YOUR SHOTBLASTING AND POWDER COATING QUESTIONS ANSWERED....

How does powder coating work & the benefits over other finishes?.
Basically, powder coating is paint in a powder form.

Powder coatings are used when a hard finish which is tougher than conventional paint is required. Basically anything capable of holding a small electrical charge can have powder applied to it. It is usually used for coating metals, however, newer technologies allow other materials such as MDF and even glass and ceramics to be coated using different coating methods.

So how does it work?

Powder application is very simple. The powder is applied to an object using an electrostatic gun. Compressed air pushes the powder out of the gun, past an electrode which gives the powder a positive charge. The object being coated is grounded so the positive powder particles are attracted to it. When the object is completely covered, the ground is removed and the object is put into the oven to be baked. While in the oven, the powder goes through a chemical change where it becomes free flowing and forms a ‘skin’ around the object. After cooling, the powder is ‘set’ and forms a hard finish.

What can I apply powder to?

Powder can be applied to items kept inside; including washing machines and lighting and also to exterior items including architecture and fencing. Powders are capable of withstanding extreme environments, thanks to our intensive testing procedures. The levels of powder durability are dependant on the mix of ingredients used.

The advantages of powder coatings over conventional paint

Powder coatings :

contain no solvent.
emit no VOC’s (volatile organic compounds) can produce much thicker coatings without running or sagging
overspray can be recycled and reused (no wastage) production lines produce less hazardous waste than conventional liquid coatings

Powder Coatings

3. Properties & Selection of use.

Epoxy powders:

Can be formulated to give high gloss
and smooth coatings with excellent adhesion, flexibility and hardness as well as solvent and chemical resistance.

The main deficiencies are their poor tolerance to heat and light as well as their pronounced tendency to yellow at elevated temperatures and exposure to diffused day light.

Acrylic powders:
Are widely used in surface coatings. They have good gloss and colour retention on exterior exposure as well as heat and alkali resistance.

Polyester powders:
General performance can be categorized between epoxy and acrylic powders. They have excellent durability and a high resistance to yellowing under ultra-violet light. Most coatings used on buildings today are based on linear polyesters cross linked with TGIC. Today modern polyester powders are TGIC-free

Epoxy polyester hybrid powders:
Are epoxy powders by origin containing a high percentage of special polyester resin (sometimes exceeding 50%). These hybrids have properties similar to those of epoxy powders, however, their additional advantage is that they have improved resistance to over bake yellowing and improved weatherability. Hybrid powders are now regarded as the main backbone of the powder coatings
industry.

Polyurethane powders:
Provide good all-round physical and chemical properties as well as giving good exterior durability.

Zinc rich powder primer coat

Zinc rich primer coating is a protective anti-corrosive powder layer and is very effective when applied, when cured in the correct manner; Maldon Shot Blasting was one of the first to start offering this product to the public. Further primers are available that do not employ any zinc based material and are becoming more popular and proved to be just as effective, and the good news is they are more environmentally friendly and cost about the same as standard zinc primers . We have been trialing these new primers and are proving to be very successful.

Plascoat

Plascoat PPA 571 has been specifically designed to provide a long lasting, tough coating for exterior applications to mild steel, galvanised steel and aluminum. It is based on an alloy of acid modified polyolefins. Therefore, it is halogen free and the combustion fumes are low in smoke and have a very low toxicity index.
Plascoat PPA 571 is resistant to stress cracking, adverse weather conditions, detergents, salt spray, and typical airborne pollutants. The coating maintains excellent adhesion to the metal substrate without the need for a separate primer. The material also provides a good degree of electrical insulation, abrasion, and impact resistance. Plascoat also has the advantage of having a warm soft touch.

Why does the Paint chip off?
Reason: - Poor or little prep work /under curing / poor quality powder.

Why is there corrosion under my paint work after a short period?
Reason: - no or poor prep work/ poor quality powder/ no primer coat.

My paint work has an orange peel effect.
Reason: - powder applied too thinly (known as dry) and in some cases to heavy.

The colour has not turned out as wanted.
Reason: - oven curing or the oven used is not set up correctly, either burning the paint or if it is a gas oven the burner is not set up correctly for sufficient air flow required or someone might just have used the wrong colour powder (tongue in cheek)

Alloy parts seem to have lumps and bubbles coming through.
Reason: - This is known as gassing out, and looks as though there are mini volcanoes on the paint surface. In some cases it can be difficult but not always impossible to overcome. Items of this nature are normally placed in the oven and left to their own devices for maybe a few hours upto a few days, this allows the product to completely dry out and degas, If this fails to work then a degassing powder would be used to help cure the problem.

Can any colour be matched?
There are hundreds of colours available with a finish in gloss, semi gloss, matt and
texture. Colour matching can be achieved by special request however this can be very
expensive therefore it may be a better option to choose a wet paint finish.

Can normal body filler be used within the process?
No, it tends to either explode, crack or just bubble through the finished work. If the
damage is light we can apply our Thermobond 3 product that has been manufactured
for the job, but if the damage is too deep then the only other option is to use body filler
and wet paint the work.