I’ve just finished my newest board (well almost finished - I’m spraying it with UPOL tomorrow). The vital stats are 9’ x 24" x 2.5" and the final weight came in around 12 lbs. Theres 1 layer of 6oz on the deck, 1 layer of 4 oz on the bottom and a layer or 2.3 oz between each skin (thanks Keith!). I put the board completely differently from my other boards and for the most part I’m really happy with how it came out.
Here’s the new things that I’ve incorporated:
horizontal redwood springer
preformed balsa rail
longboards finbox retention system (pretty cool name - huh?
preformed balsa skins bagged at 25 lbs of mercury
different types of epoxy 2020 and 2000, fast and slow hardener.
I’m not going to go into too much detail but the pictures should be sort of self explanitory
These pictures are of the skin. It requires the construction of a long cookie tray to bag the skin on. I used bent 1/2" steel electrical conduit with a bed of XPS foam for the skin to sit on. You really need a good breather material. My first attempt ended in the trash when I tried to use paper towels. The tap goes on the inside of the skin and is removed before you bag it.
This is as far as the deck skin could bend while the bottom skin could be bent in a full circle. I used the RR 2020 on the bottom and 2000 on the top. It was really cool to see the bottom skin bend.
This is how I handled the springer (I think this is the real key to Bert’s boards). You need to make the bottom skin of the board really flexy and the top skin strong to handle impact. The elastisity of the bottom skin allows the springer to kick in and store energy when the board is flexed. I tried flexing the board with just the rails and the bottom skin (I do this with each board) and this was the first time that the board sprang back and twacked the table.
I beafed up the finbox area by making specialty reinforcements (thanks Ben and Jim P) This is all done with 2 lb eps while the bulk of the board is 1 lb.
Preforming the rails really opened my eyes to how to up in flex. I make a mistake and too many of the splices lined up (3 out of 4). I found out that by varying the width of the splices you could greatly change how the board bends. This allows you to put in flex in places where you want to load up the springer but to allow the board to remain stiff where you need it to be (I don’t want flex where I put my hands when taking off - it slows it down too much). I think that this is why Bert used so many short pieces of wood on the board meant for KS. If you glue the wood ends together you are limiting flex, but if you have many joins that are not glued together you increase flex thus increase load on the springer. Here I made the rails using the rocker table. You should see how it bent around the nose area.
Here’s the nearly finished board (it still needs to be upol-ed)
You would not believe how much a difference it makes orienting the wood on the angle. When you try to bend the top skin sideways it would just roll up like a straw, but the bottoms skin twacked the table with a snap.
I tried beefing up the center of the board to increase ding resistance and increas spring. Next time I’ll do it much differently. Can you see where I used the thick wood?
Let me see if I get this straight, you bag on the outside lam first before attaching the skins to the board? If so, how do you do the lam on the rails, by hand with just strips?
Once again, many many ideas to come out from such a thead, thanks DanB. I look forward to hear how that one rides! I also checked how skins with straight balsa sheets (like on the deck of your board)and angled ones (like on the bottom) behave very differently flexwise, angled skins flex, straight ones are rigid. On my next one, I’ll try it like you, straight on top, angled on bottom. My last one had angled balsa on both top and bottom. Very nice work!
nice dan…definitely making progress in the right direction wrt weight…i really like those dimensions too…perfect for me @175lb
12 pounds…yeah assuming your design is solid, that’ll will give a performance advantage…your rail surfing should improve dramatically…bottom turns will feel real positive…but this is very rocker dependent too…design is still more important
had some more weight/responsiveness validations recently…
bad news is that my majic board is no longer majic…went for a surf tuesday and something just felt off…even though the design didnt change the responsiveness was gone…i was missing some sections and my timing was off…kind of a weird session…lots of highs and lows emotionally (got smothered by a jellyfish duckin a wave…yikes that tickles!)…anyway, emotionally i felt like i was getting old again cuz i was on the majic board but was surfing just ok, not great…after three hours i get out and head to the car…i noticed the board felt heavier than usuall but nothing strange due to muscle fatigue…but driving home i thought maybe i need to investigate this further…i had a theory…i get home dry the board off and weigh it…
7.5lb!!! holy crap that board was 6.0 when i finished it…i remember the first day out on it…just blew me away…two major reworks and some water intrusion from half-assed repairs and bye bye majic…i’ve learned that most of my really good boards weigh 6.5 pounds or less…
funny but two weeks ago i measured everything about that board except weight and concluded that the majic was from a good blend of features but with good emphasis on rocker (rocker is still king)…so rocker was the biggie…well no, it was the rocker comboed with faster response…i’ve thought about this at length and it makes sense…my style of progressive surfing just suites that combo
BUT not all is bad…the good news is that a replacement is almost done…5.1 pounder with similar rocker numbers but better curves and proper flex (getting good flex is the real challenge)…this one is gonna be reeeeeeeel good
Thanks everybody! I’m looking real forward to surfing it (this Saturday). I’m going to hold off commenting about how it surfs until I get the hang of it.
