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Home DIY Electrostatic Powder Coating

November 2, 2014
Electrostatic Powder Coating Spray Unit

DIY electrostatic powder coating requires some upfront investment in workshop equipment, but the surface coating results are worth every cent!

brush-100x100We can’t rave enough about electrostatic powder coating in our DIY workshop.

Why? Because even when most liquid paints let us down completely, electrostatic powder coat paints consistently give our metal DIY parts and projects an extremely professional looking finish.

There are no spray cans, liquid solvents or messy paint brushes involved in powder coating.

The paint is supplied as a dry, finely milled powder and applied using a specially designed electrostatic spray gun.

The array of powder coat colors available, with finishes, metallic effects and textures to suit any DIY project desire or need, is stunning. Powder coated finishes are quality coatings which are thick, vibrant and extremely scratch resistant.  They last!

With powder coating equipment available, a fully protective dimpled coating in an exotically wild metallic red or green color over a metal surface is simple to achieve – whether with or without an holographic like lustre! As is a a more conservative, yet very professional looking coating of silky matte black.

The ability to spray this level of coating quality at home expands all sorts of DIY project horizons.

Unlike liquid paints, powder paint can be applied evenly in one shoot without the risk of dripping or sagging. Over spray can be easily swept up and re-used.

Following a paint shoot, the coating is cured by heat treatment. Then, after just 20 minutes in a workshop oven …. the job is done!  The parts are good to go!

There is no waiting around for extended drying times.

The tough coating formed is a continuous, sealed flow of paint over the project surface which is long lasting and superior to most liquid paints.

Commercial application of electrostatic power coating has been used widely for decades, but it is only recently that the technique has been easier for the DIY community to get into.

Powder coating is used to produce the amazing and often mesmerising colors and textures we see in all sorts of places in our modern lives. From use on bicycles, car wheel rims, racing engines and motorcycles; to metal fencing, home appliances, office furniture and heavy machinery.

The only limitation of using powder coat paints over traditional liquid paints is that projects and parts must be both heat tolerant and electrically conductive.

The Electrostatic Powder Deposition Concept

Electrostatic Powder Coating Gun

The electrostatic powder coating spray gun fluidizes the powdered paint with compressed air and positively charges the particles to make them stick to the grounded project surface being coated.

The powder coating concept is based on paint particles being attracted to a grounded project item by electrostatic charge.

Powder coating systems are plugged into an earthed power outlet for use and have transformers which generate electric potentials in the order of 30,000 – 50,000 Volts.

The specialized spray gun required uses dried compressed air to draw powder from an air-fluidized reservoir. The paint particles pass an electrode as they flow through the spray gun and the powder picks up a strong positive charge before leaving the spray nozzle.

Project items being sprayed are hung from an electrically conductive rack connected to an earthing wire. The cloud of positively charged paint exits the spray gun and settles evenly over any connected metallic surface.

Immediately following coating, the powder is still only affixed to the project surface by weak electrostatic forces. The coating can be easily disturbed or knocked off. If required, the project can even be dusted down completely and resprayed should the coating not be as intended.

Following spraying, the sprayed item is placed in an oven to heat and fully cure the paint. Oven time is usually 15-20 minutes at a temperature of approximately 400ºF (200ºC). The results following this short curing time are usually stunning!

Setting Up a DIY Workshop for Powder Coating

In the past, it has been difficult and expensive for home DIY painters to gain access to the professional results offered by powder coating.

The spray equipment was only offered through wholesale outlets and the powder paints were only available in large industrial quantities. This has all changed in recent years.

With a relatively small investment, exciting colors and lasting professional looking results are available to any DIY handyman. And considering the huge improvement in DIY project finishes over liquid painting techniques, we believe the outlay is well worth it!

Getting started requires an electrostatic spray gun; a reliable compressed (dry) air source of 20-30 psi; a suitable enclosed dust free spray area or booth with a electrically conductive rack; and a curing oven capable of reaching temperatures of around 450ºF (230ºC) for at least 20 minutes at a time.

Powder Spray Equipment for the DIY Workshop

Applying Electrostatic Powder Coating Paint

DANGER! Extreme high voltage causes the paint powder particles to migrate onto the metal surface of the project parts.

