FAQs

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Frequently Asked Questions

Here you will find answers to the frequently asked questions

The Metal Spray Process involves heating of the material to be applied and projecting it onto the substrate no solvents or chemicals are used.

The process has been used in every conceivable industry including Aerospace, Automotive, Biomedical, Agriculture, Space travel, Power Generation, Construction, Mining and so on. The metal/thermal spray process is a coating procedure used to change the surface properties of a part by adding a layer(s) of material to increase many factors:

  • Durability
  • Hardness
  • Wear resistance
  • Increase or decrease in friction
  • Increase of corrosion protection
  • Change electrical properties
  • Replacing worn or damaged material

The materials use in this coating procedure can be:

  • Metallic
  • Ceramic
  • Cermets
  • Plastic

Substrate materials include:

  • Metals
  • Glass
  • Carbon fibre
  • Plastics
  • Plaster
  • Polystyrene
  • Ceramics
  • Wood

The Metalspray process has been in existence since the early 1900’s and has and still does progress with equipment and consumables. Please check out our Application Solutions and Industry Solutions sections.

The process of Metalspraying, Thermalspray, and Spray Galvanising all of which and others refer to the same process has been in existence since the early 1900’s and is a process used worldwide.

The Metalspray process involves the melting of a wire (Zinc in this case) and projecting it by compressed air onto the work piece to provide a coating that can be tailored to suit the environment into which the component will be located.

How does Metalspraying compare with Galvanising?

  • Low heat input during spraying eliminates the risk of component distortion
  • There is no limit to the size of component to be treated
  • Components can be treated on site and therefore no transport or waiting issues and giving you the opportunity to Up Sell to your customer.
  • Metalspraying is used to restore corrosion protection on damaged areas of welded galvanised steel and International Standards exist covering this
  • Coating thickness can be varied from area to area to provide extra protection in critical areas
  • The Metalspray process is not limited to Zinc as Aluminium, Steels, Bronzes etc. can also be applied for a variety of applications
  • No re-work required from Galvanising dross
  • The Metalspray coating is porous and therefore the perfect surface to accept paint (that’s if required as it is not necessary). No need to pre –etch etc.
  • “AS/NZS 2312 Guide to the protection of iron and steel against exterior atmospheric corrosion” is the Australian Standard based on the International ISO standard that provides guidance for architects , engineers, builders the surface coating industry and users of protective services in general, on coating system for the protection of iron and steel  against exterior atmospheric corrosion.

NO! It only uses a heat source through which a powder or wire is fed, melted and projected onto the substrate.

Metalspraying offers the following advantages:

  • Low pre-heat or no pre-heating required
  • No heat treatment is necessary after coating
  • Little heat is transferred to the substrate during coating
  • No risk of thermal distortion
  • Almost any substrate can be coated
  • There is no dilution of the coating by the substrate material
  • A wider range of coatings can be applied
  • Operator skill requirements are lower
  • Better control over deposit thickness
  • Machining allowances are reduced, thus saving material
  • Machining times will also be reduced

No it is not necessary to paint the coating afterwards however in doing so and correctly applied it can enhance the life of the coating further , plus we can’t get Red or blue or …. Zinc, Aluminium, etc.

Metalspraying offers the following advantages over painting:

  • Materials are of consistent quality and purity, no mixing required before application
  • Materials have an infinite shelf life if stored correctly
  • Fewer process steps required. This allows simpler quality control and fewer opportunities for error.
  • Sprayed components require no protracted curing or drying times giving superior utilisation to floor space
  • Sprayed Zinc, Aluminium and their Alloys give effective corrosion resistance and protection immediately
  • Sprayed metals are more robust than paints and can withstand rougher usage
  • Even if the sprayed layer is damaged the sacrificial action prevents corrosion.
  • Metals can be sprayed in a wider range of climatic conditions (temperature and humidity) than paints
  • The materials used since the early 1900’s have not changed they are still in existence today, whereas many paint systems have been superseded many times over.

