Gravity Feed Spray Guns vs Suction Feed Spray Guns (Includes Video)

Gravity and Suction are one of three ways to feed a Air Fed Spray gun.  Gravity and Suction fed spray guns allow for a lot of benefits but also have drawbacks.  We will cover the advantages and disadvantages of gravity and suction fed spray guns.  If you want to evaluate between gravity, suction, or the third style of air spray gun known as pressure fed you can check out this overview article.

Gravity Feed Spray Guns

Gravity fed spray guns allow for smaller batches of coating to be used at a time.  They are also quick and easy to cleanup.  They provide fine atomization and can be used effectively with all types of spray guns including HVLP, LVMP, or Conventional.  The main disadvantage is that they require material to be able to flow on it’s own.  Practically this means that heavy body coatings will not spray well with a gravity fed spray gun. For a coating to apply well with a gravity fed spray gun it should be able to run off the end of a stir stick easily without excessive thinner.  If you have to add more paint thinner than recommended by the Technical Data Sheet for the coating, it would be better to think about a pressure fed spray gun. Pros

• Easy cleanup
• Affordable (around $400 - $700 dollars less than Pressure Fed Spray Gun but similar to suction fed spray guns)
• Achieve a fine finish
• Able to have slower fluid amounts delivered which can be ideal for smaller projects and touch up work
• Able to change colors quickly with a disposable insert liner
• Better control of atomization air compared to a suction fed spray gun

Cons

• Smaller amount of material than pressure fed (same as suction fed)
• Painters sometimes do not like the weight of the paint on top of the gun
• Limited control over fluid delivery (controlled by changing fluid nozzle sizes)
• Cannot spray heavy bodied coatings well

Common Uses

• Automotive painting
• Wood Finishing on Smaller Projects like individual cabinets or furniture pieces
• Used for color matching in high production facilities
• Metal Fabrication touch up painting
• Frequent color changes with inserts like Dekups

 

Suction Feed Spray Guns

Suction fed spray guns use the air that passes over the coating to draw material through the pickup tube of the suction cup and through the nozzle.  One of their greatest advantages is ease of use.  Due to the way the gun uses air to pick up coating it will typically automatically have the correct atomization air pressure set by having the pressure high enough to supply coating.  This can also be a disadvantage because you cannot control the atomization air pressure like you can with a gravity fed spray gun.  The suction fed spray gun will cost about the same as a gravity fed spray gun. People also often say they prefer the comfort of a suction fed spray gun over a gravity fed spray gun because the material is below the gun and not above it.  Another disadvantage of a suction fed spray gun is that it will not allow for quick color changes as easily. Pros

• Easiest to learn how to use
• Affordable
• Greater comfort than gravity fed spray guns
• Can achieve unique finish effects and works well with specialty coatings like adhesives

  Cons

• Less control over atomization of air compared to gravity fed spray gun
• Difficulty with heavy bodied coatings
• Not as fine as a finish due to needing larger fluid nozzles
• Not as easy to perform color changes

Uses – Although it has been used for all kinds of coatings we recommend it in the following situations

• Adhesives application for low viscosity coating
• Longer paint times with small batches that the comfort is critical and finish quality is not huge concern 

 

Video highlighting gravity vs suction vs pressure feed spray guns

https://youtu.be/cceSWxOx8Eo