Suction Feed Spray Guns, Spray Gun with Cup Below the Gun

Suction feed spray gun, also known as siphon feed spray gun, is a type of spray gun where the paint reservoir is located below the gun. The principle of suction feed actually is using the principle of liquid atomization when the spray device was first invented. Compressed air flows from a hose into a nozzle where the room is designed to make air flow becomes very fast, resulting in the air pressure in the room becoming very low.  The liquid sucked from the cup to the nozzle due to the pressure difference between both rooms. Then the finishing material is atomized and directed by the gun to coat the desired surface.

This suction spray gun is a type of cup gun, the spray equipment with cup attached to the spray gun. It is very similar uses with the gravity cup gun. However, with a cup attached to the bottom of the spray gun, it has some advantages and disadvantages compare with gravity cup gun.

suction spray gun

There are several advantages of the suction feed spray gun

• More stable, more volume

This suction feed has the cup under the spray gun; therefore, this tool is relatively more stable when used. The material cup containing the material make it is easier to be moved with less risk to spilled. The cup volume can be slightly larger than a gravity cup gun. Gravity feed cups are usually 400 cc or a maximum of 600 cc volume, while the cup volume on the siphon feed can be up to 1000 cc.  With the cup positioned below the spray gun, the tool will be more stable, easier to move with less risk of spillage. 

• Easier to do finishing on the furniture

The suction feed spray gun can operate with several maneuvers that the gravity cup gun cannot do, such as: spraying from the right side, left side and from above, what he cannot do is spraying from the bottom. The suction feed spray gun is easier to be used to apply finishing materials to the stuff such as tables, chairs, cabinets, etc.

• Perfect material atomization

This tool uses a suction process to draw material from the cup into the atomization chamber. Sufficient suction power is required to counter the force of gravity, meaning that any material that enters the atomization chamber will always be perfectly atomized. If the material is too heavy, it cannot be lifted into the atomization chamber and no application material can be done.

the disadvantages of suction feed or siphon feed cup gun

Besides several advantages, siphon feed also has several disadvantages; here are some disadvantages of the suction feed cup gun

• Low viscosity

Siphon feed relies on suction force resulting from the pressure difference between the nozzle and the cup to drain the liquid. Therefore, this tool has limitations when used. The suction feed gun cannot be used for relatively "heavy" and viscous materials which might still be handled with a gravity feed gun. This tool also only can do the application with the perfect atomization. If you want to apply finishing material with some special effect such as the splash spray or very dry spray then you cannot use this tool. 

• Requires more compressed air

This suction feed spray gun requires compressed air with sufficient pressure and volume. The compressed air that flows into the tool must be sufficient to suck the material against the force of gravity until it reaches the atomization chamber. Compared with a gravity gun, the flow of material from the tank to the nozzle chamber occurs due to gravity, and compressed air is only used for material atomization, then more pressured air is needed. You will need the pressured air in certain volume and certain pressure to run this tool. 

• More suitable for small scale jobs

Even though the suction feed cup gun has a cup with a larger size compared to a gravity cup gun, basically this tool is a small size spray gun. This tool has a small material capacity; therefore, it is more suitable for small volume. For simple comparison between gravity and siphon feed spray gun you can find at the infographic below. 

gravity cup gun vs suction feed cup gun

Tips for choosing and buying a siphon feed spray gun

Currently, there are many spray guns available. The spraying equipment companies has provided many brand and types and each will showcase its own advantages. However, you need to find the best suitable tool for your need. Here are some tips for choosing a spray gun

• Make sure the spray gun you buy suit your needs 

In principle, the suction feed spray gun is a cup gun which is actually intended to carry out work with volumes that are not too large. The suction cup usually has a maximum size of 1 liter, more than that, the spray gun will become heavy and make movement difficult. Indeed, this tool will be very helpful for carrying out the spray process on some products items such as: cabinets, tables, chairs, etc. It will work better then the gravity cup gun. But this spray gun is not suitable for large scale work such as furniture production in factories or finishing applications on goods with high volume. It is also not suitable to handle the items with a very large surface area such as walls or large panels. For the big volume product or big furniture stuff you have to consider the spraying equipment with separated tanks such as pump or pressured tank. (see our previous article : spray gun with tanks and spray gun with pump

• Specs of the tool

Currently there are many brands of the suction cup gun available and each is designed for a specific purpose. When choosing the spray gun, make sure you choose a tool with the right specifications according to your usage needs. Carry out in-depth consultations with the seller and do testing first if possible.

• Consider after-sales service

Every tool that is used will become damaged after a certain time and require maintenance and service. Therefore, make sure you buy a tool that has good support. Consider the service center, spare parts availability and technical consultations that you may need while using the equipment you purchased.