STP ShaliProtek 2E PA 120
A two-component, high-build polyamine-cured epoxy that builds roughly 120 microns per coat to shield steel and concrete against corrosion, chemicals and abrasion.
What is it?
A two-pack, cold-cure epoxy protective coating from STP, built on a polyamine-adduct hardener and loaded with anti-corrosive pigments. The ‘120’ refers to its target dry film thickness of about 120 microns per coat.
Where is it used?
Structural steelwork, plant and equipment, pipe racks, storage tanks, bridges, and RCC surfaces in industrial and marine-influenced environments across Delhi NCR and pan-India.
Why use it?
It forms a dense, chemically-bonded barrier that keeps moisture, salts and mild chemicals away from the substrate, extending the maintenance cycle of exposed steel and concrete.
How is it applied?
Grit-blasted or mechanically prepared surface, then two components mixed 3:1 by volume and applied by brush, roller or airless spray, usually in two coats to reach the specified build.
About STP ShaliProtek 2E PA 120
STP ShaliProtek 2E PA 120 (formerly marketed as ShaliPoxy HB) belongs to the polyamine-cured, high-build family of industrial epoxies. Both packs are mixed on site: a pigmented epoxy base and a polyamine-adduct hardener that react at ambient temperature to form a hard, cross-linked film. Because it is designed to lay down close to 120 microns in a single application, fewer coats are needed to reach a protective thickness, which matters on large steel structures where every additional pass adds labour, downtime and cost.
The coating is surface-tolerant and self-priming on well-prepared substrates, so on many jobs it doubles as both primer and intermediate coat. That flexibility, combined with its anti-corrosive pigment package, makes it a practical workhorse for fabricators, EPC contractors and plant maintenance teams. Space Arc Engineering supplies the material and, as an authorised applicator, can carry out surface preparation and application to specification, so the film you pay for is the film you actually get on the steel.
The technical insight
Corrosion of steel is an electrochemical process: it needs moisture, oxygen and an electrolyte such as dissolved salt reaching the metal. ShaliProtek 2E PA 120 interrupts that process in two ways. First, the cured epoxy is a dense, largely impermeable barrier, so water and ions struggle to reach the substrate. Second, the polyamine-adduct hardener gives a tightly cross-linked network that resists chemical attack and adheres strongly to blast-cleaned steel, keeping the barrier intact under thermal cycling and mild abrasion. The high-build formulation is the practical lever here: laying down about 120 microns per coat means the barrier reaches its protective thickness in fewer passes and with fewer pinholes than a thin conventional epoxy. The one honest limitation of this chemistry is UV: like all epoxies, the surface chalks in sunlight, so for exposed exterior steel it is used as the corrosion-protection layer beneath an aliphatic polyurethane topcoat that carries the gloss and colour retention.
Where it is used
- Corrosion protection of structural steel, pipe racks and platforms in industrial plants
- High-build barrier coat for storage tanks, silos and process vessels (exterior and shaded areas)
- Protective lining and coating of RCC surfaces, sumps and concrete structures
- Primer-cum-intermediate coat within a multi-coat epoxy-PU protective system
- Refurbishment and re-coating of ageing steelwork during shutdown maintenance
- Coating of fabricated steel in workshops before dispatch to site
- Protection of steel and concrete in coastal and high-humidity environments
- Chemical and abrasion-resistant coating for machinery bases and equipment
Key advantages
- High-build film of around 120 microns per coat, reducing the number of coats to reach protective thickness
- Two-component polyamine cure gives strong adhesion and a hard, durable film
- Surface-tolerant and self-priming on properly prepared steel and concrete
- Good resistance to mild chemicals, salts, moisture and abrasion
- Cold-curing at ambient temperature, so no external heat or baking is required
- Can be applied by brush, roller or airless spray to suit site conditions
- High solids content means more dry film per litre and less solvent loss
- Compatible with aliphatic PU topcoats for a complete, colour-stable exterior system
Limitations & considerations
- Not UV-stable on its own: the epoxy surface chalks in sunlight and needs a PU topcoat for exposed exterior use
- Performance depends heavily on surface preparation; poorly blasted or contaminated steel undermines adhesion
- Limited pot life once the two packs are mixed, so material must be used within the working window
- Application is temperature-sensitive and should not be done in cold, damp or condensing conditions
- Being solvent-based, it requires adequate ventilation and PPE during application
- Colour and gloss are secondary to protection, so it is not intended as a decorative finish coat
Selection & best practice
Preparation decides the result. On steel, abrasive blast to a clean, angular profile (in line with SSPC/NACE practice) and coat before flash-rusting sets in; on concrete, allow the surface to cure for at least 28 days, then remove laitance and make good blow-holes. Mix the base and polyamine hardener in the specified 3:1 ratio by volume, mix thoroughly with a slow-speed stirrer, and only mix what can be used within the pot life. Apply in two coats to reach the target build, respecting the overcoat window between coats so the film keys properly. Keep an eye on ambient and substrate temperature and dew point during application. For any surface in direct sunlight, plan for an aliphatic polyurethane topcoat over the fully cured epoxy. Space Arc can execute this full system on site to the specified DFT.
Specifications
| Product type | Two-component, cold-cure high-build epoxy (polyamine-adduct cured) |
| Target DFT | ~120 microns per coat |
| Mixing ratio | 3:1 by volume (base : hardener) |
| Volume solids | ~82 ± 2% |
| Theoretical coverage | ~5 to 8 m² per litre (thickness-dependent) |
| Number of coats | Typically two coats to reach protective build |
| Application methods | Brush, roller or airless spray |
| Substrates | Steel, concrete and other prepared construction surfaces |
| UV exposure | Requires aliphatic PU topcoat for exterior/UV-exposed areas |
Industry use cases
Industrial plants & factories
Protecting structural steel, pipe racks and equipment from corrosion in humid, dusty and mildly chemical process environments.
Storage tanks & vessels
High-build exterior barrier coat for tanks and silos, extending re-painting cycles and reducing shutdown frequency.
Infrastructure & bridges
Corrosion protection of exposed steelwork and RCC elements, applied as the epoxy base beneath a PU topcoat.
Fabrication workshops
Shop-applied protective coat on fabricated steel before dispatch, so members arrive on site already protected.
Coastal & marine-influenced sites
Barrier against salt-laden humidity on steel and concrete in high-chloride coastal environments.
Frequently asked questions
What does the ‘120’ in ShaliProtek 2E PA 120 mean?
Can I use it on exterior steel exposed to sunlight?
Does it work on concrete as well as steel?
What is the mixing ratio and can I mix part of a pack?
How is it applied and how many coats are needed?
How is this different from a potable-water tank lining epoxy?
How we position STP ShaliProtek 2E PA 120
Within the STP range, ShaliProtek 2E PA 120 is the high-build member of the ShaliProtek 2E PA polyamine-epoxy series; the lower-build ShaliProtek 2E PA 80 suits thinner-film specifications, and both are typically finished with an STP aliphatic polyurethane topcoat for UV-exposed exterior steel. Where a project standardises on a different brand, Space Arc also supplies equivalent high-build epoxy protective coatings from Fosroc for corrosion protection of steel and concrete. This is a general industrial anti-corrosion coating, so it should not be confused with potable-water tank linings or severe chemical-immersion coatings, which are separate, purpose-certified products.
Fosroc Nitocote EP405 — Specify the Fosroc option when the job needs a solvent-free, IS 9833-certified epoxy for potable-water tanks or food-contact surfaces, rather than a general exterior anti-corrosion coating.
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