Composite finishing by wet blasting

The choice of abrasive media in wet blasting for composites depends on the substrate, resin system, and target surface roughness. Fine-grade media such as glass beads or aluminium oxide are commonly used because they create a controlled Ra profile without fracturing reinforcing fibres. The water-suspended slurry cushions the impact, so even harder media can be used safely compared to dry grit blasting. A Vapormatt applications engineer can specify the optimal media type and grit size for your bonding specification.

Laser ablation is an emerging method for composite surface preparation that uses focused energy to remove resin from the surface. While it offers non-contact processing, it requires significant capital investment, careful control to avoid thermal damage to fibres, and is typically slower than wet blasting for larger surface areas. Wet blasting delivers comparable surface energy results at lower cost, higher throughput, and with an established track record across aerospace and motorsport production environments.

Wet blasting is well established for thermoset composite preparation, including carbon fibre reinforced polymers (CFRP) cured in an autoclave. Its suitability for thermoplastic composites such as PEEK or PEKK matrix systems depends on the surface hardness, fibre architecture, and the adhesive or welding process being used downstream. As thermoplastic composites grow in aerospace and automotive applications, wet blasting parameters can be adapted to meet the specific surface energy requirements of these materials.

Throughput depends on component geometry, surface area, the required Ra profile, and the number of blast guns configured on the machine. Automatic wet blasting machines, such as the Oncilla, can be engineered with conveyorised or rotary indexing systems to process components continuously in a production line environment. Cycle times are significantly shorter than manual sanding and more consistent than hand-operated blast cabinets, making automatic wet blasting suitable for both low-volume aerospace parts and higher-volume motorsport or sporting goods production.

Wet blasting is inherently safer than dry grit blasting because the water suppresses airborne dust, eliminating the silica dust inhalation risk associated with dry abrasive methods. The process generates a slurry waste stream rather than dry particulate, which simplifies containment. Closed-loop water recycling systems can be incorporated into Vapormatt machines to minimise water consumption and manage abrasive media reclamation, supporting both environmental compliance and reduced running costs.