INFLATABLE CORE LAYUPS
All inflatable paddle boards start with an inner bladder made of drop stitch fabric. Drop stitch, in a general sense, consists of two parallel sheets of fabric which are connected by thousands of 5-inch or 6-inch length threads. When the edges of the top and bottom fabric sheets are joined by air-tight material and the bladder is inflated, the threads confine the movement of the top and bottom sheets so that it maintains a board shape rather than curving outward like other inflatable objects.
The inflatable core of a paddle board is made with a single layer (with several variants), fusion, or dual layer construction, while the rails are made with single or double rail bands, and in some cases and additional reinforcing strips for rigidity. Here’s a basic description and additional comments regarding each construction:
FUSION (DROP STITCH FABRIC + WOVEN FABRIC + PLASTIC COATING)
Fusion construction is a sweet spot for balance of weight, rigidity, and cost effectiveness. The top and bottom sheets of the drop stitch have two layers of fabric that are permanently bonded to each other, and a layer of PVC coating on the outside of this double ply fabric. The resulting board is significantly more rigid and puncture resistant than a single layer board. The added rigidity of the material allows boards to be made in 5” thickness without having to resort to excessive board thickness for the sake of rigidity.
DUAL LAYER (DROP STITCH + PLASTIC COATING 1 + ADHESIVE LAYER + PLASTIC COATING 2 + WOVEN FABRIC + PLASTIC COATING 3)
Dual layer construction is the “cost is no object” inflatable layup, as it involves additional materials and labor to build the board. It starts with an inner bladder made with single layer construction, but then the entire bladder is laminated with an additional sheet of PVC coated fabric. Boards made this way are superior in durability, rigidity, and rocker profile control and are more difficult to puncture and less prone to leakage since they have additional coating layers between the fabric sheets. The additional layer adds about 3-4 lbs to board weight compared to fusion construction and a significant increase in material cost. This construction can be used to produce a board that feels extremely well balanced and grounded underfoot.
Technically, fusion material also has two fabric layers, but it should be noted that there is a distinct difference between fused material boards (two layers of fabric fused at the raw material stage, with a single coating applied to the outside surfaces) and actual dual layer construction boards, in which a second distinct layer of PVC coated fabric is laminated to the board.
While some manufacturers may be using use similar materials, different methods of construction can make the most impact on the longevity and performance of a board.