I’ve made 6 boards with 2#EPS and one with 1#. i haven’t had any problems with creating/cutting the rocker on any of these but the one I’m working on now gave me some problems. I came up with a solution but I’d like to hear what you’d have done (have done). I’m sure someone out there has a better mouse trap!
The board is 11’6". I used one sheet of 2" and one sheet of 1 1/2", 1# EPS. I cut a groove in the middle for a 3/23"x3"x10’ horizontal stringer and laid 5oz carbon on top then epoxied to two together with the rocker (bricks and wood to lift the nose and tail with bricks in the middle to keep it true).
The yellow around the edge is Gorilla Glue so that I can cut the rail for a perimeter stringer.
Now… when it was all cured I took every thing off to see my creation and… it was like a wet noodle! It didn’t hold the rocker! Now the question… What would you do differently to hold the rocker? Using the foam horizontally (not twelve cuts of 2" and glueing then all together then hotwire cutting the rocker) with the springer/carbon etc.
Here’s what I ended up with. I cut the perimeter stringers as close to shape as possible and glued them in, holding the rocker at the same time. Picture shows set-up.
Next is the deck outline, with perim/stringers in and foam shaped.
Thanks in advance for all suggestion. Anxiously waiting…
I’ve made 6 boards with 2#EPS and one with 1#. i haven’t had any problems with creating/cutting the rocker on any of these but the one I’m working on now gave me some problems. I came up with a solution but I’d like to hear what you’d have done (have done). I’m sure someone out there has a better mouse trap!
The board is 11’6". I used one sheet of 2" and one sheet of 1 1/2", 1# EPS. I cut a groove in the middle for a 3/23"x3"x10’ horizontal stringer and laid 5oz carbon on top then epoxied to two together with the rocker (bricks and wood to lift the nose and tail with bricks in the middle to keep it true).
The yellow around the edge is Gorilla Glue so that I can cut the rail for a perimeter stringer.
Now… when it was all cured I took every thing off to see my creation and… it was like a wet noodle! It didn’t hold the rocker! Now the question… What would you do differently to hold the rocker? Using the foam horizontally (not twelve cuts of 2" and glueing then all together then hotwire cutting the rocker) with the springer/carbon etc.
Here’s what I ended up with. I cut the perimeter stringers as close to shape as possible and glued them in, holding the rocker at the same time. Picture shows set-up.
Next is the deck outline, with perim/stringers in and foam shaped.
Thanks in advance for all suggestion. Anxiously waiting…
All I can think of is that you’re overthinking it a little and as a result, none of your pieces is as strong as it could/should be. Go with all epoxy & glass to glue the 2 thicknesses together, or go with all Gorilla Glue. But with 1#…small areas of anything aren’t going to be strong.
GG needs moisture, while epoxy abhors it…that’s a clear conflict right there where only one of your systems was going to get what it needed.
Carbon is for stiffness, but gluing 2 sheets together in a curve is just an adhesion thing. Glass & epoxy would be plenty (or GG by itself).
KISS method
I’m a big fan of GG (actually Elmer’s Ultimate). Currently (as in right this minute) have a board in the bag that isn’t even a true sandwich. Really just a superblank - wood skins PU glued onto lightweight EPS. Next will be d-cell rails and glass (epoxy) outside only. The more I think about it, the more I agree with Sabs - the flex & strength come not from the rails (or perimeter stringers) but from the 2 skins and their relationship with the core.
I didn’t think of epoxy wanting dry and GG wet!? I’ve been using GG more lately also. I like the way it works so will use it on my next board (8’er), in my head, that I’m working on.
Let us know how that board your working on comes out!
A stringer only 3/24" THICK, no matter how wide, won’t provide much flex resistance or rocker support especially on an 11’6".
Your perimeter stringers, although thinner (at the rail) than a center stringer, seem more “back on track” with an appropriate thickness to maintain rocker and flex resistance.
The more I think about it, the more I agree with Sabs - the flex & strength come not from the rails (or perimeter stringers) but from the 2 skins and their relationship with the core.
Thats exactly right Ben. Its easy to see…the blank alone with its stringers is very flexible…but once you put on the skins (std fg/resin) most of the flex is gone. Its SW tech 101. I think that Bert style wood rails is more for core protection and ding resistance…if you use the right density wood you wouldnt even need to laminate it with fg (or just light glass)…just brush on some penetrating epoxy along the rails a couple three times sanding in between. How do you like that?
I think one the key benefits of P stringers and higher density foam rails is the use of lower density foam center and its affects on panel flex. Using higher density foam everywhere will feel more like a std construction. Although a really long board will be more sensitive to any of these types of changes.
I like that blank at the top…are those 1/2 inch stringers?
Is that a multi-layer leaf spring I see? HEY, THATS CHEATING!
The perimeter stringers held the rocker, yes. I think that using a horizontal stringer and GG to hold all the pieces together would work as Benny said and I’ll give it a try on my next board.
I just finished the deck and bottom and will vacbag them on this Thurs. It should be finished within two weeks and I’ll let everyone know how it worked out.
Craftee…“1/2” Stringers?" No, 1/4" redwood bender board that I sanded down.
