QUALICOAT UK & IRELAND
Architectural Powder Coating – What Should I Specify ?
Architects specify powder coating for the majority of their projects for use in the external envelope , but what should they specifically ask for by way of specification clauses ?
The size of the project can often have implications of what detail is entered into when it comes to powder coating . If the project is just a pair of doors or a few windows , normally only the colour will be referred too and possibly the gloss level . But if the project is significant then often architects will either employ a powder coating consultant or rely on the sub-contractor to get the coating correctly supplied , with the latter solution potentially leading to problems further down the project timeline .
Architectural powder coating is a two step process ; the cleaning and pretreatment of the aluminium and then the powder coating itself . Only when both processes are correctly done , with suitably sourced materials for the location of the project , can the project be deemed to offer a sustainable powder coating solution .
To add to the mix , projects often carry not just extrusions but preformed sheet pressings cills , preformed column casings and often aluminium sheet used in composite spandrel panels . These are often powder coated in differing locations which can introduce shading issues between batches , or indeed manufacturers of different powders . To further complicate matters should aluminium castings need to be coated , these may be coated in a further coating facility . The key to success is to discuss the finishes of various suppliers of materials and ideally have everything powder coated by the same powder coater if possible .
If this scenario is not going to be possible , quality control can be achieved by recognising what the variations in finish might be acceptable by agreeing up front both the colour variance and gloss variance on the proposed finish . The main issue is that being prepared for potential colour variation meant that this could be potentially controlled to a degree to minimise its effect .
Is it important to choose which company is going to powder coat profiles for a project ?
If the architect is specifying a known systems company for their project it is often best to allow the systems company to powder coat the profiles , or indeed allow them to specify who they use . Guarantees for coatings quality often then are passed onto the end user through the systems company who take responsibility for both the profile and coating quality . It is crucial however to note this within any specification so potential future issues can be easily rectified through the right channels .
In the UK and Ireland , independently licensed , quality powder coating is provided by members of QUALICOAT . A global organisation offering a common standard . The Association recognises the need for both quality pretreatment systems , quality finishing powders and the quality in the finish applicators .
12 DECEMBER 2020
The association therefore licences both producers of the materials and applicators to ensure that quality levels are attained and maintained . Regular inspection of QUALICOAT licence holders are undertaken by third party test houses and should failures in processes be recognised then QUALICOAT licences could be withdrawn .
This is a crucial cornerstone of the association to ensure members offer the highest level of quality for all their production output .
For pretreatment or the conversion coating of the aluminium , either a chrome free or chrome based system can be used for most locations . The aim of this pretreatment is to completely seal the aluminium substrate to stop oxidisation . Alternatively , a thin anodised finish can be used prior to powder coating which offers a more robust pretreatment . There are also variations of pretreatment options when is comes to specifying projects near the cost when a ‘ Seaside ’ class of pretreatment can be used which incorporates a longer or deeper aluminium etch process to remove substrate contaminants .
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