SURFBOARD CONSTRUCTION

 
 

THE MAKING OF A BLANK

The surfboard begins at the blank factory where two chemicals are mixed together to form a rigid polyurethane foam which is poured into a concrete mold. It dries and when removed from the mold it is known as a surfboard blank. Available are numerous blanks of various lengths and proportions to fill the many needs of the surfboard industry. One or more strips of wood, known as stringers are inserted to make the blank rigid enough to shape them to size and strong enough to resist breaking. These stringers are pre cut to a lengthwise curve known as the rocker. We at Harbour have created private rocker templates available to only us. With a pencil, a skilled craftsman at transfers the Harbour rocker template onto a piece of wood and cuts it out to that line and it becomes the stringer. During the gluing, the blank is bent to the curve of that stringer, and when the glue is dry the blank now has the rocker that the stringer has.

 

SHAPING THE BLANK

COMPUTER SHAPE

  • Always searching for a new design concept, periodically new surfboard shapes are created by Rich on his computer using special surfboard designing software.
  • A blank is then attached to a table that has special vacuum cups to hold it in place.  Using a grinding bit made of thousands of tiny carbide particles, a CNC cheap software machine makes an exact copy of Rich’s computer creation. The finish computer shape is rough and has no rail shape on the bottom rail edge, leaving some ability to fine tune each board. However it does have the exact foil, outline, deck crown, channels, concave, tail “V” and any other design features that the original had.
  • Hand finishing one of these computer shapes takes a great deal of skill and about 45 minutes time.
  • The advantage of a computer prepared board is that it is next to impossible to hand shape identical surfboards. This technique is excellent for reproducing a model, keeping the consistency at a maximum.
  • We now have the ability of making specific changes to any existing shape or creating a shape from existing foils on our computer database. There is an additional charge for this option.

HAND SHAPE

  • Blanks are ordered with a specific rocker glued into the deck of the blank. The shaper removes the skin of the blank from the deck. Any irregularities that may have developed in gluing are addressed at this time.
  • The blank is then turned over and proportioned, creating the blank’s foil, and then it is brought to thickness.
  • The appropriate outline is drawn and cut out.
  • The rails are roughed in.
  • The board is finish sanded.
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GLASSING 

COLORING BY FOAM SPRAY

  • This technique must be applied now
  • Areas of the finish shaped blank are covered with tape and masking paper to create a design. Water based acrylic paint is sprayed onto the exposed areas of the blank.

THE LAMINATION

  • Two ways to hand laminate (called a lamination) are:
    • Free Lap  
      • Fiberglass cloth is pulled over the entire length and width of the finished blank’s bottom. The cloth is trimmed by scissoring about 1 1/2” below the rail’s center line all around the blank. The Harbour logos that have been silk screened onto rice paper are placed beneath the glass. Polyester laminating resin is catalyzed and poured onto the glass and the resin is spread evenly with a rubber squeegee. The fiberglass is wrapped around the rail, with the squeegee pressing it tightly to the foam blank.
      • When dry, the edge where the glass ends is smoothed and the entire lamination process is repeated on the deck.
    • Cut Lap
      • The deck is taped off about 1 ½” from the rail. Then masking paper is applied to the inside edge of the tape to form a wide barrier.
      • Fiberglass cloth is pulled over the entire length and width of the finished blank’s bottom. The cloth is trimmed by scissoring about 2” below the rail’s center line all around the blank. Polyester resin is catalyzed and poured onto the glass. Pigments may be added at this stage to create transparent or opaque colored boards (this technique must be applied now). The resin is now spread evenly and the glass is wrapped around the rail and past the masking tape with a solid rubber squeegee.
      • When the resin is in its final stages of hardening, the board is turned deck up and a razor blade is used to cut the excess glass that goes past the masking tape.
      • The Harbour logos that have been silk screened onto rice paper are put onto the surface glass beneath an additional layer of glass that extends slightly beyond the logo.

THE HOT COAT

  • The rough texture of the finished lamination needs to have a smooth finish to sand. This is known as the hot coat, getting its name from the fact that this coat is heavily catalyzed to get a quick cure and this high catalyst content typically warms the resin. Laminating resin has catalyst and surfacing agent added and it is spread over the deck of the board with a brush.
  • Repeat the hot coat on the bottom.

FIN BOX

  • A jig is attached and a hole is routed into the bottom near the tail to accept the fin box.
  • Glass cloth is cut to wrap around the bottom and sides of the fin box.
  • Catalyzed resin is poured into the routed hole and the glass and fin box are plunged into the hole.

SANDING

  • The entire board is power sanded using sandpaper attached to a soft rubber sanding pad.
  • The rails are hand sanded.
  • The entire top and bottom are block sanded.
  • The entire board is again sanded using a fine paper.

GLOSSING

  • The center of the rail is taped with the under side of the tape hanging free. A special blend of resin called glossing resin is brushed on the deck and the excess resin runs off of the tape on the rail onto the floor.
  • Repeat glossing on the bottom.