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If you had used 2# EPS, what do you think it would weigh? 14-15? And then no vent?
I think that you could still hit 12-13 lbs. I can think of a few easy improvements in my techniques that would easily bring this board down to the 10-11 lb range (things like stratigic glassing). As far as fins go, at first I’m using the cheapest fins I can get. From that point on I’m going to start making fins at a rate that would make chipfish envious. I’m only going to build fins for the next 2-3 months.
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ou bag on the outside lam first before attaching the skins to the board? If so, how do you do the lam on the rails, by hand with just strips
I made my rail tape out of some 4oz cloth I had lying around. I made it 6 inches wide but I think next time I might do a tapered cut to reduce weight and increase flex. Sanding the premade skin is crazy. Instead of finishing the outside (its now covered with cloth) you need to sand the inside and take the edges down to nearly invisible. That way it joins nicely with the rails.
Great job, Dan. You have definitely given us a few ideas. I can even see where a few steps might be combined.
Curious how it will ride with that flexy bottom. Can’t wait to hear.
“You really need a good breather material. My first attempt ended in the trash when I tried to use paper towels.”
It sounds like the paper towels just couldn’t handle the 25" of pressure you were pulling.
Did paper towels work on your previous boards at lower pressures? I’m waiting on foam to start my first board and was planning on using paper towels as breather. Won’t be doing the skins seperate, so my pressures will be lower.
It sounds like the paper towels just couldn’t handle the 25" of pressure you were pulling
This approach worked great last time when I was bagging the glass onto the skin when it was on the board. This time I just made the skins and it totally failed. What I think caused the problem was that board used the eps as a conduit to draw the vacuum. When I removed the foam it couldn’t draw a vacuum. By cheap shade cloth from HD (its reuseable)
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Curious how it will ride with that flexy bottom.
Here’s my theory (don’t know if its true). You need to have a flexy bottom skin so that there will be enough movement in the board to allow the springer to come into play. I think that one way (besides the rail gap spacing) that Bert fine tunes his boards to specific surfer is to vary the springer’s thickness (and possibly material) to modify how much energy it stores. The flexy bottom skin takes the emphasis away from the glass and gives it to the wood (this allows the diagonal wood to come into play). The deck can have a stiffer epoxy because epoxy elongation doesn’t come into play. Its job is to stand up to a beating.
Dan, brilliant work , i have been thinking along the same lines, i have made a deck skin similar to what you have done ,full vac using the wood as breather ,but i have had air issues in the cloth, i think i pulled too much resin through the wood , did your laminations come out air free?. pete
Nice work Dan. I like the way you used the 2000 and 2020 to get different flex patterns. That’s what we designed them for. Advanced thought process here.
Thanks guys for the words of encouragement. I’ve been holding off on any comments until I’ve had time to surf it for awhile. For some reason it seems to takes me longer to get the hang of a board than it does for most people. So far I’ve surfed this board 4 times in wide ranging conditions. This board is definantly different from any other board I’ve surfed. In short, I’m finding that I’m paddling like a little old man and looking way better on the wave than I really am. I’m attributing both of these characteristics to the flex of the board (but I could very well be wrong). This board is very flexy, but not flexy the way you would describe a boogy board or piece of foam. When it gets bent out of shape you can actually feel it what to stap back into shape. Benny describe the vibration you get when you just pop over a big wave. On this board I’ve felt it on small little chop while I was just sitting there. When paddling my arms really burn when I finally make it out and my slowness is really noticable. This carries through to paddling for the takeoff. As a result I’m having to catch wave more like a short boarder. Once I’m on my feet its a whole other story. I made the board to surf small mushburgers (thus the 24" width) and I can really feel the extra planing. Today I took it out at shoulder - head high Huntington cliffs and it was pretty hollow for the break. I spent the first half of the session feeling like a kook until I figured that I had to take of much later than I was use to. Once I started riding the waves I was extremely pleased with how it surfed. The board was extremely fast and outran sections I usually wouldn’t have made. It held in nicely on the steep part of the wave. I found myself smacking the lip much more aggressively than I ever have. I currently have an incredibally poor fin selection (the cheap $10 throw aways that often come with the boxes) so I expect to see much improvement when I finally start building some fins. I need to surf this board a lot more to determine its potential, but I already have ideas on how to improve it.
Pete, my skins turned out very nice right out of the bag. This was the best glassjob I’ve done by a longshot. I got almost zero bubbles while hot coating and I could see very little weave. However, it took 2 tries to get it right (the first required me to fill up the trashcan). It was impossible to pull a vacuum without the use of the shade cloth. Next time I’m going to try and have an even smoother surface to vac onto.
Greg, thanks for the compliment. When I first started I really didn’t believe that the average layperson could tell the difference between the different epoxies, but after working with both I could see how wrong I was. It was the completely different characteristics of the epoxy that helped me start to understand how all the pieces react together. I wish I had taken a picture of how flexable the bottom skin was. I’m pretty sure that I could have rolled it in a tube like veneer comes, but because of the diaginal balsa it would not bend width wise at all.
