Pre treatment

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Metal Coating Companies

Pre treatment

Effective cleaning and preparation of components

Pre-treatment is a chemical process in which the surface of the component to be coated is cleaned and prepared for the coating operation. Our team select the appropriate chemical pre-treatment for the metal substrate dependant on size, customer specification and additional process requirements.

Our range of pre-treatments include:

Iron Phosphate – A type of conversion coating that forms a complete film on the part surface, changing the chemical and physical nature of the metal surface.   An iron oxide base is developed, followed by a metal phosphate topcoat. The treated metal surface will typically have a grey to blue iridescent finish, depending on the coating weight and the base metal.  In our iron phosphate pre-treatment process, the cleaning and coating are combined by the incorporation of a detergent surfactant into the iron phosphate solution.  Parts treated with our Iron phosphate pre-treatment will typically achieve 300-400 hours of salt spray resistance (dependant on subsequent coating system).

Toran3 Polymer – Our Toran3 polymer pre-treatment system is supplied by Envirometal Technologies and works using Plaforization.  *Plaforization is a unique and patented treatment for multi metal products which, when dipped or sprayed with fluids at ambient temperature, are degreased, phosphated/polymerised, protected and prepared, in one, single operation, for the immediate or future application of either powder or liquid paint.  Toran 3 does not contain phosphoric acid but works in a double-cure system with powder coating systems.  Greases and oils on the metal are dissolved and chemically transformed to form part of the clear protective layer laid down on the product which is impervious to water and gives high adhesion for paint. Any dirt, dust or metal particles are washed from the product and then filtered out.  Plaforization™ does not generate any waste for notifiable disposal. No sludge, no waste water, no VOC and so is one of our most environmentally friendly pre-treatment processes.*  Parts treated with our Toran3 pre-treatment will typically achieve 600-700 hours of salt spray resistance (dependant on subsequent coating system) with some tests achieving in excess of 1000 hours.  *Source – www. envirometaltech.co.uk. 

Oxsilan – Our Oxsilan pre-treatment chemical is manufactured by Chemetall and is an eco-friendly and multi-metal pre-treatment process.  **The Oxsilan® process is based on silanes that form aqueous solutions, through hydrolysis and condensation, polysiloxanes. During the coating process, the reactive silanol groups can be chemically bonded to the metal as well as to the paint coating. Heat treatment, e.g. following cathodic electropainting (CEP), further cross-links the polysiloxanes. This creates layers in the range of 100 nm. In combination with many paint systems, this is already sufficient to achieve the same degree of corrosion protection as with the ten times thicker zinc-phosphating layers, thereby reducing materials consumption and pre-treatment times and increasing productivity.**  Parts treated with our Oxsilan pre-treatment will typically achieve a minimum of 1000 hours of salt spray resistance (dependant on subsequent coating system).  **Source – www.chemetall.com

Zinc Phosphate – Another type of conversion coating, Zinc phosphate is a non-metallic, crystalline coating that chemically adheres to the substrate. Zinc phosphate coatings are extremely adherent, they provide a uniform coating with improved coating adhesion properties, better coating in recessed areas and better corrosion resistance and have been widely used in the automotive sector for many years.  Unlike Iron Phosphate treatments, zinc phosphate is unable to clean and coat simultaneously and so our 8-stage zinc phosphate line includes cleaning, rinsing and conditioning stages.

We believe that correct pre-treatment is an essential part of the coating process and our team will assess the most effective method to achieve our customer’s end result. If you’re not sure which one is best for you, please contact us for advice.

Once pre-treated we can offer customers a variety of coating processes such as metal sprayinge-coatpowder coating and paint spraying.

Surface Preparation

The performance of any coating is significantly influenced by its ability to adhere properly to the substrate material.  As the first stage of the metal finishing process, surface preparation is an essential element to ensure subsequent coating success.  Surface preparation methods are used to remove surface contaminants such as scale, rust, oxide edges caused by the manufacturing process together with existing coatings and we are able to offer a variety of both mechanical and chemical preparation methods that include those mentioned on the right.

 

The Process

 

Shot Blasting

 

Pickling

Pickling is a chemical surface preparation treatment used to remove contaminants such as scale or oxide from steel to obtain a clean surface.  Parts to be treated are immersed in a bath, called pickle liquor, made up of a suitable mixture of acids.  An inhibitor is added to this tank to prevent further attack and pitting of the cleaned metal. Steel components processed by acid-pickling will oxidise (rust) rapidly when exposed to moist atmospheric conditions.  To prevent this, a thin film of oil or similar waterproof coating is applied to avoid contact of pickled steel with moisture in the air.  Our pickling process is particular suited for thin gauge materials that are unsuitable for shot blasting as they may become distorted.

Pyrolysis furnace

Our pyrolysis furnace provides an economical existing coating removal process by the sensitive control of heat and oxygen during the furnace cycle. This entire process takes place in an environment with a very low oxygen concentration, thus there is no aggressive burning, which damages the objects from which the paint is being removed.  All the substances and gases released are heated to 850 °C – 1100 °C at which any harmful substances are burnt. This is why this type of paint removal is very environmentally friendly.  Parts would then typically move on to the shot blast process to remove any residues of the existing coating, however the time taken to shot blast items once they have passed through our pyrolysis furnace is vastly reduced, providing a more economical solution for our customers.

Further Information

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ISO 9001:2000

We are proud to have attained the British Standard BS EN ISO 9001:2000 which sets quality management system standards for our Shot Blasting, Metal Spraying, Paint Spraying and Powder Coating processes.

Proud to have worked with:

  • APB
  • Broadcrown

Great reasons to work with Pym&Wildsmith

Fast efficient collection and delivery service

Facility for large scale items up to 6.45 metres

Quick turnaround times available.