6           Shaping the board

The act of board shaping conjures up images of tanned, blonde dudes hanging out in shaping shacks in Maui.  It is thought of as a black art that needs years of practice and experience.  There is no doubt that skilled shapers can knock out a surf board in next to no time, and have finely honed techniques that mean they avoid high and low spots in the complex compound curves of a board. 

In considering how to go about shaping a board, I can honestly say that this is the most useful application I’ve had from my degree in Pure Mathematics (cheers for it university maths blokes).  The approach here does not need any deep maths, but in defining the process it was defo useful!

The key to my mechanical process for shaping is to make scale drawings of the cross section of the board at each 15cm station.  Once you have a scale drawing, you can work out how to cut slices of foam off the edge of the board at 20 and 45 degree cuts.  Don’t worry if this seems overly complex, it will become clear through the detail.

First, for preparation, take an old breakfast cereal box and cut two triangles.  The first needs to be a right-angled triangle with 45 degree corners (check out the math language).  Make the short sides of the triangle about 15cm long.  The second is also a right angled triangle but this time with internal angles of 70 and 20 degrees (insert pic here).

Now, take your design sheet, a bunch of A4 paper, some nice sharp HB pencils, your cereal packet triangles and a 30cm rule, and retire to your kitchen table.  Pick a time when the house is empty and you can get some p&q.  Make some tea.

For each 15cm station, you want to sketch out one half of the cross section of the board, i.e., from the rail to the centre.  You can do this because you know the width of the board, the depth of the board, and the rail profile, which can be transferred onto the A4 paper.  (insert pic here).

Now, draw two further lines that represent the excess EPS foam.  Use the 45 degree triangle to mark off the 45 degree cut that can remove excess foam, and the 20 degree triangle in a similar manner.

Transfer all the 45 and 20 markings to one side of the top of the board at each 15cm station.  You will notice that they do not form a smooth line along the length of the board, so you have to use judgement and a keen eye to join the dots.  Once you have smooth lines running the length of the board, transfer the curves to the other side of the board.  Then, measure the distance of each line from the edge of the board and work out the distance down the edge of the board that the 20 and 45 cuts will make.  Mark out the 20 and 45 degree cut line on the edge of the board and join the dots with your 30cm rule.

The picture shows the 20 and 45 degree cut lines on the speed board.  Note that I’ve also marked the edge of the rail – that’s the red line in the bottom of the picture.  I’m making a 20 degree cut first , so I’ve run cheap masking tape along the 20 cut lines to stop the hot wire cutter straying into foam that I don’t want to remove.  I’ve also run drafting tape along the wide point of the rail to protect the foam there.

Now take your small hot wire cutter and set it to cut at an angle of 20 degrees.  Use your cereal box 20 degree triangle to set the angle of the wire.  Run the hot wire along the drafting tape.  Once you have finished your cut, don’t discard the foam that has been cut away – hold it in place with drafting tape, as you need this foam to support the hot wire cutter as you make the 45 degree cut.  Place cheap drafting tape along the 45 degree cut lines, and reset the wire cutter to cut at 45 degrees.  Run the hot wire cutter along the 45 degree cut lines.  Now you can remove the excess foam and you should end up with something like this.  Lordy, one side is starting to look a bit like a board, but you wouldn’t want to wrap your foot round that rail.

Repeat the operation on the other side of the board, and you find yourself half way through the shaping process.  Note that I’ve not taken the hot wire around the last 30cm of foam from the tail and nose – this is best shaped by hand.

The rest of the shaping process involves knocking the sharp corners off your board, so load the 10” sanding board with 60 grit paper (or 120 grit if you are naturally cautious and/or doing this for the first time).

When you are sanding back the hard corners of the board into a nice smooth curve, try not to concentrate too much on one area, but progress up and the down the board using long strokes.  Take your time, and use your hands to find any high or low spots.  In the picture, you can see that I have shaped one side of the board.  The trick is to try and knock off the corners one at a time and then spend an hour ironing out your high and low spots.  A couple of fluorescent lights are useful for finding imperfections.

Once you completed one side of the deck, move to the other and do the same.  If you start to lose sight of your centreline, take the time to remark it.

When the deck is finished, turn the board on its side and shape the curve of the bottom of the rails.  This is a lot easier than it sounds, just take your time and use 120 grit paper.  Make sure you don’t take foam off the wide point of the board.

Here is the speed board post- shaping.  She’s looking good.