TECHNICAL INFORMATIONS

Pre-Treatment
Powder Coating
Our Coating Capabilities
Thermal Break - Pour and Cut

 

Pre-Treatment :-

Our 10-Stage Aluminium Pretreatment System
We use chrome-free technology that provides excellent corrosion resistance as well as very good adhesion properties for subsequent painting. It has the same performance as conventional chromium-containing pre-treatments but does not have the same health concerns, waste disposal costs or environmental impact.

Below is a breakdown of our 10 stage non-chromate pre-treatment system:

• Alkaline Degreasing
  This removes oil, dirt and some oxide.
• Alkaline Etching
  Removes the natural aluminium oxide layer to provide a chemically abraded surface for the paint to bond onto.
• Rinse
  Overflowing and re-circulating water rinse.
• De-smutting
  The removal by the etching bath of a layer of aluminium means that more of the alloying oxides, which are not soluble in strong alkaline conditions, will now be left on the surface as a grey 'smut'. The smut and aluminates formed from the etching operation are soluble in dilute acids and this solution removes them.
• Rinse
  Overflowing.
• Demineralised Water Rinse
  Overflowing and re-circulating.
• Conversion Coating
  Provides a Zirconium-Fluoride-Aluminium-Polymer conversion coating, which is integral with the prepared aluminium. Extensive testing has demonstrated that this conversion coating has the same performance as chromium based pre-treatments, but without the environmental issues and high costs associated with the treatment and disposal of chromium waste.
• Demineralised Water Rinse
  Demineralised water is controlled so that the conductivity does not exceed 30 uS/cm. Poor rinsing can reduce the effectiveness of the previous chemical treatments. The use of high purity, demineralised water in the final rinse ensures that un-reacted chemical is removed and the aluminium will be in optimum condition for painting.
• Drying
  Dried at 100°C for 15 minutes.
  
  
  

Powder Coating:-

Powder Coating - A definition
Finely divided polyester powders are given a polarised electric charge from a high voltage generator. The particles, being similarly charged repel each other and seek an earth (the article to be coated). The coated components are stoved to the manufacturers' recommendations causing the powder to melt, flow and chemically react to form a continuous film which is firmly anchored to the substrate. Electrostatic coating, as the process is known, provides good coverage as the powder tends to 'wrap around' the profile.

The polyester powders used by Mastercote are compliant with all of the major European architectural finishing standards. The following table shows the typical performance of the powders used over a conversion coating.

Our Testing of Coated Materials
When the material exits the oven the material shall be inspected to the requirements of BS EN 12206-1, which are detailed in our work instructions. If the tests cannot be carried out on extrusions because of insufficient surface area (width) or unevenness then they will be carried out on the test panels. The tests are summarised as follows:

Laboratory Testing - using test panels

Test	Standard Method	Performance
Impact	EN 12206-1:2004	No cracking or detachment of coating
Permeability	EN 12206-1:2004 Part 5.10 Pressure cooker	Pass - no significant blistering or detachment after 2 hours
Adhesion (sample testing only)	EN 12206-1:2004	Using a 2mm cross hatch - Class 0 - no detachment

*Appearance: A visual inspection is carried out by viewing the significant surfaces of the coated material at an oblique angle (to minimise gloss reflection) from a distance of about one metre the surface appearance should appear unbroken and consistent in texture. Full details of process capability available on request.
Records of inspection and test are completed and retained for 25 years.

Our Coating Capabilities : -

We offer a comprehensive range of architectural grade polyester powder coatings, which are highly resistant to UV, harsh weather conditions and are approved by British and European Standards. Coatings are available in a wide range of finishes; Gloss, Satin, Matt, Metallics, 'Sable'. We also offer more decorative finishes that include speciality colours, structured finishes and metallic effects, including flip-flop colours.

The standard colour range is suitable for application to outdoor fittings such as door and window frames, metal facades, cladding, guard rails and street furniture. Decorative special effects can be tailored for internal use such as metal furniture, lighting fixtures, shop fittings, shelving, etc.

To assist architects or specifiers in their choice of finish and suitability, full technical support is available. For more information, contact us and ask to speak to our sales team.

We also offer a range of wet paint systems to suit a variety of needs, which include air drying, two pack polyurethane and stoving acrylics. We can apply special finishes, including crackle, wrinkle, spatter etc. Site spraying can also be undertaken by our on-site repair team.

Thermal Break - Pour and Cut : -

Using poured-in-place polyurethanes we fill a cavity in the aluminium extrusion and when the resin has reached the required hardness we mill away the base of the cavity to separate the two sides of the profile with an insulating material. This minimises energy loss to the outside and helps to prevent the formation of condensation on the inside of your windows. We have been thermally breaking aluminium window and door sections for twelve years and have the capacity to process approximately 40,000 bars per month. We monitor the resin:hardener ratio and test the strength of the thermal break using a Shore D hardness tester and occasional shear and occasional shear and direct impact tests.