Improve the attraction of powder to your parts while powder coating.
If you are powder coating a metal part, it should be grounded. The grounding is what attracts the powder to the part. The better the ground, the less problems you have, especially when doing multiple coats. Often a powder coating gun or the guns control box will come with a little 18 gauge ground wire and a mini alligator clip that you can connect to your part to ground it. I will call this the "stock" ground. The stock ground continues through the control box, through the wire it uses to plug into a wall outlet and after that is a mystery to me. This is not a good example of a ground. No matter how good of gun you have, you should have a DEDICATED GROUNDING ROD.
What are the advantages of using a grounding rod when powder coating?
Faraday Cage Areas:
Using this ground method helps with a phenomenon called faraday cage areas. Faraday cage areas are areas of your part that get electrically shielded by a more prominent area of the part. These areas are usually recesses or tight corners. You will notice them when you are spraying powder at a part and no matter how much powder you spray, the powder will not go into one of these areas. All of the powder is attracted to the larger, more open surfaces next to this area. Having a proper ground like the grounding rod will significantly reduce these problem areas and allow these areas to attract the powder more easily.
After you have sprayed your first coat of powder and cured it, you may want to another coat after this, whether it be clear, a candy, or any other coat. This is another area where the grounding rod will help. That first coat of powder acts as an electrical insulator covering the entire part. It is insulating the ground that attracts the powder. This causes the following coats to fall right off of the part UNLESS the ground is sufficient. The strong ground that is provided by the grounding rod will attract powder even through coats of powder. This will not be accomplished by the tiny gauge wire that came with your powder coating gun. Mutli-coats are much easier after a properly installed grounding rod is connected to your part.
So What is a Grounding Rod?
A ground rod a long bar copper coated bar that gets driven into the ground. The sizes vary, but for the powder coating application, I recommend an 8ft or a 10ft bar. It can be bought at your local Home Depot or Lowes for $10.00, see: Lowes Grounding Rod. The ground rod gets hammered into the ground almost entirely. You want to leave about 6 inches of the rod protruding above the ground to attach the wire to. You then attach this wire to your parts and your parts are now grounded with a very strong ground.
While you are out buying the grounding rod, you should also buy a grounding clamp, this is a clamp that fits around the rod and has a bolt to attach your wire to. Like this:
You will also need a length of wire to connect your grounding rod to where you hang your parts. 8 gauge wire is the recommended size as long as you are not running the wire long distances. If you need a long distance run, then it would be best to opt for a larger wire size to reduce resistance. Although you want the shortest wire and the least amount of connections possible to make sure you have a reliable ground. If you plan on powder coating in your garage or shop, you can actually drill a hole in your garage floor using a masonry bit, and hammer the grounding rod through the garage floor down into the ground below. If you no longer want it in the garage, just pound it the rest of the way down and fill the hole up.
What I did was install the grounding rod right outside my garage door, I put an upside down flower pot on top of it to keep anyone from tripping on it, don't want to get sued by the guy who checks my electrical meter. The ground rod has a foot of lead wire with a little quick disconnect plug. I coated the ground rod and connection with some dielectric grease to prevent corrosion. Then on my rack I have a 9 foot long wire that I just connect to to the grounding rod wire via the plug. It takes less 10 seconds to plug in and is very convenient. On my rack, the wire runs up the side and over to the middle and it is soldered to my "master hook". I hang everything from this hook and it has worked very well. Testing with a multimeter has confirmed the resistance from the ground rod to the part hanging on the rack is 0. Once your grounding rod is set up, you no longer need the "stock" ground clip that came with your powder coating gun. Just coil it up and put it to the side.
|This is the ground rod and lead wire outside my garage door. I hammered it down more since then and only about 3 inches is protruding from the ground.|
|My old powder coating rack setup. I have since switched to a powder coating booth with 8 gauge wire.|
|You can see the wire running up the rack and is soldered to the hook.|
|I soldered ground wire directly to the hook which minimizes resistance.|
Now that you have seen a proper grounding rod setup, set one up yourself. It is worth it! I noticed improvements immediately. 2nd coats sprayed on like they were the 1st coat. Faraday Cage areas were minimized to only the tightest areas.
One more thing to add about the grounding rod. If you live in a dry environment with dry soil, you can improve your grounding rods performance by wetting the ground around it before powder coating. I live in Florida, where the dirt is more sand than anything so I just keep a gallon of water next to the garage door. Before I powder coat, I just dump the water all around the base of the grounding rod. Give it a couple minutes to soak down into the soil. This improves the grounding rods connection to the actual ground.