Grounding for Powder Coating – A Complete Guide (with video)
Having a thorough understanding of grounding is critical as a powder coater. Powder coating relies on a grounded target in order for your powder to stick. Failure to properly ground a product you are trying to powder coat or to not ground your product thoroughly enough can result in a variety of issues from wasting excessive powder, to finish defects like back ionization, and can even cause you as the operator to get shocked. In this guide will cover what grounding is, why it is so important for powder coating, and how you can ensure that your grounding is solid when powder coating so that you get the best possible results out of your powder coating.
What does it mean that something is “grounded”
Before we cover how to ground a part for powder coating it is critical to understand what it means when we say something is grounded. When something is grounded it means that the object is in some way connected to the earth which allows for any static charge that may build to be dissipated through the earth.
Why Grounding is Important for Powder Coating
In powder coating good grounding is critical because powder coating becomes highly charged by a powder coating gun and due to its negative (or positive) electric charge, the powder then seeks a grounded surface as charged particles will generally always seek to return to a neutral state and so the negative charge is attracted to the grounded surface which has a more positive charge.
A list of issues that can occur due to poor grounding in powder coating
Common issues that result from poor grounding include issues with back ionization, an inability to successfully apply two coats of powder, getting shocked regularly, excessive powder waste, and a multitude of similar problems.
Steps to establish and verify a good ground when powder coating
Knowing all the potential problems that can result from having a poor ground in powder coating, we can now cover how to establish and maintain a quality ground in powder coating as well as cover how you c verify if your product has been effectively grounded.
- For a good ground to exist their must be a way for current to flow through the material that is desired to be powder coated, that is it must be conductive, enabling the dissipation of electric charge to the ground that will be in contact with the product that you want to powder coat. This means certain materials may not be able to be powder coated without additional sprays or additives to help enable the product to be conductive.
- A surface that is well grounded – the best grounds are made of conductive materials that are then inserted into the earth or in direct contact with the earth enabling them to carry any charge that may build to the earth. Common options include galvanized or copper grounding rods driven into the earth usually 6 to 12 inches or a booth that is secured into the ground which can often also be grounded, be sure to check your booth with a ground tester as not all booths will be well grounded.
- A strong connection from the grounded surface to the part that will be powder coated – this is one of the most critical steps, you need a strong connection between your part to be powder coated and the earth ground. This is generally a conductive wire that is connected directly to the grounding rod, that is then clipped on a rack of parts or in some situations directly on the part. If you wonder if you have a good ground, you can get a grounding tester which is essentially measuring how much resistance is between a surface and the ground you have in place. You want as low of an Ohm reading as possible as this indicates that you have achieved a strong ground. If you have a good ground and still have trouble getting good results, you may want to check that your grounding cord is directly on the powder coating piece you are wanting to coat rather than the rack, or if you use a rack ensure the attachment point is kept free from powder build up and that the rack is conductive. Essentially if you know your ground is good you need to check between your ground and how it attaches to the product you will be powder coating to verify that the connection is smooth and continuous from the ground to the product itself. Any powder build up between your grounding clip and the product or product rack can create poor grounding.
Summary
Establishing a good ground is critical to get good results powder coating. To ensure a good ground is achieved ensure your product is conductive, that a grounding cable that is also conductive is used and grounds the rack your using or if having issues that you attach the ground cord directly to your product. These steps will help you ensure you have properly grounded your product for powder coating.