How To Apply Conductive Foil Masking Tape Before Painting
EMI (electromagnetic interference) is the disruption of the operation of an electronic device when it is near an electromagnetic field in the radio frequency spectrum that is caused by another electronic device. When used with a conductive EMI gasket, conductive foil tapes with a polyester paint masking provides a conductive, non-corroding surface on painted metal electronic enclosures that forms and effective EMI shielding solution.
But sometimes, applying conductive EMI foil masking tapes can be tricky and quite the hassle. Luckily, we’ve come up with five easy steps to make applying conductive tape easy and worry-free.
Step One: Prepare your surface
To ensure maximum adhesion of your conductive foil tape with peel-off mask, remove all surface oils and dust. In large volume applications, proceed through your normal automated cabinet cleaning procedures. In small volume applications, clean cabinet flanges thoroughly with a cloth dampened with an industrial cleaner (acetone, toluene, or isopropyl alcohol).
Be sure to wear rubber gloves, because some cleaning agents tend to be nasty chemicals, and you do not want them to get on your skin. It is important to avoid contact with or handling of the adhesive on the back of the tape. Oils from the hand will affect adhesion. If oxidation or rust is present, abrade surface with sandpaper to expose clean metal before cleaning.
Step Two: Remove the release liner from the tape
Still wearing your rubber gloves, peel away the release liner of the conductive tape and apply the tape to cabinet flanges, being careful to avoid wrinkles. Extend the tape beyond the corners and cut away excess. This prevents residual stress in the foil from lifting tape at ends. Run your finger along the mask to provide initial adhesion.
Step Three: Trim off excess
The excess tape in each corner should now be trimmed, and it is not necessary to overlap the tape in the corners. It is recommended that a gap be left between the vertical and horizontal strips. The gap should measure about .080 in. (2.0 mm) wide (which is equivalent to the recessed edge of the tape). Later, when paint is applied to the cabinet, this gap will be filled and serve to edge seal the tape ends.
Then, using a precise cutting tool, cut about a .080 in. (2.0 mm) piece of the mask layer on each strip and remove. This will further ensure edge sealing when the cabinet is painted.
Step Four: Smooth over your surfaces
Smooth over the surface of the conductive foil tape with a small rubber roller. Touch down the exposed tinned copper edges until they are flat and even. Note: Only moderate pressure is required (about 5 psi).
Step Five: Time to paint
Now your cabinet is ready for normal phosphatising and painting. Follow the manufacturer’s instructions for paint application and curing. Note: Recommended paint thickness, including primer, is 4 mils (0.1 mm) or more.
Step Six: Remove your conductive masking tape
When the cabinet has reached room temperature, remove the mask of the conductive foil tape at a 180° angle from the foil tape leaving a clean, conductive grounding surface. The mask is easily removed at room temperature, with or without baking.
Looking for the perfect conductive foil tape with a peel-off mask? Check out Parker Chomerics CHO-MASK® II EMI Foil Tape . CHO-MASK II tape provides effective shielding performance and grounding points within the painted enclosure, and can accommodate a wide range of enclosure finishing processes, including powder coating.