Kitespar
Kitespar (Filament Wound Epoxy Tubing, FWET) is a type or hollow fiberglass originally designed for use in kite framing (hence the name), and is often used in weapon construction for creating lightweight/ultralight weapons. It is one of the most popular core materials. It is much more optimized weight-wise than solid fiberglass, but is less durable.
Several diameter sizes are popular: .505, .524 (same inner diameter as .505, which gives it thicker walls and less flex), and .602 for javelins and short one-handed spears (out to around 60". If it can be found, .625 works for longer javelins).
When looking for kitespar, you generally want "Filament Wound Epoxy Tubing," not "Pultruded."
Properties of pultruded structural shapes:
Lightweight - less density - 20% of steel; 70% of aluminum
High Strength - stronger than structural steel pound for pound
Superior dimensional stability - wide temperature range uses and thermal expansion values better than 50% of mild steel 35% of stainless steel and 25% of aluminum
Thermal insulation - high strength and insulating values
Corrosion resistance - harsh elements and environments
Consistent cross section
(as found on Tencom's website)
Sources of Kitespar
- Goodwinds, the current generic source for kitespar