6'2" hollow poplar XPS surfboard

Hello everyone,

I read this forum quite a lot and it inspires me every time. I’m  into alternative ways of surfboard building and found tons of information here, thanks guys for sharing your ideas. At the moment I’m building my second surfboard and wanted to share a few pics of the building process. The first was a “traditional” Hollow wooden surfboard with rips, 3mm poplar plywood skins and cork/poplar rails. It turned out quite ok for a first build, but was a bit on the heavy side with over 5kg (5’11’’ Fish like Lost RNF) and very stiff due to the traditional internal HWS frame with rips and spine.

The second one is a combination of ideas i got reading this forum.

I want to make a board that meets the following criterias:

- lighter board, aiming in the 3,5-4kg range

- cheap materials (No Balsa, No expensive cloths like carbon fiber)

- hollow construktion

- locally available wood

-no cork rails, because i think it takes a lot of resin during glassing to make the surface smooth without air bubbles below


First I was thinking about a wooden aviso type of board, like kevin from spirare surfboard made one, without any internal structure, just poplar skins that have glass on the inside and the outside. But I think those boards need quite a high amout of glass to make them durable, which also makes them more expensive.I then jumped on the idea of Hess Surfboards, or also spirare surfboards, replacing the traditional wooden internal structure of a HWS with some foam rips.So thats the plan:

3mm Poplar skins, internal rips of XPS foam, rails made from poplar and XPS rails.

I will try to paste the first pics right now and add pictures as the build goes on, hope you guys enjoy!


Surfboard Design 6’2"x21

Surfboard spe[img_assist|nid=1054828|title=6'3" surfboard specs|desc=|link=none|align=left|width=640|height=560]cs

building the rail frame (two layers of 3mm poplar glued with PU) on the adjustable rocker table


[img_assist|nid=1054829|title=rocker table with rails|desc=|link=none|align=left|width=640|height=480]

Gluing on one of the XPS ribs (thats the one closest to the nose) with pu

[img_assist|nid=1054830|title=XPS rib|desc=|link=none|align=left|width=640|height=480]

All XPS ribs glued on the 3mm poplar plywood bottom skin


[img_assist|nid=1054831|title=xps-ribs glued on|desc=|link=none|align=left|width=640|height=480]

closer look at the rocker table: to create a concave bottom, i glued some poplar strips on the bars of the rocker table an shaped them accordingly.

[img_assist|nid=1054856|title=creating concave by sanded poplar profile on each of the rocker table bars|desc=|link=none|align=left|width=640|height=480]

A look at the tail to check if the poplar rail frame fits to the bottom/ribs before gluing them together










Cool project.  I’ll be interested to see how it turns out for you.    


You probably already know this, but if that is XPS foam and not EPS you might want to drill a few holes in each rib to allow air to pass through from one chamber to the next.  XPS doesn’t breathe, leastwise not in a good way.  

I like the concept of translating curves from the outside frame.  It reminded me of when Bert showed adding the bottom contour templates when he bagged.  Thanks for sharing.

Gdaddy, i’ll definitly drill some holes in, forgot to do it before i glued the ribs on. Speaking about the ribs, they seem to be quite heavy as well, probably the holes help to keep the weight down. I guess I could have used some thinner XPS foam, like 2cm or so, it makes a really rigid impression.

Here’s like i’m going to clamp the rails for gluing them to the ribs and the bottom. I’ll use the same method to clamp the deck skin on later:


Just attached the rails to the bottom and the ribs. can’t wait till the glue sets…[img_assist|nid=1054957|title=attach the rails|desc=|link=none|align=left|width=640|height=459]

Great project. So all the longitudinal stiffness comes from the rails and skins?

thanks for your comments. concerning your question, Rikds: Yes, I’m planning to have no stringer. I’m not shure yet about the glassing schedule.

On my traditional hws I did one layer of 50g/m² cloth, which is around 2oz. At this project I’m going to have a big patch in the “stepping” area on the

inside of the poplar of probably 2oz, and probably 80g/m² (around 3oz) on the outside. What do you guys think?


2 layers of 2 oz would do the trick. any update?

I added some EPS blocks for the fcs-plugs that I will install later.

[img_assist|nid=1055208|title=eps blocks for fcs plugs|desc=|link=none|align=left|width=640|height=480]

Hi Florian

EPS is not very strong to take the loads from fins. I know that FCS plugs are supposed to be attached to the top skin by a plug of resin but in my experience (which is small compared to many on this site) you would do better with a higher density foam for the fin installations. I have repaired a few fin plugs in EPS cores boards and the best solution was always to install a high density foam or balsa block to take the fins.

Just my view and I’m no God of boardbuilding. Still a great project, I am really tempted.

Hi Rikds,

actually the fcs plug is going to be installed like in the picture below, i hope the drawing makes sense to you.

I drilled a hole with the wholesaw through bottom and xps. The round leftover piece is glued in again, but with an offset that allows the fcs plug to go flush with the bottom. To have enough strength, i also wrapped a few layers of glass around the round piece before gluing it in. hope this explains my idea, and also hope that the strength will be sufficient.

File attachments[img_assist|nid=1055219|title=fcs glue|desc=|link=none|align=left|width=640|height=265]

a look at the bottom with the holes for the fcs plugs, which aready have the leftover pieces of the holesaw glued in



i already installed my selfmade leashplug, witch might be a bit unconventional at this stage of the build, but i thought it might be stronger if the final poplar deck skin is glued over the curb of the leashplug and holds it at its place. excuse my rough german english btw.

[img_assist|nid=1055221|title=selfmade leashplug|desc=|link=none|align=left|width=640|height=506]

Nice project!

I think the fins will be fine but you may be over thinking the leash cup.

It would be a drag if it broke or leaked.

Good luck,