Build a Mako wide from scratch #1

[Lonny]

So here it is, I introduced this board in the blog. This board is sold by Ocean Rodeo as a strapped board, and it is a blast ridden strapped; different animal, nothing to do with anything else out there. Some wise kiters took off the ball-and-chain and waxed theirs up, and found it to be an even bigger blast without straps.

Let's make one! Out of wood!

This is definitely NOT a first project. The board has got a 3D curvature which does not allow to build it on a rocker table. But with the experience of a couple of boards done, you'll have fun to do this one. It's also NOT a quick project; in order to achieve the complicated 3D shape, we have to glue 1" (2.5cm) wide strips, pair by pair, for the width of the board, top and bottom. Before glueing the next pair, you'll have to wait a good 5 hours until the glue sets.

Anyways. From scratch.

We will need software to do this project. I recommend AKUshaper, which is a free software running under java and thus on all operation systems, and which can be downloaded here http://aps3000.com/ . Not that it is worse or better than other software (I don't know), but it's easy to use, intuitive, runs on all machines with java on them, and it's for free.

In order to create your board in AKUshaper, you get yourself a good photo of a Mako outline. If you want to know if it's a good photo, measure it and mirror it in photoshop or the like, and you'll know how good the photo is. Reason for this is, by using a wide camera angle, the curvature is changed quite a bit.

Download and install AKUshaper, and spend 2 hours of your time to run all the tutorials that are offered online. You need to understand how the software works, and there's quite a couple of really nice features you would not even think of.

Now, we start to create the outline of our board.
-Create a new board from their choice of boards, delete all the slices but the center slice.
-adjust the length of your board
-import the picture of the Mako outline "file/image board"
This results in the picture sitting behind the outline to create. Adjust your outline accordingly.

[tungsten]

Now that the outline is done, we need to do the profile. This is a cut through the middle of the board, following the stringer. The lower part is the rocker line, the upper part is the deck line.

We start with the bottom line (= rocker line). If it would be any other board, you would do the same as with the outline: search a photo of the board's profile, put it behind your bottom line, and adjust. Not with the Mako. The Mako has 3/4" (1.9cm) of concave in the middle, and some 1/2" (1.2cm) in the tips. If you look at the photo of the Mako profile, you would assume it has 3" of rocker in the tips. In reality and due to the massive concave, it has 2 1/4" (5.7cm) of rocker. You have to know some details of the rocker line, and therefore need a friend who owns one, and give you a hint. I found such a friend on the internet, and he gave me the rocker line measurements along the stringer, every inch. With the help of AKUshaper, you only need to know 2 things: rocker is 2 1/4" tip and tail, and the rocker curvature is a steady curve, close to a circle line. By pure chance I found a screenshot of my bottom line.

[tungsten]

Now that the bottom line is done, we go on to do the deck line. This is called "Top" in AKUshaper. We are designing our stringer right now.

Choosing the board's thickness, you decide upon the volume of the board, and the flex. More thickness is more volume, and less flex. I chose to stick with the original measurements. As I am using 1/8" (3mm) plywood to plank top and bottom, the stringer has to be thinner by twice that margin: I want the board to be 16mm thick, in the middle. The stringer therefore has to be 16mm -3mm -3mm = 10mm. You get the point.

Towards the tips the board is thinned out. My stringer was something like 10mm high in the middle, and 6mm in the tips. As you see, this is quite thin and fragile. I therefore chose to use a stronger plywood to do the stringer, 10mm (3/8") thick.

Congratulations, that would be your stringer! now we move on to do the slices.

[tungsten]

The slices are basically a cut through the board along the width, like chopping up your board into pieces. You create the bottom shape (which is a huge concave in this case) and deck shape along the width of the board.

In "Slices", we have deleted all preset slices but the middle one, and we have centered the middle slice. We adjust the middle slice using the known measurements (1/2" = 19mm of concave, and a constant bottom curvature, see pic). Once the middle slice is to your liking, you add further slices. The distance between slices is an important decision to make work easier. I chose 8" (20cm) between slices. Something between 6" and 8" should be a good measurement.

Choosing the right curves makes or breaks your board. As I mentioned, the Mako is a difficult one. It's a big help if you can study an original Mako to get the grip. I am lucky to own the slim version 150x34, which I used often as a reference.

[tungsten]

Now we've got a basic version of our board in AKUshaper. Wanna have a look at it? in "The bay" you can display a 3D picture of your board, turn it, change lights and shadows, and in general see if this is what you want to build. Check the tutorial for shortcuts, or just play with your keyboard.

[tungsten]

Now we're happy with the plans so far. Time to start building. Get your tools together, and a solid 160x50cm working table ready. I used plywood 3mm for the planks, 5mm for the slices and 1cm for the stringer; the glue is PU glue, like Gorilla glue; I used PU foam from the can, 4OZ E-glass, some nobrand epoxy (cheaper than the good West System stuff), fumed silica to thicken the epoxy, a sharp knife for cutting the 3mm ply in strips, an electric jig saw, a drill, sand paper in 40, 80, 120, 180 and 400 grit (120-400 for sanding wet!), loads of clamps, pieces of wooden battens of many sizes to support the construction on the table, lead and books and water bottles as weights. A couple of liners. That's basically it.

Out of AKUshaper, I print out the slices, outline and stringer in 1:1 size. AKUshaper allows to tile, so this is really easy.

I glued the prints on the ply and cut the slices and stringer out with a jig saw. You can use thinned white wood glue if you want to peel the paper off afterwards; or you just leave it on, it's all inside the board, who cares.

