Clean Surface
Before applying release agent, remove concrete residue, dust and other contamination from the mould surface.
A practical guide to mould preparation, controlled release-agent application and careful demoulding — while recognising that concrete strength, mould condition and handling can also influence the result.
A clean mould, a suitable release agent and careful demoulding all contribute to efficient production and good surface quality. Release agent should assist separation between the concrete and mould surface, but it cannot compensate for poor mould condition, unsuitable concrete or incorrect handling.
Successful demoulding begins long before the concrete product is removed from the mould.
Before applying release agent, the mould should be clean and free from hardened concrete, dust or other contamination. Release agents are intended to assist separation between the mould surface and the concrete and should always be applied in accordance with the product manufacturer's instructions.
Applying excessive release agent does not necessarily improve release. Depending on the product and application method, excess material may contribute to surface blemishes or require additional cleaning before the next production cycle.
The release agent is only one part of the process. Concrete strength at demoulding, mould condition, handling methods and production practices should also be considered when reviewing product quality or investigating defects.
A release agent should be selected to suit both the mould material and the production process. Always follow the product manufacturer's application guidance and your organisation's established quality and safety procedures.
The aim is not simply to apply release agent, but to prepare the mould consistently before every production cycle. Cleanliness, suitable product selection and following the manufacturer’s guidance all contribute to reliable demoulding.
Before applying release agent, remove concrete residue, dust and other contamination from the mould surface.
Select a release agent that is suitable for the mould material and intended application, following the product manufacturer’s recommendations.
Apply the release agent as directed by its manufacturer. A thin, even coating is generally preferred to excessive or uneven application.
If products begin sticking or surface quality changes, review the complete production process rather than assuming the release agent alone is responsible.
Remember: successful demoulding depends on several factors working together, including mould condition, release-agent selection and application, concrete strength at demoulding, handling methods and the wider production process.
Demoulding should only take place when the concrete has developed the strength required by the product specification and established production procedure. Careful, controlled removal can help reduce avoidable damage to the surface, edges and corners.
Follow the approved production procedure for determining when the product is ready to be removed. Appearance alone should not be used as confirmation that sufficient strength has developed.
Open or release the mould using its intended sequence and operating method. Avoid uncontrolled movement that could place unnecessary stress on the concrete or the mould.
Give particular attention to edges, corners, slots and projecting details, as these areas may be more vulnerable to damage during removal and handling.
After removal, check the product and mould for sticking, surface loss, recurring marks or damage. Record repeated issues so that the wider process can be reviewed.
Repeated sticking, surface loss or damaged edges should not automatically be blamed on one factor. Review concrete strength at demoulding, mould cleanliness and condition, release-agent suitability and application, removal technique and subsequent handling.
Do not use this guide to establish a universal demoulding time or concrete-strength requirement. Follow the product specification, approved quality procedure, mould and lifting-equipment instructions, and your organisation’s health-and-safety controls.
Release agents should be selected to suit the mould material and used in accordance with the product instructions. Armcon Precast’s CRA3 is a solvent-free mould release agent formulated specifically for use with polypropylene liners. Apply it using the recommended method and avoid assuming that excessive application will improve release.
Explore CRA3 →Release agent is one part of the process. Mould condition, concrete strength, handling and established production procedures should all be considered together.
Clean the mould before application and remove concrete residue, dust or other contamination from the casting surface.
Select a suitable release agent for the mould material and intended production process.
Follow the product manufacturer’s instructions for preparation, application method and coverage.
Demould in accordance with the approved procedure once the required concrete strength and handling conditions have been achieved.
Investigate recurring sticking or damage across the full process, rather than assuming one product or production step is solely responsible.
Where a mould has become difficult to clean, damaged, distorted or unable to produce the required dimensions, its condition may need further assessment. Armcon Precast supplies polypropylene slotted fence post moulds for precast manufacturers worldwide.
Explore Fence Post Moulds →Technical note: This guide provides general information only. It should be considered alongside your organisation’s production, quality and safety procedures, the mould and release-agent manufacturers’ instructions, the concrete specification and any standards applicable to the finished product. Demoulding requirements vary according to the product, concrete, mould design, curing conditions and handling system.