Dripping High-Solids Paints

Q. I am the paint line foreman in our plant. We have recently started using new paints and upgraded our painting equipment in an effort to improve our finish quality and bring finishing costs into line. We are now spraying high-solids paints. We are using automatic electrostatic spray guns mounted on reciprocators in the main booths and electrostatic hand spray guns in the touch-up booths. These upgrades were installed on our existing paint line.
The resulting finish looked great for a while. After a couple weeks, we started having problems with blobs of paint on our parts. We finally figured out that the problem is caused by paint overspray that gathers on the overhead conveyor and then drips on parts as they are being carried along. We have three other paint lines and were in the process of upgrading all of them. This is a serious problem that is causing many rejects. What can we do? E. O.

A. I hate when that happens. I found the problem you described, high-solids paint dripping from the overhead conveyor on to parts, unacceptable. It’s probably no consolation to you, but it is something that has happened to others as well. Although it can happen using conventional paints, it is more prevalent using high solids paints. With conventional paints, the overspray is drier and is therefore less prone to flow and drip.

Unless someone has a better solution, there a couple of things I can suggest you do. One is redirecting the airflow in the spray booths to carry the overspray away from conveyor. The other is to install a protective cover on the conveyor in the spray booth. Suppliers of equipment and devices to correct this problem can be found in the PF Suppliers Directory under the various Conveyors headings.