|Photo Imaging Technical Information|
Materials and Processes
a) Powder Properties
DecoWood is available in two different textures – Natural and Smooth. These textures are different powders with different properties, as listed below.
DecoWood Natural (textured)
Powder Type: Polyester
Micron Thickness: 80 – 100 microns
Gloss Level: 7±3 gloss
Applications: suitable for exterior use
Characteristics: optimal mechanical properties; marine grade
Powder Type: Polyurethane
Microns Thickness: 80 – 100 microns
Gloss Level: 19±5 gloss
Applications: suitable for exterior use
b) Aluminium Properties
Below is a list of the feature characteristics of aluminium as a building material.
Good Conductor of Heat: Aluminium is approximately three times as thermally-conductive as steel, which is important in
Lightweight: Aluminium is one of the lightest available commercial metals with a density approximately one third that of steel or copper. Its high strength to weight ratio makes it particularly important for building materials that need to be transported over long distance and installed manually.
Easy to Work With: Aluminium displays excellent machinability and plasticity ideal for bending, cutting and roll forming. Almost
High Reflectivity: Aluminium is an excellent reflector of radiant energy through the entire range of wave lengths, from ultra-violet through the visible spectrum to infra-red and heat waves, as well as electromagnetic waves such as radio and radar. Aluminium has a light reflectivity of over 80% which has led to its wide use in lighting fixtures. These reflectivity characteristics also lead to its
Non-magnetic: Aluminium has non-magnetic properties which make it useful for electrical shielding such as busbar or magnetic compass housings.
Non-toxic: Aluminium is non-toxic and can be easily cleaned due to its smooth surface, promoting a hygienic environment.
Shock-absorbing: Due to its low modulus of elasticity, aluminium is a good shock-absorber.
Non-sparking: Aluminium is void of sparking properties against itself and other non-ferrous metals.
c) Mechanical Testing
The quality of photo-imaged powder coating is determined by the characteristics hardness, elasticity and adhesion. The following tests are designed to examine one of two of these characteristics, as in the table below.
DecoWood has passed all tests listed in the table above according to international standards where they exist. Below is a more detailed description of what many of these tests entail. In addition to proving the quality of DecoWood surface finishing, these tests also give you an idea of what is possible with DecoWood.
Cupping Test: Measures the elasticity of the coating layer. To pass this test the surface finish must not crack or detach itself from the aluminium when deformed at least 5 millimetres above the surface (see diagram below).
Impact Test: Also measures the elasticity of the coating layer. When the aluminium is submitted to direct impact using 2’5 Nm of energy, it must not crack or detach itself from the metal.
Bending Test: Measures the elasticity of the coating layer. This test must not cause any cracking or detachment from the aluminium when a finished flat sheet is bent over a 5mm diameter cylindric mandrel.
Adhesion Test: This test determines the level of adhesion of the coating layer to the metal. The coating layer is subject to cross hatched incisions approximately 2mm apart. A piece of tape is applied over the incisions and then sharply removed. There must not be any detachment of the coating layer on the tape. Please note that Decorative Imaging performs this test on at least one random
Sawing/Countersinking/Drilling/Cutting Tests: These tests determine the resistance of the surface coating when subjected to such mechanical processes.
Buchholz Test: This test looks at the hardness of the surface coating. A 1mm incision is made in the coating layer which is then inspected under a microscope for any signs of delamination.
Polymerisation Test: This test examines how well the powder coating has cured in the oven. A cotton wad soaked in an MEK solution is wiped over the finished metal 30 times. If the coating layer becomes matt, soft and easily removable it has failed the test. Please note that Decorative Imaging performs this test on at least one random piece of metal within each order processed to ensure our high quality standards are maintained.
d) Chemical Resistance Testing
The DecoWood finish has a high level of resistance to a range of chemicals. These are tabled below, along with the ambient temperature, time exposed to the chemical and the result.
The DecoWood Smooth finish also has a high graffiti resistance, making it suitable for public projects where this is an issue. The finish was subjected to marker pen and spray paint ink and left for 48 hours. After this time, the ink was completely wiped off with a 1:1 mixture of Metileticheton and methylated spirits (Xylene, a 1:1 mixture Acetone/Ethyl Acetate and Acetone/Ethanol can also be used) with no effect to the wood grain pattern. This is shown in the diagram below.
e) Extreme Exposure Testing
A number of atmospheric agents affect the durability of any manufactured article, including the DecoWood finish. These agents include salt, pollution, wind, ice, heat, light, steam and water. Most of these agents are tested through the Extreme Exposure Test, while the other agents are tested in laboratory using purpose-built machines. The Extreme Exposure Test is the most important of all the tests as it measures DecoWood’s performance in real conditions, which no machine can replicate exactly.
The Extreme Exposure Test involves DecoWood samples laid out on a frame facing up, with part of the surface covered. The locations for the testing –
DecoWood performs very well in these conditions, as indicated in the image below. The left sample in the image is DecoWood and to the right is a non-DecoWood wood grain finish on aluminium. These samples were exposed to the natural conditions in