taking removable fin systems to the next level

Creating superior boards with superior boxes.

Under-the-glass

Boxes are placed beneath the glass to ensure structural integrity and a watertight installation.

Adjustability

The system provides 3/8" of adjustment for precise fine-tuning, which greatly influences performance.

Strength

The system's design highlights strength in all areas. The elliptical shape enhances stability and efficiently spreads loads.

Easy Install

The box has a distinctive dam shape that makes installation easy, allowing the glass to drape smoothly over it.

Installation

Fin systems are commonly utilized with various construction techniques, and the routing system is designed to encompass all of them.

Critical information is provided here to help simplify the understanding of how the system is intended to be used.

There is only one installation methodology. This guide outlines the pre-lamination installation process and discusses the post-lamination (post-lam) installation process.

The routing system is a comprehensive tool that facilitates a successful installation. Thanks to the box's distinct shape, it features a unique capability for trimming down the box dam. The guide below provides additional information on this topic.

The installation guide discussed here is also available for download as a PDF file from the RESOURCES page.

Step-by-Step Guide

A guide through the entire installation process.

Preparation

Before the installation process can continue, we must ensure everything is on hand and ready.

Before the installation process can continue, we must ensure everything is on hand and ready.

For individuals, this begins with purchasing a STARTER KIT, as it includes everything needed to install the fin system. The kit provides all the parts mentioned in this guide. The starter kit does not include a router; we recommend using a trim router because they are easy to handle.

Other routers with wider bases will work, as guiding the router is managed by the router bit, not the router itself.

Preparation

This guide will use our Starter Kit as the starting point, containing everything needed.

This is an introduction to the parts that make up the routing system.

Almost any router can be used for the installation process. It just needs to be able to fit a 1/4" shank router bit.

If you use a Makita trim router, install the provided router base before setting up the router bit.

Before any routing can begin, the depth of the router bit needs to be correctly set.

NOTE: if needed, the depth gauge can be skipped in favor of the second step.

Before any routing can begin, the depth of the router bit needs to be correctly set.

The final step in preparation for an installation is to get the boxes ready.

WARNING: MAKE SURE THE SCREWS ARE TURNED DOWN BELOW THE DAM, SO THERE IS NO RISK OF HITTING THEM WHEN SANDING.

The final step in preparation for an installation is to get the boxes ready.

WARNING: WHEN COVERING THE SCREW HOLES WITH TAPE, ENSURE THAT THE TAPE DOES NOT EXTEND DOWN ONTO THE FLANGE. OTHERWISE, IT WILL BE LEFT UNDER THE GLASS AFTER THE DAM IS TRIMMED DOWN.

Layout

Fin systems are installed according to the shaper's preferred fin layout on the board.

The routing system allows for the precise positioning of the router jig on these marks. It must accommodate both side and center box layouts.

This section will outline the layout process.

Layout

As part of the setup the blank must have the shaper’s marks and fin layout lines for the desired setup.

Place the router jig on the marked surfboard blank, roughly lining up with the marks.

NOTE: The jig features an optional attachment system. This system consists of two tabs on either end of the jig. Masking tape can be applied over these tabs to anchor the jig to the surfboard. This is handy when performing a post-lam install, as the jig is more likely to slip on the bottom lamination. The tabs can also be placed in a couple of alternate positions.

Next, place the layout guide inside the router jig.

The meaning of the various lines on the layout guide.

Routing

This stage of the process involves creating the box cavities.

Now that the router jig is aligned with the shaper's marks, we are ready to proceed with the routing process.

Routing Steps

Remove the layout guide from the inside of the router jig. Use the center handle for this purpose. Try not to move the router jig.

Ensure the replacement router base has been attached to the router before proceeding, only for the recommended Makita trim routers.

Start the router and plunge it into the foam until the router base rests on the router jig.

