STP TarStilTar
STP’s economical, quick-drying coal tar coating for everyday steel and concrete corrosion protection, available in Grade A and Grade B to IS 290.
What is it?
A coal tar based, single-pack anti-corrosive paint from STP Limited, offered in Grade A and Grade B to suit different exposure and finish needs.
Where is it used?
Structural steelwork, pipe supports, gates, ducting, bridge steel and buried or damp-side concrete where a low-cost protective film is enough.
Why use it?
It gives proven coal tar barrier protection at a fraction of the cost of two-pack coal tar epoxy systems, and dries fast enough to keep maintenance turnarounds short.
How is it applied?
Brushed, rolled or sprayed onto clean, dry, de-rusted steel or sound concrete, usually in two coats with the recoat interval governed by the current TDS.
About STP TarStilTar
TarStilTar is STP Limited’s economy-grade anti-corrosive coating, built around coal tar chemistry that has protected steel and concrete on Indian sites for decades. It is aimed squarely at the jobs where a full coal tar epoxy build would be over-specified and over-budget: routine maintenance repainting, temporary works, buried steel, pipe cradles, and the endless linear metres of secondary steel that still need a dependable barrier against moisture and mild chemical attack. The product is single-pack, so there is no mixing ratio to get wrong on site and no pot life racing against the crew, which matters when the work is spread across a plant or a bridge deck rather than a controlled shop.
STP supplies it in two grades so the specifier can match cost to duty. Grade A conforms to IS 290 Type A and is the choice where a good-quality, quick-drying finish is wanted; Grade B conforms to IS 290 Type B for more general-purpose work. Both trade on the same core idea, a coal tar film that seals the substrate cheaply and cures quickly, which is why contractors reach for TarStilTar on maintenance rounds and on projects where the protective spec is modest but the surface area is large. As an authorised STP channel, Space Arc Engineering supplies TarStilTar with grade guidance, the governing technical data sheet, and applicator support across Delhi NCR and Pan-India.
The technical insight
Coal tar coatings protect by physical barrier rather than by sacrificial or inhibitive action. The coal tar pitch forms a dense, hydrophobic film that is very slow to let water and dissolved oxygen reach the steel, and without water plus oxygen at the metal surface the electrochemical corrosion cell simply cannot run. Coal tar’s aromatic, largely non-polar molecular structure is what makes it so water-repellent and so resistant to the dilute acids, alkalis and salts found in soil and effluent, which is exactly why the chemistry has survived on buried pipelines and immersed steel long after fancier binders came and went. TarStilTar is formulated to build that barrier economically and to lose solvent quickly, so the film sets and can be recoated without the long inductive and overcoat windows that two-pack epoxies demand. The trade-off is deliberate: it is a single-pack barrier paint, not a chemically cross-linked lining, so it protects well in the low-to-moderate exposure band it is designed for rather than in aggressive immersion or heavy abrasion, where STP’s ShaliPoxy CTE coal tar epoxies take over.
Where it is used
- Maintenance repainting of existing coal tar coated structural steel
- Anti-corrosive protection of secondary steelwork, gratings, gates and ducting
- Coating of pipe supports, cradles and buried or damp-side steel sections
- Bridge and infrastructure steel where an economical protective film is specified
- Protection of sound concrete surfaces against moisture ingress
- General-purpose corrosion protection over large steel surface areas
- Temporary works and stored steel needing low-cost interim protection
- Touch-up and recoating during routine plant maintenance shutdowns
Key advantages
- Economical compared with two-pack coal tar epoxy systems for the same barrier duty
- Quick-drying, which shortens recoat intervals and speeds maintenance turnarounds
- Single-pack — no mixing ratios, no pot life, minimal site error
- Two grades (A and B) let you match cost and finish to the exposure
- Coal tar chemistry gives proven, water-repellent barrier protection
- Conforms to IS 290 (Grade A Type A, Grade B Type B) for specification comfort
- Applies by brush, roller or spray, suiting awkward site geometry
- Works on both steel and sound concrete substrates
Limitations & considerations
- A single-pack barrier paint, not a cross-linked lining — not for aggressive chemical immersion or potable water contact
- Coal tar coatings carry health and handling cautions; follow the MSDS and use PPE and ventilation
- Dark coal tar colour only — not suitable where a decorative or light finish is required
- Solvent-borne, so surface must be genuinely clean, dry and de-rusted for the barrier to perform
- Less abrasion and impact resistant than high-build coal tar epoxies
- Consumption, film thickness and recoat times must be taken from the current STP TDS, not assumed
Selection & best practice
Performance lives or dies on surface preparation. Steel should be cleaned to remove rust, mill scale, oil and old loose coating, and must be dry before the first coat; on concrete, the surface should be sound, clean and free of laitance and standing moisture. Apply in two coats by brush, roller or spray, keeping film thickness even and letting the first coat dry to the manufacturer’s recoat window before the second. Stir the material before use, do not over-thin, and coat within the ambient conditions given on the TDS — avoid application onto hot steel in direct sun or in damp, condensing conditions. Because it is coal tar, work with adequate ventilation and full PPE, and confirm the exact consumption rate, dry film thickness and drying times against the current STP technical data sheet for the grade you are using before ordering quantities.
Specifications
| Product Type | Coal tar based economical anti-corrosive coating |
| Brand / Manufacturer | STP Limited |
| Grades | Grade A and Grade B |
| Standard (Grade A) | Conforms to IS 290 Type A |
| Standard (Grade B) | Conforms to IS 290 Type B |
| Number of Components | Single-pack (ready to use) |
| Drying | Quick-drying (see TDS for stage times) |
| Application Method | Brush, roller or spray |
| Substrates | Structural steel and sound concrete |
Industry use cases
Infrastructure & Bridges
Economical anti-corrosive repainting of secondary and maintenance steel on bridges and civil structures where the protective spec is modest but the area is large.
Water & Utilities
Barrier protection for pipe supports, cradles and buried or damp-side steel sections outside potable-contact zones.
Industrial Plants
Routine shutdown touch-up and recoating of gratings, gates, ducting and structural steel during maintenance rounds.
General Building & Fabrication
Low-cost interim and permanent corrosion protection for stored steel, fabricated sections and secondary steelwork.
Frequently asked questions
What is the difference between TarStilTar Grade A and Grade B?
How is TarStilTar different from a coal tar epoxy like ShaliPoxy CTE?
Can TarStilTar be used on concrete as well as steel?
What surface preparation does it need?
Is it suitable for drinking-water tanks or aggressive chemical immersion?
Does Space Arc supply TarStilTar across India and provide application support?
How we position STP TarStilTar
TarStilTar is the entry point of STP’s coal tar protective range — the economical, single-pack option for everyday, low-to-moderate corrosion duty. When the exposure gets tougher, step up within the same STP family: ShaliPoxy CTE 103/203/303/403 for two-pack high-build coal tar epoxy protection, the moisture-insensitive CTE 103 MI / 303 MI grades for damp concrete, ShaliMastic HD/LC for thick thermoplastic coal tar coatings, and ShaliEnamel or the PipeWrap CT hot-applied tapes for pipeline work. Where a project calls for a light or decorative protective finish instead of dark coal tar, Space Arc can cross-refer to epoxy and acrylic protective coatings from Fosroc (Dekguard, Nitocote) or our other brand families. Talk to Space Arc for grade selection so the coating you order matches the exposure rather than over- or under-specifying.
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