STP ShaliPoxy GF
Two-pack, 98%-solids glass flake reinforced epoxy from STP Limited that armours steel and concrete against abrasion, acids, alkalis and salt — built for splash zones, jetty piles and tank linings.
What is it?
A two-component, high-solids epoxy coating from STP Limited, reinforced with glass flakes that stack into an overlapping barrier within the cured film. Standard shades are grey and brownish, with other colours on order.
Where is it used?
Marine splash zones, jetty pilings and working decks, boat bumpers and landings, and as internal lining for crude oil, fuel oil and storage tanks — on blasted steel or prepared concrete.
Why use it?
At 98 ± 2% volume solids it builds 300–400 microns in a single spray pass, shows no corrosion after 3,000 hours of salt spray, and loses under 50 mg in Taber abrasion testing.
How is it applied?
Blast the substrate to Sa 2½, prime with ShaliPrime Zn Ph 60, then spray with a plural-feed or single-feed airless gun; brush or roller suits smaller single-feed jobs.
About STP ShaliPoxy GF
ShaliPoxy GF is STP Limited’s heavy-duty response to the twin problems of mechanical wear and chemical attack on marine and industrial structures. It is a two-component epoxy loaded with lamellar glass flakes, mixed 3:1 by volume, curing to a dense film at 98 ± 2% volume solids — so almost everything sprayed stays on the surface as protective thickness instead of evaporating as solvent. Supply formats match the application method: 200 L drum sets for plural-feed spray crews, or a 20 L unit pack (15 L Part A, 5 L Part B) for single-feed work.
Space Arc Engineering supplies and applies ShaliPoxy GF across Delhi NCR and pan-India for ports, refineries, shipyards and chemical plants. The laboratory record is demanding: pull-off adhesion above 7 MPa on blasted steel, Shore D hardness of 75–80, and no sign of corrosion after 3,000 hours of ASTM B 117 salt spray at 300 microns DFT. In 24-hour exposure trials it rates excellent against 10% sulfuric acid and 10% sodium hydroxide, and good against 50% sulfuric and 10% nitric acid — numbers few plain epoxies can match.
The technical insight
Glass flakes change how an epoxy resists its environment. As the coating is applied, thousands of thin lamellar flakes settle roughly parallel to the substrate, layering into an overlapping, roof-tile arrangement through the film. Water molecules, chloride ions or acids trying to reach the steel must detour around each flake in turn, so the effective diffusion path becomes many times longer than the film is thick — this tortuous-path effect is why a 400-micron glass flake coating outperforms much thicker plain epoxy on permeability. The flakes also share mechanical load, spreading impact and gouging energy across rigid platelets rather than concentrating it in the resin — which is what the sub-50 mg Taber result and 4 kg scratch resistance reflect.
Where it is used
- Splash-zone coating on marine structures and vessel areas above and below the waterline
- Jetty pilings and working decks in ports and harbours
- Internal lining for crude oil, fuel oil and storage tanks
- Boat bumpers, landings and other impact-prone marine faces
- Steel and concrete in chemical handling areas exposed to acids, alkalis, solvents and salts
- Corrosion protection of structural steel in coastal, high-salinity industrial environments
Key advantages
- 98 ± 2% volume solids — negligible solvent loss, so dry film build is close to wet film thickness
- High build of 300–400 microns per coat by plural-feed airless spray
- Taber abrasion loss below 50 mg (CS-17 wheel, 1,000 cycles, ASTM D 4060)
- No corrosion after 3,000 hours of salt spray at 300 microns DFT (ASTM B 117)
- Pull-off adhesion above 7 MPa on blasted steel and 2.5 MPa on concrete (ASTM D 4541)
- Rated excellent against 10% sulfuric acid and 10% sodium hydroxide in 24-hour exposure
- Works with both plural-feed and single-feed airless equipment, plus brush or roller for smaller areas
Limitations & considerations
