features
#036 / 2001

Spray Booth and workstation

Powder coating mdf in canada: not just for metal anymore

Powder potential

Are you frustrated with the design limitations of edge tape, t-moulding and 90-degree corners? Would you like to produce seamless contoured shapes for table tops and other components with a tough stain-resistant one-coat finish?

The solution can be found in powder coating. The same process commonly specified for metal furniture components is being adapted to finish MDF.

This potential revolution is on hold, though, because two competing technologies are involved, and most of the Canadian coating industry is taking a wait-and-see approach until a definite winner emerges. One method, known as Thermoset, uses powder "cured" by heat, and the other, known as UV, cures with ultra-violet radiation.

Both technologies use a chain conveyor ("line") from which the components, such as table tops, are suspended by wire. The parts move through the finishing process as follows: [1] pre-heat tunnel oven; [2] electrostatic spray booth (left image top); [3] cure/fuse tunnel oven; [4] cooling/packaging area (centre image top). The UV process requires the additional stage of a shielded UV lamp tunnel between stages 3 and 4.

Thermoset lines operate at 130-150 degrees centigrade (35-45 degrees higher than UV lines) and are longer (60+ metres). The extra length is required for additional heating and cooling. A table top can speed through the UV coating cycle in a third of the 20-30 minutes required on a Thermoset line.

So, how can the Thermoset process compete with the superiority of UV, which is faster, cooler and has equal or better coating properties? Thermoset has two advantages - the line is cheaper to construct and the powders are available off-the-shelf in a range of colours and surfaces (see chart below). The equivalent options in UV powders are a few months to a few years away from commercial production.

Chart of Thermosetting vs. UV Powder Properties

Kenex Powder (Mississauga, Ontario), a division of Adams Packaging, is the Canadian pioneer in powder coating. Their Thermoset line began operation in September 1999, and has successfully coated components for several furniture manufacturers, including Global Contract (Concord, Ontario) and Fluid Concepts (Toronto, Ontario) (right image top). Smaller-scale producers outside the Mississauga region may be interested in Kenex's ability to router MDF components in-house on CNC equipment and then ship the finished component. For more information about this service, contact Andy Joyce.

Office furniture maufacturer Teknion (Concord, Ontario) is not taking the wait-and-see attitude. Teknion's Ken Brown told furniturelink that their Thermoset line, incorporating convection and infra-red heat sources, will start production in February to make components for Teknion's new XM office furniture range.

RadEX Powder Coating (London, Ontario) is the only custom powder coater in Canada (at time of writing) committed to the rival UV technology. Glenn McLean of RadEX is convinced that UV is the superior technology, and to justify his optimism gave furniturelink the following price quote as a challenge to his competitors:

Quantity: 1,000

Product: "Typical" MDF desk top finished both sides

Cost: $2.00 per board foot

The RadEX quote gives designers and smaller manufacturers a clear way of measuring the cost effectiveness of the new technologies' potential. Add in that only certain grades of MDF are suitable for powder coating - requirements include a fine, even fibre distribution and higher density. A number of applicators named Ranger Board from West Fraser Timber as the most suitable Canadian-made MDF panel for powder coating.

Update (2014): Woodworking Network provides a more recent description of the powder coating technology and services provided by RadEX.

furniturelink thanks the following individuals and companies for their assistance with this article:

  • Andy Joyce and Chris Hornung, Kenex Powder (custom coater)
  • Glen McLean, RadEX Powder (custom coater)
  • Ken Brown, Teknion (office furniture)
  • Glen Storey, Nordson Canada (equipment and powders)
  • Bill Whitely, Kiss Equipment Corporation (ovens)
  • Tracy Mitchell, West Fraser Timber (MDF)
  • Mike Favreau, Morton Powder (now Rohm & Haas)
  • Peggy Coop, Powder Coating Magazine

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© furniturelink 2001 (text and images)