There is no getting around the requirement for a specialized electrostatic spray gun. There are varying levels of quality options available on the market, from cheap and nasty, to expensive, heavy duty industrial systems.

For most DIY users, professional level systems will be absolute overkill for smaller projects.

The flexibility to adjust transformer output voltage can be handy to help adherence of powder when spraying in difficult right angle corners, etc, but it is not always essential.

The larger external paint reservoirs offered with many professional systems are mainly suitable for large scale or repetitive bulk spraying operations.

Cheaper systems which often have paint reservoirs on the spray gun itself however, can become cumbersome in some instances.  The choice of spray gun is a personal one and depends on the typical project requirement.

We have generally found that more expensive units often include additional air outlets, pressure regulators and gauges The extras can assist in achieving equipment setting and coating consistency from one job to the next, but the ‘features’ also usually come at a highly elevated price.

Powder coating systems in general are definitely not rocket science. They are simple in construction, function and design.  This being the case, eager, but budget strapped DIY enthusiasts can easily add their own extra design features after purchase of a relatively simple base unit.

We did exactly this!  We bought a mid-range system and then built our own work stand to make it easier to use.  We also added extra air taps, pressure gauges and an air moisture trap. We haven’t felt the need for externalizing paint reservoirs, but it wouldn’t be a stretch to do so if desired.

This said, even the simple systems can produce reasonable powder spray and coating results at home.

Spraying Racks and Booths

The spraying area too, does not need to be high tech. It does however, need to be relatively clean and free of dust, as the positively charged powder will attract debris into the surface coating if it is present.

A parts hanging rack for projects can be as complex as a professional spray booth with all the extraction fans, lights and dust collection filters; or as simple as a large open cardboard box with a metal rod pushed through the sides.

Ideally, the conductive metal surrounding the parts being hung should be kept to a minimum as this will attract powder paint unnecessarily during sprays.

Workshop Curing Ovens

DIY Powder Coated Parts Oven Curing

Powder coating is cured by heat in a DIY workshop oven to form a tough, scratch resistant coating which looks great.

A suitable curing oven is a key element to achieving consistent color and quality from one job to the next.

Some beginners start out by using cheap range toasters or kitchen ovens to cure DIY projects. This gets people started and allows DIY’ers to learn the basics of curing powder paints, but generally leads to mixed results. It isn’t an option for producing consistent quality coatings in the longer term.

Smaller capacity ovens without air circulation tend to cause hot spots, overheating and uneven curing on parts. Without insulation, they are not particularly energy efficient for extended use either.

It should also be kept in mind that some powder coat paint formulas on the market produce carcinogens (cancer producing agents) during heating and curing. Powder paints therefore, shouldn’t be cured in living areas, or cured in ovens used for food.

The powder can also be flammable, so ovens exposing powder and curing vapors to open flames are also a no-no.

After working with various configurations of ovens while perfecting our own curing techniques years ago, we discovered that ovens didn’t need to be perfect to produce excellent curing results. Since professional large capacity ovens are expensive and unjustifiable for our uses, we ended up making two very suitable workable DIY curing oven designs in our own DIY workshop. One was even made from an old filing cabinet for less than $50! (Check out that DIY project here and here).

As a final note…. Yes, constant care, awareness and attention to safety is required when working in a powder coating workshop!

When any equipment generates electrical potentials in the tens of thousands of Volts, there is always potential for all sorts of death and sorrow!

Always be aware of where you place your extremities while shooting powder spray.  Also be aware of where any onlookers, children or boisterous pets are around the equipment!  Voltages this high allow sparks (and potential for serious electrocution!) to jump inches through air without any direct contact with conductive surfaces!

A life threatening shock potentially awaits carelessness or inattention.

If pursuing powder coating, take utmost care and always assume all circuits are live and deadly as soon as the main transformer unit is switched on – even if the foot pedal controller of the spray gun is not pressed.

Oven burns can also be nasty.  Take all precautions necessary to protect against any risks of injury or damage.

DIY Parts Powder Coating

Beautiful satin black surface coating on DIY metal parts … but an exotically wild metallic green or red would have been just as easy!

With all care taken, DIY projects large and small will benefit from using electrostatic powder coating paints.  The finished results always look great!  We can’t recommend powder coating enough.

Happy coating!

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