Processes are compliant with the requirements of British and European standards, BS6496/ISO12206 and BS6497/ISO13438 as well as being approved for the application of Syntha Pulvin Architectural polyester powders.
Galvanizing deposits a layered structure of Zinc onto your steel fabrication. This gives the steel long-lasting corrosion protection. We work closely with you and our galvanizer to ensure the design optimizes the corrosion protection and the powder coated finish. However the finished surface may need additional smoothing (fettling) which is the first stage in the process at Powdertech.
Fettling removes zinc spikes and surface roughness common to the galvanizing process. Attention to detail at this preparation stage is the key to a successful finish in safety critical applications.
Correct jigging makes sure that the chemicals and coating powder cover all surfaces. Only with full coverage of chemical can we be sure that paint adheres evenly.
Pre-treatment consists of a 10-stage process for aluminium and a 7-stage process for galvanized steel. Material is fully submerged in a series of 6000 litre tanks containing cleaners to remove grease and oils; surface etching agents to provide a key for powders; apply a Chrome based film to seal the surface and give a corrosion resistant finish even before powder coating! Between each of the 3 critical stages there are water rinses. Finally the material is rinsed in demineralised water to leave a perfectly clean metal.
Immediately before the application of the powder all galvanized material is heated to force out (degas) remaining moisture trapped within the Zinc.
Powder is sprayed onto the prepared metal surface using a “gun”. The material is earthed through metal jigs, the powder particles are positively charged as it passes through the gun. The opposite charges attract each other and the powder sticks to the metal in an even layer.
The coated metal is transferred to a large oven and heated to approximately 200 degrees C and held there for 20 minutes. This causes the chemicals in the powder to “Cross link” transforming the powder into a smooth surface. A temperature recorder (left) accompanies the work into the oven. Thermal characteristics are analysed on a computer.
When the metal has cooled, the finished article is checked three times to make sure the process has been successful. The gloss of the surface is measured. The thickness of the paint film is measured and the whole surface is visually checked. Test panels of similar material are more extensively tested once per day to international standards.
Methods vary depending on customer requirements. Generally a combination of card and bubble plastic is used to make sure all material is kept separated and arrives at the customer in the same condition that it left Powdertech.
Dispatch labels record the customer name and a traceable number from which all the details of the contract can be recalled.
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