STP ShaliSeal PS GG
A two-component polysulphide gun-grade sealant that stays flexible for the life of a movement joint, resisting UV, chemicals, fuel and permanent submersion.
What is it?
A two-component, polysulphide-polymer joint sealant of gun-grade consistency, mixed on site and gunned into movement and construction joints.
Where is it used?
Expansion joints in buildings, concrete pavements, bridges, runways and water-retaining structures such as tanks, pools and reservoirs.
Why use it?
It stays rubbery and elastic for years, absorbing joint movement of up to +/-25% without cracking, while resisting UV, weathering, chemicals and fuel.
How is it applied?
Mix Base and Accelerator (92:8 by weight), prime the joint faces, then gun the compound into the primed groove within its pot life and tool to a concave finish.
About STP ShaliSeal PS GG
STP ShaliSeal PS GG is the gun-grade member of STP Limited’s polysulphide sealant range, formulated for movement and construction joints where long-term elasticity matters more than anything else. It arrives as two pre-weighed parts, a grey Base and an Accelerator, that are blended on site into a homogenous compound. Once cured it forms a tough, rubbery seal that bonds to cementitious substrates, aluminium, glass, timber and mild steel, so a single product handles most of the joint details found on a typical Indian project. The formulation is built to conform to BS 5212:1990 Part I (Type F and Type FB, flame and fuel resistant), IS 12118 Part 1-1987, BS 4254 and ASTM C 920.
What makes the polysulphide chemistry worth specifying is its endurance. The cured sealant keeps its recovery characteristics after long spells of compression or elongation, shrugging off the daily and seasonal cycling that opens and closes joints. It is genuinely UV-resistant, so it survives exposed vertical and horizontal joints without chalking or going brittle, and it holds up under a wide chemical and weathering load. After full cure it can sit fully submerged and is rated suitable for contact with potable water, which is why it turns up repeatedly on water tanks, swimming pools, reservoirs and treatment structures. For engineers and applicators in Delhi NCR and across India, it is a dependable, standards-backed workhorse for joints that have to move and stay watertight.
The technical insight
Polysulphide sealants cure by a chemical reaction, not by drying, and that is the whole point. When the Base and Accelerator are mixed at 92:8 by weight, the accelerator cross-links the liquid polysulphide polymer into a three-dimensional rubber. Because the network is built by chemistry rather than solvent loss, the sealant cures right through the section with almost no shrinkage and reaches a Shore A hardness of around 20, soft enough to flex yet firm enough to resist tearing. That elastomeric network is what delivers the elongation at break of roughly 400% and the tested movement accommodation of +/-25% on butt joints and +/-50% on lap joints under ASTM C 719: the joint can open and close through thermal cycling while the sealant stretches and recovers instead of splitting. The sulphur-rich polymer backbone is also inherently resistant to UV, ozone, fuels and many chemicals, and stays serviceable from -40 C to +85 C, which is why the seal keeps working long after cheaper sealants have hardened and pulled away from the joint arris.
