If you’ve been shopping for a manual powder coating gun, you’ve seen the terms “box-fed” and “hopper-fed,” but which type of gun do you need? We’ll cover the basic differences and how each gun can work for you.
Box-Fed Powder Coating Guns
A box-fed powder coating gun – like the one shown – uses the powder directly from the box. A tube is placed in the powder which draws the powder into the gun for smooth application. The box of powder constantly vibrates on the platform, which prevents the powder from clumping or surging through the gun.
Box-fed guns are great if you want to get started quickly. As long as you have the color you want, you can start coating right away. They also let you change colors quickly (once you get used to the process, it should only take about 5 minutes to swap hoses on professional models like Wagner). They are cheaper than other manual guns and are easier to move around the shop.
One of the biggest strikes against using a box-fed gun is that you can’t use special effects powder. Special textures and fade effects require particles of different size to be constantly mixed (a process called fluidization) to produce the special effect – which is something a box-fed gun just can’t do.
Also, since the powder is exposed to the air and the shop, humidity and contamination can be a problem, especially if you don’t have a clean room.
Hopper-Fed Powder Coating Guns
A hopper-fed powder gun has a sealed steel container where the box sits on a box-fed gun. This hopper constantly pumps compressed air into the powder – keeping it fluidized, dry and free from outside pollutants. If you look at the top of the hopper while it’s in use, the powder will look like it’s boiling. If you put your hand in the powder while it is being fluidized, it should feel smooth.
A hopper-fed gun provides a more consistent color. Because not all powders are evenly mixed when they arrive and even the same color can be slightly different across multiple boxes, the fluidization keeps all the powder mixed properly so you get the same result when you spray. This is great for color-matching across many applications and is perfect for special effect powders. Also, because of how clean the powder stays in a hopper, using hopper-fed guns is the right way to go if you want to reclaim your powder.
What are the biggest issues with a hopper-fed gun? It takes a long time to clean hoppers, up to an hour for every color change. If you are spraying multiple colors a day, that’s a lot of time you aren’t coating. However, adding a new hopper for every color will get very expensive. As most hoppers are 60L, each one you add takes up floorspace and can soon get hard to store. Hopper-fed guns are bulkier than box-fed guns and are harder to move around – this can affect your output, but it depends a lot on your setup.
Choosing the Right Manual Powder Coating Gun
Each type of powder gun has it’s uses – shops that coat only one or two of anything will typically use a box-fed gun, while a shop that has to keep the color consistent across dozens of products will use a hopper-fed system. For an even more detailed breakdown of how these two guns are used and what you can expect, please read a more in-depth article at our manufacturer’s website.
If you have any questions at all about which gun you should be using for your application, feel free to contact us or give us a call today!