Tuesday, 5 January 2016

What is Duco Paint? How is it applied?


Duco is a brand marketed by Imperial Chemical Industries (ICI now merged with Akzo Nobel) under which it sells its popular Automotive paints. The Duco brand represents a range of products meant for auto painting and refinishing. The topcoat or the finish coat available under the brand Duco is a Nitro Cellulose (NC) Lacquer. Due to its wide spread use and popularity, the name "Duco" has been genericized to refer to Nitro Cellulose (NC) Lacquers.

Duco was vastly popular as an automotive finish before the advent of Polyurethane paints. Now a days Duco has found a new life as a high quality finish for interiors and other architectural projects. 

NC Lacquers typically are a clear or coloured wood/metal finish that dry by solvent evaporation and produce a hard, durable finish.  (Read more about Lacquers in general here)

Duco being an NC Lacquer has the following properties :

  • Fast Drying
  • High Solid content 
  • Excellent Water Barrier
  • Excellent Self Leveling properties
  • Takes very well to buffing to give a high sheen 
  • Smooth and Hard finish
 Areas of Application :
  • Automobile body
  • Plywood and MDF
  • Sheet Metal
  • MS angles and flats
  • Architectural and Industrial metal structures
The different surfaces require different preparations. Let us look at the application methods for each of the surfaces mentioned above.


Application method for Sheet Metal and MS Structures :
Materials Required
  • Compressor capable of delivering 30-40 psi pressure consistently.
  • A good quality spray gun - preferably HVLP type.
  • Safety Equipment - Mask, Glasses, Gloves and Overalls.
  • Degreaser solvent
  • Degreaser Cloth
  • Duco Oil Primer / MRF Etch Primer
  • Tak Cloths - to remove sanding dust.
  • Duco Primer Surfacer - Grey / White - depending on the top coat colour you choose. For Lighter coloured top coats, use Primer Surfacer White and for darker topcoats, use Primer Surfacer Grey.
  • Duco Soft Cut Putty 
  • Water Emery (Latex paper backed) of grits 220 and 320
  • Sanding block
  • Duco NC Lacquer
  • Duco Thinner
  • Rubbing Compund - 3M 1Step is highly recommended.
  • Cotton Waste
Application
  • Scrap off any loose particles, dirt and old paint from the metal surface to bare metal.
  • If the base metal is galvanized, an etch primer is recommended.
  • For bare sheet metal, a coat of Duco Oil Primer thinned with a General Purpose thinner in the ratio 5:1 must be applied and allowed to dry overnight. The Duco Oil Primer has excellent adhesion, corrosion resistance and is air drying.
  • Apply 2 coats of Duco Primer Surfacer (PS) thinned with Duco Thinner in the ratio 1:1.5 with a flash off interval of 15 minutes between coats.
  • Rectify any minor dents and scratches using Duco Soft Cut Putty and a putty knife.
  • Wet sand with water emery of grit 220 followed by 320 to level any imperfections.
  • Apply a coat of Primer Surfacer on the puttied areas.
  • Choose a colour!
  • Apply 2 coats of Duco NC Lacquer thinned with Duco Thinner in the ratio 1:2 of the selected colour. Allow flash off interval of 15 minutes between coats.
  • Leave to dry overnight.
  • Wet sand flat (remove gloss) carefully with emery grits 600/800and apply one mist coat thinned 1:3 with Duco Thinner.
  • Allow to dry overnight and polish the surface using 3M 1Step Rubbing compound. 
  • For a higher gloss polish use 3M Premium Liquid Wax.
Application for wood and MDF surfaces follows the same procedure as above except for priming using Duco Oil Primer. The Duco Primer Surfacer is applied directly onto the wooden surface.

The finish thus obtained is long lasting and durable.
Duco has the following limitations :

  • Requires elaborate equipment to apply - compressor and spray guns are the basic requirements.
  • Colour stability on exposure to sunlight is average - easily yellows.
  • Attention to surface preparation is required before application - needs a skilled workman.
  • Duco is sensitive to the atmospheric conditions during application - A change in temperature can affect the finish.
  • Being solvent based, it is not environmentally friendly and precautions must be taken against the health hazards during application. At minimum a respirator mask, gloves and glasses are required. Body overalls are highly recommended. An exhaust system must be in place to extract the solvent flashing off the surface.
 A range of Duco Products is available for delivery across India @ paintnhardware.com
Also available at our store :

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