Bases, edges, and nose/tail spacers
The base, with edges, defines the final shape of the board. The edges are used as a guide when trimming the board out after lamination. The nose and tail spacers serve the purpose of sidewalls on the nose and tail past the effective edge.
A length of base material is cut off of a roll just a little bit longer than necessary, then the actual base shape is cut on the CNC machine. The base is cut 2mm smaller all the way around. This allows the edge material to define the final shape for the base. The base is cut with a 1/4″, two flute, straight cut bit that we reserve only for cutting base and nose/tail spacer material. This keeps it sharp, which yields a better finish on the cut base material. I use one of two base materials: ISOSPORT 7500 or ISOSPORT ISOHIGHSPEED 2112, both of which are black, sintered PTEX. The ISOHIGHSPEED is a race base with 10% graphite proven to be consistently faster over the many years we’ve been testing with these two materials.
There is always a little bit of “fuzz” around the edge of the base, left by the cutter. I’ve never found a cutter that prevents this. I remove the fuzz with some 320 grit sandpaper attached to a small wood block. It knocks the fuzzy off easily without changing the shape of the base.
Edge material is steel. It has a Rockwell hardness of HRC 48, which is the industry standard. I have some edge material that is pre-cut in 84” lengths and sandblasted at the factory for bonding. This is a good length to work with for boards up to about 185cm long, depending on the shape of the board. For boards longer than that, I cut edge material from a continuous roll of material that is raw and untreated for bonding. I then sandblast these edges using a small sandblasting rig that I can setup in our shop when needed.
I’m pretty anal about good surface preparation on the edge material, so I check over both types of edges very carefully and mark any places that could use improvement, then send them through the blaster again for any necessary spot touch-up. I then make sure to only work with the edges while wearing gloves to ensure I don’t contaminate the surface with any oil from my skin.
I use a 60 grit aluminum oxide blasting media. It takes about 10 minutes to blast a single length of edge material.
Edge bending and tacking to the base
Next, I bend the edges to match the base material perfectly. I start by running the ends of the edge through a modified ring roller, then finesse the rest of the bending by hand. Any excess edge past the centerline of the board is trimmed off and filed. Once the edge fits perfectly, I clamp it down and tack it temporarily in place with cyanoacrylate glue (Super Glue). When the board is laminated, epoxy provides the final bond between the edges and the base material, as well as to the rest of the laminate.
This part of the process is fairly painstaking. Sometimes it goes quickly, but often it takes about 2 hours to edge a base completely, including drying time on the glue.
The super glue doesn’t bond immediately like you would expect. It takes about 20 min for it to dry and hold the edge on, but once it does dry it holds extremely well.
Nose and tail spacers
I use PTEX for nose and tail spacers. This extra material is needed along the perimeter of the core at the nose and the tail. It serves a similar purpose to the PTEX sidewalls, namely to protect the core over time. This material comes to us on a roll, sanded and flamed on both sides, ready for bonding. I cut it to shape on the CNC machine so it matches the core perfectly, and temporarily hold it in place with small pieces of a thin tape made mostly of paper. I leave a little more room on the nose and tail for PTEX than we do on the sidewall mostly because the board is thinner up there, and takes a little more abuse.
Note: some others have had trouble using tape like this. The tape does remain inside of the laminate, and I’ve never had a problem with that. But some people have used similar tape as me and had it cause small bubbles under the top sheet. Alternatives to holding these pieces on include staples just outside the laminate, an extra step to laminate them on with a light weave of glass, etc.