thickness and strength

Hi everyone, quick question for you all- I am considering getting a new board. I tend to use a single board for most conditions so I'd like to get a really durable board if I can. So, I was wondering about the relation between thickness of a board and strength. Ideally, I would prefer a thinner board, but I don't want to have to get a new one too soon. Does the strength of a board come from the thickness, or mostly from the glass? Does this relation still hold for epoxy, as I was considering a surftech board? Thanks for your advice.

Get an extra thick stringer and lots of glass.

The stringer prevents the board snapping in half, and the glass works on the smaller dings.

Actually, the stringer doesn't do much beyond giving the shaper a centerline to work off of. The actual contribution to overall strength is miniscule. The extra glass - and maybe a heavier blank - really does do something. Go with it.

Also, for real durability:

Get a stomp pad. I fix a lot of boards that get stomped to death, delammed to hell and gone.

Get a padded board bag. The non-delams I get to fix are mostly garage dings: dings accumulated from banging the board into this and that over time, like cars, doorways and etc.

Also, don't take the board out of the bag unless it is going right in the water. UV light beats hell out of poly resin and foam.

Last, fix your dings right away, don't let them soak up water and get worse. Boards that crumple and break usually do so with the start point at an old, unfixed ding.

Unless it's a longboard. Those break like breadsticks on a good day.

Aloha,

Ummmmmm...........many of us old timers who work with board builders know that the stringer lends rigidity to the blank and holds the rocker during the glassing/curing process. Without the stringer boards have a tendancy to twist and tweak after they have been glassed.

If you would like true durability you can request a higher density blank (Clarke makes what he calls 'the classic' which has the same density as the blanks from the 60's). This blank can be special ordered by most major manufacturers.

Also you may want to consider 8-10 oz. glass in what is becoming a new retro movement toward more stable and durable boards.

Ride Well,

Are you qualified or experienced in this area????? I really have a problem with your understanding.

'Actually, the stringer doesn't do much beyond giving the shaper a centerline to work off of. The actual contribution to overall strength is miniscule.'

The comments above are flawed.

A stringer does add strength (among other things). A thicker stringer adds more strength. A T band stringer yet more strength. Multiple stringers etc., etc.

There are things one loses with 'more' stringer (added board weight, flexability, etc.).

Whoa...Doc after all the good advice you've given I guess your bound to mess-up somewhere. Do you work on your boards in well ventilated area?

I was always told (from professional shapers) that stringers prevent the board from buckling or breaking and the more stringers you add the less the likelihood of such an occurrence would happen.

I switched to a T-band stringer form the standard 1/4in job in my previous board and notice a huge difference in the way the board simply flexes. I would say that it's twice as ridged. In fact, even if it was a miniscule 10% stronger, it's still 10%. Add on direct-sized or s-glass and you have another 10-15%. Use epoxy resin and add another 25%. So you can see all those miniscule amounts add up to a stronger board in a hurry. However for every plus there is a minus and aside from cost you have a heavier board which leads to less performance oriented attributes.

doc, from what i understand, the stringer provides the lateral strength in a surfboard. the thickness and material used or using multiple stringers affects it's overall strength. i think you have downplayed it's role in your statement above.

a couple of references that specifically describe how stringers fit into the strength of a surfboard : http://www.harboursurfshop.com/breaking.htm http://www.pointblanks.com/stringers.html

Thanks for the advice, but I guess I better clarify the kind of board I was thinking of getting: longboard. Sorry about that. Anyhow, I like to use one board as much as I can, so I was thinking of a longboard in 9' range. Wave conditions, at least at the breaks I like, tend to be from waist high to 1 1/2 overhead, or thereabouts. Mostly I have been using a 9'2' shaped locally and I like it quite a lot, but I don't think it has a lot of life left. Anyhow, I was looking at some surftech boards and I like both the Robert August boards and the Donald Takayama boards. Well, what it really comes down to is I like the takayama board since it seems like a versatile shape (it is the diamond tail, you can see it on the surftech site), but it is sub 3 inches in thickness which is what worries me. The robert august boards I like are all 3 or more, but I wonder if they are as well designed to handle steeper drops and that sort of thing. Anyhow, I have had lots of good advice already so if anyone has any more ideas, that would be great.

Okay, I have been fixing boards for thirty years. Sorry your understanding is having problems.

Hi Lloyd,

The stringer provides a little initial stiffness, true, but not much beyond that, as I mentioned in another post. During the manufacturing process, the blank is cut in half lengthwise and the stringer is glued in. It's real useful fo changing the rocker of the blank a bit, as Denny mentioned, but how good is the glue? For that matter, foam compresses and flexes, and that in turn distorts the glass, which leads to failue of the glass-stringer bond.

From the references above

5. The combination of the stringer and fiberglass surfaces form an 'I' beam. Increasing either will dramatically increase the rigidity of the surfboard.

It forms an I - beam, of sorts. However, unlike a steel I-beam, it's not all one material, and when the glass to wood bond fails the I-beam fails catastrophicly.
http://www.pointblanks.com/stringers.html

I kinda like that they have taken the trouble to use a laminated stringer. Laminated beams can be pretty strong, stronger than solid wood beams of the same dimension. And aircraft-grade spruce is a nice wood to use.

However - they are overestimating the strength of the bond that the (rather flexible) cloth . Under very heavy loads, it is not the stringer that's important, it's the foam-glass-resin that fails. And that's what has to be beefed up to make a stronger board, not the stringer.