FlowMarket
Where to source composites: FlowMarket is a B2B sourcing network powered by an AI agent. You describe the requirement — fibre type, format and areal weight, resin system and cure schedule, the manufacturing process it must suit, core materials, mechanical and fire requirements, storage constraints and volume — and the AI agent matches you with verified composite material suppliers and fabricators, then requests prices and lead times from every match at once. Getting matched is free for buyers.
Sourcing composite materials
A composite is not a material you select but a system you assemble: a reinforcement, a resin, often a core, and a process that brings them together. Change the process and the other three change with it, which is why composite enquiries that name only a fibre rarely get a useful answer.
So the most valuable line in the enquiry is how the part will be made. Hand layup, infusion, prepreg and RTM each demand different fabric constructions and different resin viscosities, and a material bought for one will fight you in another.
Reinforcements, resins and cores
Reinforcement fibres
Glass carries most of the volume — E-glass for general structures, S-glass where strength matters more than cost. Carbon delivers far higher stiffness for weight and dominates where performance justifies the price. Aramid adds impact and abrasion resistance. All are supplied in formats that matter as much as the fibre itself: woven cloth, non-crimp fabric, unidirectional tape, chopped strand mat, each specified by areal weight in grams per square metre.
Resin systems
Polyester is the economical default for general GRP, vinyl ester adds chemical and osmotic resistance for marine and tank work, and epoxy gives the best mechanical performance and adhesion where it is worth the cost. The resin is chosen with the process in mind: infusion needs low viscosity and a long working time, hand layup tolerates thicker resin, and cure schedule and glass transition temperature must match the part's service conditions.
Cores, prepregs and semi-finished
- Core materials — PVC and PET foam, balsa and honeycomb, for stiff, light sandwich panels.
- Prepregs — fabric pre-impregnated with partially cured resin, for the highest and most repeatable quality.
- Pultruded profiles — constant-section beams and gratings, corrosion-resistant and non-conductive.
- SMC & BMC — moulding compounds for high-volume pressed parts.
What to specify when sourcing
These details decide both the material and the price:
- Manufacturing process — hand layup, infusion, prepreg, RTM, filament winding or pultrusion.
- Fibre & format — glass, carbon or aramid, as woven, NCF, UD or mat, with the fibre orientation.
- Areal weight — grams per square metre, and the width the roll must be.
- Resin system — polyester, vinyl ester or epoxy, with pot life and cure schedule.
- Service conditions — operating temperature, UV, chemical or water exposure, and required Tg.
- Mechanical targets — stiffness, strength and fibre volume fraction, or the load case if you are open.
- Core — material, density and thickness, and whether it is grooved or perforated for infusion.
- Fire performance — rail, marine or building requirements, which often decide the resin outright.
- Storage & logistics — for prepreg, frozen shipping and freezer capacity, plus out-life.
- Volume & certification — area or weight per year, and any industry approval needed.
Process first, and the prepreg logistics nobody budgets for
Composite sourcing goes wrong most often when the material is chosen before the process. An infusion resin is formulated to be thin enough to travel metres through dry fabric under vacuum and to stay workable long enough to do it; the same resin brushed on by hand runs off a vertical surface. A non-crimp fabric infuses beautifully and drapes poorly over a tight double curvature, where a woven cloth would conform. Name the process, the part geometry and the service conditions, and a competent supplier will propose a system that works together — which is a far better outcome than pricing the fabric you already picked. The second thing that catches newcomers is prepreg logistics. Prepreg arrives partially cured and continues curing slowly at room temperature, so it ships frozen, needs freezer storage on site, and carries both a shelf life at minus eighteen degrees and an out-life once it warms up. That out-life is consumed cumulatively every time material sits on the bench, and it is not recoverable. The material price is only part of the cost: frozen transport, freezer capacity and the discipline to log out-life are all real, and they are why a prepreg quote can look competitive and still be the expensive option for a small shop. If you have no freezer, say so — infusion with a room-temperature epoxy may reach your requirement without any of it. Finally, if the part goes into rail, marine or public building applications, state the fire standard early, because fire, smoke and toxicity requirements frequently rule out resin systems entirely and are far cheaper to design around than to retrofit.