You may not think about the way your surfboard is finished to have an effect on performance, but it does.
The final step in your surfboard’s construction will not only affect its appearance, but it will also influence how the board moves over the water (or how water moves over the board) and the overall strength and weight of the board.
The final common step in the glassing and sanding phase between all surfboards is the hot-coat. The hot coat is the layer of resin that follows the lamination coat (the step when the glass is layed on). The hot coat is necessary to fill any gaps in the fiberglass weave left behind during the lamination phase. The hot coat creates a stronger, smoother finish and prevent water from wicking into the weave and foam over time.
You can finish the surfboard by either sanding the hot coat and calling it a day or continuing with a gloss coat.
There are a few defining differences between each finish, these include:
- Final weight: the more layers of resin you add, the heavier the surfboard will be.
- Strength and ding-resistance: the more resin you add, the more resistant the board will be to dings and damage.
- Appearance: The finish of the surfboard will determine whether it has a more shiny or more matte appearance.
- Water flow and friction: The finish affects how water flows over the board. Speaking generally, a totally smooth surface is going to be slower through the water as it creates direct friction between the water molecules and the material surface. A rougher, slightly textured surface(usually microscopic), however, will pickup a layer of water that allows water to flow over it, rather than the material itself – making for less friction and more speed.
Sanded Hot Coat
The sanded hot coat finish is the lightest option for surfboard finish and is commonly used on high performance shortboards to keep weight down as much as possible.
A surfboard with a sanded hot coat only will be more fragile, more prone to dings, and more prone to pressure bumps.
Sanded Gloss Coat
A sanded gloss coat is essentially the hot coat step repeated.
The hot coat is sanded and a little more resin is applied. Once this coat of resin cures, its sanded up to about 400 to 600 grit.
The sanded gloss coat finish adds a little more weight, but adds strength and ding resistance. The sanded finish also works to create less friction with the water than a totally smooth finish would.
Polished Gloss Coat
A polished gloss coat is finished with some sanding as well, but then finished off with a polishing compound and polished until it shines.
This makes for a nice glossy, smooth finish that’s perfect for a classic log or retro shape. The smooth surface will create more friction with the water, but if you’re on a board with enough weight, you’re probably not going to tell the difference.