It is definitely the result of flex/stress. Nothing to do with temperature.
I’ve owned numerous boards that were subjected to all sorts of weather extremes and never had one crack for that reason. The worst thing about sub-freezing temps is if you have a leaky ding. Water freezes and expands, causing delams. I stopped leaving my boards outside in cold weather a good 25 years ago. I think letting your board bake in the hot sun for long periods is also a bad idea. I’ve seen the finish layer on a Surftech bubble because it was left in the sun, in a board bag.
i live up in maine and have left my boards outside for entire winters to see if there would be damage or increased wear on the boards,i have not seen any damage i can say was caused by severe cold,mind you we are taking dips in the ocean under 40 degrees during our coldest peaks.left a dark resin tint board out in the sun too long and what happened was a delam,big bubble with no visible stress to the resin and glass,just a big ol oops bubble.more than a couple of my longboards have stressed out like this from shorepound and the likes of top to bottom beatings.
Two things… one, the cracks may allow water to penetrate and two, the structural integrity of the glass job has been compromised. You could ride it but the risk level for further, possibly catastrophiic damage has been raised.
Ambrose hit it dead on!!! Tension, the resin has been flexed to far. The reason you didn’t see them before is simple, you didn’t clean it before. This same thing happens with glass paddle shafts but they show up fast on a paddle shaft because you are rubbing your grubby little hands over them and filling them with crud. So in your case when you cleaned your board all that crud that was on the board was wiped into the cracks highlighting them!!! Yes your board strength is compromised. If you like the board you need to at least reglass the bottom with 4 oz… I would not repair it but instead ride it untill it breaks. OH honey!!! LOOK I broak my board!!! OH Poor you. You will have to get a new one! The perfect excuse. Ahui hou- Wood_Ogre
Hey ECA did you by any chance wipe the bottom of your board with acetone???
I know that it would greatly decrease the integrity of your gloss/hot coat and cause those fractures. I discovered this when I removed a large decal from a board with acetone. Sand tape and hotcoat.
Thanks for all the comments - you’ve educated me greatly. Never used acetone on it, in fact I stay away from all solvents, just use a good old fashioned wax comb to clean it up. I’ll definitely go down the repair route - can’t stand the thought of it snapping on any wave soon. Just hope it won’t add too much to the weight.
I agree with balsa about water in the cracks that freezed and made the cracks visible, but they probably existed before the cold.
a little side-note:
This is a typical polyester fracture. This doesnt happen with epoxy. The problem is that polyester is stiffer than the glass, the glass flexes and the polyester cracks.
With epoxy the glass will fail first (so an epoxy board is as strong as the glass, a polyester board is weaker)
I do not want to claim that epoxy is better (that’s a matter of taste), I mention this because these pictures are nice to illustrate the resinflex to glassflex ratio.
