Hello Eric, yes thanks, that explanation on the string line helped. I found freeform shaping without a stringer ok too, even the blended panel v in the rear of my hull. Flex is one of those controversial subjects. The rolled deck and hull, 3" of thickness plus 4oz s-glass x 2 on hull and 6oz glass x 2 on deck means my board feels stiff. My very nice Takayama mini tank is built stiff too, so my personal belief is that flex isn’t useful. So putting in some carbon fiber seems like a good idea to me, particularly if you are going to glass lighter than what I did - although I seem to remember that you prefer the heavier boards. I believe blue xps could get away with less glass than what I did, but a bit early to tell how it is holding up. About your yard with the pink frosting,well at least you can say you truly shaped, skinning a close tolerance clark blank is merely scratching the surface of shaping in comparison (pun intended). Good to hear your board is progressing, I look forward to your next post, but you shouldn’t feel the need to rush. Certainly our projects have some similarity, its no coincidence that my blue reports ended up on your pink thread! but we do have slightly different agendas. Mine included getting my pinholed boat afloat in a fairly short space of time whereas you are incorporating more exotic construction techniques.
Hey Mr. J… The CF strip is in and the fin boxes are in (Futures in the sides and a 10.5" FU box in the center). After routing all the box slots I looked at the side fins and realized that I set them as positioned for a 6’2" board I had shaped (about 12" up), not a 7’6". Re-routed further up & out (about 14"), and filled the original slots with cut foam plugs - arghh - what a pain - but I’m so glad I moved them and the plugs worked fine. The middle (fu) box starts 6" up from the tail. I’ll be able to make almost a straight-line cluster, a tri, or a twin. The CF strip already lends a lot of stiffnes to the blank. I set it in the routed slot and flooded it with epoxy. I had to come back a few times to make sure that I pressed down spots where the resin had lifted the strip (floats) and to release some air bubbles. After a day of curing it was an entirely different blank to work with. I do have a little concern that the blank will tend to twist around the strip - either in laminating or in riding. Probably over thinking that. It’ll probably be 3x6 over 2x6, and I have warp-bias E glass. It’ll be strong. - maybe heavy to - your right, extra weight is not a big problem for me, sometimes preferred. I wanted to do the foam stain this weekend too. I mixed up what I hoped would be about enough to color the deck and it just didn’t go very far at all. Probably my technique (first squeege - then brush) was wrong. Essentially I stained the strip/center line, and a portion of the tail before running out. Not alot went on the floor, but it does not seem to cover as well as I’d hoped. So I trudged off to the marine supply store and bought some white epoxy paint to color the blank - that’s the next step. First I’ll test on some scrap and if that works, the blank gets painted. I continue. Thanks for the props too. I’m forced to take my time by family & work obligations - I try to remind myself if that were not the case, I’d spend far too many hours in the shed, and have ears full of dust for sure. I got the Jim Phillips shaping video this weekend as well. I’ve watched up to the start of the shortboard section, after I view that I know I’m going to be kicking myself for not getting it before making this board. I still have my fingers crossed though. the pink lumpy thing may end up being useful. The back yard is still kind of foamy, but I’m getting used to it! More to come. Eric J
Well… for those following. The epoxy paint eats the foam. Glad I tested it on scrap first. in the end I’m using latex to color the pink XPS. Aint nothing easy when you are cutting corners. EJ
that’s good to know. if i ever find the stuff it will come in handy. one store said they’d look into for me and they only had pink. I’m thinking red tint on a pink blank will at least look really red.
Victor, red tint on pink sounds do-able to me. I’m painting the blank to avoid having to do cut-laps with epoxy. Being new to epoxy I’d rather avoid it. The pink foam can work, I can vouch for that. If you do build a stringerless board you want to make a very clear center mark to start from - and be extra careful when templating and cutting out the outline - it’s real easy for a shape to get more & more asymetrical as shaping progresses, especially without the visual reference a centerline/stringer provides. Eric J
Hello Eric, with your 3 x 6oz/2 x 6oz glass job its going to take a superhuman power surfer to twist your board while surfing. I seem to remember someone here posted that reverse lapping a flexible blank can warp it. Mine was done with the normal hull lam first and didn’t warp just resting on the rocker table. Your fins seem very far up, but its consistent with your other boards and from the way you described the ride of your twinnie you obviously like it like that. My xps project remained unused on the weekend, but two of my point break boards got some usage. One of them is my Takayama tri-fin mini-tank which has the fins very far up 13 3/4" and 5" (trailing edge not box measurements). A thruster with trailing fin the largest. The rear fin is in a box and I intended playing with it, but set it in the middle upon purchase and have had absolutely no desire to move it. This is the reason: I know whats going to happen if I move it forward - looser/less drive, and if rearwards - more drive/stiffer. It doesn’t have large drive in its current position. However I’ve enjoyed developing a different sort of surfing to my shortboards. Its low entry rockered large planing surface lends itself to building glide and momentum rather than drive. I feel in my element when I’m able to do such things as run it down the wave onto the flat and use the momentum to climb back up. Also with fins that far up it seems to go into a cruisey large arc cutback without losing much speed.
