Looking good there Paul! 
Will the tail be deeper once the tailblocks are added? What will the finished tail span be? Tail at 12? Looks INSANE!!!
Looks great Paul,cork or balsa rails?ILL send coat next week been busy with holidays and getting My daughter up there, moving in the snow good timing. KP
how long is it?
You asked for it…The link below has pictures to accompany the text… Building even the simplest hollow wood board takes significantly more time, skills, and patience than the most complex foam /fiberglass board …The time to build a hollow can take weeks or even months… The tools needed to build a hollow are what a cabinet shop usually has…Table saw, stationary planer, routers, belt sanders…etc… An understanding of wood’s properties and its tendencies to move are also required…Also, there is a need to be open to materials not specifically designed for surfboards… The number of steps to make a hollow board are many…Foremost is the planning of how to create a blank from thin flat wood…It requires a vision, and a plan with flexibility to make the complex form take shape…It requires getting the right materials for the specific task … understanding the differences in selecting the right adhesives for specific tasks…It requires cutting the rough parts to precise pieces…A typical hollow board has over 300 pieces…It requires sensitivity with the tools, where one mistake can and will ruin weeks of work…It requires patience beyond belief…It requires a mastery of the process…With the ability to adapt to minor crisis’s and be open to new ideas and materials… The board you choose to build should be a design you like…For a first board, I’d recommend a simple planshape…One with a more pointed nose, as opposed to a round nose…Similarly, I’d suggest a round pin or square tail…A fully rounded nose or tail is considerably more difficult when it come time to put on the rails… Templates You’ll need a couple of full size templates…A ½ board planshape template and a full size rocker template… The planshape template can be transferred from an existing board by tracing onto a piece of 1/8” plywood, cardboard, or heavy paper…Or you can plot your own template with numbers you create… The rocker template is created by laying the board to be copied on a flat surface, top up… You’ll need to be able to look under the board so having the board on the floor won’t work…A flat work table is needed…At least as long as the board… Make sure the fin(s) don’t contact the flat surface…Get a piece of template material (1/8” x 6” x board length plus a couple inches) and measure the length of the board and put that length on the rocker template…Next make perpendicular pencil marks on the template, measuring from each end at 12” increments…These will represent where the cross ribs will be…I identify each of the ribs with a name – N-12 would be the rib that is 12" from the nose…T-36 is the rib that is 36” from the tail…It helps to keep the parts separated… They will look similar so it helps to keep things simple… Next go to the reference surfboard, and make the same 12” from each end measurements on the flat surface the board is on… Use a square to locate the nose and tail…I sometimes use a long piece of masking tape to put the marks on…Write on the tape the rib names (T-12 …N-24, etc.)… Next, holding a ruler look under the board and measure the bottom rocker of the reference board at each of the 12” marks…Write them down…Be as accurate as possible… Transfer those numbers to your rocker template…Measuring and marking carefully…Next connect those dots with a flexible strip of 1/8” plywood…Smooth is important…Take your time to get it the way it needs to be… Next, with calipers measure the thickness of the reference board at the 12” intervals…Write them down…Before you transfer those numbers to the rocker template, you’ll need to subtract the thickness of the top and bottom skins that the hollow board will have…Remember right now you’re making an interior part…You’ve just measured an exterior surface…There’s a difference…. I usually figure the deck and bottoms to be each 3/16” thick…Combined that’s 3/8”…So if you subtract 3/8” from your reference board thickness measurements, you’ll have the measurement of the hollow boards stringer…Now you can transfer those numbers to the rocker template…Again you can connect the dots…Mark the nose and tail with perpendicular marks to the straight template edge…This is important…Looks good…???..If not take the time to smooth out the lines… Getting back to the planshape template…You’ll need to adjust the width of the template to account for the built up sub-rails and finished rails of the hollow board…You’ll need to allow 1-1/2” for the finished rails, and ¼” for the sub-rail…So you’ll need to subtract 1-3/4” from the outside edge of the planshape template…Make the necessary compensation and your ready to do some cutting… Now that you’re ready to cut out the templates, congratulate yourself for getting this far…The 1/8” plywood cuts well with a SHARP utility knife…A jigsaw works well, too…I use a knife…Make the cuts on both templates then clean up the contours with a sanding block… Your rocker template is now your stringer…There’s more to do with it later… Smile you’re on your way… Gluing Forms Gluing Forms are needed to provide a mold for the rails to be bent to, and to keep the stringer and ribs aligned during construction… You need two pieces of 1/4" plywood that’s the size of your board…Trace your adjusted planshape template onto both pieces, then cut them out… After they’re cut out, make sure they are both identical…Sometimes it helps to flip one on top of the other and belt sand the edges to make sure they are the same… Take your time to get it right… With these two identical pieces, drill 2” holes at 6” o/c. along the outer edges…The hole centers were 3” in from the edges…The purpose of the holes is for clamping the rail strips to the forms. Next, cut