- Plural-feed pot life is only 5–10 minutes and components need pre-heating (Part A to 60–70°C), so dedicated equipment and an experienced crew are essential
- Application window is +10°C to +40°C with substrate moisture below 5% — not for damp or cold substrates
- Performance depends on Sa 2½ blast preparation; quoted adhesion assumes properly blasted steel
- Chemical contact causes slight discolouration (protection is retained), and like any epoxy it will chalk under exterior UV — specify it for protection, not appearance
- Full cure takes 5–7 days at 27°C, which sets the earliest return to immersion service
- Flammable during application — ventilation, ignition control and static-discharge precautions are mandatory
Selection & best practice
Surface preparation decides the outcome. Blast steel to Sa 2½ (grind or shot-blast concrete), removing all oil, dust and loose particles; STP recommends priming with ShaliPrime Zn Ph 60. For single-feed work, mix the full 3:1 pack for 3–5 minutes with a slow-speed stirrer, keeping the paddle below the surface — never mix by hand. Thin only if unavoidable, with 1–5% STP Thinner, accepting reduced sag resistance and film build. Spray at 300–400 microns WFT by plural feed using a 70:1 pump at 2,500–4,000 psi tip pressure, or 250–300 microns by single feed. Apply the second coat once the first has dried — 6–10 hours (plural feed) or 5–8 hours (single feed) at 30°C — and solvent-wipe first if the interval stretches past 16 hours. Clean tools immediately with STP Thinner.
Specifications
| Supply form / mixing ratio | Two-pack epoxy, Component A : B = 3 : 1 by volume |
| Volume solids | 98 ± 2% |
| Density of mix | 1.52 ± 0.02 g/cc |
| Theoretical coverage | 2.20–2.50 m²/L at 400 microns DFT |
| Recommended DFT per coat | 300–400 µ (plural feed); 250–300 µ (single feed) |
| Pot life @ 27°C | 5–10 min (plural feed); 30–40 min (single feed) |
| Drying time @ 27°C | Touch dry 1–2 h; hard dry 10–14 h; full cure 5–7 days |
| Pull-off adhesion, 7 days (ASTM D 4541) | >7 MPa on blasted steel; >2.5 MPa on concrete |
| Salt spray (ASTM B 117) | No sign of corrosion at 3,000 hours, 300 µ DFT |
Industry use cases
Ports & Marine Infrastructure
Jetty pilings, working decks and fender areas take tidal abrasion, salt and vessel impact — the glass flake barrier addresses all three in one system.
Oil & Gas Storage
Internal lining for crude oil and fuel oil storage tanks, where the 98%-solids film forms a dense, low-permeability barrier between product and steel.
Shipbuilding & Repair
Vessel areas above and below the waterline, plus boat bumpers and landings that need a coating tolerant of both immersion and knocks.
Chemical & Process Plants
Steel and concrete around acid, alkali and solvent handling, backed by 24-hour exposure ratings against sulfuric acid and caustic soda.
Coastal Industry & Power
Structural steel in salt-laden coastal atmospheres, where the 3,000-hour salt spray result translates into longer repaint cycles.
Frequently asked questions
What is the difference between single-feed and plural-feed application?
How much area does a 20 L pack cover?
Is a primer compulsory?
When can a lined tank return to service?
What if we miss the recoat window?
Will the colour change in chemical service?
How we position STP ShaliPoxy GF
Within the STP family, ShaliPoxy GF sits at the aggressive end of the protective coatings range: pair it with ShaliPrime Zn Ph 60 zinc phosphate primer on blasted steel, and keep STP Thinner on hand for dilution and tool cleaning. For concrete bunds and containment structures at moderate chemical exposure — rather than steel in immersion or splash-zone abrasion duty — many consultants specify the solvent-free Fosroc Nitocote EP410, which we also stock. Space Arc supplies and applies both systems and can advise which suits your exposure schedule.
Fosroc Nitocote EP410 — Specifiers protecting concrete bunds and containment structures at moderate chemical exposure — rather than steel in splash-zone or immersion duty — often choose the solvent-free Nitocote EP410 instead.
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