It was love at first ride when I gave strapless surfboard a try. After spending a good chunk of my summer in 2019 riding a Naish Skater, I decided to make my own board. A number of folks at my local spot and at Hood River told me the Skater was not a great board to learn on since it was narrow and nimble especially for a big guy like me. I was definitely having trouble learning to swap feet. So for my board, I wanted to go big. I went wider, thicker and opted for a quad. I didn’t expect much for my first try at a surfboard but the Sensei Sebastian blew away my expectations and has become my main ride!
Specs
- Designation: BPXS-4 – Sensei Sebastian
- Length: 5′ 8″
- Width: 22″
- Thickness: 2 3/4″
- Core: EPS Foam
- Deck Glass:
- 4oz Warp Glass
- 6oz S-Glass
- Bottom Glass:
- 4oz Warp Glass
- 4oz S-Glass
- Resin: Resin Research 2000 CE Ultra Epoxy
- Hardener: Resin Research 2100S Slow Hardener
- Paint:
- Hand painted in Acrylic on foam
- Soundtrack Highlight:
- Chance the Rapper – The Big Day
- Lizzo – Coconut Oil
Building the Board
Step one was to lay out a template. My whiteboard material that I had used as the base of my vacuum bag on my previous board had taken enough damage that I decided to give it new life as template material. It was so nice to be able to draw out shape ideas and measurements that I’m probably going to use this material for all templates going forward. It’s only a couple of bucks more than masonite and a sheet will cover you for several different board ideas.
Cutting the template. 
Smoothing out the template.
Once cut, I smoothed out the template by clamping it into a vice to hold it vertical. This worked out well.
With the template cut, it was time to transfer it to the blank. I laid it out and found that the nose of my blank was a little too narrow for my template. I decided to roll with it and marked what I could. As long as it was symmetrical I was happy.
I cut the blank to the template outline with a hand saw, making sure to keep it vertical as I did. I then squared up the edges with a rail runner and skinned the deck with a planer. I worked on the tail and nose to get the rocker I was looking for. Once I was happy with the deck and bottom, I put in some concave. I used a small trim plane for the stringer then different stiffness sponges wrapped in sandpaper depending on what I was shooting for. A stiff sponge works better for removing material and a squishier sponge for light sanding. The bottom contours goes from flat to concave to flat.
Taking down the stringer for the bottom concave. 
Checking the concave.
Concave will help you grip the water and prevents the board from slapping especially when you’re going fast. My next step was to work on the rails however in retrospect, I think I’ll be doing the rails first and then add the concave later in future boards. Using the Fred tool in shaping the rails can gouge the bottom a little bit which you can smooth out when you are removing material for the concave.
For the rails, I went with guidelines I had found for knifey rails. I traced out the rail bands and then used a sureform to shape down to the first band. Then I marked out the midpoint on the edge created from the first band and then I shaped out the second band. I used a Fred tool for the bottom tuck and blended it all together with dragon skin. Then it was some light sanding to smooth it all. I had installed side lights in the shed and it was pretty amazing how much easier that made it to see uneven areas.
Marking the rail bands. 
Shaping first band. 
Shaping second rail band. 
Final shape!
With the board pretty much where I wanted it, it was time to cut the slots for the fin boxes. At first I tried to make my own jig but after a few attempts of trying to reinvent the wheel I cracked and bought the pro jig from Futures. It’s pretty pricey but if you plan to do this regularly, it’s totally worth it. On the upside, I happened to already have the Makita router that the jig is made for so I didn’t have to buy the super expensive kit (just the expensive one).
Cutting fin boxes with Futures jig. 
Fin boxes cut.
My plan for this board was to make it a quad. At the last minute, I decided to cut a center fin box so I can have the option of riding it as a quad or a thruster.
After cutting the fin boxes, I sealed the board with DAP Fast and Final spackling. This was mixed with distilled water to get it slightly thinner than toothpaste. It was a pain to work around the fin slots so for future boards I’ll be swapping those steps. Unfortunately I didn’t take any pictures of that step.
With the board sealed, it was time to paint. The board is hand painted with acrylic. I try to make my boards look like bananas but some of my markings were showing through the spackling, and primer so I made the green portion of the board come down a bit further than I had intended to cover it up. The result is not very banana like. Oh well, I also think Brazil is cool and I have no qualms with Green Bay.
Masking off green areas. 
Yellow painted 
Green painted
After painting the foam, I decided to paint the stringer black because the natural wood faded in with the other colors especially the yellow. The black stringer really pops and I dig the overall paint job.
Next step was to set the fin boxes. As I was checking everything out, I noticed that the center fin slot was very slightly off center. I tried to squint and cock my head to convince myself the only thing crooked was my head but it was definitely a pinch off. With an exacto knife, I shaved a bit of foam off the right front side until I could line up the fin with the stringer. To keep the fin box in place, I stuck a felt pad on the side of the box to push the box in place. It worked out perfectly!
Center box slightly off center. 
Felt pad stuck to fin box. 
Setting the fin boxes.
I thickened the epoxy to fill the fin boxes with cabosil. This will help it stick to the sides and will provide additional stiffness and strength.
Once the boxes were set, I taped them up to keep epoxy out of them during glassing. Then I taped off the deck so I could glass the bottom. I’ve seen folks only cover a few inches past the cut lap but after having done this a couple of times now, I would really cover it all up. Sometimes you get a long strand of fiberglass during glassing and you really don’t want to worry about where to stick it when you are doing the lap. I use masking paper to help cover the bigger areas and that works fine.
