Metal finishing Q&As since 1989

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Need Info on the Process of Powder Coating Wood MDF

I am looking for any info on the process of powder coating wood and MDF materials.

Norman L. Clark
Taylor-White - Greeneville, TN
2000

You can get further info from Radtech, which is an independent organisation for uv-curing of powder.

R. de Boer
- Netherlands
2000

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2001

Powder coatings, widely used in the metal finishing industry, are now coming of age as it is now possible to apply such coatings to M.D.F. and other wood based products.

Powder coatings involve little over-spray as they are typically applied electrostatically: furthermore any excess powder can be recovered and re-used.

Powder coating systems, once set up properly, require less skill on the part of the operator than conventional wet paint spraying.

Powder coatings can provide, in a single-coat, a high-build, tough high-quality finish equivalent of up to five coats of a conventional wet finish. Textured or mottled finishes are available, as are a wide range of colours. Powder coating is of course entirely solvent free, so changing to powder coating, at a stroke, eliminates all concerns about V.O.C. emissions and solvent disposal.

Traditionally it has been very difficult to get a good electrostatic charge onto a non-metallic substrate such as M.D.F. This can be overcome by using a catalytic oven.

Now, In the U.K. alone there are at least 2 full scale production ovens for this process. Firstly the board in pre-heated for approximately 30 seconds. This makes it much easier to get the powder to stick to the board prior to curing. Then the boards are coated (either by hand held powder applicator guns or by reciprocator). The boards then enter into a second gas catalytic oven where powder flow can be achieved in less than one minute. This rapid flow out is instrumental in achieving a good finish.

The board then continues along in the oven for the baking of the powder. This can be done in a conventional hot-air convection oven . However it can be achieved in a further catalytic oven section in 2 ñ 3 minutes, giving a total curing time of less than 4 minutes as opposed to 1-15 minutes with hot-air convection . In a conveyorised system such as the above, this time saving translates directly into savings in oven and conveyor length as well as floor space. It is also cheaper to run.

U.V. curing powder are not required, ordinary heat-curing powders will work just fine especially is reformulated to flow at lower temperatures e.g. 140 degrees C.

Catalytic ovens typically allow a better finish than that possible with flame-infra red. They are also far cheaper to run than electric infra-red systems. Catalytic test ovens are used by the two major suppliers of the specially formulated powder coatings used with M.D.F.

David Miller
- Birmingham, England

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There are two types of systems and are approx 10 running in the stats.

The powder coating UV is being don on MDF, SOLID and Plywoods. Powder coating on wood is interesting for the display, office equipment, RTA, and Kitchen Cabinets to date.

William P Coronato
- Reigelsville, Pennsylvania
2002