Compared to Electroplating Metalspray offers:

  • Adhesion is usually better
  • Non- metallic surfaces can be treated
  • Engineering alloys can be applied as coatings
  • Thicker deposits can be applied
  • There is no risk of Hydrogen embrittlement
  • Deposition rates are higher
  • There is no component limitation size
  • Coatings can be applied on site
  • There is no effluent disposal problem
  • Complex chemical control techniques are not required.

Yes the Flame, Arc and HVOF processes can all be operated on site as they are available in mobile forms. Standard Health & Safety procedures need to be applied after undertaking a site risk assessment as with any other process to be used on a site scenario.

Yes over the years the Metalspray Industry has developed International standards (ISO) as well as regional standards based upon the International ones.  The standards cover such things as:

  • Technical supply conditions for wires, rods, cords and powders
  • Approval testing procedures for Sprayers
  • Acceptance Inspection of equipment
  • Protective coating procedures
  • Design of articles to be metalsprayed
  • Quality requirements for sprayed structures and more

If you are applying and Anti corrosive coating Zinc , Aluminium or one of their alloys to a substrate then the surface would need to be clean and dry and then Grit blasted . If an Engineering coating is being applied then the component should be de-greased, pre -machined normally by turning a rough thread.

If the component has been in service running in oil then pre heating the component to between 260° C and 370 °C and maintaining this temperature until oil ceases to come to the surface or until all smoking stops will satisfactorily clean the component.

No, the media to be used for surface preparation should be:

  • Metallic grit-normally angular chilled iron
  • Non Metallic grit – Aluminium Oxide
  • On site blasting – Garnet or Copper slag

Generally speaking there is no limit; however from a practical point of view excessive coating thickness is unnecessary.  In some cases the coating thickness maybe determined from standards that will give life expectancy until first maintenance in other cases it can be the requirement necessary to restore a part to its original condition.

The International Standard BS EN ISO 2063 as well as AS/NZ 2312 gives recommendations of coating thickness and time until first maintenance.

In North America the Metalspray process is known as “metallizing” or “Thermal Spray” with early work being carried out by the American Welding Society (AWS) who in 1953, exposed panels coated with flame sprayed zinc and aluminium and various sealers. Very favourable results were reported after 19, 34 and 44 years of exposure at coastal and industrial sites. This work was followed up by the US Army Corps of Engineers with successful trials of Metalspray as a more abrasion resistant coating than vinyl on dam gates, and which resulted in a comprehensive design manual (USACE, 1999) which is available on the internet.

The US Federal Highway Agency noted (FHWA 1997) that work by the AWS and US Navy showed that “properly applied metallized coatings (zinc, 85% Zinc/15% Aluminium, and Aluminium) of at least 6 mils thickness provide at least 20 years of maintenance free corrosion protection in wet, salt-rich environments and are expected to provide 30 years of protection in most bridge exposure environments”. The FHWA has sponsored several research projects coating steel bridge beams with TSM, including one of environmentally acceptable materials which found that the thermal sprayed zinc (TSZ) systems were the best performing over 40 coating systems tested (which included top coated and single coat “high-ratio” and other inorganic zinc silicates) with no undercutting at scribe marks after 6.5 years exposure, and had the lowest Life Cycle Cost.

Thermal Sprayed Aluminium (TSA) has been widely used in offshore oil and gas industry and by 1997 over 400,000 sq. metres of TSA had been applied to oil platforms in the North Sea to provide corrosion protection to flare stacks, riser pipes in the splash zone and submerged tethered legs (e.g. Conoco’s Hutton platform built in 1984). Experience indicated that TSA coatings, when properly applied and with the use of specific sealer systems, will provide a service life in excess of 30 years with zero maintenance required.

In short, the years of testing and results which have accumulated into the various standards demonstrate the coatings ability to withstand the harshest of environments and to with stand the test of time.

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