A friend of mine just handed me an EPS blank he picked up for cheap and he wants a longboard. It’s a 24" wide sled cut so widths and template aren’t an issue but I’m concerned about the rocker. I measured it at 5.25" at the nose and about 4.75" at the tail, nearly a continuous curve. 9’4" x 3.5" thick.
I’ve dabbled with longboards in the past but I’m not tuned into any of the subtleties. This seems like a lot of rocker to me compared to what I’ve done in the past but what do I know?
Therefore I’m soliciting suggestions for what do with this blank. FYI, the surfer is a young guy who rips on a shortboard so I’m not worried about his ability to adapt. I just want to find the right design for the rocker.
Thinking about it, maybe it would be a good idea to put the blank up on the racks and hang a weight then measure the rocker and adjust 'til you find the right combo then, glass it like that?
So you’re talking about hanging the bucket from the middle, between the stands? If so, how much could I reasonably expect to flatten this out at the entry and exit points? The foam looks to be 2# or maybe a bit heavier, and there’s a 1/8" stringer.
I guess I’m pretty much committed to an HPLB design with this blank, right?
That is a lot of tail rocker, maybe the reason the blank was cheap as it may have been for a gun. My hi performance longboards at 9'3" have the same nose rocker, but tail rocker is 3.5" or so depending on the surfer. (I have them put their personal info on the order card) There are a couple of things you can do to adjust that blank without spliting it and re-stringering it. (you could do that too, it's EPS and a lot more flexible than PU) First, take your measurements ever 6" and check the curve to make sure you arn't just measuring tail kick, nose flip, etc. I hope you are measuring from the center point with the blank level on the racks. Second, use a shaping program like the free version of Shape3D to draft out the numbers on a lower rocker. Using these numbers you can then plane out the center of the board and then re-cut in the new rocker. You have a 3.5" blank and a finished board of 3" is still pretty thick so you have a lot of thickness to play with here. Also, you said the guy is a young ripper so you can cut the blank shorter by an inch or two at the nose or tail to take out some of the curve. You are moving the center either back or forward when you do this so if you mark the center point and then move it forward or backward by that amount before you cut you will get a firm idea of how that will change the rocker. Let me know if you need more info or pics on how to do this. For young guy rippers I keep my lb's around 2.5-2.7" as they really like the thinner rail that is more like a short board. Just my 2c.......
Oooh, that sounds interesting… hmmm, maybe if he likes the nose rocker but wants to relax the tail rocker he can adjust where the board is on the stands and where the weight hangs from?
the only way I can see to shape the rocker out is to take foam off the bottom, so the question is, is the blank thick enough to allow that?
otherwise, its a matter of "splitting it and re-stringering it", as surfteach says.
another option is just to go with it. I've noticed a lot of modern longboards with the rocker you describe. I still build with the rocker I'm comfortable with, flatter in the middle and tail, but I've been wanting to try one of those "continuous curve" (as you call it) rockers. You might compensate by giving the planshape a bit less curve, which should be easy with a longboard.
and after all, the guy who wants the board did provide the blank - just show and tell him, this is the rocker that this blank has, this is the rocker you're gonna get. Let him make the call.
Just shape it and when you go to glass the bottom, screw a little hook in to the stringer on the deck side. Hang a bucket with some sand in it to flex the blank downward. Make sure the resin has cured before taking off the bucket and removing the hook. Epoxy glass jobs tend to shrink a bit anyway so don't be surprised if you lose quite a bit of rocker while using this method.