My neighbor built his first board. A 9-2 Harbour inspired beauty. He’s a craftman and pays close attention to the details. The board came out fantastic. Glassed with 2 layers of 6 on the deck and one layer of 6 on the bottom. Airbrushed with acrylic paint. Polished gloss coat. He’s a pretty big boy, about 220 I guess. Board is about 3 inches thick at the most. Anyway, he was pulling into small little close-out tubes. Bottom line is he has perhaps 40 to 50 stress cracks in the lam perpindicular to the stringer on the bottom. We’ve all seen a few of these, but the bottom is covered with stress cracks from about 12 inches from the nose(where I normally seen them) to past the midline. There are quite a few in front of his rail fin boxes, too. Needless to say, he was bummed. Any ideas as to why he got so many? Anyone else had this experience? He’s getting ready to start boards 2 and 3. mike
Need heavier glassjob for 200lbs’ers to fall on their boards.
If it’s hollow waves, maybe they happenned on pushtrus.
I’ve seen plenty of new logs get stressed here in OBSF head high and smaller surf, when it’s hollow.
Tuberiding, ride a conventional NARROWER board!!!
I"m 145lbs. stress fractured my 9’ BlueHawaii made for MOK board third day in head high steep waves.
not enough glass to reinforce the amt of resin.
flex ed beyond the tolerance of the resin
fractured the resin.maybe not the glass… sand the fractures out down to glass then put anoher layer o’ glass…4oz.?
the glass matrix inforces the resin
then we may consider flexi nature of shape
leedd has a point about 200# persquare feet
or elongated slender graceful feet.
Americans are sometimes geneticly refined to wreck all toys
if they last til 10:30 xmas morning …they were well built
some kids could break tonka trux
se la vi
la vi
LA VI
I personally brlieve that a thick leash may have contributed to this fracturing
200# sea anchors are prehaps as abusive as
200# trampoline specialists…
…ambrose…
FWIW, I have lots of them on my 7 year old Harbour longboard and my Bonzer 5,too. Everyone says to ignore them since it’s just in the resin. One ding guy said people will use mop-n-glow or something like that to fill/hide them?
Usually, leave said stress fractures alone, your board will turn color there, meaning some amount of moisture got in.
Yes, gloss coat fails. But that exposes the hot and lam to moisture, and given more stress bending, the hot gives, and the lam bleeds.
Mine turned brown in about 2 years, only 13 countable gloss fractures.
If you have more, …
Thanks for the replys, all. What was unusual was the number of fractures. 50, maybe more. I’ll pass on the information. He aint no kid and takes care of his stuff. It was the usual fast hollow little pounders at our local beach. The board came out sweet. I’m guessing he’ll want to try a repair. I’ll pass on your idea, Senor Ambrose. Mike
Rooster,
We see a lot of this type of fracture inside of concaves. We usually attribute this to too much resin pooled in the concave. One typical thing that new board builders do is leave too much (or not enough) resin on their boards. If you friend left too much resin on his board it might have caused this excessive cracking. In something that bad we usually take 100 grit and sand the board all the way down to the weave and then regloss with extra styrene in the mix. This helps with any left over cracks that didn’t get sanded off. An extra step that helps the outcome, if you want to take it, is to hotcoat again/sand then regloss. This makes sure the cracks do not reappear.
Sincerely,
Troy
Stress fractures are the hairline cracks that are the result of a surfboard going into an extremely stressful flex. The films of resin above and beneath the glass cloth are usually both cracked. These can happen to any board on the first wave or the 10,000th. It was simply in the wrong place at the wrong time. These cracks usually happen while the rider is not standing on it, so the rider’s weight has little to do with them. While certainly more layers of fiberglass will help reduce the potential of getting stress fractures, a single 6 oz. bottom is well within the industry standards for a longboard. Most high performance longboards, as well as most short boards have a single layer of 4 oz. glass on the bottom.
The bottom line is that this board almost broke. Salt water weighs about 64.3 lbs. per cubic foot. The lip of a wave can contain many cubic feet of water and if the board is exposed to this with no support, it has the potential for breakage or stress cracks.
or you could just use epoxy .
i have never seen an epoxy glass job with stress fractures , it will bend as far as the glass can tolerate …
polyester resin fails way earlier than the fibreglass fabric its combined with …
the stuff is total shit when it comes to strength and tolerating flexing , i used to use it for finish coating over my epoxy glass jobs , but it would crack ,even snap off , tho the epoxy glass job underneath was perfectly intact …
what a way to fix the problem , just add more glass ???
i wont condem that approach completly , if you want a heavy pig that cruises and nothing else , then thats a valid approach …
but if your looking at performance and you want to keep the weight down , and not have it crack while flexing , then epoxy is your answer …
gregs now has a uv filter and stabeliser , so it will even keep your board white and crispy …
regards
BERT
Hind sight is the exclusive oppertunity to install optics on your butt.
the lack thereof sufficient fiberglass to resin ratio is the real topic inferred.
the quality of resin … poly , epoxy , or trans galactic gorgonzola sleengarf
all forms can truly be a superior option if applied in an integroous manner.
mixing incompatible materials is not a dicisive testimonial or example.
appropriate resin to glass ratios increase strength,basic premise.
the superiority of the EPOXY alternative is well taken again master burger,
too bad you wernt in monterey when roster’s kin was makin this here beauty!
an inspirational geographic localle, monterey county,watch " One Eyed Jacks"
is it true that it doesnt dent? this here polyester?
as our friend epoxy has a tendency?
