Powder Coating

A tough versatile finish
Powder coating is a hard, durable decorative finish that can be applied to steel and aluminium. It is available in a wide range of colours and textures including metalic and hammer finishes.

The process
Metals are coated in electrostatically plastic particles, baked on at 200 degrees, to produce tough but decorative finishes in a vast of colours and surface textures.

Powder coats, such as epoxies and polyesters provide hard impact-resistant coating 40-80 microns thick. There are commonly in use for decorative applications and can be matt, gloss, textured and hammered in appearance, coating thicknesses can be controlled by pre-heating the work or by varying the amount of powder applied.

Pre-treatment selection
As for all finishing the selection of the pre-treatment is important to achieve the right results.

Internal mild steel will generally be shot blasted prior to coating to clean off mill scale and give an adequate key for the surface.

Steel for external purposes will normally be coated with zinc, which will be degreased and “converted” prior to powder coating. This is done using phosphate treatment, which etches the surface and allows the powder to key securely to the substrate.

Aluminium is degreased and the surface etched with chromate give a chemical and mechanical key.

The options for zinc coating steel to rust - protect it are discussed below

Rust protection - the choices for steel
Where steel is being exposed to the elements various options are available.

Hot zinc spraying-this finish is as rust - resistant as galvanising but has a more consistent and smooth surface to key to than and galvanised. Power coating onto hot zinc spray gives a very high quality finish - durable, flat and extremely will bonded together.
Blastreat’s top quality zinc spraying and powder coating finish is second to none.

Zinc rich primer- this is a power primer that is applied prior to powder coating with the final colour. This will give most of the characteristics of zinc spray in terms of quality of surface finish, but it is generally accepted that flame applied zinc or galvanising is superior in rust protection.

Galvanising-hot dip galvanising is tough and durable but somewhat “industrial” in thatsurface finish is unpredictable. It does have the advantage of coating the insides oftube sections but also may damage and distort delicate work and needs considerable “fettling” to make it suitable for coating (Blastreat can arrange and quality control if required).

Standards
ß BS 6496 : 1984 Powdercoating of aluminium
ß BS EN 13 438 : 2005 Powdercoating of galvanised steel

Capacity
We have two large ovens, the largest of which is 6.4m long x 3m wide x 3m high, which
enables us to handle and heavy items.

Testing and inspection
Film thickness gauges, cross hatch adhesion tests, scratch resistance tests and Gloss
level tests

All items are wrapped prior to despatch. All finished work is checked and wrapped for
protection during transport. We can supply matching aerosol touch up paint if required
for large items if the work is damaged in use.

We run a comprehension QA and inspection procedure to check work to conformity
to British Standards and our own high internal quality standards.