hairline/stress lines in glass

guy i know in the industry has been telling me ci stories for some time,now,and he has no reason to make it up

 

live4truth... here's my theory (and yes, I'm making this up): Sometimes stress cracks go all the way across the board, rail to rail. But sometimes you see them only on one side of the stringer, from stringer to rail, and that's what I'm struggling to explain here.

If you can imagine a cross section of a board, the stringer and skins create an I-beam, and that becomes the stiffest part of the board. Second to that are the rails, which are stiffened by the shape of the rail... a tube of any material is stiffer than a flat sheet of that same material, and a rail is essentially a half of a tube. So the increased stiffness of the rail and stringer make the flat sheet of foam between them more flexible than both, relatively speaking. On a hard turn, either frontside or backside, you're loading the board with your toe or your heel directly over the flexiest part of the structure, making it flex sort of like a trampoline between both stiffening structures. (You can also add some twisting forces to this scenario, as the load is not evenly distributed along the deck of the board) A hard turn puts a lot of stress on that trampoline... more than you might think... and it takes very little strain to create enough deformation to cause a brittle hotcoat to crack.

That's my theory, anyway...

 

LBC...theory works for me--sure there are a few other dynamics at work, but inessence I'm with you...I think this link will illustrate. Check it out at 39 seconds...http://www.youtube.com/watch?v=Vmv1Ql0xs-8

 

Feesh - I've had a CI Skinny Fish for about 3 yrs, and mine has the same issue - hairline fractures on the bottom of the board from rail to rail accross the stringer, from about 8" from the nose to not quite halfway down the board. I probably had the board for about a year before these appeared. No water getting in and seems structurally sound so i haven’t been worrying about it... I love this board, and I have/have had other CIs but never seen anything like this before. Interesting you're seeing same on the Skinny Fish...must be the glassing? Mine has the "OceanWorks-CA USA" stamp...

 

once upon a time, i think you'd be right. but CI took a lot of the criticism aimed their way a few years ago to heart & reduced their involvment in over-seas production...they shut down anacrapa, brought all production back to CA, & scaled back their offerings from surf-tech.
as such, production CI's are made in the USA (machine cut, hand finished). unless it's a pop-out, in which case it didn't come out of the CI factory to begin w/...it came out of surf-tech's thailand factory. i know this to be current & factual.

 

sorry,42,you're correct,i trust you,haven't followed ci since the burton thing,please forgive

 

no worries at all, man. not angry or upset at all, i just feel like a lot of people jump on the "hate CI" bandwagon & toss out things they've heard from friends of friends of friends w/out even thinking about it; it's easy to hate on CI b/c they're such a huge company. since i work w/ them quite a bit, i feel it's necessary to set the record straight if & when i can.