I told you guys a while back that I would try to find out what kind of stringer material to use for eps blanks and where to get it in your area. I haven’t found out the specific name of the company, but I did find out that the common material is 3mm matted finish pvc sheets. I was told that just about any plastics company can order it if they don’t stock it. You have to use the matted finish, the slick stuff won’t stick to the foam. I will keep trying to find out what I can, if you guys are still interested. The info is kind of hard to come by on this subject. People are kind of thight lipped about it. Just wanted to give you an update, and to let you know I did not forget about it.
I also found out the ideal way to glass an eps blank. In short, cheater the blank with a thin layer of resin, let that kick. Then come back with one layer of 4oz., laminate it and pull it bone dry with your squeege, let that kick and sit for a day or so. Knock off the high spots and unwanted hard areas, skip sand it or you can take a copper brush and soap and water and brush the haze/film off the first glassed layer. If you skip sand it wipe it down with alcohol, if you wash it let it dry (the advantage of washing it down is that you are not sanding any of the cloth, and not weaking the cloth layer in the process). Then laminate it again (like normal) with either another layer of 4 or 6. The layer on top will take care of any of the cosmetic issues related to pulling all of the resin out of the first layer. Let that kick and skip sand or wash again, then put on you sanding layer. It obviously is not meant to be done for production use, but you will net a much lighter board that is super strong. In essence you are sealing the blank before you add your layers of cloth. I am going to try it on my next board (got my blank yesterday!!).
Thanks for the PVC update. Is it stronger than wood for stringers? “Cheatering” has been mentioned here before. Cheatering solves one problem, epoxy lam gassing. When laminating the second half of a board the EPS soaks in resin. The displaced air gets trapped inside the board. If the air builds up enough pressure, it can cause glass to delaminate. However, cheatering would cause other problems: 1)No resin, including epoxy resin, adheres well to dry epoxy without thoroughly sanding the dry epoxy first. A dry cheated surface would be too thin to thoroughly sand. If you sand through the cheated surface, you will defeat your gassing solution, the reason for cheatering. Cheatering is proposed as an alternative to spackling. The idea is to let the cheatered epoxy reach deep into the EPS, then let the lam epoxy adhere to the cheater layer. If the lam epoxy doesn’t adhere to the cheater layer, the lam job wouldn’t be as strong as spackling. So, instead, cheatering is proposed as a lighter alternative to spackle. Set two blocks out. Coat one block with lightweight spackle, and coat the other block with epoxy resin. Let both coated blocks dry. Sand any excess off each block and tell me which one is lighter. 2)All those tech sheets you read which prove that two layers of 4 oz glass are vastly stronger than one layer of 8 oz glass are predicated on a monolythic lam. In other words the fibers from each layer must interweave with fibers from the other layer. The resin must set them interlocked in order for your lam job to be strong. Your staged lamination defeats interlocking and, I think, would make a much weaker glass job. Further, interlocking glass layers squeezes out resin. Above and below any lam surface, whether the lam contains one glass layer or four glass layers, resin builds up. Your staged layup invites twice the lam-surface resin buildup as monolithic lams. Making a strong, light, non-gassing glass job is a function of technique. You have to fill all those EPS pits with spackle. As I described below, the preferred method of epoxy lamination uses a cut lap. Laps always cause surface undulations in the lap area. The idea is to fill the undulations with spackle, then sand spackle and glass to a smooth surface. Make the surface under all glass so that it has no space for extra resin. Another important weight saving in muti-layer lams is in the lap schedule. Schedule your laps so that you give each point on the rail an equal number of layers to the rest of the board. Too many three layer boards have five glass layers in the rail, for no better reason than poor planning. The only time I had a gassing problem was when, unknown to me, I glassed with damp glass. The cure for excess gassing is to thoroughly dry your glass, foam and spackle before glassing. I’m an idiot. I recently lammed my longboard bottom in 60 degree weather. It soaked up a whole pound of extra resin. The board is 9-6 x 14.8t x 23 x 18n x 3.1". I glassed the board with 3-6 oz on bottom and 3 2/3 - 6 oz on top, and it has a fabric nose inlay. The board has 3 O’fishl fin boxes and a 5/16" bass stringer. It weighs only 19 pounds. You be the judge.
