Manufacturing guide
Most climbing holds are made by shaping a master, taking a silicone mould from it, and casting liquid polyurethane into that mould before trimming, texturing and inspecting each hold. Large macros are made as hollow shells, either from hand-laid fibreglass or from ABS sheet vacuum-formed over a mould, while climbing volumes are cut and assembled from plywood. The process chosen depends on the size of the feature, the weight a setter can handle and the edge detail the design needs.
Every moulded climbing hold starts as a single original shape, called the master or pattern. The master is what the designer actually sculpts; every hold that follows is a copy of it. Masters have traditionally been carved by hand from materials such as foam, wood or modelling clay, and many are now designed digitally and milled or 3D-printed so the geometry can be refined and repeated precisely.
At this stage the designer decides how the hold will climb: its usable surfaces, intended orientation, edge profiles, and where the bolt hole and any screw holes sit. The back of the master is shaped to sit flat against a wall panel, because a hold that rocks or spins on the wall is a safety problem regardless of how good its shape is.
The mould is a negative copy of the master, and for cast holds it is usually made from flexible silicone rubber. The master is fixed face-up in a box, liquid silicone is poured over it and allowed to cure, and the master is then removed to leave a cavity in its exact shape. Flexible silicone lets a cast hold with undercuts and pinches be peeled out without breaking either the hold or the mould.
Moulds wear with use, so a manufacturer producing the same shape over many years will periodically remake them from the original master. For thermoformed and fibreglass macros the mould is a rigid form instead, because the material is laid on or drawn over it rather than poured into it.
Polyurethane (PU) is the standard material for small and medium climbing holds because it is tough, slightly resilient under impact, and reproduces mould detail accurately. Two liquid components are mixed with a colour pigment, poured into the silicone mould, and left to cure into a solid hold. A steel washer or sleeve is normally set into the casting around the bolt hole so the bolt head bears on metal rather than on the resin itself.
Once cured, the hold is pulled from the mould, the excess material along the back (known as flash) is trimmed, and the back face is checked for flatness. Casting is efficient for jugs, edges, crimps, slopers, pinches and pockets, but it becomes impractical for very large features: a solid casting the size of a macro would be far too heavy to lift onto a wall.
Large macros are made as hollow shells so they stay light enough to handle. The two main shell processes are fibreglass lay-up and vacuum thermoforming.
Fibreglass (GRP) lay-up. Glass Reinforced Plastic is built up by hand in a mould: layers of glass-fibre mat are wetted with resin and consolidated until the shell reaches the required thickness, then left to cure, demoulded and trimmed. GRP gives rigid shells with thin, crisp edges, but it becomes heavy and brittle as feature size increases, so large GRP macros can crack if dropped or knocked during a reset.
Vacuum thermoforming ABS (VTF ABS). A sheet of ABS (Acrylonitrile Butadiene Styrene) thermoplastic is heated until soft, then drawn tightly over a mould using vacuum pressure. It cools into a rigid, thin-walled shell that is approximately half the weight of an equivalent fibreglass macro and far less brittle under impact. Thermoformed shells usually retain a flange, a lip around the perimeter left by the forming process, which is trimmed and finished afterwards.
Plywood volumes are not moulded at all; they are fabricated like small pieces of joinery. Production starts with the geometry and panel layout, followed by accurate cutting, shaping and assembly of the faces. Joint design, fixing positions and finished edges all matter, because commercial volumes are moved and reinstalled repeatedly and have to carry climbing load across a large footprint.
Texture is what gives a hold its friction. Depending on the manufacturer, texture on a cast hold is either reproduced from the mould surface or applied as a coating; on VTF ABS macros it is applied as a coating, and plywood volumes are given a textured surface finish. Dual-texture products carry a coarser grit on the intended contact zones and a smoother finish elsewhere, which lets a route setter show climbers which part of a feature to use.
Quality checks should follow the process rather than one generic test. A typical inspection covers the shell or casting, edge condition, surface finish, the bolt hole and fixing areas, and for volumes the assembly and joints, followed by a check that product, colour and quantity match the order. Buyers should still inspect every item on delivery and before each installation.
Each process suits a different size and type of product. This table summarises the main options.
| Material | Process | Typical products | Key trade-off |
|---|---|---|---|
| Polyurethane (PU) | Liquid resin cast into silicone moulds | Jugs, edges, crimps, slopers, pinches, pockets | Tough and detailed, but solid castings become too heavy at macro size |
| Fibreglass (GRP) | Glass-fibre mat and resin laid up in a mould | Large macros and hollow features | Rigid with thin edges, but heavy and brittle at large scale |
| VTF ABS | Heated ABS sheet vacuum-formed over a mould | Large and competition macros | Rigid and about half the weight of GRP; forming leaves a flange that must be dealt with |
| Birch plywood | Panels cut, shaped and assembled | Volumes, wedges, ramps and terrain features | Large terrain change at manageable weight, limited to flat-faced geometry |
Rockcity manufactures its VTF ABS macros and plywood volumes in-house in Hull, UK, where design, manufacturing and dispatch operate from the same facility. Development starts with the movement the product needs to create, and prototypes are reviewed before a design becomes a repeatable production item.
VTF ABS macros. Rockcity ceased GRP macro production in 2025 and now makes its macro range in VTF ABS. Its main development is a flangeless method: rather than leaving the perimeter lip that many thermoformed macros carry, the process achieves thin edge profiles and insert geometry previously associated with fibreglass. It was developed over three years with aerospace and mechanical engineers and is covered by Patent Pending WO2025/191268. Each formed shell is prepared for full-texture or dual-texture coating before the fixing points and finished product are checked. The VTF ABS macros explained guide covers this in more detail.
Plywood volumes. Rockcity volumes are made from birch plywood, cut, shaped and assembled in Hull, then finished as full-textured, Iconic dual-texture or Safari Print (Leopard, Tiger and Zebra) volumes. Assembly, faces, edges, finish and the fixing arrangement are reviewed before dispatch.
Rockcity's polyurethane holds are available through the catalog alongside these ranges. For the full picture of the Hull facility, lead times and quality control, see the Rockcity manufacturing page.
Most small and medium climbing holds are cast by pouring liquid polyurethane into a silicone mould taken from a hand-shaped or digitally modelled master. Large macros are made as hollow shells, either by laying up fibreglass in a mould or by vacuum thermoforming ABS sheet, and volumes are fabricated from cut and assembled plywood.
Most bolt-on climbing holds are made from polyurethane (PU) because it is tough and casts accurately. Large macros are made from fibreglass (GRP) or vacuum-formed ABS thermoplastic, and climbing volumes are usually built from birch plywood.
A cast PU hold is a solid or near-solid piece formed by pouring liquid resin into a mould, which suits smaller shapes. A VTF ABS macro is a thin-walled shell formed by heating ABS sheet and drawing it over a mould with vacuum pressure, which keeps large features rigid but light enough to handle during resets.
Rockcity manufactures its VTF ABS macros and plywood volumes in-house in Hull, UK, where design, manufacturing and dispatch operate from the same facility.
Rockcity ceased GRP macro production in 2025 because fibreglass becomes heavy and brittle as feature size increases. Its macro range is now made in VTF ABS, which is approximately half the weight of an equivalent fibreglass macro while remaining rigid under climbing load.
Many thermoformed macros keep a visible perimeter flange left by the forming process. Rockcity's flangeless method removes it to achieve thin edge profiles and insert geometry previously associated with fibreglass, and is covered by Patent Pending WO2025/191268.
Featured macros, volumes and holds in the catalog
Browse the full product catalog or contact the team to discuss a project.