Powder coating seems simple when you first get into it but there are a lot of tricks to and tips to help you coat parts more efficiently and also to get better quality coatings on your projects. We decided to give you some of our best practices for improving the transfer of powder to your parts.
Your powder coating spray booth or area you apply powder can benefit from a few things to help with the transfer efficiency of powder. Temperature and humidity can play a role when extreme swings in temperature or humidity occur. Optimal Temperature and Humidity for powder coating we’ve found is 60F to 80F degrees and 40% to 70% humidity. We’ve found high temperatures or humidity decrease powder retention and can cause difficulty in powder adhesion in tight areas. On the flip side a little humidity is helps with the electrostatic transfer. The rule of thumb is that if it is extremely hot, muggy, and humid you should time your powder coating job until the weather has evened out or spray very early in the morning or late in the evening when temps and humidity are a little more moderate.
There is some room for error when applying powder and technique does come in to play. If your powder coating gun is too far or too close to the part you could be wasting powder or hurting the transfer efficiency of the powder. When the gun is too far away you could lose some powder that is suspended in the air and isn’t attracted to the part. Because most home powder coaters don’t have a good way to recover powder this truly throwing away good powder. Alternatively if your gun is too close (less than 6 inches away) to the part you may get uneven coverage because the air pressure blowing the powder out is overcoming the static charge and the powder can tend to clump in certain areas rather than “wrapping” around the part. We’ve found the optimal gun distance from the parts is 6-12 inches. If your air pressure is set correctly it should propel the powder with enough force for the electrostatic charge to take over and pull the powder onto the part.
Similar to discussed above, the distance the gun is from the part or the speed at which powder is shot at the part can cause uneven coverage and overcome the “static cling” when powder coating. This means that while you will get more powder shooting at the part when you crank the air pressure up; it doesn’t mean you’re efficiently coating the part. We suggest keeping the air pressure lower (around 5-10psi) so that the powder is fogged on to the part and stays suspended in the air longer so the static charge can grab it and pull it on to the part. This well reduce over coating flat and easy-to-reach areas while under coating crevices and hard to reach areas.
The way you hang your parts and the hangers you use will make a difference to how powder transfers to your parts. This is because normally when you’re powder coating you attach the ground for the powder coating gun to the hanger or the booth and not the part itself. This means you need to have a good connection between the booth, the rack, and the hangers. We suggest cleaning your hangers back to bare metal regularly to assure the best ground connection for your gun and part. We like to submerge our hangers in Paint and Powder stripper after each job to clean them back to bare metal. This will take baked on powder off easily and they can be cleaned with PRE and hung to dry; ready for the next job.
Hopefully those quick tips help with your future powder coating projects and assuring you get the best coverage on parts as possible and reduce powder waste when working. To shop our entire line of powder coating guns, ovens, powders, and accessories visit our site HERE.