Where it is used
- Expansion joints in industrial, commercial and residential buildings
- Construction and movement joints in concrete floors and structures
- Joints in concrete roads, bridges, subways and flyovers
- Joints in airport runways and taxiways
- Joints in water-retaining structures: tanks, swimming pools and pool decks, reservoirs
- Joints in aqueducts, dams and canals
- Joints between concrete pipelines and around roof-light details
- Movement joints on nuclear power station reactor domes and similar heavy civil works
Key advantages
- Excellent UV resistance keeps exposed joints from chalking or going brittle
- Cures to a highly resilient rubber with excellent recovery after repeated compression and elongation
- Accommodates joint movement of +/-25% on butt joints and +/-50% on lap joints
- Bonds to most construction substrates: concrete, aluminium, glass, timber and mild steel
- Resistant to a wide range of chemicals, plus flame and fuel (BS 5212 Type F and FB)
- Suitable for fully submerged service and rated for contact with potable water after full cure
- Conforms to IS 12118 Part 1, BS 5212, BS 4254 and ASTM C 920 for specifier confidence
- Wide service range of -40 C to +85 C suits Indian climatic extremes
Limitations & considerations
- Two-component product that must be fully mixed at 92:8 by weight on site; poor mixing means poor cure
- Requires priming of joint faces and a compatible back-up rod or bond-breaker for correct behaviour
- Substrate moisture must not exceed 5% at the time of application, so damp joints need drying first
- Not for grooves wider than 50 mm, and joint depth must not exceed joint width
- Limited application window: gunning starts about 30 minutes after mixing and must finish within the pot life
- Supplied in grey only; not a decorative or colour-matched sealant
Selection & best practice
Start by cleaning the joint back to sound substrate, removing loose gravel, dirt, oil and grease with dry compressed air and mechanical grinding, and confirm the surface moisture is below 5%. Run masking tape along both arrises for a sharp, clean edge and set a back-up rod to break the third-face bond and control depth. Prime the vertical side faces and let the primer become tacky. Mix the whole pre-weighed Base and Accelerator together with a slow-speed paddle at about 400 rpm until the grey compound is uniform and free of entrapped air. Begin gunning roughly 30 minutes after mixing, keeping the depth no greater than the width and never exceeding a 50 mm groove. Tool the sealant to a concave profile with a wooden batten dipped in soapy water or white spirit, pull the masking tape within 30 minutes before it sets, and clean tools with a solvent such as xylene. Allow full cure before flood-testing or submerging.
Specifications
| Chemistry | Two-component polysulphide-polymer sealant, gun grade |
| Colour | Grey |
| Standards | BS 5212:1990 Part I (Type F & FB), IS 12118 Part 1-1987, BS 4254, ASTM C 920 |
| Mixing ratio (A:B) | 92:8 by weight |
| Theoretical coverage | 550 gm/rm for a 25 x 12.5 mm joint |
| Movement accommodation | Butt joints +/-25%, lap joints +/-50% (ASTM C 719) |
| Elongation at break / Shore A | 400 +/- 100% (ASTM D 412); Shore A hardness ~20 +/- 3 (ASTM D 2240) |
| Service temperature | -40 C to +85 C |
| Packaging | 4 kg unit (3.68 kg Component A + 0.32 kg Component B) in a 16 kg carton |
| Shelf life | 12 months in original sealed packing, stored at 5-30 C |
Industry use cases
Water Retention & Treatment
Sealing movement joints in tanks, reservoirs, aqueducts and pools where the potable-water-suitable, fully submersible seal is essential.
Transport Infrastructure
Sealing expansion joints in concrete roads, bridges, flyovers, subways and airport runways subject to heavy traffic and thermal cycling.
Commercial & Residential Buildings
Weatherproofing expansion and construction joints in facades, terraces and floors where UV exposure and long-term flexibility are needed.
Industrial & Heavy Civil
Chemical-, fuel- and flame-resistant joints in plants, pipeline junctions and demanding structures such as reactor domes.
Frequently asked questions
Is ShaliSeal PS GG safe for drinking-water tanks and swimming pools?
How much sealant do I need per running metre?
What is the maximum joint width it can handle?
Do the joint faces need priming?
How long do I have to apply it once mixed?
What pack size and shelf life does it come in?
How we position STP ShaliSeal PS GG
Within STP’s own range, choose ShaliSeal PS GG for vertical and gun-applied joints; for horizontal floor and pavement joints where a self-levelling pour is easier, its sister product ShaliSeal PS PG (pouring grade) is the natural companion. Where movement demand is very high or a modern facade needs a paintable, colour-matched finish, STP’s polyurethane gun-grade sealant ShaliSeal PU GG is the alternative to consider. As an authorised distributor and applicator, Space Arc also supplies equivalents across our other brands, including Fosroc’s polysulphide and polyurethane movement-joint sealants and Sika’s Sikaflex range, so we can match the sealant to the standard your consultant has specified rather than force a single product onto every joint.
Fosroc Thioflex 600 — Specify the Fosroc option when the project documents call out Thioflex 600 by name or require a Fosroc-approved polysulphide system for the movement joints.
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