About Sika Separol WB-23

Sika Separol WB-23 is the water-based member of Sika’s Separol form-release family. Instead of the neat mineral oil used in the classic Separol grade, WB-23 is built as a milky-white emulsion of refined oils and emulsifying agents carried in water. When the thin applied film meets fresh concrete, the water phase runs off or evaporates and a very fine release layer is left on the mould face. That layer breaks the bond between the shutter and the hardening concrete, so panels and moulds strip away with a light pull rather than being levered off. For a contractor that difference shows up directly as fewer damaged ply sheets, faster turnaround between pours, and a cast face that needs less making-good.

The reason many Indian sites now specify a water-based grade over an oil one is housekeeping and safety as much as finish. Being water-borne, WB-23 has a very low flash risk, minimal solvent odour, and tools, spray jets and spillages all clean up with plain water. On fair-faced and architectural concrete it earns its place by cutting down the blowholes, dark oil staining and patchy tide-marks that neat-oil agents can leave behind, which is exactly the sort of blemish an exposed-concrete elevation cannot hide. As an authorised Sika distributor and applicator, Space Arc supplies WB-23 across Delhi NCR and Pan-India and can advise on dilution and coverage for the shutter type and finish class on your job.

The technical insight

A form release agent has one job: stop a chemical and mechanical bond forming between the mould and the concrete pressed against it. Neat-oil agents do this by sitting as a continuous oily barrier film. A water-based emulsion like WB-23 works a little more cleverly. The product is shipped as an emulsion, so the active release oils are held dispersed in water; the film you brush or spray on is therefore very thin and even. Once it is on the shutter and left to dry, the water leaves and only a fine, uniform release layer remains, tightly keyed to the mould rather than sitting in puddles. Because that residual film is so thin and regular, two things follow. First, air is not trapped in thick oily pools against the form face, so far fewer blowholes and pin-holes telegraph through to the finished surface. Second, because there is minimal free oil to migrate into the concrete skin, the cast face stays light and stain-free and remains ready to accept later paints, renders or coatings. The trade-off to respect is that a water-borne film must be allowed to dry before concreting and must be protected from rain in that window, whereas an oil film is essentially water-resistant from the moment it goes on. Get the drying discipline right and the emulsion route gives a cleaner, safer, better-looking result.

Where it is used

• Steel and aluminium panel formwork for columns, walls and cores
• Coated and uncoated plywood and timber shuttering for slabs and beams
• Precast moulds for cladding panels, staircases, boundary walls and drains
• GRP and plastic moulds for architectural and profiled features
• Fair-faced and architectural exposed-concrete elevations
• Bridge, culvert and retaining-wall shutters on infrastructure works
• Tunnel-lining segment and paving formwork
• Repetitive precast-yard casting where fast, clean de-moulding drives output

Key advantages

• Water-based, so low fire risk, low odour and safer use in shafts, ducts and confined pours
• Quick, positive release that reduces de-shuttering labour and damage to forms
• Cuts blowholes, pin-holes and surface blemishes for a cleaner fair-faced finish
• Non-staining film keeps the cast face light and ready for later coatings
• Very thin, even emulsion film gives economical coverage per litre
• Tools, jets and spillages clean up with plain water, not solvent
• Progressively better results on timber forms with continued use
• Extends formwork and mould life, improving reuse cycles

Limitations & considerations

• The applied film must be allowed to dry before concrete is placed, unlike an oil film that is ready at once
• Freshly applied coating must be protected from rain during the drying window
• Not a curing compound, waterproofer or bond-breaker for slabs-on-grade; it is a form release agent only
• New or unsealed timber and ply may drink the first coat and need a heavier or extra application
• Formwork must be cleaned of hardened concrete build-up before every re-coat or release quality drops
• Over-application leaves excess film that can dust the concrete face and defeats the economy of the product

Selection & best practice

Specifications

Industry use cases

How we position Sika Separol WB-23

Within the Sika range, choose the water-based WB-23 emulsion when low odour, water clean-up and stain-free fair-faced concrete matter most; step up to oil-based Sika Separol (ready-to-use) when you need a film that is weather-resistant almost immediately and want to skip the drying-before-concreting step, and look at Sika Separol Plus for demanding architectural finishes. Pair the release agent with a Sika curing compound such as Antisol to protect the freshly stripped surface, and with the Sika MonoTop repair range for making good any blemishes or tie-holes. Where a project is standardised on Fosroc, the closest equivalent is Fosroc Reebol Emulsion, a water-dilutable chemical release agent covered separately.

Related Concrete Admixtures products

View all Concrete Admixtures products →