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Design Considerations for Powder Coating MDF
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To maximise the performance and quality of the powder coat finish on MDF board, we recommend
specifiers and joiners consider the following.
Sections
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Pre-cut Panels
Given the nature of powder coat application and cure (or baking), it is recommended that all
panels are powder coated in flat sheet stock. Pre assembled or three dimensional components should
be avoided as they are impractical to handle.
A consideration when designing componentry is to make a special feature of the joints rather than
concealing these areas with cumbersome glues or fillers.
To ensure maximum protection and performance of the powder coated material, MDF board is powder
coated on all sides and faces. This is done in a similar fashion to some laminates and liquid coatings to ensure maximum protection of the MDF board.
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Hanging Points
Products being powder coated are suspended from a production line, so pre-cut panels and boards
require somewhere to hang these items, ideally from insignificant (non visible) surfaces. In many
cases the use of hinge or screw points of components can be used for hanging, otherwise new holes may
need to be created.
To avoid unwanted delays in coating, discuss appropriate hanging points and drill bit sizes with
your Orica Trimatrx Applicator before fabrication and delivery to the powder coat plant.
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Square Edges
Wherever possible it is best to avoid sharp edges in designs. The removal or rounding of the
"arris" improves the delivery of a uniform powder appearance. Preparation of the edges is critical to ensure the powder coating provides a smooth consistent finish. Failure to prepare the edges may cause the powder to highlight original or fabricated edge markings or defects.
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Routing, Cutting and Sanding
As the Trimatrx System requires no primers, particular attention needs to be given to those edges
that are significant surfaces (visually seen).
The recommended finishing of edge and routed surfaces is to start with coarse sand paper
(eg 220 grit) then work down to a fine sand paper (eg 400 or 600 grit) to achieve a successful
smooth appearance free of "hungry" or dry edges. High quality cutting and routing tools
are also recommended to help reduce the amount of pre-finishing.
Deep routed grooves should be limited to no more than 50% of the board thickness to avoid
impact on the core density of the MDF, which can ultimately affect the powder coat finish.
Where routed areas are considered significant surfaces, special attention to sanding is required to
ensure a uniform appearance. Indeed it is a good idea to test run a routed part through the powder
coating process to decide the optimal design and powder coating process before full scale production.
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Glues and Fillers
Powder coating of MDF requires a baking process up to 160°C, so heat and shrink resistant glues
and fillers will be required to avoid unsightly seepage or expansion.
Wherever possible, gluing of components should be performed after application of the powder coat.
If this is not possible, we recommend you contact your Orica Trimatrx Applicator to trial components
for suitability and to assess shrinkage of the edges, etc.
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MDF Board Size for Application
Most Orica Trimatrx Applicators are able to powder coat full size MDF board, however, you should contact your powder coater beforehand to clarify whether their system has any size restrictions and discuss how best to accommodate these variations.
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Pencil Markers on Visual Faces
Avoid felt tip or and biro pen marks on significant surfaces of joinery. Such markings may bleed
through the coating after powder coating. Where markings are required, use pencils sparingly!
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Packing and Transportation
Care needs to be taken when packing and transporting components. All components should be clean
and free of dust or grit prior to stacking. Use of packing foam or paper sheets between components
ensures the high quality finish is maintained during transportation.
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Time Frame Considerations
Prior to powder coating, the MDF is conditioned for moisture control for approximately 48 hours.
This conditioning process protects the MDF board during powder coating application and ensures the
best possible finish on the board.
Discussion with your Orica Trimatrx Applicator is advised on appropriate conditioning and
application turnaround times.
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End Use Considerations
Orica Trimatrx Powder Coating has been used for many applications, and these include office furniture, workstations, office partitions, cabinetry, shop display furniture and trade show exhibition stands. As powder coating is a spray application, some inconsistency from panel to panel and within a panel, can be expected. This variation is more noticeable on wide surface areas, and where viewed on sharp angles, or in areas where there are critical or unusual light sources.
Some colours and finishes offer better results within the Orica Trimatrx range, such as mid to dark colours and smooth finishes. We suggest you discuss with Trimatrx Applicators or Orica direct your application if large surface areas and multiple panel work is desired.
Trimatrx®
is a trademark of Orica Australia Pty Ltd.
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