I had an epoxy board bend to 45 degrees once
I was at a loss to fix it.
materials failure achieved by test pilots in abusive situations
are primary educational circumstances.
hail to the kevin breedlove spirit to take the craft to the breaking point without destroying the toy.
hail to the true believer in us all.
may we survive til the transgalactic gorgonzola sleengarf is released for
plebian consumption.
Until then happy new year all .
…ambrose…
every thing could be better
everything can be repaired
you can line a pigs ear to make a silk lined pigs ear purse.
Ambrose,
I have been laminating surfboards for 47 years. I have done extensive experiments evaluating stress fractures. They go from the gloss coat through the hot coat, through the fiberglass and into the thin film of resin underneath the glass fibers.
Yes, a resin rich hot coat over a transparent glass job might be a little more prone to showing them, however “rooster” on the first post says it is an air brush.
With a surfboard that has an acceptable weight, there is no way a hand lay up using polyester resin can be guaranteed to not be susceptible to stress fractures.
Clear nail polish to keep the water out, then ride it till it breaks.
Hpwzit elewis, If there's not to many srtess cracks I scrape little vees in the cracks with the corner of a razor blade then use a couple of strands of glass rope to fill the vees and then hot coat and sand. Seems to work pretty good and never seen any of the stresses come back.Aloha,Kokua
in the 47 year time line?..
when did tension cracks become a factor?
I would speculatively wonder if the single bottom
in conjunction with the reduced stringer widths of the early 70’s
may have been the emergence of the malady.
being out the industrial mainstream
in the ignored unpaid r&d sector
this was when I first saw the tension crack malady.
the leash whiplash factor has been one of my suspicions for some time
yet my first tension crack array was from
running into/over driftwood of magnatude
while riding a wave at the flatrock
after burning a friend I thought wasn’t gonna make it.
[it coulda just been karma]
thank you mr. harbour for your input.
acceptable weight as well as industry standards
admitedly are in flux according to the whim of the
marketplace but the durability features
of a given construction medium does have limits.
what pray tell are they?
did the harbour cheater,yater spoon,greek eliminator,
bing Nuuhiwa lightweight.and other stepdecks
tension crack before they broke in half?
[the common demise of the step deck]
those were commonly less than 1/2’’ of wood stringers
although some like yater split the wood to accomodate the box.
…ambrose…
just a thought
ok that starts to make good sense ambrose …
i remember thraikil saying once he didnt like his board to flex (get back to that one later )…
polyester resin will bond fine to epoxy if the epoxy is prepared and sanded thoroughly …
if you made some wooden furniture , combining epoxy and polyester would work fine …
but the problem with combining them on a surfboard is the fact one will flex further than the other …
its a standard composites issue , that when combining different materials , we have to consider the limits of each component …
and by doing combinations it starts to highlight the weakest link …
polyester resin hates flexing , now backing this off your comments ambrose …
if you look at where surfboards started , 2 or 3 layers of 10oz glass , higher density urethane foam , stringers so thick as to diminish flexing …
in that case polyester resin worked well in conjunction with the other composite components …
now as boards get thinner , foam gets lighter , stringers get thinner , glass gets reduced , it all points to a disaster for the resin , it simply cant cope and becomes the weakest link in those type of combinations …
this means to continue the use of polyester resins in surfboards , there comes a point where your forced into certain design parameters just to allow for the inadaquacies of the resin …
so when i said polyester resin was shit , thats coming from someone who has pushed past its limits …
it has no place in a modern high performance surfboard , it just cant cope with the flexing and repeated cycles of stress , its currently the weakest link , followed closely by urethane foam …
but going back to thraikils comment , the type of boards being built with polyester resin in the first 30 years of its use are fine …
building old school boards that dont flex , wont stress the resin , so it doesnt show any weakness …
so its good for some applications and bad for others …
i wanted to clarify that one , because it must look like im always writing polyester resin off because i say its no good …
but its just no good for what i do …
but its also got to the point where its no good for what others are doing as well , because the line is being crossed by making all sorts of changes to the structure of a surfboard highlighting the weakness of the resin …
epoxy solves those issues and opens the door to new design parameters , because we dont have to retard or try and reduce flexing to cater for our resin which cant flex …
and going back to a long thread discussing epoxy with rich …
when building old school boards , there is no real benifit in using epoxy …
but when design and other aspects of the surfboards structure start to come closer to modern themes , then there is a benifit in using epoxy …
so in answer to the original question …
your board is flexing to much for the resin to handle …
either change the design and like rich said more glass , which will reduce the flexing and stop stress fractures …
if you want to keep with the glass schedule and the shape , stringer, etc , then epoxy will solve your problem …
regards
BERT
…I laminate myself all the 9 ´ with 4oz bottom and 3 4oz deck speed finished and never had been stress fractures… (the min. thickness of the shapes in the middle area are 2 3/4)
…epoxi resins were and are better than polyesters…but not until now that RR s got new products that is safe (in all the aspects)to do the change…
Let me try and get the board builder to put his $0.02 in, but I will add the stringer was not a thin little spar of wood. I believe the blank was custom ordered and the stringer about 1/4 inch thick. Mike
Rooster,
I’d love to be able to answer all of your questions, but a BB is not the place. Please email me at: . If you are local, I would like to see both you and the board. If you are out of the area, I would like a phone number.
Howzit rooster, 1/4" stringer is normal for a longboard blank, 1/8" or 3/16" is what you get on short board blanks these days. Seems to me that back in the days of classic longboards the smallest stringer for a longboard was 1/2" redwood.Aloha,Kokua
Thanks, Kokua. I didn’t know that. I walked to my neighbors house to tell him his board situation is being discussed. His daughter will hopefully help him find us and he can read for himself the generous responses. Mike