The talk about Bert’s classic thread and other methods over on the new compsand query fired me up to draw a picture and ask a question. I’ve sketched out three ways of lapping the skins onto rail bands.
I followed the classic way last (first compsand) board and did the top method. The bottom tuck came out OK, but the top layer meeting the rails got too thin in places and needed some filling and touching up and hiding with paint.
This board I’m considering following the middle method. I’ll shape the top and bottom, glue on the deck skin, trim the deck to the outline, glue on bottom skin, then proceed to finish. Any comments or other people doing this inlay/rail/overlap method that can give me advice?
Surely the top method would be the strongest/least likely to cause problems?. Wouldn’t the bottom one, and to some extent the middle one be asking for trouble??
hi, its easier and better cosmectically finished if you glue up the rail pieces to the bottom skin as in the bottom picture , then when you shape in the deck foam you can bring the rails down to an approximate 45 degree angle in the middle of the board tapering away to a bit of a flatter angle in the nose and tail ,
do one rail first and then transfer the height of the rail by measurement to the opposite rail so that they are the same ,
the deck skin is vacced over the angle and then blended in with the roundness of the rail to give the strongest join and a seemless and neat transition from rail too deck , pete
Hey just doing one now and I have done them like this before,this way you dont risk shaping through your deck skin but i found you gotta get the deck roll and rail very close before vac bagging…
The cleanest looking to me was do the bottom skin, trim, attach rails like the bottom example, shape deck roll, but leave a flat band on the top of the rail, then vacc the deck skin, and finally turn the top rail. Only hassle with this way is it’s lots of steps.
Lately, we start with the bottom skin then add the first layer of rail, then after shaping the deck we add the deck skin over the rail edge, then add more layers to build out the full rail. Turns out like the middle but upside-down.
My brother has also made a bunch of blanks with the bottom skin and full rails that have a parallel profile. I think we’re down to the last one or two. I have one of those blanks at my house waiting to have the deck shaped, and another shaped but waiting for the deck skin.
What Karl said, bottom–rails–top over rail—blend. Look at (SpeedNeedle) on Sway’s-Josh Dowling boards. Now I just use cork and wrap the top rail to the bottom…and it rides better with no water issues.
Great! Thanks for the responses. Wow, it’s interesting to see the mix of methods, but especially to see so many using the 3rd method.
Thinking about it more (even after a long time of going over it in my head before I posted the question), method 3 may prove more practical, because there’s less need to have the rail bands dry fit perfectly to the botton skin, as in method 2 (i.e. the rail bands can be a bit oversized and cut wonky) and both skins can go on in one pull.
As you guys say, there are extra steps, almost regardless of how you do it.
Beerfan, I don’t think the glue-up pattern makes a huge difference to structural integrity because the core is skinned, but let me know if I’m wrong about this.
I don’t know anything mate haha, I just figured the top would seal off the super light weight foam in the centre. I’m a compsand owner, not a compsand builder!. Totally ruined after buying a josh dowling. Don’t want to surf anything else. Got 2 now, when my knee gets better hoping for a third.
One thing to think about, but others will have more experience than me, is overlapping both top and bottom skins over the rails may lock the flex up a bit. There’s been quite bit said about this over several other threads if you’ve got the time to read it up.
I’ve found bamboo veneers on top and bottom, lapping the rails did make for a stiff feeling board.
After reading Bert’s post, long time ago. The first attempt was total rail wrap of balsa. Since then I’ve always used method three:
Shape foam (lately I’ve used EPS covered with XPS), leaving rails square about 1" thick, VacBag balsa/palownia, square off rail edges, glue on 1/8" thick cherrywood (strong/long fiber/good bending wood), then add 3/8"x3/8" palownia*
*palownia rails… stack 3/8"x3/8"x length of board on top of each other and bend to shape of rail. tape to hold in place temporarily then use car tubes cut in 1" width x 15-20’ to wrap the rails and hold wood inplace. Shape rails, glass.
If you don’t support the deck skin, you will get what we call in the building industry differential settling. That is when you build a house, half on bedrock, and half on loose fill, the bedrock half is stable, and the loose fill sinks. The structure shears at the point where the two meet.
In a compsand, if the skn rests only on the EPS, it will compress, while the rail band doesn’t. You will eventually end up with a crack in the fiberglass right at the joint where the unsupported deck meets the stronger rail.
If the entire core is uniform, like a foam blank, with just a wood or corecell skin, you don’t develope the shear as much (but you still can develope a crack at the edge of the stronger skin).
If you run the skin so it covers the rail bands, the rail supports the deck skin, so it doesn’t crack.
Sorry everysurfer but I’ve built over 30 boards, at least 25 using this, unsupported, method and no cracks…broke in half, puka in deck from hitting screw sticking out of garage and other problems. And this is covering the above boards with just one layer of 4oz. S glass.
I’m sure your correct that this is method is weak but I’ve never had a problem with it.
I haven’t had problems with rail caving in at the seam yet. I found several shots of boards that don’t have the overlapping top skin. I don’t think my feet get that close to the rail to make it an issue.
