Short answer: National N.C. Primer Surfacer is a single-pack primer based on nitrocellulose and alkyd resins, for automotive and steel surfaces and cabinet work. National says it balances sandability, water resistance and topcoat holdout. It is touch dry in about 30 minutes, recoats in 3 to 4 hours at 30°C and covers 10 to 12.5 m² per litre. Thin it with National Lacquer Thinner, not G.P. Thinner.
Where it fits in the N.C. range
| Product | Job |
|---|---|
| N.C. Primer Surfacer | Primer and sandable build coat on steel, car panels, cabinets |
| N.C. Putty | Thin glazing of small marks (40 to 50 µm) |
| Polyester Putty | Thick dent filling (100 to 1000 µm) |
| N.C. Auto Lacquer Topcoat | Coloured finish |
| N.C. Lacquer Clear | Clear finish |
Key facts
| Type | Nitrocellulose and alkyd primer surfacer, single pack |
| Uses | Automotive and steel surfaces, cabinet work |
| Finish and colours | Matt; white, grey |
| Volume solids | 44 ± 2% |
| Spreading rate | 10 to 12.5 m² per litre (theoretical) |
| Film per coat | 35 to 45 microns dry (80 to 100 wet) |
| Drying at 30°C | Touch dry 30 minutes; recoat 3 to 4 hours; hard dry 4 to 5 hours |
| Application | Brush, roller or spray (airless 2000 to 2300 psi, tip 0.017 to 0.021 inch) |
| Thinning | 10 to 15% with National Lacquer Thinner |
| Flash point | 7°C |
| Shelf life | 18 months, sealed |
Step 1: prepare the steel
- Degrease first, as National’s surface preparation guide requires before any mechanical cleaning.
- Remove rust and mill scale: blast to Sa 2.5 where possible, or hand/power tool clean to St 2.
- On old paintwork, sand to a key, then wipe clean and dry.
Step 2: the system
- N.C. Primer Surfacer, one coat.
- N.C. Putty or Polyester Putty, as needed, sanded.
- N.C. Primer Surfacer, one coat.
- N.C. Auto Lacquer Topcoat, two coats.
What the numbers mean
Coverage = 44 × 10 ÷ 35 ≈ 12.6 and 44 × 10 ÷ 45 ≈ 9.8 m² per litre, matching the sheet’s 10 to 12.5. The system uses two coats of surfacer, so double the per-coat figure.
How much to buy
| Area | 1 coat | 2 coats (full system) |
|---|---|---|
| 5 m² of panels | about 0.4 to 0.5 L | about 0.8 to 1 L |
| 10 m² | about 0.8 to 1 L | about 1.6 to 2 L |
| 25 m² (cabinet run) | about 2 to 2.5 L | about 4 to 5 L |
Mistakes to avoid
- Using G.P. Thinner. The sheet lists National Lacquer Thinner.
- Sanding too soon. Hard dry is 4 to 5 hours at 30°C.
- Working near flames or sparks. The flash point is 7°C.
Frequently asked questions
Is it flammable?
Yes. With a 7°C flash point, keep it away from heat and flames, ventilate well and read the safety data sheet before use.
Can I use it under enamel instead of lacquer?
The listed system ends in N.C. Auto Lacquer. For alkyd enamel on steel, National’s route is Red Oxide Primer, Undercoat and Gloss I.
Buy in Sharjah and Dubai
Al Tashteb Al Saree is an authorised National Paints retailer in Bu-Tina, Sharjah. Message us on WhatsApp for Primer Surfacer and Lacquer Thinner.
Sources
- National N.C. Primer Surfacer data sheet (PDF)
- National Paints surface preparation guide, Sec. A-2 (PDF)
All via AEC Online, retrieved 4 November 2026. Quantities are our own calculations. The main image is illustrative.