I don’t know about the whole monolythic vs. whatever (I am just not that smart and I mean no disrespect) but I do know that a high boat builders will use this staggered lay up method, and when done correctly nets a much stronger/lighter boat/product. Again I am not too smart when it comes to engineering concepts etc., but I have seen/felt boards done like this and it seems like the way to go (if you have the time to do the stages). I was not suggesting that anyone replace cheatering for spackle or vice versa. I have been told that you should do both and that you do not have to skip sand (or anything else) the cheater layer before laminating it (the lam layer will stick, just do it within 24 to 48hrs). I have also been told that by using this staggered method you end up using less resin. Again I have not read very many studies on epoxy (just the one from stage 3, that was posted here), but it seems to make sense that it would take less resin to laminate your board (and limit the amount the blank can draw in) if you do it one layer at a time. With the underlying layers you pull the resin out. As you know the strength comes from the glass not the resin. When you put your top layer on you don’t pull as much out to cover up the cosmetic problems caused from your dry underlying layers. It seems to me that by saturating multiple layers at a time you are leaving unneccessary amounts of resin in you bottom layers that really do nothing more than add weight. I have also been told that eps blanks do not emmit gas because they are blown with steam. Another reason why they are enviro friendly. I am not at all trying to be argumentative, I just want to learn as much as possible about this medium.
For forty years professional surfboard builders have been building stronger, lighter surfboards with monolithic glass layups. Boat builders use monolithic layups. I know. I worked at two new-boat shops. Now that board builders are beginning to laminate with epoxy, we’re supposed to believe that monolithic lams are weaker. Why? Epoxy’s different? I don’t think so. Look at “cheatering” this way. Spackle or don’t, a glass structure with resin bonding to the foam is good. Why would it be stronger to break the glass-to-foam bond with a glass to resin bond? It wouldn’t. If builders build the “new” generation of epoxy/EPS boards with all of its super potential strength/weight ratio, epoxy construction will take over the surfboard market. This fact threatens the businesses of poly board builders and suppliers unwilling to change… but not if the new epoxy boards are built incorrectly, and fail. As a result lots of misinformation propagates the epoxy surfboard market. I just don’t want your information, which I believe to be incorrect, to find its way via Swaylocks into the surfboard market unchallenged. In my opinion “Cheatering” and splitting glass layers make weaker, heavier surfboards. That said, feel free to glass any way you want to with my best wishes. Good luck.
If builders build the “new” generation of epoxy/EPS boards with >all of its super potential strength/weight ratio, epoxy construction will >take over the surfboard market. This fact threatens the businesses of poly >board builders and suppliers unwilling to change… but not if the new >epoxy boards are built incorrectly, and fail.>>>As a result lots of misinformation propagates the epoxy surfboard market. >I just don’t want your information, which I believe to be incorrect, to >find its way via Swaylocks into the surfboard market unchallenged. Whoooah, hold on there, Mr. Noodle! What threat?? If you build two identical boards, and even allow a volume handicap for the EPS foam
s increased bouyancy, the polyurethane foam board will still feel and perform superior to a lot of surfers who have the opportunity of comparison. These two substrates not so subtle contrasts in basic resonance, overall bouyancy, active flex and throw weight are crucial to one`s preference in any “for serious fun” surfboard! Whether for performance, durability or both, shaped and constructed properly, neither one is necessarily all good or bad, just different strokes for different folks. The only real “threat” is to the usual builders… the bad ones!
