Some "shooling" for those following along. Fabric has a warp and fill direction. The fill direction is widthwise and is perpendicular to the warp or lengthwise direction.
Composite fabrics have a breaking strength value, normally expressed in pounds per inch. The first number will be the breaking strength in the warp direction. The second will be the fill direction. Most fabrics are stronger in the warp than the fill because higher tension is placed on the warp fiber keeping it straighter during the weaving process. Rare exceptions occur when a larger, therefore stronger thread is used in the fill direction than the warp direction. Fabrics are generally considered ”balanced” if the breaking strength is within 15% warp to fill. “Unbalanced” fabrics are excellent when a greater load is required one direction and a lesser load in the perpendicular direction. Unidirectional Carbon runs mostly in the warp direction, with a few in the fill direction to hold it all together.
Carbon is great in tension, not so much in compression. The compressive forces are on the top of the board, the tension on the bottom...so the BEST use of carbon is on the bottom of a board or the bottom of the sections of a sandwich. For our purposes, we have more forces applied to the board through it's length than through the width (hence lengthwise stringers), but there are some widthwise forces.
Based upon that, I intend to run some uni carbon lengthwise in the tension side of the components in this build.
That said, Carbon is super stiff in a laminate, 1# density foam isn't. Further 1# EPS is mostly air or blowing agent. Typically 1# eps is sealed to prevent outgassing, but another good reason is to create a uniform surface/uniform dispersion of resin in the attached laminate (reduces absorption from the laminate).
This is a close up picture of some shaped 1# EPS you can see the pukas or craters in the foam.
Hybrid Mode