test session 3 took place early this morning. I leave a windless valley during dark with the anticipation of encountering a totally different weather system in SF. I arrive to find things are not too oppressive, the light fog clearing as dawn broke. It remains overcast. Same car park, the diligent martial arts enthusiast who was there last time is practising with some sort of weapon. I park facing the sea and a respectable looking elderly couple passes in front of me. The lady opens a garbage bin, inspects it for a while then closes the lid without retrieving anything. I wonder what is in the plastic bag she is carrying? A few spaces to the right of me a woman is towel drying her car. Used towels are piled on the roof and the trunk. Forgive my social commentary, I do think America is a great place and I’m enjoying it here, but it is different to the rest of the world. No other surfers to be seen as I walk to the sea with my board in its twin fin mode for the “control” part of the experiment. I assume that underneath the red blanket some way to the right of me is a sleeping human. If I seem a little distracted its coz the surf is really not very exciting today. The smallest I have ever seen it here. Knee height on the wall and no more than waist height on the peaks. Some sort of crosshore wind is texturing the surface, but no white caps. Tiny South groundswell and NW gulf of Alaska windswell are both reported to be in the water. Even windswell looks like proper waves at this beach though. There is no shortage of waves either. The board is everything I hoped for. I’m catching and making heaps of waves. Its flying up and down the waves with ease in long skating motions. I can get the occassional wave gouging cutback in too, reminiscent of my younger days on twinnies in tiny waves. Its extreme width does however prevent it from being pushed as hard into a cutback as my smaller boards. After 45 minutes of flat rockered fun its time to put the 1/2 trailer fin in the rear center box. I question why should I bother? I’m having so much fun in its present form and I know whats going to happen anyway. Its going to feel somewhere in between a twin and tri. There is still at least one unanswered question I suppose. I had set the rear trailer a full 4 5/8" up from the tail intentionally packing the tri cluster together. I’d learned from my experiences with the mini-tank that maximum drive isn’t necessarily best for all types of boards and with the larger front fins I’d probably want the extra looseness of a more forward placed trailer fin. So I interrupted the session to insert the fin. It took just one wave to discover the effect. 3 more waves confirmed that the result was disappointing. It felt more like a thruster than a twin. It had reasonable speed but was unecessarily stiff, about as stiff as the large area quad. The quad at least felt it had its fins in the right place though. This setup felt like the cluster was too far back. Ah well the trailer fin is a bit of plastic I won’t need again. I walked back to the car and then an idea for my next session popped into my head.
Hey Mr.J,(and anyone else following along) Thanks for the wake-up about the glass job. you are so right - I have a relatively bomb-proof longboard that is just 2x6, same thing on my twin fin too. I’ll stop over analyzing. The fins just seem right at 14" to me. 2 inches back even looked like a mistake visually (again - to me). Right now I have a 7" fin for the center box and a choice of 3" or 5" fins for the sides. I’d like to find a small (5") fu box fin for a regular tri-fin set up. Any ideas? I painted the pink foam with regular old white latex paint - just one coat to cover the pink. Sanded it lightly. Looks much better than pink though the paint covers no surface imperfections - I’ve got a few around the fin boxes. Hoping that the paint does nothing to affect the bond with the resin. I may opt, in the end, to do a colored acrylic coat on the sanded board to get the whole thing looking a bit better. Sounds like the waters been good to you lately - even on the small day. And the twin option sure sounds like the way to go. I hope you post a pic of the board sometime. And don’t be too wierded out by the beach culture - or lack of it. America is truly the land of the ‘free’, which isn’t always seen, or exercised, in the most positive light. Surfer Magazine once did a story on the beach I surf at most often - the only way I could tell it was the result of an actual visit is because they perfectly described one seriously crazy woman who lived right there by the boardwalk - otherwise they caught none of the local flavor - just cliche. I’m amazed that you can find a beach in CA that has even small waves and no one else out! Proof that there is hope for that state. … and your idea for the next session…? Eric J
I’m giving up on my xps project. I just can’t find it. Called for distributers and not even they carry it. With it being this hard to find getting a clark blank is just cheaper and easier.
