is there much difference in strength and weight between a board glassed in double 6oz on the deck with polish and 6/4 deck polish and 6oz bottom. does 2 oz make that much difference.
Two more ounces in cloth on the deck translates to 1/4 lb. extra weight in the finished board. For your 1/4 lb (or 4 ounces) of extra weight you get an almost 20% increase in ding strength. Also the stiffness in your laminate, which keeps the deck from denting, is increased by 75%. Now denting is a function of the laminate AND the foam so you don’t get the whole 75% because the foam isn’t changed, but you do get a significant advantage.
I researched the archives on this bb and can up with some info I found a post that gave 1.5oz for every foot for 6oz glass. This next part is totally unscientific… I upped that to 2.0oz per foot for a wider longboard. I then multiplied by 1.25 to account for the difference in density between water and resin (Again totally unscientific) to convert from liquid to weight for a total of 2.4oz in weight per foot for 6oz glass on a longboard. 4oz cloth is 1.6oz/ft and 8oz cloth is 3.2oz/ft. For 6oz glass layer on a 10’ board 2.4oz x 10 = 24oz Fiberglass weight is the ounces per square yard. A 10’ board will have about 20sqft or 2.3sqyds. 6oz glass times 2.3 = 13.8 ounces. 13.8oz + 24oz = 37.8oz divided by 16 = 2.4lbs per layer of 6oz glass. There may be a whole bunch of folks out there that disageree with this, but it seemed to work pretty well when I was debating what glass schedule I wanted on my new board. If someone has a better way please post it. On the other hand, I may already have too much time on my hands.
a while back there was a discussion of using 3 layers of 4 oz on this site- was said to be stronger and lighter than 2 layers of 6 oz. my latest board is 9’8" X 23X 3 3/8 and I went 3 layers of 4oz top and bottom. It came out a good bit heavier than i expected but not too heavy for my uses- 22lbs. yesterday a loose board crossed the front of my board- no dent no ding no problems-the fin hit hard and dragged across my deck. Verdict: very strong glass job but a little heavy
John, To wet the foam on a 6’ shortboard costs about 1 lb. Each layer of 4 oz. after that weighs about 1/2 lb. You have to separate the foam wet from the laminate or the numbers never quite come out right. One layer of 6 oz. weighs about 3/4 lb. after the foam wet. Fin boxes weigh about a pound installed and the blank weight varies from there. If you use these numbers you can figure the finished weight of a board before you start it. And it’s fairly accurate. Now longboards vary drastically because their size varies so much. But they can be figured in a like manner. Likewise strength can be figured mathematically and fairly easily.