A mould for paving slabs or decorative stone made from cheap formoplast loses its relief after just a few dozen pours: the walls sag, the edges disappear, products go to scrap. A silicone matrix holds detail better, but tears at the corners and costs a lot. Polyurethane solves both problems: it copies relief accurately while resisting the abrasion of the cement mix. This article explains why casting tooling is worth making from cast polyurethane and how to order a mould for your own product.
Why polyurethane suits casting moulds better than silicone or formoplast
Polyurethane combines two qualities that rarely meet in one material: high elasticity for product release and wear resistance for a long production run. Formoplast is soft and cheap, but it shrinks after cooling and quickly loses the tightness of its walls. Silicone reproduces relief accurately, yet has low tear strength and is worn away by an abrasive mix. Polyurethane withstands serial casting while keeping the sharpness of its edges.
The key advantage lies in resistance to abrasion. Abrasive particles of sand and cement gradually eat away the working surface of a mould, and this is exactly where polyurethane pulls ahead of its rivals. Per DIN 53516 its abrasion is 38-39 mm³, whereas for silicone rubber this figure reaches 150-350 mm³. In practice this means a polyurethane matrix holds precise relief geometry longer, and therefore yields more good products from a single mould.
The material is resistant to the alkaline environment of cement, to technical oils and to the release agents applied before pouring. It is not afraid of moisture and does not swell, so the mould can be washed with water without risk of deformation.
Comparison of materials for casting tooling
The table below sets cast polyurethane against silicone rubber by the characteristics that matter for moulds. The numbers are taken from standard material reference sources (DIN 53516, ISO 37) for typical grades.
| Characteristic | TIMOL polyurethane | Silicone rubber (VMQ) |
|---|---|---|
| Abrasion DIN 53516, mm³ | 38-39 | 150-350 |
| Tensile strength, MPa | 39-87 | 5-12 |
| Tear resistance, kN/m | 40-120 | 5-30 |
| Operating temperature, °C | -60…+100 | -60…+230 |
| Shore hardness | 85A-95A | 20A-80A |
| Rebound elasticity, % | 34-61 | 40-65 |
The most important rows here are the first three. In abrasion polyurethane beats silicone several times over, and in tensile strength (39-87 MPa versus 5-12 MPa) and tear resistance (40-120 kN/m versus 5-30 kN/m) the difference reaches several times. It is precisely tearing at the corners and deep walls that puts silicone moulds out of service first. Silicone wins only in heat resistance (up to +230 °C), but for casting concrete, gypsum and polymer concrete the operating temperatures of polyurethane are entirely sufficient.
Technologist’s tip: for moulds with fine relief and undercuts, take a softer polyurethane around 70-80 Shore A, it releases from the product more easily without chipping the edges. For large flat matrices with high walls and vibration casting, a hardness above 90 Shore A is more suitable so the walls do not flex under the weight of the mix. Make the master model with a smooth surface: polyurethane copies even microscratches, so every defect of the model will carry over to the product.
What moulds are made from polyurethane
Cast polyurethane is used for tooling across a wide range of products. The most common direction is moulds for paving slabs, kerbs, decorative and artificial stone, facing panels and landscape design elements. The elasticity of the material makes it possible to reproduce the relief of natural stone, wood and brick in high detail.
A separate group is matrices for gypsum and polymer concrete products: 3D panels, mouldings, facade decor. Here both the accuracy of the relief and easy demoulding of complex shapes with undercuts matter. Polyurethane handles both tasks thanks to elastic deformation: the mould stretches during release and returns to its original geometry.
Moulds are made both as open type for manual casting and closed for a vibrating table and pressing. The number of cells per matrix is calculated to suit the productivity of the customer’s line. You can review the range and the production directions in the catalogue of polyurethane products.
Care of a polyurethane mould is simple and directly affects its service life. After each cycle the mould is cleaned of mix residue and coated with a release agent that eases demoulding and reduces wear of the working surface. Polyurethane is not afraid of moisture, so the matrix can be washed with water without risk of deformation and stored flat with no load on the walls. Following these simple rules lets the mould work through its full designed service life without premature loss of relief.
Free casting technology and made-to-order production
Moulds at the TIMOL factory are made by free casting into open and closed master forms. This technology yields a solid part with no seams or joints, and therefore no weak points along which tooling tears first. The mould surface comes out even, with accurate reproduction of the master model.
Production begins with the geometry of the product. The customer supplies a drawing, a 3D model or a physical sample of the finished product, from which a master model is made, and from that the polyurethane mould. This approach lets us reproduce any texture and size without being tied to a standard catalogue. The service of making tooling to size and drawing is described in more detail in the factory services section.
Selection of the hardness and wall thickness of the mould is carried out by the technologist based on the type of mix, the compaction method and the desired service life. This reduces the risk of premature wear and gives a predictable number of pours.
How to order polyurethane for moulds at the TIMOL factory
You can buy polyurethane for mould making or order finished tooling for your product directly from the manufacturer in Dnipro. Direct contact with the factory means the hardness, size and relief of the mould are matched to the specific task rather than a compromise standard offered from stock.
To get a quote, prepare the geometry of the product (drawing, model or sample) and specify the material of the mix the mould will work with. The technologist will recommend a polyurethane grade, hardness and tooling design. You can discuss the parameters and place an order through the factory contacts page. Making a mould to drawing gives a higher service life and sharper relief than universal solutions, and therefore less scrap and a lower cost per product.