As we have a symmetric board, you can double the ply layer and cut 2 slices at a time. After cutting them, put them together mirrored and sand them to perfect symmetric shape.

Now you have to do the cut outs in the stringer and slices, in order to build the main skeleton. You figure that with the picture below. The wood is quite thin a fragile, so be careful. Once all is nicely cut out, glue it together, supporting it with the batton supports to keep everything in it's exact place. When you fark it up now, it will be really difficult to do corrections later. Tolerance is half of a millimeter. So before glueing, put it together without glue and adjust until you're happy with the result, then take it apart, and do all the same with glue as a last step. You will find you have to do many small corrections until everything fits.

[tungsten]

The main skeleton is ready! A big step forward. It's really thin and fragile still, but this is what we're going to build our board around. Now we cut the 3mm plywood in equal strips, a bit longer than the board, and 1" (2.5cm) wide. Use a long liner and a sharp knife. Bit boring this part, AC/DC and a can of stout helped me to get over it.

Start glueing the strips on the skeleton, beginning with the BOTTOM. We need to support the skeleton most accurately on the building table, using the supports as displayed in the pic above. Glue one pair of ply strips (left and right of the stringer) at a time, and clamp to the slices. Pay attention as the slices are thin and bend, make sure everything is in its most accurate position. With every pair of ply strips, the skeleton is gaining stability. Let glue set for at least 5 hours before going on to the next pair of strips.

I used a syringe without needle for glueing, 20ml. Works perfectly with PU glue. Fill it from the big can.

[tungsten]

Some pics of the bottom growing. Once the bottom is done, you want to think where you're going to have the holes for the fins, and maybe inserts for footstraps. I know how this forum is called , but with a Mako (and only a Mako), you might consider putting inserts in, for those 40kn days.

Around the inserts and fin holes, I beefed up the construction, using ply. Glued the inserts in place with epoxy & fumed silica (West System nº 406 colloidal silica), and got everything ready for the planks on the board top. Start glueing on the top planks, in pairs.

[tungsten]

Some pics of the side walls glued in, using 3mm ply cut to shape and stapled to size, and the top growing. Glue the side walls in pairs (left and right from the stringer), to keep symmetry of the board by not adding twist. When the side walls are in, you draw the outline to get an idea if you're within the margin. If not, add ply.

Before we close the board, we have to fill it with PU foam, so don't just finish the top yet!

[tungsten]

CHecking the bottom concave, looking good!

[tungsten]

Now this is an important one. In order to add strength, we will fill the board with PU foam from the can. PU does give a lot of strength, and it does expand with a lot of force. So you MUST NOT blow your foam into the board and rely on the excess to escape. It is REALLY important to put one tiny little bit of foam, like the size of a walnut, in each compartment (between slice and slice). It will expand to the triple of its size. Wait for 2 hours until the foam is dry, and add another tiny little bit.

If you blow in too much at a time, the foam will lift your top and bottom and destroy your board's shape. I did that mistake and had to cut out the foam with a long kitchen knife. Twice. The picture below is HOW NOT TO MAKE IT. Too much foam. WRONG.

Tell me how it went and how many times you had to cut yours out

[tungsten]

Now all that foam business is done, board shape still OK, and you have sanded exceeding foam to level and glued the last strip onto the board. the board is closed.

Congratulations! Another big step forward. Now we want to draw the outline on the BOTTOM of the board, and plane it to near shape.Save the last millimeter for sanding, that's more accurate. This is how it looks like by now:

[tungsten]

Sand the board, starting with the rail, then top and bottom. Work by hand, 80grit until perfect, then 120grit. Now you have a board with still some cracks in it where the glue was sanded off, but with a perfect shape. Nice. This is how it looks:

[tungsten]

And this is almost it! Glassing, drilling and filling the fin holes, the and we're done.

For the fin holes, we drill 12mm holes into the wood, in the accurate place.

As we still have cracks in the wooden surface, we want to make sure we smooth everything out nicely. Prepare everything for glassing as usual. But in a first step, you add 40ml of epoxy to 40ml of fumed silica, making for a nice pasty gooey glue. Squeegee on in a very thin film, filling all the cracks;

get on directly with laminating, first bottom with a wrapped rail. wait until hard, then turn the board around, fill the fin holes with epoxy & fumed silica, squeegee the top with epoxy & fumed silica mix, and laminate the top.

I put on 2x 4OZ bottom and 2x 4OZ top which is plenty. I won't go into the details of laminating, there are good tutorials out there, google for it.

Once the board is laminated, you have to wash off the anilin (an oily chemical which appears on the top of your epoxy surface as a result of moisture in the air) with warm water before adding the hot coat. I found a 2 stage hot coat avoids fish eyes: first step is a thin layer of epoxy & fumed silica, squeegeed on. Wait 1 hour and get right on with brushing on the epoxy for the hot coat. No fish eyes whatsoever

When the bottom hot coat is done, do the top. Finally sand your board WET with 120, 280 and 400 grit, or leave it shiny if you're happy with the outcome of the hot coat.

Drill the fin holes, put on a deck pad, and you're done!

Hope you enjoyed it, let me know how your board goes.

cheers, tungsten

some more pics:

[tungsten]

Some more of the Ghetto Shark

Material cost is around 60€, all in all. Don't count the hours though, it's a hobby And for you tekkies: It came in, foot pads and fins included, at 2.8kg.