some 4" x 3/4" plywood blocks that will be used to make the gluing form onto a surfboard shaped “box”…Space the blocks about 3 or 4 " apart and fasten them to the plywood with nails or screws…Keep the top and bottom pieces aligned vertically… -------------------------------------------------------------------------------- Interior Ribs The interior stringer you made when you were doing the templates…The cross ribs are also 1/8" Lauan plywood. Next get the Gluing Form and make a straight pencil line, on one side of the gluing form, it doesn’t matter which side, from nose to tail …Next get your stringer and transfer the cross rib locations to the gluing form… Make perpendicular pencil lines all the way to the rails at the cross rib marks…This is where the cross ribs will be. The cross ribs are cut from 3.5” strips of 1/8" Lauan plywood…Each rib was cut to width as indicated on the gluing form…Then ripped to height as measured from the stringer… Each rib is different… Mark on each rib it’s location so as not to confuse it with a similar one…T-36, N-24, etc… Where the ribs attach to the stringer, lay out on the stringer an area that would allow a rib to be inserted diagonally though the stringer’s webs then rolled vertically to lock it into place…Look at the picture of the parts at the top of this section… The webbing of the stingers and ribs is 1/2”… Cut away the stringer and rib’s excess plywood carefully with a sharp knife, or a jigsaw. This significantly reduces the weight if the framework. On the center of each rib cut notches that are the depth of the webbing of the stringer. These aren’t notched yet… Next, the stringer is reinforced with a layer of Carbon Fiber/ Epoxy to significantly strengthen the stringer… I only lam the stringer with Carbon Fiber, the ribs only hold the rails apart until the deck / bottom is on…I’m not looking for any real strength there… I lam the stringer after I’ve done the webbing cutouts…Put masking tape on the other side of the stringer that you’re laminating…It helps to keep the other side clean…I like to wet out the wood stringer with epoxy then lay on the cloth, then fill in with more epoxy on top of the cloth…After the epoxy has gelled pretty firm but not rock hard, it’s easier to cut away the CF from the cutouts and edges…When you’re ready to do the other side of the stringer, again use masking tape on the down side… Finally, on the bottom Gluing Form are small blocks of plywood… The blocks hold the stinger and ribs temporarily in position. The blocks are attached with hot melt glue… Add blocks under the cross ribs at the rails, to keep the ribs aligned…This helps to keep the frame from twisting… -------------------------------------------------------------------------------- Gluing the Interior Rails The interior rails are strips of 1/8” Lauan plywood or 1/8" Bending plywood if the template is more curvy…The strips are about 4.5" wide…They need to be wide enough, so that when you lay your stinger on a strip, the stringer doesn’t extend beyond the wood strip…Just make sure it’s wide enough… Two wood strips are coated with yellow glue, laid together then clamped to the gluing form…The clamping starts mid-board and proceeds toward the nose and tail… The next day, after the glue is dry the clamps are removed…Then the glued rail is loosened and removed… The gluing procedure is then repeated on the other edge of the Gluing Form. -------------------------------------------------------------------------------- Attaching the Rails Get the gluing form…Have it block side up…Attach a small block of wood under the top edge of the gluing form extending at least 1" beyond the rail line…This is to keep the rails from dropping while you’re working… Get your stringer and cross ribs…Put them in place, on the blocks of the gluing form…You’re ready to attach the rails to them… Apply Hot glue to the vertical edges of the ribs where they contact the rail…Do only one edge of the board at a time…Clamp the rail to each rib… Allow the glue to set firmly… At the nose and tail cut off the excess rail to allow the other rail to be glued to the ribs. Repeat the gluing procedure on the other edge of the board. -------------------------------------------------------------------------------- Router Guide Strips To cut the excess rail material from the frame, router guide strips are attached between each rib at both the top and bottom…The router guide strips are 1/4” x 1/2"” plywood strips…Hot Glue each strip in place… Remove the framework from the Gluing Form. With a 5/8” drill bit, drill a hole through the rail between each of the router guide strips. Using a pilot bearing flush trim router bit, remove the excess rail material from the top and bottom. On the inner rails, drill out the excess material with hole saws… -------------------------------------------------------------------------------- The Deck / Bottom Skins I use a variety of woods for the finished deck / bottom skins…Balsa, Basswood, Cedar, Douglas Fir are all light, strong enough and are comparable in sandability…The wood strips are planed to 1/8” thick and vary it width from ¼” to 2 ¼”… A typical board might have 30 strips per side… I arrange all the wood strips top side up on a large table… With good quality masking tape, starting from the center of the board, I use the tape to “tie” one strip to the next…I put tape pieces on perpendicularly from one strip to the next…About every foot…Good quality tape has some stretch, use it to your advantage…It works great…You’ll figure out how much tension to use in a short while… After the perpendicular tape strips are all on. Tape over all the wood seams lengthwise…The reason for this is you don’t want epoxy draining through, and gluing your deck / bottom to your work table …I learned this the hard way…You’ll easily go through a full roll of tape per side… After all the taping is done, carefully flip the deck / bottom over, so that it’s tape