What to do when the powder won't stick to the part?
There is nothing more frustrating than incorporating powder coating adhesion issues into a project. At this point, you've probably invested a lot of time cleaning powder parts and prepping your powder Spray Gun and powder coating supplies. We've decided to give you a quick troubleshooting guide for adhesion issues when powder coating.
1. Contamination on the surface - Even if you have cleaned the part well, you may still have problems with the powder sticking to the surface due to some hidden oil, dirt or grease. We recommend pre-baking a portion to bake off any hidden oil or grease, and brushing with PRE Paint Prep after it cools. For great results, you should also do a medium rinse to clean it and give texture to the powder. If your part is not clean enough, the charged powder may not adhere to areas where it has an oil film or grease.
2. Incorrect grounding on the part - if you connect the ground cable to the part itself, it needs to have a good connection or the powder won't stick. The ground connection completes the electrostatic circuit and helps attract powder to the part. Check the ground clip to make sure the wire is not frayed or damaged, and the clip is not coated with old powder. You may also want areas on the part to be clean, free of paint or other coatings. This problem can arise when applying multiple coats, as you can lose a place to attach the ground. Sometimes you need to get creative with stainless steel wire wrapping around an exposed area to ensure proper grounding. Whenever we use a powder gun, we make a habit of cleaning out the ground fixtures of the old powder.
3. Improper Booth Grounding - If you are a serious hobbyist or professional, you probably have a dedicated spray booth for applying powder to your parts and you need to properly ground the booth itself . This allows you to simply hang or place the parts in a metal compartment and they will be grounded without attaching the clamps directly to the parts. You can lay out your booth by driving ground stakes deep into the ground and attaching heavy steel wire from the stakes to the booth to get a nice dedicated ground. If the stakes or jumper wires are loose or damaged, you may have a loose ground connection. You can test if your stand has a good ground by holding the gun some distance to the side and hitting the powder gun trigger (ground clip on the stand) and you should see an arc jump from the tip of the gun to the stand. If you don't see this, then you probably have a grounding problem. Over time you can build up old powder, causing bad ground from the booth to the part itself. Be sure to get into the habit of cleaning old paint and powder booths before starting a new project.
4. Faulty Powder Coating Gun - You may experience a similar problem if the power supply to the Spray Gun fails, which may lead you to think that this is a basic problem. You can do a quick check by pointing the tip at the ground clip and pressing the trigger to see if the arc jumps to the ground clip. If there is no spark, your gun may have a bad power supply and you should contact the manufacturer.
