Definition:
“Powder coating is a type of coating that is applied as a free-flowing, dry powder [unlike conventional liquid paint which is delivered via an evaporating solvent]; and the powder coating is typically applied electrostatically and then cured under heat”.
Not all sheet metal items will have an external finish applied. For example:
However other sheet metals will most often need to have an external finish applied, particularly in the outdoor environment. The three principal reasons for this requirement are:
Cheaper, more reactive metals – most notably Mild Steel – need to be externally finished to protect against corrosion.
There is a plethora of external metal finishing systems available, including electroplating, galvanising, anodizing, and paint finishing – along with many, highly specialised, coating systems for specific industries and applications. Each finishing system will deliver its own solution to a particular combination of design and specification requirements.
Within the landscape industry, and industry in general, overwhelmingly the most popular and prevalent choice is paint finishing – which may be either wet painting, or Polyester Powder Coating [PPC].
Of these two generic paint finishing systems, PPC is by some margin the most commonly specified option. So what are some of the key benefits of PPC…?
There is a prejudice, amongst some specifiers, that PPC is functional, utilitarian, and dull. In fact, nothing could be further from the truth.
What is true, however, is that PPC is not good for super-funky art finishes, and/or faux finishes [like, say, finishes replicating naturally-patinated Copper]. High-end wet paint systems can offer this – but at a cost of somewhere between £200-400 per sq metre [or somewhere around 8-10 times the price of high-quality PPC]. In the real world, these kind of price premiums for specialist wet paint finishes are almost never justifiable for exterior, landscape products. In Plain English: what a client might be prepared to pay for a hotel reception desk, they will not pay for the planter outside the door…!
With the above caveat only, PPC offers enormous aesthetic choice, and creative licence to a specifier.
In addition to the standard RAL, BS, or Pantone colour series, there are myriad proprietary ranges available from specialist, high-quality paint manufacturers – such as Interpon/AkzoNobel, ISG, Tiger Drylac and Syntha Pulvin. These ranges include, inter alia:
And the above is truly just the tip of the iceberg.
As the essential PPC application technology is common, new powder coat formulations tend to go from the development bench to market swiftly [without the ‘black arts’ of some wet paint innovations]. Thus new PPC ranges are being brought to-market all the time, further expanding the aesthetic choice.
PPC is a very cost-effective paint finishing system; and it is often a half, or a third, of the cost of equivalent wet paint systems.
There are a number of reasons why PPC is so cost-effective – and these include:
The efficiency of PPC, and its corresponding cost advantage, is a core reason for its use in the landscape industry – where budgets are typically constrained. While much of the work we do in PPC is bespoke, we do have a range of standard sizes and shapes which offer the best value for money. They are available in any RAL colour, and the delivery time is around 8 weeks. See the range here.
Perhaps the most common misconception about PPC, amongst specifiers, is that PPC is a ‘thing’ – like timber or steel or trees [or whatever…]
In fact, ‘PPC’ is merely a generic description of a paint application process, which has a great many variables, which need to be defined in a precise specification – such as:
All of these variables impact on technical performance; and PPC is thus a highly flexible technology, which can be tailored precisely to the requirements of the brief.
And the good news, again [vs. wet painting] is that adding extra functional requirements to a PPC specification tends not to break the budget. Indicatively, the cost difference between a 'Rolls Royce' vs. 'Mondeo' specification in PPC might be 20% or so – whereas in wet painting it could quite easily double the cost.
IOTA is always happy to advise on what would be suitable PPC systems for a particular brief. However the specifier should at least give prior consideration to what are the requirements of the brief, on issues such as:
The above are the kind of considerations which would go into decisions on what would be suitable PPC systems for a given brief.
Finally, below are three common specifications routinely used by IOTA. They are listed in order of increasing technical performance; and are ‘badged’ with common car names, to make the point that there is an inevitable link between cost and technical performance and cost.
The PPC products given are from the Interpon ranges by Akzo Nobel, simply because these products are what IOTA uses most. However IOTA also routinely uses equivalent coatings from other PPC manufacturers [such as IGP and Syntha Pulvin], which can readily be substituted within a specification.
This is the PPC system that IOTA is using on a daily basis. This option meets the minimum quality standard to which IOTA is prepared to put its name; and it is fit-for-purpose for the vast majority of residential and light commercial schemes.
The system comprises:
Material: Zintec [Zinc-Plated] Steel
Pre-treatment: Degrease and Abrade
2-Coat application:
Please note: IOTA uses most often Zintec [Zinc-Plated] Steel, on which basis a first coat of Etch Primer is acceptable. If Mild Steel were used, then a Zinc Primer would have to be substituted.
A lot of IOTA’s work is in public realm, where a more robust surface is required.
A formulation which IOTA uses a lot for public realm, and highly recommends, is the Interpon D1036 Textura range which has a finely textured, highly-durable finish. Textura is described by Interpon as: “A hard-wearing , scratch and knock-resistant powder coating, perfect for high-traffic areas. The durable finish disguises imperfections and offers a low maintenance, easy-cleaning solution for public areas.”
The exact system used with this option will vary, as public realm schemes often come with additional requirements and complexities that need to be taken into consideration.
Finally, there are some extreme environments, where a ‘Rolls-Royce’ PPC system is cost-justified.
This subject is more fully discussed in two further articles on the Specifiers Area of IOTA’s website – namely:
A Coastal environment is self-evidently ‘extreme’; whereas what is ‘extreme’ in Super-Prime Residential Developments is the level of client expectations in terms of quality, longevity etc. In both cases, we recommend the same PPC system.
The essential specification requirement is to state that:
The PPC coating and application system used must ensure extreme longevity in C3/C4 environments – defined as:
Two such systems commonly used by IOTA in these circumstances follow a 3-coat system with coating products from Akzo Nobel, which might be used as example specs. – these comprise:
Option A
Material: Mild Steel
Pre-treatment: Blast Cleaned SA 2.5
3-Coat application:
Option B
Material: Zintec [Zinc-Plated] Steel
Pre-treatment: Degrease and Abrade
3-Coat application:
There are indeed PPC systems that are ‘above Rolls Royce’ in terms of cost and technical performance, which IOTA has the skills, experience and resources to apply. [For example: IOTA has a contract to manufacture some elements for the Hinckley Point C nuclear power station, the PPC specification for which is extraordinarily complex]. However, for 90% of the requirements of the UK Landscape Industry, the Rolls Royce spec given above is as good as it needs to be.
Contact IOTA T. 01934 522617
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