Here are a few common fiberglass lay-up terms you will run across when building your experimental airplane.
BIAS: Cloth fiber orientation, measured in degrees from the pattern longitudinal axis.
BID: (Bi-Directional Glass Cloth) Woven fiberglass fabric with 50% of the fibers parallel to the finished end of the cloth and 50% running at 90° to the finished edge. “2 BID” indicates 2 layers of bi-directional cloth, almost always cut on a 45° bias.
CFC: Carbon Fiber Composite. Black material using carbon or graphic fibers in place of fiberglass to give a lighter and stronger structure.
CURE: Resin that has reached full hardness and strength.
EXOTHERMIC REACTION: The chemical reaction that releases energy in the form of heat.
FIBERGLASS: The trade name for glass fibers woven into various forms such as bi-directional and uni-directional cloth, usually white, turning to light tan or green when laminated with the epoxy resin used to build your experimental airplane.
FLOX: Cotton fibers mixed with resin to form a structural filler.
FOAM: A lightweight cellular plastic material made when gasses are added during manufacturing.
FOAM CORE: Foam used as the core or edge material in a composite panel.
GELTIME: The time it takes epoxy resin to set up in the container after thorough mixing.
GREEN CURE: The point at which a laminate has cured enough to be cut with a knife, but is not fully cured. Green cure time depends on ambient temperature and the laminate thickness.
JOGGLE: A feature of many of the pre-molded parts. The joggles overlap, easing the task of aligning the parts. Joggles also increase the strength of the lay up.
LAMINATE: A layer or layers of fiberglass or graphite cloth, impregnated with epoxy resin. TO LAMINATE: Saturating cloth with resin.
LAY UP: Same as laminate.
MC (Methylene Chloride): The cleaning agent for removing unwanted contamination. Acetone also will work, but MC is superior. Remember to always follow safety instructions on the container and always allow the parts to dry thoroughly prior to bonding, after cleaning with MC.
MICRO/MICRO BALLOONS: Tiny glass bubbles that are mixed with resin to form lightweight, non-structural filler.
PEEL PLY: Dacron fabric used as a protective coating for molded parts. It is white but looks transparent when stuck to a part. Remember that peel ply must be removed. You can’t form a structural bond over it.
SCRIBE LINES: Reference marks scribed into female molds (they make raised lines on the finished parts).
RELEASE TAPE: Common clear packaging tape.
RESIN: Epoxy used to saturate fiberglass cloth, bonding parts together. It is mixed with hardener in small batches just prior to use.