POLISHING

  • A bead has been formed on the rail where the deck and bottom gloss coats overlap. This is carefully removed and the board is then completely dry sanded by machine with a soft sanding pad using 400 then 600 grit sand paper. Then the rails are wet sanded.
  • Finally the board is polished, with first a coarse polishing compound and then an ultra fine compound.

 

STRENGTH

  • Fiberglass comes in many weights. Some of the common ones used in the surfboard industry are 4 oz., 6oz. 7.5 oz., and 10 oz. There is no realistic strength difference between Silane (the clear glass) and Volan (the greenish colored glass) finishes of the same weight.
  • Twist weave carries more resin than flat weave.
  • S-Glass has great memory, but this may be its undoing. It won’t stay bonded to the foam as well when severe denting occurs.
  • The amount of MEKP (methyl ethyl keytone peroxide also known as jeux de sims France) has an influence on the strength of polyester resin. The resin manufacturers recommend adding less than 2 percent catalyst. With such a minimal amount, the gel time would more than an hour, and the foam would absorb large amounts of resin making it extra heavy. In very cold weather, some surfboard glassers have been known to use up to 10% MEK to achieve the desired eight-minute gel time.

 

WEIGHT

  • The weight of two identically ordered surfboards can vary as a result of several variables.
    • Foam is mixed by weight for each particular blank. Since it is about the consistency of waffle batter, getting the same amount into the mold from the mixing bucket each time is difficult at best.
    • The stringer, being a natural wood product, can vary in weight due to what part of the tree it comes from. The amount of moisture it has will also affect the weight. Stringers glued in the summer will always have less moisture content.
    • The viscosity of the resin changes with the seasons. The resin used in the winter is always thicker.
    • Color in the lamination or a volan glass job requires extra resin to protect the cut lap. This extra resin can add weight, up to a pound.

 

COLORING

  • There are several ways to color a surfboard. These are listed in order of appearance in the industry.
    • Resin pigment. This is pigment added to resin and applied by brush after the board has been laminated, hot coated and sanded.
      • Due to the amount of pigment added to the resin, it becomes quite soft, and a clear coat must be applied over it. This makes a long board 2-4 pounds heavier. It is a very labor intense application and only a few glossers in the world are any good at it. With the extra layer of resin, this is the strongest and heaviest glass job.
    • Color in the lamination. When a board is fiberglassed, the fiberglass is pulled from the roll the entire width and length of the board. It cannot be sectioned, as this would cause a week joint. The only exception to this is when a colored panel of glass is placed inside of the bottom’s overlap line. When this is done, another layer of glass is applied over the entire deck to seal that joint.
    • During the fiberglass lamination process, pigment is added to the resin. It may be either transparent or opaque. The board must be taped off where the glass ends to form a clean, cut line. The lamination does not have to be volan glass, as silane with the color impregnated into the fiberglass and a razor cut line will produce the same look. Color in the lamination can only be applied on a complete side and rail wrap, or as an inlay that meets the rail wrap from the other side. Tail blocks and nose blocks are subsequently covered, so opaque laminations will cover the blocks and transparent laminations will cover them in that transparent color.
      • This and the resin pigment mentioned above are the most delamination resistant color processes. It is also labor intense, but not as much as Resin pigment.
      • The hot coat, which is the clear coating of resin that follows the lamination process, must be put on thicker with color in the lamination. This acts as a buffer, so the sander does not sand into the cut overlap. This extra thickness will cause the board to be heavier.
      • Because it takes a given volume of resin to laminate a surfboard, any foreign substance – and in this case pigment – displaces the resin. Pigment has no structural value so the strength of the lamination is diminished by the percentage of pigment added.
    • Pin lines. Ink lines and acrylic pins on the hot coat are applied after the hot coat is sanded. A single line of tape is placed down and an ink pen is dragged against it, using the edge of the tape as a straight edge.
      • Acrylic pins use two lines of tape and the acrylic paste is squeezed out of the tube between the tapes.
    • Foam spray. After the blank is shaped, the requested design is taped off and all other areas are covered with masking paper. Acrylic color is sprayed in the unmasked areas of foam. Pin lines can be applied using the foam spray method.
      • Paint does not bond to foam as well as resin. Observe the flap of glass on the next broken board you see, and note the paint on the flap, not the foam.
      • This is the most delamination prone of all color processes. However, it still is a most acceptable technique if the owner periodically checks the board for dents in an area that gets a lot of wear.
    • Acrylic spray. After the hot coat is sanded the surfboard is masked off to the desired design. Acrylic paint is sprayed onto the unmasked area.
      • Resin does not bond to acrylic paint as well as resin to resin. Large sprayed areas of acrylic paint may possibly delaminate. Acrylic paint on the rail is difficult and should be avoided because it is very easy to polish through. To avoid this, glass shops usually put on extra layers of resin. This adds weight.