I´m new to this site but have been lurking for sometime … Thanks to all, I have learned a lot here and always found answers to all my doubts.
I´ve done a few surfboards with great success till now , two paulonia hollow wood fish, one paulonia hollow wood minisimmons, and a small performance minisimmons from EPS(30 kg/m----2Lb) , with stringer, all glassed with epoxy.
I´m on my next surfboard at the moment and It´s ready for glassing, . This time I want to try a stringerless EPS board but I´m not sure if I can glass the board like all others, I always start glassing the bottom first, I have read something about board loosing rocker because of epoxi shrinking and the board flexing , It´s a small board, 5´5 x 20 x 2(1/2) made out of EPS 2lb, high density. Any ideas ?
Thanks for reading and excuse my bad english, i try my best,
Unless the nose or tail are super thin, with a board that short and thick you should be ok.
I’ve done a couple. One was was a 5’8" x 2.5" fish which came out fine. The other was a 5’9" x 2.25" shortboard which was heavily foiled in the nose and tail. On that one it seemed like I lost a little rocker. Both my boards were made with 2 lb. EPS.
OK. … thanks a lot newschoolblue. , nose and tail are not really that thin so I guess I won’t have any problem with this board… next boards are gonna be a bit thinner so It would be interesting to know what people do to solve this problem… thank you very much
Depends on how your going to glass it. If your vacuum bagging it - Yes you can definitely change the rocker unless you use a “strongback” or laminate it against a rocker table. If your just doing a hand lay-up, you should be o.k. unless your an “animal” and can stretch the cloth too tight while using your squegees (Doubtful!) which might pull the rocker a little as the cloth “settles” against the foam.
Yeah, when dealing with thinner boards that are prone to flexing/twisting during the lamination process, you have to incorporate some mechanism to keep the rocker fixed. A rocker bed (which can simply be the off-cut from hot-wiring) is a good start.
With my thinner board, I kept the blank stored on the rocker bed (off-cut) whenever I wasn’t working on it. I did a full-length 4-oz. deck lam on the board with it laying on the bed and allowed it to cure hard, hoping this would preserve the rocker. But then I glassed the bottom with double 4-oz (around the rails), and this is where I think it flattened a bit. Then I did a double 4-oz on the deck (around the rails), but at that point the damage was done. The board feels great, but rides stiffer than I had hoped.
parthenonsurfer, I´m gonna hand lam. the board and I´ll be careful with it
Newschoolblue, Thats what i had in mind, glass a wide strip of fiberglass or carbon on deck with the board sitting on the off-cut of the hot-wiring, let it cure, sand with 80grit and then laminate as usual, 6oz bottom and 6+4 deck, not sure how i´m going to place the carbon fiber yet. I´ll probably place two strips of carbon fiber from nose to tail on the bottom and some hybrid carbon and glass strip on deck for foot pressure dents.
I glassed this on on a the off-cut. I used epoxy on the bottom with the glass cut as normal. I just did center and left the rails until the flat of the bottom was fairly hard. moved it to the stands for the rails then left it on the off-cut to harden. You won’t get much stiffness from just a strip of cloth down the length. Wrapping the rails is where you will lock in the rocker.
Mataco,
Independently glassed rails, creating channel beams.
Interesting.
Have you independently glassed the rails first, allowing them to harden some before doing bottom or top?
Mataco, cool idea. I like it. But just for the data point, I’ve built over a dozen stringerless EPS shortboard and found that if you place your glassing racks correctly, the proper rocker is preserved. And I’m pretty sure the converse is true, too.
Greg, do you ever use a third stand in the center for keeping a stringerless in shape while glassing?
I have seen video of someone using strings pulling on the nose and tail to add/keep rocker while glassing.
I’ve had trouble with keeping the rocker correct before. So I do it this way to make sure it is exactly what I designed. I tried to get a pretty dry lam on this since I was going to cover it with divinicell/wood veneer. I used a smaller amount of epoxy to do the bottom and stopped a the edge. I waited about 45 minutes (RR Kwik Kick) then finished the rails on the stands. I put it back on the off-cut to make sure it kept the correct rocker while it finished drying. Here’s the link to the build thread
I’ve been meaning to make some new ones that weren’t attached to each other but haven’t put them together yet. That is just my work around. The 1 lb foam really flexes easy and I want to know the rocker is exact.
I’ve only glassed one stringerless for myself, I realized how noodley it was before lam. I double sealer coated it top and bottom with epoxy resin and a mix of baking soda, easy to sand, but the real benefit was, it created a skin top and bottom that could not stretch. so it really limited the flex on the glass stands. I was a super hot rod of a board, but snapped it at San’o, so the little bit of weight loss by no stick versus a stick or sticks is minimal, I use center sticks on all now, if it were a sub 7 footer I thinks breakage is greatly reduced
My next project is an XPS stringerless. I will free lap each side, only slight overlap, with a single layer 2-oz first to get a thin exoskeleton.
I figure laminate the deck first to prevent potential flattening of the rocker due to any epoxy shrinkage. On this one, I prefer more rocker than less.
After that, alternating layers of 4-oz cloth in a more standard approach with cut laps.
IMO, worth a try…
Good idea… I will probably do the same , lam the deck first, don’t mind gaining some rocker. What I don’t want is to flatten it cause its already a low rocker board.
I’ve been riding stringerless boards for a while. Made about 10. I don’t know if the rocker is changed from the glassing. I really didn’t think about it much. If you are worried, you could make a rocker template and use it to keep the rocker you want. I don’t know if this would keep it from twisting though. Most of the stringerless boards I do are made from rocker slices, so there’s a glue line running from nose to tail. That may help keep the rocker intact. I have made at least 5 from a single slab of foam. I made 2 from un-stringered poly, 1 from EPS, and several using XPS. These boards range from 5-8 to 8’ long.
I have added rocker on some of the boards with weights on the nose.
One thing I would think about is the strength. I usually do at least 2 layers on each side, and have done 3 on the deck. I also wrap the glass around the rail onto the other side with all layers to get a really strong rail. This makes my boards stiffer, but I like them that way. Sometimes I’ll sand a little chine along the rail where the extra glass is. I do it after taping the rail for a cut lap.
I was trying to find Deadshaper’s old stringerless longboard thread. It had some great pointers about the importance of keeping the glass schedule fairly even on top and bottom. Harry’s (shark country’s) use of 2 layers on bottom falls in line with this philosophy. I’ve done similar with both of mine.
If anybody has the link handy, would you mind posting it?
A professional deck builder (snowboard and longskate) recommended always using the same glassing schedule top and bottom.
I am heeding this guidance with a stringerless surfboard, 2-4-4 top and bottom.
