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Which is best,
powder coating, spray paint stove enamelling or air drying?

Paint or powder, powder or stove enamel, powder vs spray paint, or powder coat vs air drying?

Windridge Coatings is a commercial paint application company. In over 25 years we have applied heavy-duty corrosion protection paints, aesthetic auto paints, powder coatings and stove enamel. We have a fairly good knowledge of all processes and have taken the commercial decision to specialise in powder coating. Powder coating has been the fastest growth area of painting for the last 25 years at the expense of other paint systems.

Powder Coating
Improvements in application techniques have meant small decorative items to heavy and large components are suitable for powder coating. What was once the reserve for architectural and mass production is now available for garden gates and powder coating motorbike frames.

Application equipment for powder coating is more expensive than wet paint systems. The gun alone can cost £4500. The paint is purchased as a powder, hence the name. It is temporarily stuck to the metal with an electrostatic attraction. (In the same way as you rub a balloon on your jumper and watch it stick to a wall, the granules of powder stick to the work piece). The oven is more expensive than stove enamelling because it has to heat the component to a higher temperature, about 200 degrees Celsius.
Why is powder coating better?
Good pints

bullet pointPowder coating done properly is tougher than stove enamelling and air drying paints. This means it will take more of punishment before chipping.
bullet pointThere are no solvents used during the application and so it is environmentally greener.
bullet pointRequires factory processing making a better chance of the component being stripped and blasted, for better corrosion resistance and adhesion.
bullet pointIt produces a more waterproof barrier than liquid paint (for comparable thickness) and therefore offers better protection against corrosion.
bullet pointTo hide metal imperfections, a Powder coating finish can achieve in two coats, what stove enamelling requires in 15 or more coats.
bullet pointTherefore the price is comparable, or even cheaper than stove enamelling.
bullet pointPowder coating is more resistant to scratching and marking.
bullet pointGood quality powder coatings are available in high gloss and have negligible orange peel.
bullet pointDirt is easily washed off.
bullet pointPowder coating can be compounded, polished and waxed like any other paint.
Bad points:
bullet pointCannot be applied on site, therefore not convenient.
bullet pointUsually takes 2-3 days to process. (Can be quicker.)

This why powder coating has been the fastest growing area of the paint industry for the last 25 years, and why nearly all mass produced items are powder coated.

Stove enamelling
Stove enamelling is like air-drying paint, but the curing is accelerated by stoving at 120 degrees Celsius. It is sprayed with the sort of spray guns you would expect to see spraying a car in a garage.
Good points:
bullet pointRequires factory processing making a better chance of the component being stripped and blasted, for better corrosion resistance and adhesion.
bullet pointExcellent finishes can be achieved as each coat can be flattened (rubbed down smooth prior to the next coat, this reduces orange peel).
bullet pointIt is easier to mask and paint over with a different colour, something very difficult to achieve with powder coating.
bullet pointNearly any colour including metallics can be produced cheaply and in small quantities.
bullet pointHigh gloss and matt finishes are achievable.
Bad points:
bullet pointCan be not be applied on site, needs an oven.
bullet pointBrittle, will chip if abused.
bullet pointRequires many coats to achieve good finish.
bullet pointCan suffer from runs if not skilfully applied.
bullet pointDoes not adhere (stick) strongly to metal, results in chipping.
bullet pointNot environmentally friendly due to solvent emissions.

Air drying spray paint
Wet paints can be applied as single pack air-drying or two pack air-drying.

Single pack air drying
Good points:
bullet pointGood finish can be achieved.
bullet pointCan be applied on site.
bullet pointEasy to apply and requires minimal equipment. (Aerosol)
Bad points:
bullet pointThe evaporation of the solvents determines the speed of curing. This can mean the paint remains soft for days and can take weeks for a full cure.
bullet pointGenerally the most brittle of all three types of painting.
bullet pointDoes not adhere well to previous powder coating and can peel off.

Two pack paint
Good points:
bullet pointGood finish can be achieved.
bullet pointCan be applied on site.
bullet pointNearly any colour including metallics can be produced cheaply and in small quantities.
bullet pointAdheres better to powder coating than air-drying.
Bad points:
bullet pointNot environmentally or user friendly, due to solvent emissions and carcinogens.
bullet pointTime consuming, can suffer from contamination whilst wet and sticky.
bullet pointCan take days to harden.

If the above reasons where good enough for us to move to powder coating, you may feel the same.

Where can I get a good powder coating job done?
It is another case of you get what you pay for. The powder coating industry suffers from the cowboy element just like any other industry.
bullet pointOnly go to a company that will ensure the component is grit blasted.
bullet pointIdeally the component should be chemically pre-treated to reduce corrosion.
bullet pointOne coat of powder is not enough it should have a primer.
bullet pointDo not allow aluminium components to be stripped of powder coating by blasting alone. It must be chemically stripped first, or it will end up pitted.
bullet pointIf in doubt ask to see some of their work.