WARNING: ALWAYS WAIT FOR THE ROUTER BIT TO STOP SPINNING BEFORE REMOVING IT FROM THE JIG. THIS WILL HELP PREVENT ACCIDENTALLY KNICKING THE JIG.

Box Install

Now that all the box cavities have been created, the boxes can be installed.

We suggest pre-potting the boxes before the lamination process. This procedure minimizes stress and ensures a precise fit between the glass and the box.

The boxes will be secured with polyester laminating resin for polyurethane foam or epoxy for EPS blanks.

Box Install Steps

The first thing that will be installed is the foam collar.

The box is glued into the cavity first before the lamination process.

Once installed, the box should sit slightly below the cavity's lip at its lowest point.

We can proceed with laminating once all the boxes are glued in.

WARNING: DO NOT PLACE THESE PATCHES UNDER THE MAIN LAMINATION!

Finishing

The sanding and finishing process can commence after the boxes have been installed and the bottom lamination has been completed.

At this stage, the bottom lamination and hot coating will be done. Everything is now prepared for sanding and finishing.

Finishing

To facilitate the sanding process, we provide a unique trimming operation. This operation can be skipped in favor of simply sanding down the dam.

After the trimming process the box will be flush witht he bottom of the board.

Now that the board and boxes have been sanded, if a gloss coat is going to be added, that is the next step.

If a gloss coat was applied, polish the board!

Congratulations the installation process is complete!

Post-lam Install

In addition to the standard installation process described above, another option is a post-lam install.

A post-lam install is conducted after the glass on the bottom of the board is applied. This method is commonly used with a tinted or opaque-color glass job where having the color over the box's flange is not desirable.

Due to the unique shape of the GB24 box's dam, it looks fantastic with a color lamination directly over the box. This post-lam methodology is optional. Post-lam installs add strength to the box installation. This is because the box butts against the edge of the glass when installed in the cavity, helping to dissipate side loads.

Post-lam Install Steps

Create the box cavities.

Install the foam collars.

Install the box.

Add the reinforcing glass layers over the box.

To facilitate the sanding process, we provide a unique trimming operation. This operation can be skipped in favor of simply sanding down the dam.

Finish the install process.

Finish the board.

Congratulations the install process is complete.

Misc

Things we learned about the system installation process. This information will help achieve a better installation.

Introduction

As with any installation methodology, it helps to run a few test installations before making any changes. This will give you a better feel for the process and boost your confidence that the right choice was made.

For now, the most essential detail regards installing boxes in deep concaves.

As always, if there are any questions, CONTACT us; we are here to help.

Deep Concave Installs

When installing boxes on a board with deep concaves, an extra precaution must be taken to ensure the boxes are installed cleanly.

When a router jig is placed over a deep concave area, it can span the curve, as illustrated in the figure below. In this case, using the standard router depth will prevent the box from sitting flush against the bottom of the board.

To compensate, you'll need to increase the depth by the amount of bridging that occurs. Your goal is to position the box below the lowest point of the concave surface. Be aware that the depth gauge by itself won't provide sufficient measurement due to the curvature.

For typical concave surfaces, you'll need approximately 1/32" (0.5 mm) of extra depth.

Always perform a test run to verify adequate depth.

The illustrations below show what things will look like with a standard rout and the compensated-depth version.

Router jig sitting on a deep concave

End view shows how the router jig spans the concave

After routing with the standard depth, the box would end up sitting slightly above the lip of the cavity

Normal rout would leave the box sitting above the lip of the cavity

Box set slightly below the lowest lip of the cavity by utilizing a deeper rout

The box needs to be sitting below the lip of the foam at the lowest point

Routing System Details

The routing system is fundamentally key to the successful installation of the system. It is essential to understand the role of each of the components.

Routing system details

The illustration details each component of the routing system. The router jig is the central component—everything revolves around it. The jig's primary role is to guide the routing cavities where boxes are installed. A guide insert in the jig, made of phenolic material for strength and wear resistance, serves as the guide. This insert is removable for easy replacement and allows different inserts to be swapped in for future system parts (e.g., a canard box or leash plug).