I appreciate your view point/information, but I still think that if you could see & feel a board done like this you might change your mind. Like I said before this is not something to be done in a production setting. Of course the boat or board industry will support a monolythic method because, yes, it is strong, but most of all it is faster. By laminating in stages you are obviously creating many more stages to the process but if the layers are preped correctly between laminations, those layers will lock/bond with less resin and be very strong. Because of the fact that I have to drive about an hour (one way) to do my glassing, I won’t use this method. The drive time combined with the extend time the epoxy resin takes to kick, it would take me forever. It is just that after seeing and feeling some boards at my buddys place I just thought I would share the technique with you. When I get a place to glass closer to me I am going to try it out.
I agree that poly boards can, built well, have much better “flex” characteristics. This flex lasts through four typical surf sessions before falling well below the ongoing flex of epoxy boards. Good only for Slater and the other pros who buy new boards for every contest. Epoxy performance boards can be built much thinner than poly boards with equivalent outlines, rockers, buoyancy, and strength. Thinness makes the feel of epoxy much better. I’m betting the average surfer will go for epoxy’s added durability and buoyancy every time. Added “throw weight” is a fabrication. Epoxy can be built with all the added weight you want. The idea is to remove weight, not add it. Methinks thou doth protest too much, further evidence of epoxy’s “threat”. Mike, I hope you can see the need for my post now. This is what I’m talking about.
I agree that poly boards can, built well, have much better > “flex” characteristics. This flex lasts through four typical > surf sessions before falling well below the ongoing flex of epoxy boards. > Good only for Slater and the other pros who buy new boards for every > contest.>>> Epoxy performance boards can be built much thinner than poly boards with > equivalent outlines, rockers, buoyancy, and strength. Thinness makes the > feel of epoxy much better. I’m betting the average surfer will go for > epoxy’s added durability and buoyancy every time.>>> Added “throw weight” is a fabrication. Epoxy can be built with > all the added weight you want. The idea is to remove weight, not add it. > Methinks thou doth protest too much, further evidence of epoxy’s > “threat”.>>> Mike, I hope you can see the need for my post now. This is what I’m > talking about. Noodle, Sorry, but epoxy ain
t no threat; were all on the same side! I think we can agree that theres still plenty of room for discussion on this issue, as both sets of materials and methods have their weak and strong points. I wasnt aware that you or anyone else were capable of quantifying exactly when a boards specific flex characteristics begin to diminish, either. With all due respect, hopefully we all know there are far too many variables involved in board manufacture and the act of surfing itself to intellectually swallow blanket statements such as that one. Epoxy is a superior product to polyester resin in many ways, but we must remember that its application is not limited to EPS foam for achieving performance and durability. Polyurethane foam still has much to offer in its defense, especially when combined with epoxy resins and exotic laminates other than the ubiquitous fiberglass cloth. As for Mr. Average Surfer, methinks that in The Real World the influence of marketing and advertising plays at least as large a role in his choice of surfboard purchases as does durability and flotation; this is an unfortunate fact of life within the surfing subculture that every industry-driven product, worthwhile or not, must deal with if its to survive on a commercial level. Its a shame that quality isnt always self-validating in a “flavor of the month”, consumer-driven society such as ours. Plus, if the pattern of history holds true, while we mull over the merits of these two approaches to surfboard construction, someone, somewhere is likely developing something that will improve upon and eventually replace both! Anyway, Im certainly not the one thats protesting too much; as stated previously, Im very supportive of BOTH sides of this small issue. The very fact that epoxy is open to question, discussion and continuing, evolving experimentation (both from within and outside of the surfing industry) only serves to prove its definitely NOT perceived as a threat by anyone, but just another alternative. Thats a good thing for everyone. I will grant you that "throw weight" may well be a fallacy, but its imagined illusion still feels like the real thing! Cheers!
Whoooah, hold on there, Mr. Noodle! What threat?? If you build two > identical boards, and even allow a volume handicap for the EPS foam
s > increased bouyancy, the polyurethane foam board will still feel and > perform superior to a lot of surfers who have the opportunity of > comparison. These two substrates not so subtle contrasts in basic > resonance, overall bouyancy, active flex and throw weight are crucial to > one`s preference in any “for serious fun” surfboard! Whether for > performance, durability or both, shaped and constructed properly, neither > one is necessarily all good or bad, just different strokes for different > folks. The only real “threat” is to the usual builders… > the bad ones! I second that! As I watch exactly this same sort of comparison weekly, since the mid eightys. I’ve been building this Yin and Yang of my shapes since then. And that’s correct, to each his own. Yes, threat to the builders… The Bad Ones!!!
