reducing the tail rocker. I think that had a lot to do with the speed of the board.
Yup, that's a biggie! Yeah dont go too thin on the rails. My 7'4 weight is w/o fins so its not ultralight but light enough to throw it around a bit and I can pump it too. Its a quad based on suggestion by GG. I rode it a few days ago in some lined up summer swell and it worked just as I planned. Its got more glide, like a funboard, but its still quite maneuverable and pumpable. Very close attention to rocker. we get a lot of mushy days where you need some glide to get thru phat sections and tricky rips to paddle thru. it paddles really well. When the waves are right I pull out my 6'3 GG 5 fin from the man. Love the five fin! That fin design is pure genius! Too bad you busted yours. Cheers, D.
I think wouter is on to something. My first thought was it looked like a surftec break. Very clean and abrupt. So the flex or lack of it could have been the culprit and the vent just gave it a convienent place to start the process.
one of my mates balsa 7 6 got hit square on the deck by a lip that was a foot thick and doubleoverhead square. didnt hurt it at all. someone made a comment how it was amazing the board didnt break. in contrast ive had three boards snap that used paulownia. one was 9 ft. all were stiffer, used gorilla glue and one had a shitty rail build out. also a point is that airex and the like a lot less strong then balsa or other woods
there are reasons for snapping . gorilla glue delaminating. glass under too light( the 2oz stuff)
skins to thin. any less then 3mm is getting to thin
the core breaking down from point load compression damage
a big heavy wave
its hard to say what causes a board to snap, and i think at the end of the day if your pulling into DOH barrels in knee deep water, you can probably snap any board. so i wouldnt worry or discredit certain materials or methods over others just due to a snap
i do know that gorilla glue has always been a common factor and in conjunction with delams there is potential problems using it
i just make poly boards now . i prefer how they ride and since i make my own i can afford to make 3 or 4 a year.
i dont think epoxy composite buildouts are really ready to be marketable until they are white and compatible with polyester topcoats and sanding resin for repair work.
a case in point i just got a compsand(not mine) in for repair. it has sandthroughs in the tail and the 2 pac is peeling off the wood and i really cant fix it cosmetically .
some balsa boards ive done are actually realy long lasting boards after 4 years. others craped out due to shitty glassing method or pinholes( thats why you should all stop fucking around bagging lams. that right there is some of the dumbest shit ive ever seen on swaylocks)
so be happy your making your own board for what ever reason and enjoy the process. just dont get hung up on it. its only one way to make a board. same as timberflex et al. they all have issues.
the reasons why balsa is bad is the reason why it is good. u see its
peel strength is adequate in a composite build. its good it doesnt
drink resin like dcell. thats why the boards are lighter/stronger
a
shortboard that uses superlightwieght 4mm thick balsa is so much
lighter and stronger then anything else using d cell or bamoo or
whatever. i wish sabs was still here. im starting to think he was the
only one with a clue.
do not treat the wood. just glass it
properly without pinholes and sandthroughs and uses
thicker/lighterwood. the stuff that has no grain
its that simple to make a light balsa board that flexes
dont try and take stuff from greg and mix it with bert
they dont work together as they are two entirely different principles
greg build gets its strength from the core. berts gets his from the skin
Well, I’ve decided to try a repair. My wife says, “You’re wasting your time. It’ll just break again.” She may be right, but what the hell? As a replacement I’ve been riding a buckled board that I repaired. The Snapper was a much better board to begin with so I figured it was worth a try.
First I cut back the shattered rails. Then used Gorilla Glue to glue the blank back together.
Then I marked out the replacement skin’s location. I tried to intervene as little as possible and just bridge the break.
Then I did a freehand rout job. Far from perfect (but hopefully perfect from afar).
I had to peel off most of the bottom inner glass as it was delamed. I found a big hole as well. I just filled it with lightweight spackle.
I put 4oz cloth under the replacement skins. I know I’ve set up new weak spots as the inner glass is no longer continuous, but what else could I do?
It’s in the bag now. Tomorrow I will build the rail back up. Then glass with 4 oz top and bottom.
after seeing the photos of the board i noticed that all the balsa grain is at a 45 degree angle to the stringer. this is refered to as "on the bias" and greatly reduces the strength of the balsa. if you had the same balsa thickness running lenghtwise down the line of the stringer, the board would be much stronger. if you take a one foot square of laminated fiberglass and try breaking it over the edge of a table with the fibers at a 45 degrees to the load, that sheet will break with almost 50 percent less force than if you tried breaking it with the fibers at 90 degrees to the load. some people will try and tell you that the skin of the composite takes 90 percent of the load and the core only needs to support the other 10 percent but that's only if your skin is strong enough in the first place. with surfboard the skin is more of a waterproof shell around the core and doesn't offer that much support. my point is that i think that your problem is not enough glass to compensate for the balsa being at 45 degrees or you need thicker balsa.
Thanks for the tips. I actually put the balsa on the 45 bias in an attempt to increase flex. Maybe I should have used 1/8" instead of 1/16". Oh well, Should woulda coulda. Now I’m just going for a simple fix.
Is on 4oz on top and bottom enough? Or should I stagger an extra layer in there?
Durbs, I decided not to replace the balsa around the plug just because of the complications of removal. I hoping the rebuilt skins, balsa rail and glass will suffice.
ps I went back to the Bu Thursday and Friday last week. Thursday was the money day- less crowd and bigger.
