Understanding the difference between Gravity and Suction Spray Guns

There are different types of spray guns??

So, you want to get some spraying done. Whether it's a new coat of glossy pearl paint for your project car, or spraying something for work, you're gonna want the right spray gun for the job.

Shopping for a new spray gun can be difficult. There's so many options - Gravity? Suction? Which one is the right one?

Well, there is no right choice - it depends on many factors, including the type of job it's for, the type of paint you're using, and of course; personal preference. But if you're a newcomer to spray guns, or you just can't decide on a new gun, we're here to help you make that decision.

1) Suction Feed

Suction fed spray guns, also sometimes known as Siphon fed spray guns, are your more "conventional" spray gun. These feature the paint pot attached at the bottom of the gun, using suction to siphon the liquid paint up and into the gun. Hence the name.

Suction fed guns are what a lot of people tend to imagine when they think of a spray gun - they've been around the longest, and they're known to be easier to learn and use than their gravity counterpart. They're comfortable to use, and quite affordable too!

One major difference between Suction and Gravity feed is the atomisation of the paint. Newer sprayers may not really care, but atomisation happens automatically using a suction feed gun. This can be both an advantage and a disadvantage - this lets you spray smoothly and evenly, but you miss out on the control you get with other guns. Some painters don't like the finish you get from a Suction fed spray gun quite as much, as the lack of control over the atomisation can lead to overspray and paint wastage.

Other than this, Suction fed guns can hold larger paint pots, which can make things easier for spraying larger projects. However, it can be harder to change colours mid-project, so it's more suited for one-colour jobs.

2) Gravity Feed

On the flipside, Gravity fed spray guns don't have this issue. Colour changes are quite easy, only needing a disposable insert which makes quick swaps very simple for multicoloured projects. Gravity guns feature the paint pot on top of the gun, using the natural forces of gravity to feed the paint into the sprayer. This needs a lot less air pressure to feed and atomise, which means the painter has much more control over the feed and the output of the gun. This can lead to finer finishes without the overspray issues common with Suction fed guns.

Gravity guns are also quite affordable, though they're a little less comfortable to use to some. The pot being on the top of the gun adds a fair bit of weight, which some painters dislike - though personally, it's fine when you get used to it. As well as this, the top-mounted pot can't be too big, so you won't get the capacity as some Suction fed guns. You also can't paint upside down with a Gravity fed gun, though you can with Suction. These are relatively minor and trivial differences, but game changers to some.

Clean-up is quite easy with Gravity fed spray guns, especially compared to Suction guns. It's also more portable and much easier to set up, making the gun suitable for quick touch-ups and longer projects alike.

At the end of the day, a lot of it comes down to the all-important personal preference. A lot of painters started with Suction guns and either never had the urge to change or could never get used to the Gravity fed guns - but the high-quality finish you can achieve with Gravity guns speaks for itself.

3) Pressure Feed

Wait, there's a third??

Many people forget about Pressure fed guns, as they're more suited for higher-end, large scale spray shops. Instead of drawing from a pot attached to the gun itself. Pressure guns feed from a remote pressure pot - this makes the gun a lot more expensive to run, as needing a separate pressure tank is much more expensive than just drawing from the gun itself. The feed system requires a second hose for the paint, which on top of being a pain to deal with, can again increase costs. It's also much harder to clean, needing to clean up to 10 metres of feed system as opposed to just the gun and pot of the other two.

Why use Pressure then? Well, Pressure guns are great for if you need a lot of paint - way more than just a hobby project. Pressure tanks can range in size, all the way up to hundreds of litres!

Pressure fed spray guns also offer the greatest control in terms of finish, being able to control the fluid pressure and air pressure separately with the use of a dual pressure tank. Pressure guns also aren't limited in the viscosity of the fluid used like Gravity and Suction guns are. These guns can really struggle with heavier, thicker coatings that Pressure fed guns aren't.

Despite this, Gravity and Suction guns are still much preferred for smaller-scale operations, and very few places actually need a Pressure feed system. For the newcomer hobbyist, a Suction gun is the best to learn with. As you start to need higher-quality finishes, moving to a Gravity gun is a good idea.