What is in the system
| Stage | Material | Purpose |
|---|---|---|
| Substrate prep | MDF or HDHMR, sanded to 180 grit, edges sealed | Board texture must be closed before any colour goes on |
| NC putty | 1 – 2 applications, block sanded | Fills grain and router marks |
| NC primer surfacer | 2 coats, sanded at 320 | Builds the flat base; most of the film thickness sits here |
| NC colour lacquer | 2 – 3 thin coats | Tinted; flashes off in 20–30 minutes between coats |
| NC clear or matting topcoat | 1 coat | Sets the sheen and the wipe resistance |
Total film thickness typically 50–70 microns against 90–120 for a full PU system — which is exactly why it costs less.
Rates in Mumbai, 2026
| Work | Rate (₹/sq ft elevation) | Comment |
|---|---|---|
| Duco matte on MDF, flat shutters | ₹380 – 470 | Bedroom and study joinery |
| Duco matte on HDHMR, routed profile | ₹450 – 560 | Shaker and fluted work on a budget |
| Duco high gloss, buffed | ₹520 – 650 | Needs buffing; the gloss is softer than PU gloss |
| Duco on MS or wrought iron elements | ₹220 – 380 | Grilles, partition frames, bed frames |
| Full re-spray of existing Duco joinery | ₹240 – 380 | Strip, sand, re-lacquer in place |
A 12 ft bedroom wardrobe elevation at 8 ft high in matte Duco is roughly ₹36,000–45,000 in finish.
Duco against PU, stated plainly
| Criterion | Duco / NC lacquer | Two-pack PU |
|---|---|---|
| Cure mechanism | Solvent evaporation | Chemical cross-link |
| Handling time | Same day | 24 hours; full cure 14–21 days |
| Film hardness | Moderate — marks with a fingernail at the edge | High |
| Water and grease resistance | Fair | Good |
| Touch-up | Excellent — new melts into old | Panel-face repair only |
| Yellowing | Noticeable on whites by year four | Slower; aliphatic topcoats resist it |
| Rate per sq ft | ₹380 – 650 | ₹640 – 1,150 |
Drying, humidity and blushing
NC lacquer releases solvent fast, and in a humid room that rapid evaporation chills the surface enough to condense moisture into the film. The result is blushing — a milky white haze, usually across a whole panel.
- It happens most often between June and September when relative humidity crosses 80%. A retarder thinner slows the flash-off and fixes it; an unskilled sprayer will simply apply another coat over the haze and lock it in.
- Blushed panels can be re-flashed with solvent while fresh. Once the film has hardened, the panel is sanded back and re-sprayed.
- Because the cure is physical, an old Duco surface still softens when new lacquer hits it. That is why touch-ups blend — and also why a solvent spill leaves a permanent mark.
- Near the sea, salt on a low-build NC film abrades the surface. We do not specify Duco for exposed joinery in sea-facing flats.
Where we use it, where we do not, and the BOQ line
- Use: bedroom wardrobes, study units, TV panelling, bed backs, pooja unit frames, MS grille and partition frames.
- Use: rental and short-horizon fit-outs, and any scheme where cheap, invisible future touch-up is worth more than maximum hardness.
- Do not use: kitchen base units, sink surrounds, bathroom vanities, utility joinery, anything within reach of steam.
- Do not use: pure white on a large, well-lit elevation you expect to keep for a decade.
- BOQ: “NC lacquer (Duco) system on 18 mm HDHMR — NC putty, two coats NC primer surfacer block-sanded, two coats tinted NC lacquer, one matting topcoat at approved sheen; minimum DFT 50 microns; retarder thinner to be used when site RH exceeds 75%.”
Specification summary
| Property | Specification |
|---|---|
| System | Nitrocellulose lacquer, single pack, evaporative |
| Substrate | 18 mm HDHMR or MDF, dry locations |
| Film thickness | 50 – 70 microns |
| Rate | ₹380 – 650 per sq ft elevation, ex-GST |
| Recoat / touch-up | Excellent, blends into existing film |
| Expected life | 7 – 10 years before a re-spray reads as needed |
| Humidity note | Blushes above 80% RH without retarder thinner |
| Avoid | Kitchens, bathrooms, utility areas, sea-facing exposed joinery |
Frequently asked questions
Is Duco the same as PU?+
No. Duco is nitrocellulose lacquer that dries by evaporation; PU is a two-pack coating that cures chemically. Duco is cheaper, faster and far easier to touch up. PU is harder, more water resistant and lasts longer. Vendors sometimes use the words loosely — ask which resin system is in the can.
Can Duco be used in a kitchen?+
On tall units away from the hob and sink, at a push. On base units, no. Kitchen joinery in Mumbai meets water, steam and hot oil aerosol daily, and a 60-micron evaporative film is not the right barrier. Specify PU or acrylic for the working part of a kitchen.
Why did my white Duco wardrobe turn cream?+
Nitrocellulose ambers with age and light; it is inherent to the resin, not a defect in application. A re-spray restores it, and because Duco touches up so well that re-spray is comparatively cheap. If you want white to stay white for ten years, use PU or an acrylic sheet.
How soon can furniture be used after Duco spraying?+
Handled the next day, loaded after three or four days. The solvent smell clears in 48–72 hours with ventilation. That speed is the main reason Duco survives in a market where site programmes are tight.
Is Duco cheaper enough to justify the shorter life?+
Often, on bedrooms. You save roughly ₹250–450 per sq ft of elevation, and a re-spray at year eight costs ₹240–380 — so two cycles of Duco can still come in under one PU job. On kitchens, the maths does not work, because the failure mode is water damage rather than wear.