According to the sandwich handbook, and the material properties here and here(great resource!!!) I get something in the order of 90% of the load on the fiberglass at the balsa thickness used in compsand. That’s not to say that the balsa cannot fail, but the sandwich will take 10 times the load the balsa could take on it’s own before the sanwich fail. Contrary to popular belief you increase the risk of the core failing when you increase the thickness of the core as you put more of the load on the core and less on the fiberglass. Regardless, when the fiberglass fails the sandwich fails.
If you believe that the fiberglass only act as waterproofing, try a balsa plank with only epoxy on both sides and one laminated with fiberglass on both sides. While the epoxy actually strengthens the balsa tremendously, it’s no match to the fiberglass.
Most of the guys on this site will most likely throw rocks at me for saying this:
How come you don't use a stringer? Boards snap in the ocean. (OK i've had two boards snap with stringers in 25 foot Todos) I used a 1/4" Basswood stringer (What a goof!) So now I use 3/8" for Sunset and Todos Guns. Overhead surf at Malibu? Two (1/8") stringers 6 to 8" a part you can use bending popular so you maintain your flex without loosing integrity of strenght. Building a board without a stringer is like building a house with no headers over the windows and doors?
You also talk about weight how you prefere a lighter board?
I'm no compsand expert like you guys on this blog however the last one I made was 4.65 pounds with parabolic xps rails with 1/8 basswood between the 1 pound EPS and the DOW XPS - 3 1/2 years later it's still being riding in macking surf (It's been to the North Shore and INDO over and over) Ok those places are not Malibu but good strong never the less. Sure it has some pressure dings however it's still functioning today and still weights 4.65 pounds.
Why not add a stringer? (A real one) All your beautiful work down the drain?
So sad!
Without a stringer you become too dependant on the skin. (Balsa Skins have nothing to do with strenght)
Your construction is cosmetically pleasing to the eye however for surfing it's pretty expensive to take an art piece without a real stringer into overhead surf? Sorry for your loss! If you need a stringer for your next project I will make you one for free.
hmmm… Stringers in my mind are the culprit of many snapped boards. Let me explain my logic: When you put a stiff piece of wood down the middle of the board, surrounded by significatly flexier foam (not sure exactly how the fiberglas fits in relatively), when the board is loaded up (flexed) stress concentrations exist in the stringer as it is carrying/transfering a significant amount of the load, making the stringer likely the component that goes first, then the foam/fiberglass follows in failure. Im all for exoskeletan boards, where the mechanical structure serves durability purposes also. A beefier glass (compsand skins… or just more glass, etc.) schedule to make up for lack of stringer results in a board with more evenly distributed loading with less intense stress concentrations at the interface of materials with significantly different stiffnesses. Mike, the use of bending poplar seems intuitively like it would definitely help with some of the issues i am conceptualizing here.
not trying to hijack the thread, but curious about what others think of my logic here… if Im way off base, please help educate me!
How is the repair going Jeff? Im bummed I didnt make it north with you that Thursday… but i did get some of the tropical storm swell at the base that friday afternoon, very humbling experience.
Technically the board had stringers- 9/16" balsa rails/perimeter stringers. I’m pretty sure the nature of the hit I took sent the energy of the wave directly to the stringers ( arms locked straight, lip lands on shoulders and sends the energy straight down to stringers, in two concentrated load points- the palms of my hands). You may have a point, though- if the stringer were in the center, the energy might have been dissipated and I might have just had two pressure dings on the rails
And yeah, I know, First Point ain’t Sunset or Todos. And it weren’t no 25 feet. But the wave was big enough and I was in a bad enough position that, were it not Malibu, I might have bailed. But I was thinking, “Ah come on, it’s only First Point…” Not only that, but I was thinking, “This is First Point, there’s probably 15 guys right behind me. Better not bail…” Damn! Wish I’d bailed. Might still have an intact board.
Here’s some progress photos-
Rebuilding the rails…mmm…stringers…
Attached with high tech, multi purpose, adhesive strips
I use to use Bending Popular however I got a pallet of the stuff a couple of years back.
I guess Gruby, Hobie and Dave Sweet were all wrong in adding Stringers to blanks?
The orginal poured blanks had now stringers and they broke boards right and left.
Therefore: Spruce, Redwood, Cedar, Basswood were milled and used for stringer material which improved the surfboards performance and reduced breakage!
Making the skin strong instead? Well I made 8 stringerless epoxies for a famous WQS surfer and he said they suck for Hawaii they were exact copies of his standard PU/Poly. He prefered his boards with a stringer. I have access to many pro surfers so maybe I have the wrong view point? I believe surfboards need some kind of structual reinforcement. A combinatiion of the core and skin to blanace the strength to weight ratio. To use only one element is risky. Any board can break under the right conditions. I sent 3 boards to a guy on Kauai that rides my boards. He is a bit crazy and surfs over dry reefs in big barrelling conditions. The first day at Acid Drops he broke the stringless epoxy in half (First Wave). The other two boards have been in service for 3 years and still in use in heavy surf. I send him about 4 boards a year. He only wants to ride Epoxy. Some are EPS and some are XPS. WE found from our testing that we need stringers. I maybe wrong?
Thanks for the explanation mike, was merely expressing an idea I had in my head, completely theoretical. Experience trumps thoery and you have much more experience than me, so kudos to you. Happy Labor Day!
I'ts nice to take a day off. I only shaped one board for my son today. He just got back from Europe after a month so it was nice to spend some time with family and putting in a couple of hours shaping an EPS quad for him. My vacuum press should be up and running so I look forward to making compsands on a regular basis. That's an area that I'm a full rookie. However that's were I find it amazing the boards being made by guy's like Jeff or Aloaf. Their so stoke on the boards they make. Jeff makes one a year he say's?