Hey Victor - Where are you located? Anywhere in North America you should be able to find wall insulation foam boards at a home center (Home Depot, Lowes, Menards). If you are not in America, then I don’t know - but one guy her (Havard) built with alternative foam in Norway. That said… If you are close enough to a Clark dealer to get blanks, excellent. I wouldn’t have tried this if I had easy & cheap access to Clark blanks. I needed to find a way to make a cheaper, experimental board. and to test the properties of the insulation foam for shaping. It does work, but a regular blank is better, and much easier to shape.
I have been looking for 4" inch xps or extruded foam in any color and can’t find squat. Are you guys glueing up the thin blocks of foam to finally get to a thicker blank?
Have you guys called the Dow customer service number on their website? I did, and they gave me about 5 different suppliers within a 50 mile radius. I ended up getting mine from Foam Sales & Marketing in Burbank, CA. They have all the sizes up to 4" thick.
I glued up 1" thick and 2" thick 24" x 8’ sheets of insulation with the ends of the sheets propped up to provide rocker. Used Elmers glue between the sheets and put heavy weights (paint cans, cinder blocks, wood, and power tools) on top to hold all in the bent position till dried. Worked fine, but Elmers took a few days to dry between the sheets where no air was getting to it. Regular Home Depot insulation foam - Owens Corning brand. The pink color is the main draw back so far… though I should say it is also harder to shape than Clark/PU foam. Eric J
hello Eric, the imagination can create some bad case scenarios, like you suggested my board doesn’t seem to be any of the large foam eaten cavities which I feared. I’ve been trying to analyse why a flexy reverse lapped blank might warp tho and maybe if curing lam shrinks then with little rail lap it might bow out the rocker even more - just guessing don’t know about this. Your CF strip seems to be an alternative to putting a stringer in. I’ve personally found out a long time ago that a handsaw although fine for an outline doesn’t do a good job of splitting a blank down the center and my hot wire isn’t long enough. If I was about to lam xps/expoxy again my concern would be blow-thru leading to pinholes. I’ve been analysing this and wonder if the following might work: 1. Leave the curing lam until just after it has reached its peak temperature - not sure when this is, epoxy does get hot. 2. in theory all the blowing agent gases that were going to expand would have been expelled now and we can aim for “suck-in”. So at this point do a baste over the non lap regions. the multiple overlaps on the rails are less prone to pinholes and putting a layer of baste in between the overlaps would be bad news anyway. what does anyone think about this? About your concerns of the paint reducing lam adhesion I think from looking at the texture of xps, that being similar to clark a mechanical bond will be achieved so provided the paint hasn’t gone on really thick nothing to worry about. The bond between polyester and polyurethane foam is mechanical, although future boxes say they get a chemical bond with poly or epoxy so don’t paint the box flanges. But I remember you foam stained the centre - you didn’t paint over that did you? ps I’ve uploaded some pics of my project onto the surfline forum. I’m going to try and get a better pic which illustrates the shape to submit to swaylocks resources.
