When you want a paint finish to be as fine as possible, spray painting is the most diverse way of achieving that. And it doesn’t mater what type of surface you have.
The versatility involved in spraying a paint, coating or specialized finish product depends on three things: (1) specific kind of surface that you have, (2) specific material you wish to use, and (3) method of spray that you intend on using.
Most of us haven’t thought of spray painting as having many options. Specifically, there are three types, or systems:
1. Conventional system. Air pressure is supplied to a paint tank or container. In turn, it applies a pressure to the paint fluid. It becomes atomized by using a specially designed paint metering gun. The spray gun is highly adjustable. It allows for changes to paint volume and pattern of the paint spray.
* Uses include: all fields of painting, especially in the finishing of wood and metals.
2. Airless system. An electric or gasoline powered hydraulic pump is used to apply a pressure to the paint or coating. Pressure can vary, anywhere from 3000 to 5000 psi. The material then passes through ahigh-pressure supply line. And, the material flows to a spray gun, with a varied selection in spray tip sizes.
Next, the paint is atomized in a flattened pattern, that delivers a high volume of paint to the surface.
* Uses include: commercial, industrial and residential painting.
3. Electrostatic system. Paint finishes are applied through an electrolytic charging process. The paint and surface are charged with electrons, creating a magnetic streaming effect. It incorporates an electronic controller unit, and a specialized spray gun, designed for applying thin coatings as fine as possible.
* Uses include: automotive and parts painting industries.
Several variables that allow paint spray finishing system to perform at most optimal level.
1. Make sure all equipment is clean. This includes the inside of the paint hoses, moving hydraulic parts, paint pressure tank, and internal and external surfaces of the spray gun.
TIP: Proper spray gun maintenance is critical. Please: Learn to do it right. Don’t try to wing it.
2. Thin and strain paint to the recommended viscosity, to promote a steady, even flow.
3. Regulate an accurately adjusted spray pattern, to promote evenness of the paint film.
SPRAY PAINTING A SURFACE
There are various techniques available to use, when painting irregular surfaces or objects. When painting a flat wall, airless spraying is the method of choice. With the system ready, and the spray line under pressure, you are ready to begin.
To apply the material, maintain a position which is perpendicular to the wall. Try to hold this general stance as you move from side-to-side, or vertically.
Firmly hold the spray gun. Allow for flexibility in the entire forearm, wrist and fingers. As you press the trigger of the gun, the material will flow into a set fan, aimed toward the surface.
For optimal control of the paint pattern, hold the spray gun perpendicular to the wall. And, maintain your stance. At all times, try to develop a spray fan overlap of between 50 and 70 percent. Keep an 8-to-12 inch distance between the gun tip and surface – eg. ceiling, or wall.
The passes of the spray gun should be no wider than you can maintain the correct hold on the spray gun. The width of your shoulders, or length of your arms, is considered to be the standard spray distance.
RECOMMENDED SPRAY GUN EQUIPMENT – BY SYSTEM
1. Conventional System
Equipment: Spray guns, paint pressure pots; gravity cups, remote paint cups and containers; fluid and air hose, hose fittings; fluid nozzles and needle configurations for various finish types and HVLP paint systems; viscosity testing cup for measuring paint viscosities.
Other equipment: Air compressor which supplies recommended psi and cfm for spray gun applications and specific type of paint that will be used.
Parts: Keep on hand replacement gaskets for cups, tanks, etc.; spray gun filters in at least two main sizes.
SYSTEM BRANDS: Sharpe, Binks, Devilbiss, Sata.
2. Airless System
Equipment: Electric/gas/air compressed operating spray pumps; high pressure hoses, heavy duty spray guns, extensions, seal replacement kits, siphon filters; wide selection of spray tips.
* TIP: With air compressed operating pump, choose one with a 30 cfm rating. This depends on hose length and viscosity of material to be used.
Parts: Keep on hand hydraulic shaft seals, multiple spray tips used consistently, and several spray gun filters in at least two main sizes.
SYSTEM BRANDS: Graco, Titan.
3. Electrostatic System
Equipment: Electrostatic spray gun with adjustable current and voltage settings; electrostatic charge controller, with ground-loss indicator; twin hose sets. Also, check the lists above for conventional and airless systems.
Parts: Fluid nozzles, air caps.
SYSTEM BRANDS: Graco Pro XP, Lemmar Spray Systems, Ransburg.
RECOMMENDED BREATHING APPARATUS
You will want to use one or more of the following systems:
1. breathing apparatus,
2. ether facial respirator,
3. self-contained breathing system.
Spray painting offers a nearly endless list of creative opportunities. I’ve used a spray gun system on many, many professional/work projects – interior and exterior. Some have cried for the ultimate in creative touches.
On private projects, I’ve used special systems to paint/decorate autos, boats, furniture, fixtures, sculpture pieces, garden areas, lake cottages, graphic murals, nautical scenes, etc.
Each spray painting/finishing project has been taken on with “creative opportunity” in mind, and at heart! And, with the mission of producing the very finest finish possible.
Leaving behind a fine, precision spray finish – on every surface and with every project – is a great accomplishment for every professional painter.
Many thanks for checking in with “Painting with Bob.”
Copyright 2015. Robert D. Hajtovik. All rights reserved.