The jig features optional tape tabs that help attach it to a board during routing. Multiple tab positions facilitate the attachment process. A soft rubber pad on the bottom protects the board, while a beveled edge around the outer perimeter creates a narrower bottom and makes lifting easier. The layout guide, when inserted into the jig insert, helps position the jig on the shaper's marks using engraved layout lines.

A replacement router base, wider than the standard base, is provided for our recommended trim routers. This increased width enhances stability during the routing process and is compatible with our router bit and bearing.

We also provide a replacement base that incorporates a bushing guide and a straight router bit. The router bit must be precisely sized to create the box cavity. The standard router bit features a ¼" diameter shaft, ⅜" diameter cutter, one-inch cutter length, and ½" diameter bearing. The straight router bit has a ¼" shaft and a ⅜" diameter cutter with a one-inch cutter length.

A depth gauge is provided to help quickly set the initial depth of the router bit in the router. Details on the trim spacer can be found in the next section.

Trim Spacer Details

The trim spacer can save time when sanding down the boxes' dams, but it is crucial to understand how it is utilized.

Trim spacer details

As part of our routing system, we provide a TRIM SPACER to remove the excess dam material before sanding the board. It is utilized after the board has been hot-coated and before sanding.

The trim spacer is designed to sit underneath the router jig and raise it by a fixed amount off the bottom of the board. It has two locator pins that align the router jig correctly on top of the spacer. The shapes are symmetrical, but to keep things simple, we ensure that the labels on the jig and spacer are at the top when assembled. The arrow on the jig points towards the rail of the board.

The spacer has four feet, two movable on either end. These movable feet can be relocated to avoid sitting on adjacent boxes or if one is off the rail's edge. The two center feet are fixed and hold the locator pins for the jig.

Each end of the spacer has seven holes into which the feet can be inserted. Each foot has a pin that fits in these holes.

Rubber pads on the bottom of the feet protect the board. Double-sided tape can also be attached to the bottom of these feet to secure the spacer on the board and prevent it from moving during the trimming operation.

Once the jig and spacer have been assembled and placed on the board, the trimming operation can proceed.

WARNING: Before proceeding, ensure the router bit's bottom is above the bottom of the board. If not, the router bit must be adjusted by placing a small spacer between the trim spacer and the router jig, enough to raise the jig without changing the router bit height. We provide small rubber spacers that can be used if needed. The bottom of the router bit should be at least 1/16" [1.5mm] above the bottom of the board.

Place the router on top of the jig and make small passes around the dam, removing the excess material. Following the jig edge is unnecessary, as we are not routing that far out. We recommend going slowly and removing small amounts at a time. Ensure the spacer and jig do not move during the process.

WARNING: It is crucial that when the boxes are prepared for installation, the screws are either removed or turned down well into the box, as we do not want to run into them in this trimming process.

NOTE: This process can be skipped if the sander is willing to sand down the dams with a grinder. We recommend using a 40- or 50-grit disc and running the grinder slowly, which helps reduce the plastic's melting. Go slow!

BE VERY CAREFUL WHEN USING THIS PROCESS. IF THE HEIGHT OF THE ROUTER BIT IS NOT SET CORRECTLY, IT COULD EASILY DAMAGE THE BOARD. DOUBLE-CHECK EVERYTHING BEFORE PROCEEDING. GO SLOWLY WHEN REMOVING MATERIAL, AS THE ROUTER BIT COULD BIND IN THE PLASTIC.

Still need help?

If you want more personalized help, you can contact us with questions. Also, check out our FAQ, as answers might be found there.

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Evolution of a fin system

GB24 takes the GEARBOX fin system to the next level, adding simplicity, adjustability, strength, and ease of installation.

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