With the fin boxes taped and the deck covered it was time to lay out the glass. I cut ovals of leftover glass to reinforce each fin box. then covered that with the warp glass. Warp glass does not handle wrapping very well, it tends to come apart when you bend it so I wouldn’t use it on your upper layer. I cut it to the shape of the board and then layered on the S-Glass. This I cut down to cover the lap to the masking tape on the deck plus a couple of inches.
Taping fin boxes for glassing. 
Taping deck for glassing. 
Prepping fiberglass.
This was my first time glassing a surfboard and I had no idea how messy it was. My biggest mistake was that I did it in shorts and a t-shirt. Maybe this is fine for the pros posting videos of their awesomeness but for a kook like me this led to me learning the exfoliating properties of Orange Goop. Unfortunately, no amount of scrubbing could get the epoxy off of the hair on my knees and I ended up shaving my knees to give them a fresh start.
I waited about five hours for the epoxy to cure before doing the cut lap. I should have waited a little bit longer, the epoxy was still really tacky. It cut fine but I have found it’s a little easier if it has cured enough to not be tacky.
While cutting the cut lap, I noticed that there were spots that the epoxy crept under the masking tape and I pulled up the paint. The is the reason why surfboards have pin-stripes, to cover up the cut lap munching the foam. I wasn’t planning on pin striping this board so I touched up the paint.
Getting ready to do the cut lap. 
OHHH NOOOOO! 
Boo-boos repainted.
Before doing the deck, I sanded down the areas where the cut laps overlapped on the nose and tail. I learned it’s good to be aggressive in cutting the excess glass that will overlap as much as possible. The more that’s there the more sanding you need to do to flatten it out. I don’t feel I flattened this out enough at the tail but to the unknowing it looks like I meant to put in little lift to help out the kicker pad. Yeah, I totally meant to do that.
Glassing the deck went smoother than the bottom. This time around I wore a very fashionable Tyvek suit to save the skin of my knees. I also waited a bit longer to do the cut lap from the deck and the difference was noticeable. Sometime while the board was curing however I got a half dollar sized blister near the nose and another about the size of dime. I cut those out and repaired them before moving on. For the smaller one, I just filled it with some epoxy mixed with microballoons. For the larger one, I made a fiberglass patch. You can still feel a bump at that spot on the board but it’s been fine otherwise. My board just has a few birth marks.
Blister formed on nose. 
Cut out, and patched.
After glassing, it was time to apply the hot coat. For epoxy, that just means another coat. Since my previous board I had watched a ton of videos on this and picked up a few super important tips. The first is that between glassing and the hot coat, you should NEVER touch the board with your hands. I was very careful about this and only touched it with gloved hands. The oils on your hands create fish eyes that are a pain to deal with.
The other big tip was to apply the hot coat with a nice big brush, get it on nice and thick then walk away. In my previous boards, I had tried to apply it with a spreader which doesn’t let it get thick enough to pool. Between that and handling it with my oily hands and it’s no wonder I had found this step difficult. This time around the hot coat went amazingly well.
Taping bottom for hot coat. 
Taping deck for hot coat.
With board hot coated on top and bottom, it was time to move on to final sanding and polishing. In the course of sanding, you’ll sand down to the tape on the fin boxes to open them up.
Final polishing. 
Sensei Sebastian Haiku
The final step is to apply the traction pads and fins.
The Ride
The parallel rails, and quad configuration help this board rip upwind. The quad fins and width make it not nearly as nimble as some of the thinner thrusters out there but it’s a more stable ride. It does take some leg strength at times to get it in the direction you want but I have some beefy thighs. (I actually met the creator of He-Man once and he asked what I do for my leg workout!) Some friends have complained about quads they’ve ridden slapping the water, the concave on this one prevents that.
I have found that after riding my 18″ wide board, I had to get used to positioning my feet further up on this board during a water start. It can be easy to be too close to the edge which will put you off balance.
This board has done great from flat water to 4+ ft swells. My favorite session was a magical October day at Jetty Island where I had mispredicted the wind and found myself in 20+ kts with a 13.5 kite. I was determined to make it work and went blasting up and down the island. I would shoot upwind to control my speed and then let the wind blow me back while I took a breather. My friends thought I was crazy but it was a ton of fun.
On the other end, this board and my 17m have been some great session savers in the 10 kt range, allowing me to cruise around with the folks foiling while everyone else is packing it in. Overall, the Sensei Sebastian blew away my expectations for my first surfboard and has been my go to board ever since I finished it!
About Sebastian Smith
Every once in a while you meet a person who just makes you happy to know they are doing what they are doing in the world. Sebastian is one of those folks for me. A surfer and a sailor who found that kiteboarding offers the best of both worlds and so he took up kiteboarding instructing. Like a migratory bird, he goes to locations around the world following the wind and spreading the good word of kiteboarding. You’ll often find him at Jetty Island in the Summer and Costa Rica in the Winter months.
Because I signed up for a season pass of lessons, I got to spend quite a bit of time hanging with Sebastian at Jetty Island while I was getting started. He taught me what I know and taught me how to learn the rest. There are some folks who have the knack for teaching and Sebastian is definitely among their ranks. He’s super skilled, extremely patient and gets creative in finding what works for each student.
He’s learned to improve his instruction by really listening to his students. He realizes that insights that one student has while they are struggling is probably something another student needs. It’s an astounding skill that I wish more teachers were capable of.
The name of my imaginary board company comes from me feeling like the motion of water starting was like slipping on a banana peel. I’ll never forget him shouting, “You’re doing it! You’re slipping on a banana peel!” when I got my first water starts.
I’ll also never forget his parting words to me when he told me that kite is my teacher now. It’s so true, listening to what the kite is telling you is probably the best skill you can have to move to the next level.