This tutorial will show you how to install a leash plug. Most boards use a single leash plug approximately 6-inches from the tail but some builders like to install 4 extra leash plugs in front of the standing area to carry their sandals, water bottle, etc. The four extra leash cups are the anchor points for a bungee cord similar to the deck of a kayak so they should be install in the same manor as the cup that stops your board from floating away from you.
Before the top is attached it is important that you can locate the internal blocking. This board is using 2″ squares on foam blocking so it isn’t important if this is the leash or the vent side. The two vertical lines are showing the edges of the blocking and the arrow is showing the location of the fishbone’s rib.
After the top is attached and before rails are shaped it is recommended to drill a pilot hole to mark the location of the internal blocking. It is very hard to remember where the blocking is after the taper has been removed, rails shaped and the board has been laminated. It is much nicer to miss your blocking with a small pilot hole like this than hunting for your blocking on your nearly completed board with a 1-inch bit! The second benefit of these location holes is they allow the board to equalize pressure as the board is being glassed.
A 1-inch Forestner bit is the tool of choice for drilling flat bottomed holes on the boards curved surface.
Forestner bits are pretty good for not walking but a guide never hurts to protect your board. This guide is also used to confirm you are drilling the correct sized hole for the insert.
Be sure to test fit the depth of your hole before mixing the epoxy. If you are unsure of how deep to drill you can drill into a piece of scrap wood and then mark the shank of your drill with a flap of tape. For the bits I am using I can usually just visualize that I need go go a bit deeper than the head of the cutter. I recommend installing the vent, leash cup & handle at the same time so you are not mixing 3 small batches of epoxy.
Leash hole on the left and recessed vent hole on the right.
The leash plug has a stepped side profile to ensure it can not be easily pulled back out after the epoxy cures. When the epoxy cures it looks like you drilled your hole 1/8″ larger than was required. If you want to hide the oversize hole you can add black epoxy pigment to your epoxy and the insert will look perfect. You can also use the leftover toner from a laser printer cartridge to colour your epoxy. The insert shown was installed without dye and hasn’t been centred in the hole yet.
Painters tape and a folded scrap of sand paper is being used to make sure the leash cup is firmly pressed down as they have a tendency to float up in the epoxy. The bolt on the right is being used to align and hold down the vent. This bolt is much longer than is required but it had the correct tread and it was handy!
If you are surfing with your board it is recommended to insert a small patch of fibreglass clothe with the leash plug if you are using foam as your blocking. This patch of cloth is simply pressed into the hole as the leash cup is being installed in the epoxy. The cloth will reinforce the epoxy and link the leash cup to the top skin on all sides. The excess cloth will be sticking up on the sides of the plug but it is sanded flush with the deck after the epoxy cures.
Mark a line on the painters tape to show the orientation on the brass pin. The orientation doesn’t matter for its function but it looks silly if it is just randomly inserted.
If you do missed your blocking, forgot to install blocking or decide you don’t like where you installed it there is a solution. You can drill the required hole anywhere you like. I recommend having a vacuum sucking up the chips as you drill because they are hard to locate inside the board. With the holes drilled you can very carefully use the smallest shot possible of spray window sealant. Let the foam cure. Drill the foam to the correct depth and insert your inserts. It is recommended that the leash plug is inserted with a small patch on fibreglass cloth for extra support as this type of foam doesn’t have the greatest strength but it will get you out of a jam. If you decide to use this technique you have to know that the chemical reaction with this style of foam will buckle windows if too much is used so be very careful and it is better to use too little and have to add some than to have it explode your board.