Whats up with all the cracks down the stringer edge??? I have repaired at least 5 in the last two weeks. Have instructed some of the groms to try not to use their knee in the deck to Duck with. Stringer doesn’t move foam does …glass cracks! Surfshop was full of them waiting for repair…one came in while I was there…first day in the water for that one. I am going to try laying an additional 3" strip of 6 oz down the stringer on the deck lam to see if that helps on my boards. Any of you guys been noticing this problem??? Is there a better fix in the building stage? Repair is difficult as it usually involves a nice big deep pressure ding along with the cracked glass.
I notice those knee induced dents in 1968, and watched them occur on all lightweight glassed boards since.
On another note…ever notice how coldwater surfer’s were out there wetsuits ABOVE their knees? That one is waaaay beyond most surfer’s comprehension level!
I am no pro shaper but I had this problem on a few of my boards. I fixed it up by putting an extra 5 inch wide strip between the 2 top layers in the area of where the guys knees normally go. One was for my brother and even though he used his knee it was still my fault and a bad glass job.
Krokus, Since I deal with wood boards I’m quick to wonder if it’s the age old usual problem of poly resin not liking to adhere to wood. On my laminated wood skegs I sometimes have to brush coat as many as 4 coats of resin to fully seal the wood. I keep sealing until there are no remaining flat un-shiney wood spots before going to glass. You probably do the same on wood.
On a recent multi stringer balsa board with redwood rails, the rails had to be sanded back down through the glass and started all over due to the fact the glass didn’t adhere because of improper sealing (initial cheater coats). As you can relate, I had meticulously finish sanded the board to keep the integrity of the finely rounded pointed tips of each of the stringers and rails where they open onto the nose and tail area rails. It was pretty scarry and frustrating to watch a disc grinder go down on em.
Would the fact you’re seeing the cracking with or under the pressure dings indicate the glass is just not adhearing to the wood? I know a lot of guys go with epoxy on wood because of this problem, but for the guys doing poly I vote for really good sealing of the wood before glassing, perhaps a brush coat of resin down the length of the stringers and allow to cure prior to glassing? About a couple of years ago a lot of guys had problems with redwood stringers due to sap, and improper kiln drying (a bad run of redwood through the foam factory?). The wood HAS to be dry, but unless you poke a moisture meter in it you’re not going to know.
Cleanlines and you other pros much more knowledgeable than I, what say you?
I too have had this problem…I glass with a 6/4 deck combo is this too light? what is the standard? I have also had a problem with longer strait gloss coat cracks…the 6oz down the stringer thing sounds great thanxs buddy…
Howzit Krokus, I’ve had the same problem on a couple of boards. But what I wonder is why not all boards especially if it has to do with knees. Probably is due to the density of the blank or if the shaper took to much foam out of the deck of the blank.Aloha,
Howzit Krokus, I’ve had the same problem on a couple of boards. But what I wonder is why not all boards especially if it has to do with knees. Probably is due to the density of the blank or if the shaper took to much foam out of the deck of the blank.
Both my roommates get this problem. One is a bigger guy, 230-ish, the other is a rookie. Neither is a true shortboarder, they both seem heavy on their front foot. Both of their boards are around 7 foot, so their knees are going to be on the tail, on the stomp pad. I think it’s from the heel of their foot…
One of their boards was clearly overshaped, the thing would get a ding if you looked at it wrong… it also had the crack running across 2/3 of the stringer. The other guy is just big, and 230 pounds, un-gracefully compressed to the size of a heel, could do some damage.
I’ve been thinking about running a strip along the stringer as well, let us know how it works out…
Try this: Plane the stringer down an additional 1/8" on the deck when you are finished shaping. Leave the stringer and surrounding 1/2" inch of foam on either side at the lower depth and then glass it. When the foam is compressed from riding it, there is not as much stress at the stringer because it is already at a lower depth and the glass is not as stressed. I’ve seen this done on short boards, and although it does not stop the problem, it does help relieve the glass cracking and stress.
i have had this problem on almost every board i’ve ever owned. My 9’6" is classic foam, volan glass + deckpatch, and still the thing split along the stringer. It even cracked all the way up to the nose. Where ever my feet have touched there are cracks.
Oh yea, the stringer is two 3/8" balsa t-band, if I remember correctly. I bought the blank from someone else, not my normal Foam-ez purchase. I thought that may have made it more immune to the cracks. Wrong.
The reality is that foam will compress with impact and/or repeated loading to the same spot. Far enough away from a stringer and you just get a dent. Next to the stringer starts a shearing action on the glass and cracks develop. They’ll propagate the full length of the board eventually. I’ve never had this problem (or delams) with any of our personal boards which are used daily. Why? All boards (long and short) have a front traction pad. Cheaper and easier solution than extra glass, additional/wider stringers, etc. Some may say these are for kooks and old guys, but screw 'em. I charge a minimum of $50 for repairing glass splits along the stringer (and no guarantee) mostly to people who think they are too cool for these pads. And I use that money to buy more pads. For those interested, just buy the 1/4" waffle pattern or 1/8" flat, cut your own shapes, and glue down with contact cement. I buy the sheet material from www.northshoreinc.com/deckpadz.
Good ideas all, It is definitely shearing caused by the foam compressing and the stringer not! I’ve been using some ultralight blanks for the groms contest boards and that foam is SOFT! Going to try the lower stringer along with some reinforcement. Also these boards were glassed 4/4/4 so the deck is not super sturdy. I just shaped a little comp hybrid fish and had to overshape the deck a little. It’s going to get a 4/6 deck to help compensate. Sending two groms to the State Championship this weekend! Hope they do well.