Finding the Best Sprayer, Part I

Choosing the proper finish for a woodworking project is a critical part of the process and can make or break the results. Choosing the proper way to apply the finish is just as, if not more, important. I’ve been spraying my projects for over ten years and really like the process. I think many woodworkers don’t even consider spraying due to the higher start up costs and a fear of making a mistake. I started with a HVLP (High Volume, Low Pressure) gravity gun, which are comparatively reasonably priced. I still use this setup on many projects, but have also tried many of the other options available.

WoodRiver HVLP cup over gun sprayer

The goal of any spraying system is to atomize (turn into a mist) the material and then apply it to the surface. There are many different ways to accomplish this process, I’ve listed the most common types of spray systems below.

• Conventional: Uses a standard air compressor.
• Conventional with HVLP: Uses a standard air compressor, the gun converts the air to HVLP.
• Turbine HVLP: A turbine generates the air.
• Airless: A high pressure pump moves the material without any air.
• Air Assisted Airless: A combination of a high pressure pump and a HVLP gun.

Earlex and Apollo turbine spray systems

Picking the system is only half of the spraying equation. There are three styles of spray gun with most systems having all three options available. Take care to make sure the air output of the compressor or turbine (measured in cubic feet per minute or CFM), is sufficient for the spray gun.

• Cup under Gun: The material cup is under the gun and is pressurized. The cup normally holds about a quart of material.
• Gravity Feed: The cup is above the gun and the material is fed by gravity. This cup normally holds about a half quart of material.
• Gun with Pressure Pot: The gun is connected by two hoses to a pressure pot which holds the material. One hose is for air and one is for material. Pots vary in size from approximately two quarts to two and a half gallons.

In Part II of the article I will give my experiences and recommendations for the various systems and guns.