I wasn
t aware that you or anyone else were capable of quantifying exactly > when a boards specific flex characteristics begin to diminish, either. > With all due respect, hopefully we all know there are far too many > variables involved in board manufacture and the act of surfing itself to > intellectually swallow blanket statements such as that one. Well, for what it’s worth: polyurethane cores are only used in the cheapest of cheap snowboards. Why? Those boards loose their flex within a season. Not so strange really since the core will crush when deformed. To me the way surfboards are constructed also seem like the boards are not made to flex, atleast not in a performance enhancing way. The likelyhood of a board twisting is much greater. As far as I know the length/thickness ratio of normal board plus the fact that they have this I-beam construction created by the stringer is not a constuction that promotes flex. Maybe a thin potato chip will have some flex characteristics aiding performance, but not in you avarage board. regards, Håvard
To me the way surfboards are constructed also seem like the boards are not > made to flex, atleast not in a performance enhancing way. The likelyhood > of a board twisting is much greater. As far as I know the length/thickness > ratio of normal board plus the fact that they have this I-beam > construction created by the stringer is not a constuction that promotes > flex. Maybe a thin potato chip will have some flex characteristics aiding > performance, but not in you avarage board.>>> regards,>>> Håvard From this example, does it then follow that EPS foam is used as the primary core material in the best snowboards? I
m not sure you can draw too many similarities between modern snowboard function/technology and surfboards. George Greenoughs carbon fiber and high temp epoxy “edge” kneeboards probably bear the closest resemblance. Dale
From this example, does it then follow that EPS foam is used as the > primary core material in the best snowboards? Nope. I’m just saying polyurethane and surfboard in general are not made to flex. I don’t believe that beaded foam are made for flexing either. It would be interesting though to compare an epoxy board made with flexible resin, a flexible core with memory and a “stringer” construction created to flex(maybe like the swizzle) and compare their performance. regards, Håvard
It would be interesting though to compare an epoxy board made with > flexible resin, a flexible core with memory and a “stringer” > construction created to flex(maybe like the swizzle) and compare their > performance.>>> regards,>>> Håvard Higher density polyurethane foams have been manufactured for years to provide excellent flex and compression strength characteristics. Inside the rails of flexible kneeboards and paipos (alluded to in my previous post), hand pour/two part, higher compression (about 10 to 15 lb. density) polyurethane foam has been very successfully used to prevent point loading, structural fatigue and eventual compression breakage. Prior to that, very lightweight balsa placed ENDGRAIN to direction of stress resolved the same problem, but was very labor intensive to fabricate. You
re right about the unsatisfactory compression strength aspects of typical surfboard foam if used for a flexible structure. Regarding the latter means of construction that you mentioned, a similar method is being employed by <a href="http://www.surflight.com/">http://www.surflight.com/</a> and is definitely worth taking the time to check out. Its unfortunate that Surflight isn`t receiving more substantive publicity on their product and its performance. Dale
Regarding the latter means of construction that you mentioned, a similar > method is being employed by http://www.surflight.com/ and is definitely > worth taking the time to check out. It
s unfortunate that Surflight isnt > receiving more substantive publicity on their product and its performance. I’ve visited that website once before, it seems like they are making a ‘true’ flexible standup surfboard. Looks really nice, would love to try one. regards, Håvard
I’ve visited that website once before, it seems like they are making a > ‘true’ flexible standup surfboard. Looks really nice, would love to try > one.>>> regards,>>> Håvard Yes, and those board
s internal structure is built around a certain type of tuned torsion box, much like what I think Ive seen inside better snowboards and skis? Dale