test session 4 took place early this morning. I arrive in the car park and can’t see the martial artist although I think I recognise his car. Nothing unusual happening this morning or maybe I’m getting used to the place. My concentration is on the surf which appears to have improved. Can see a couple of black dots in the water thru the fog. One of the dots catches a wave and stands up - ah other surfers today. Put on my 4/3 wetsuit, step over a large roll of carpet and onto the sand. Avoid a broken bottle and I am on my way to the sea to implement the idea I had at the end of my last session. I’m not performing the usual pure twinnie control session today and already my board is in a tweaked mode. The left side of my board is supercharged and the right side normally aspirated! Yesterday evening I hacked away at the unwanted trailer fin with my dremel tool. Its been reduced in height and width by about a 1/3, reducing its area considerably. I’ve tried to copy the shape of the superchargers shown in the photo archives and placed it in the left twinzer box and it is just over 2 1/4" tall. Its had its outline shape reduced evenly to maintain the centralisation on the leading edge of the main fin. It looks quite small. I’m regular foot so in theory the supercharger will kick in when I’m going backhand, performing frontside cutbacks and performing frontside off the lips. Unfortunately the fog had been playing some tricks with my imagination and wave utility was slightly down from last time. Some occassional bigger ones, less wind but the consistency was down. Maybe the tide was a bit low. Still good fun though and my board is the perfect choice for this stuff. Unlike my other tweaks this one is the most subtle. I think I can feel it project and drive more on the lefts. It seems much the same on the rights, maybe its coming off the top frontside better but I’m not sure. Maybe its a bit stickier in the frontside cutback but I’m not sure. After almost an hour I leave the water briefly to switch the position of the supercharger. Its foiled both sides so I can do this and sits upright and doesn’t follow the cant of the main twin fin. So now I’m supercharged frontside and normally aspirated backhand. I think I can tell the difference going right (frontside) - it does seem a bit stiffer into the bottom turn. I’m not sure if there is a speed difference. I fly along on a lefthander, confounding my thought that it was helping me project better backhand in the first part of the session. On a frontside wave I throw in a cutback and feel that twin fin slide. Something I didn’t experience with the supercharger on the opposite side. I don’t mind the controllable drift of a twin doing a cutback though. hmmmm???
On the paint adhesion - yes I painted over everything - even the areas that I tried the foam stain on. so there is an epoxy strip down the center of the boards deck (over the CF) that might tend to delaminate and a little on the end of the tail. I’m going to scuff up all the paint well before glassing it and hope for the best. The paint is a thin coat - the texture of the foam is still very evident except for directly over the strip. The CF strip was an alternative to putting in a stringer. I have a table saw so I could have made a straight cut… But it seemed uncecessary and the CF strip will, hopefully, provide some strength and spring that the stringer would have. We’ll see. The future boxes and the FU box were epoxied into the foam before the paint job. Futures will get lammed over - with patches added - and sanded down to expose the slots. FU will also get an overlay of glass to help hold it in. I did not slop paint onto the box lips and will take off what I did get on them to help the glass bind to them. On twist - I think I’ve heard here that one cause is not keeping the weave of the cloth straight when laminating and uneven lamination (more resin on one side of the deck than the other). So there is tension in the cloth which is accentuated with the uneven curing of the resin and it can pull one rail up at bit. I thought a reverse lap is supposed to help avoid this problem, but it would seem, if there is enough tension created in curing the resin, either revese or regular laps would warp/twist. Life might actually allow me to get into the water this weekend. If so I’ll be a new man on Monday… though the pink project will still be on the racks. Off to do some work now… EJ
Hello Eric, hopefully by the time you read this you will have had some waves. My blue board wasn’t used this weekend, instead a job for one of my professionaly made point break boards. About our boards: I was literally panicking when my hot coat seemed to go wrong, but mustn’t let the resin fumes make us neurotic. Despite my less than perfect glass job my board seems to be holding up fine. I would also go as far as to say I’m delighted with the results and not too worried if the construction starts to fail. As anyone who has been following my posts would have realised I didn’t entirely know what I was doing, and therefore likely to produce unpredictable results. But that was part of the enjoyment. If my board does start to come apart then I’ll post the symptoms so that we can all learn. Our boards both have a fairly solid glassing schemes so they aren’t going to disintegrate on contact with the water. It takes a lot of surfing to send a board to destruction. There was a thread on spraying in between the hot coat and gloss which may be relevant, but I’m not sure if its necessary to scuff the paint as epoxy is good at sticking to things but other things aren’t so good at sticking to epoxy. To prevent ppl having to wade thru the entire thread and weed out all my off topic verbage I plan to confirm my design findings with more beachbreak testing and then post a summary here. But apart from that and any possible durability reports thats it for my blue xps project. Swaylocks is a great place and if it wasn’t for your post at the top of this thread Eric, where you described your rocker glue up, my project would never have got started. I’ll be monitoring this thread for any sign of activity in your shed 
Thanks Mr. J. Swaylocks is a great place indeed. Glad you got a surf this weekend - I did as well, proving that I’m not in the best surfing shape! but with my work and a few family members in and out of hospitals in recent months there has been little opportunity. Things are freeing up now though. The pink project waits for glassing. I hope to get to that next week. I’ll post back when I’ve been able to do more work on this. Glad that blue board is working for you. In the words of Herb S… ‘Keep building!’ EJ