side down…You are now looking at the surface that you’ll laminate with the Carbon Fiber and epoxy… I put one layer of CF on the bottom and two on the deck…In the future I’ll add a 2" strip where the stringer makes contact with the deck / bottom skin… To attach the deck / bottom skin to the frame, I use a heavy duty construction adhesive from a caulking gun…Run a bead on top of the ribs, stringer and rails…Carefully lay the deck / bottom skin on the frame, and use spring clamps to hold the skin to the rails… Let the adhesive set up firmly before removing the clamps, overnight is good… Use a flush trim router bit to remove any deck / bottom skin overhanging the rails. Repeat procedure on the other side of the board. -------------------------------------------------------------------------------- Building out the Rails The rails are built out to a thickness that allows for a shaped rail. It requires multiple layers of sheet cork and thin bendable plywood. A 4’x8’sheet of 1/8” plywood and a 4’x8’ sheet of 3/16" cork are cut to 4” strips. One sheet of each is needed per board. The first layer and all subsequent layers are attached with industrial strength contact cement. For aesthetics, I like to alternate between cork and plywood layers, for interesting contrast… The strips are attached starting at the nose then working towards the tail. Subsequent strips are overlapped, allowing for a stronger rail. Multiple layers of cork/plywood are applied until the final rail thickness is about 1.5”. Use a flush trim router bit to remove any of the rails overhanging the deck and bottom. Sometimes I’ll add a tail block or wedge… -------------------------------------------------------------------------------- Shaping the Rails The shaping of the rails is done with a belt sander with a 36-grit belt and hand sanding blocks… Before shaping the rails, put on the outer edge of the deck/bottom one or two layers of masking tape as a guard against sanding into the finished deck/bottom… Hold the sander parallel to the rail and move the sander horizontally in long smooth strokes. Don’t work on one rail too much. Stay smooth. “Screen” the rails with a 50 grit-sanding belt. Sand the deck and bottom with an orbital sander followed by hand sanding parallel with the grain of the wood. Progress through the grits finishing with 220 grit. Look carefully for cross grain scratches. -------------------------------------------------------------------------------- Fiberglassing . Following sanding, the board is covered with 4oz. fiberglass cloth Due to the inconsistency of polyester resin to bond with wood, Epoxy resin is always used. One layer of fiberglass cloth on the bottom and two on the top and are adequate. I use polyester resin for everything after the lamination… -------------------------------------------------------------------------------- Now that it’s done The Ride The finished boards are eye candy, but the true pleasure is in the ride… Wood boards typically feel heavier on land, but surf lighter than they feel…The hollow core is the reason…A typical hollow board can be made at least ½” thinner and still float the same as a foam board…The weight of a hollow wood board results in a board with more drive…A momentum that catches waves easily and carries well down the line, through flat spots… The hollow core and tensioned skins of a hollow allow for an efficient energy transfer between the wave and the rider…The feeling of the wave is amplified on a hollow…The tension built into a hollow results in a more alive feel…a better transfer of power … Then there is the strength …With a carbon fiber/epoxy re-enforced framework and inner skins, a hollow is stiffer than a foam board…Similar in feel to a chambered balsa, but more alive…With thin re-enforced skins there is a significant resistance to denting… As incredible as they look, they’re built to be ridden…They are not intended to be wall hangers, unless the wall is 6’ of moving water… These boards are a stretch for me …Starting with flat plywood then finishing with the board I now have, is gratifying…I knew I would end up with something, but again, this surpassed my expectations… I’m going to continue exploring the hollow wooden boards for a while, it’s fun to push boundaries. -------------------------------------------------------------------------------- Send e-mail to: http://www.hollowsurfboards.com/howto.htm
“… They are not intended to be wall hangers, unless the wall is 6 feet of moving water…” I love that!!! http://www.hollowsurfboards.com/ 
The finished dimensions of the board will be close to: Length – 5’8” Nose – 17 ¼ “ Wide – 21 ½ “ Tail – 17 ½ “ Thickness – 3” Nose Rocker – 3 ½ “ Tail Rocker – ½” Finished tail span – 13” The deck is a “Domed S – Deck”… The bottom is predominantly flat, with ¼” Vee at the tail… The rails will be laminated layers of 1/8” sheet cork and 1/8” “Bending Plywood”… The fins will be “Rising Sun - Lis Template Fish Fins”… http://www.hollowsurfboards.com
Paul you’re one sick puppy.
paul that is insane, post a final pic of the fish soemtime!!! looks rad.
How much???Have you ever thought about a urethane clear coat ?or does the epoxy have a UV?
what is it laying on…a cloud?
Yea …a cloud of fresh powder!. BRRRRRR. Good job Paul. I spent about two hours over on your site the other night. I love engineered structural components. What a great concept. I will definitely try one as a project. It was 35 degrees here the other night and I thought I needed to live further south…say IXTAPA! I feel for you guys in the brutal north. Krokus
“How much???” …My costs for premium materials are about $30 a lineal foot… “Have you ever thought about a urethane clear coat ?” …Not only thought about it, but used IMRON as my exclusive finish coat on all my polyester boards…It’s expensive, tough, and shiny… “or does the epoxy have a UV?” …Resin Research and System Three’s SB112, are UV stabilized… http://www.hollowsurfboards.com