Powder coating is terrific, but only when it’s on the outside. Sometimes it manages to creep into tight places, such as threaded holes in walls, machined pieces, or the like. If the powder coating gets in, it can harden and cause several problems. For example, threads can become ruined and need re-tapping, redrilling, and rethreading. You may need to laboriously strip the powder coating from the surrounding surface. This is why professionals make sure to cover and protect every exposed threaded hole when powder coating. Here are a few ways to mask threaded holes before powder coating.
Use Polyester Tape
Tape is a wonderful tool in all its forms, and the right polyester tape is best for masking holes and other parts even in the high temperatures that occur during the powder coating process. Make sure you only use high-temp polyester tape—any other kind is apt to burn up, melt, or otherwise disappear and mar the surface and powder coating. Tape features straight edges, and simply placing a strip over a round hole can leave an unsightly mark around the edges. Still, you can cut it to almost any required shape, and some forms of polyester tape come in precut circles.
Use Plugs and Caps
Plugs and caps are just what they sound like. They’re plugs and caps of silicone that come in assorted sizes. Grab a handful of plugs, and push them into any hole. Silicone won’t melt and will only crack or combust at temperatures exceeding 842 degrees Fahrenheit. Even better, you don’t need to throw them away afterward; they provide years of protective service. Caps provide the same sort of protection as plugs in reverse by covering bolts, screws, and other parts that stick out. You can have some custom-made, while others have a flange that keeps the area around the hole neat and clean.
Removing Powder Coating
When you use high-temperature polyester tape or plugs and caps, you reduce the likelihood of powder coating getting into the threads. But what happens if it does get in? There are a few removal alternatives, but none are guaranteed quick fixes. Acetone or even some paint strippers may be able to remove the powder coating inside the hole when applied with a swab or similar cleaning tool dabbed with the remover. A fully cured powder coat won’t come off easily, however, which is the point of it. Also, you run the risk of damaging the external coating if you’re not careful. In the worst-case scenario, you’ll need to dip the entire part in a chemical bath and start all over again.
Those are just a few ways to mask threaded holes before powder coating and solutions should some powder coating get inside. For more information about powder coating masking services, contact us!