When it comes to finishing architectural metalwork such as balustrade, handrails, brise soleil and louvres, traditional painting is rapidly being brushed aside by the advance of powder coating. In contrast to conventional liquid paint, powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form and is applied electrostatically as a dry powder. It is then baked at high temperatures which cures the powder and causes it to set solid, creating a smooth, even protective coating. The finish is much tougher and more durable than conventional paint, which is prone to flaking and cracking over time.
With its low-maintenance qualities and smooth appearance, it’s hardly surprising that countless building professionals have cottoned on to the advantages of powder coating. What is less widely appreciated is the fact that there are different types of powder coating which between them offer their own advantages and disadvantages. The most commonly used powder coating across all applications is polyester powder coating. In architectural applications the second most common is nylon powder coating. Both are non-toxic and provide good resistance to corrosion. Both offer the smooth, even and durable surface which is characteristic of all powder coating. However, they also have significant differences which are worth considering. We’ve listed the benefits of each option to enable you to make an informed comparison.
POLYESTER POWDER COATING
- Polyester has excellent weather and UV resistance which provides greater colour stability than nylon, which will fade faster with prolonged exposure to sunlight
- Polyester powders are easier to apply than nylon and can use lower film thicknesses (typically 70 microns compared to nylon’s 150 microns)
- Unlike nylon, polyester does not require a primer prior to painting
- Unlike nylon, polyester does not re-melt when exposed to higher temperatures
- Polyester powders have a much lower cost per kilo than nylon and will give lower overall coating costs.
- Polyester facilitates a wide range of colours and a full range of gloss levels and textures
NYLON POWDER COATING
- Nylon is more resistant to wear and abrasion. An abrasion test carried out by the Paint Research Association in 2003 compared the abrasion resistance of nylon coating to two types of polyester coating (Bonalux and Interpon) – the results showed nylon to offer an expected lifespan of over 7 times that of Bonalux and almost 6 times that of Interpon
- Nylon is manufactured from renewable resources
- Neither polyester nor nylon are cold to the touch, but nylon’s thermal insulation is superior and ideal for warm-to-touch applications
- Nylon has superior chemical resistance compared to polyester
- Nylon offers more flexibility at low temperatures
Hopefully this comparison helps you to determine whether polyester or nylon is better for your particular design or project. In summary, the most significant difference is the lower cost and superior colour retention of polyester versus the superior durability of nylon. Neaco would advise that, on balance, nylon powder coating provides a more valuable range of benefits overall. However, all powder coatings give metalwork greater durability and comfort to touch and offer compelling advantages over conventional painted finishes.