Liquid metal, also known as cold-cast metal, lets you achieve a genuine metal surface without a foundry. The finish is real metal because metal powder, not pigment, sits at the surface and can be patinated and polished like solid castings.

How liquid metal and cold-cast finishes work

Metal powder is loaded into a clear resin or binder, typically an epoxy or polyurethane, at high concentrations. When the resin is brushed as a face coat into a mould, or backfilled behind a gel coat, the dense metal particles migrate to the surface. Once cured and demoulded, the surface is abraded to expose the metal, then polished and patinated. Because the exposed layer is true metal, it reacts to patinas and burnishing exactly as the parent metal would.

Which metals suit which look

The base metal sets the colour, the ageing behaviour and the patina chemistry. Selecting the right powder is the single biggest decision in the finish.

  • Bronze: Finish and appearance: Warm gold-brown; takes classic brown, green and black patinas; Typical use: Sculpture, architectural mouldings, plaques
  • Brass: Finish and appearance: Bright yellow-gold; polishes to a mirror sheen; Typical use: Decorative hardware, signage, interiors
  • Copper: Finish and appearance: Rich pink-red; develops blue-green verdigris; Typical use: Panels, art pieces, feature surfaces
  • Iron: Finish and appearance: Grey to dark charcoal; can be rusted for an aged look; Typical use: Industrial styling, faux ironwork
  • Aluminium: Finish and appearance: Bright silver-white; light and corrosion resistant; Typical use: Modern furniture, lightweight panels
  • Tin: Finish and appearance: Soft grey pewter-like tone; gentle lustre; Typical use: Tableware styling, heritage effects

Why particle size and morphology matter

Particle size governs fill, coverage and how the surface finishes. Finer powders pack more densely, give higher surface coverage per kilogram and produce a smoother face that polishes to a finer sheen. Coarser powders can read as a more textured, cast appearance and may fill deep mould detail differently.

Morphology, the shape of each particle, is just as important. Spherical or nodular powders flow well and disperse evenly in resin, aiding consistent fill. Irregular or flake-like particles lock together and can improve surface metal density, but may raise viscosity and demand more thorough mixing to avoid settling before cure.

Balancing fill, polish and patina

A fine, well dispersed powder favours a bright, even polish and predictable patina. A coarser blend favours texture and depth. Many finishers combine grades to balance coverage against cost, since a fine face coat carries the appearance while the bulk provides body.

Practical selection guidance

Artists usually prioritise colour and patina response, so bronze and copper are common choices. Architects weigh durability and weight, where aluminium and iron effects earn their place. Manufacturers focus on repeatability, so consistent particle size distribution and reliable dispersion matter most for batch-to-batch uniformity. Always test the intended patina on a sample before committing to a run.

  • Colour and patina are set by the base metal, so choose bronze, brass, copper, iron, aluminium or tin to match the intended look.
  • Finer powders improve coverage and polish; coarser grades add texture and cast character.
  • Morphology affects dispersion, viscosity and surface metal density, so mix thoroughly and guard against settling.
  • Consistency of particle size distribution drives repeatable results across batches.
  • Always sample the patina and polish routine before full production.

Working with Ronald Britton

Ronald Britton has supplied metal powders since 1945 and holds ISO 9001 and ISO 14001 certification, with an EcoVadis rating in the top 8%. Powders are typically dispatched within 48 hours across the UK, and grades can be matched to specification for a given finish.

To discuss which metal powder and particle grade suit your liquid metal or cold-cast project, request a quote or contact the Ronald Britton technical team for guidance tailored to your finish.