anyone see what is under the pad, or watch his construction methods, but > think Greenough spoon. What he does, (I think) is glass the bottom, then > scoop out the foam from the flex area on the deck and then glasses the > deck, creating a Greenough spoon type flex panel. He then fills the void > with the soft, flexible foam pad. I have no idea where he gets the stuff, > it’s his closely guarded secret.>>> I have been working with a variant of this idea which is much more simple. > Get a “Rusty” 3/4 stringer blank from Clark Foam. They were > using this blank for their CJ Hobgood model. I had my friend shape me a > 6’5" x 19.5 squashtail from one of these blanks, we used flatter than > usual tail roocker, with intent that the ricker could be bent into the > board via back foot pressure. We also put extra glass in the area where > the stringer tapers to a mere glue line, in order to avoid rumored > breakage problems with the Rusty production boards. So far the board has > not snapped, or even shown stress cracks, its fast out of the chute and > flies in straight (or pumped line) but really changes direction in a > hurry. It feels like it is flexing, but then one never knows for sure. All > I know is that it is tons of fun to ride.