Heraeus Vulcan has been at the forefront in developing the technology which enables MDF to be powder coated. Over the last 10 years we have designed and built some of the largest MDF powder coating cure ovens in the world. We have also had significant involvement in the development of a single coat oven cure system, along with the industry leaders.
MDF Powder Coating – The Technical Challenges
In order to become the world leader in this technology we have had to identify and overcome a number of technology challenges. The issues that surround MDF powder coating can be summarized as follows:
- Being a wood based substrate, MDF is not naturally conductive
- MDF quality varies between suppliers and grades
- How to improve powder adhesion during application
- When heated, MDF “out gasses” from cut edges. This causes pin holes to appear in the powder coating as it gels and cures
- If the MDF gets too hot during curing, it will burn or scorch
- Moisture content varies between grades, manufacturers and storage conditions
- Higher moisture content can make the substrate more conductive, allowing better powder adhesion, but the downside is that it also causes edge splitting and cracking
MDF Powder Coating – The Solutions
The technical problems surrounding MDF can be mitigated by:
- Careful selection of MDF
- Maintaining stable storage conditions for the MDF
- Using a two coat system of primer (to seal the edges) and top coat
- Using a low bake powder system
In order overcome the inherent limitations of curing powder on MDF, Heraeus Vulcan has achieved the following:
- Development of a two oven system for pre heat of the MDF before powder application and a final cure oven
- By understanding the required time v. temperature profile, PLC control systems have been developed
- Careful design of the oven and catalytic heater positioning ensures even heating of edges and surface
The result of this development means that two coat MDF powder coating systems are capable of producing a very good quality finish suitable for kitchens where a tough and attractive finish is required. The only potential drawback has been the performance of these finishes in a high humidity atmosphere such as a bathroom.
MDF Powder Coating – The Future
Heraeus Vulcan has been addressing this last issue of high humidity applications. Over the last three years we have been working with our partners to develop a single coat oven cure system which meets the requirements for high humidity applications. This corner of the market has been dominated by liquid finishes which do not have the inherent toughness of powder coated surfaces. Please read our Latest News for further details of our progress.