"Anyone who thinks there’s no right way to file is wrong.” says Lin Halpern, director of new product development for NSI (W. Conshohocken, Pa.), who has supplied these filling dos and don’ts to ensure flawless application of product.
Don’t file the natural nail plate from left to right during preparation. This severely damages the nail plate’s ability to provide underlying strength, diminishing the performance of the product applied to it.
Do file vertically on the natural nail plate in the same direction as the nail cells. (Layers of nail cells grow downward. Horizontal filling can break down and damage the cells.) This etches the surface and removes the waxy layer, exposing a surface that acrylic can bond to.
Don’t use a grit normally used on acrylic to reduce thickness or length on the natural nail plate.
Do use the proper grit abrasive according to manufacturer’s instructions for each product –usually 180 or 240 to rough up the nail.
Don’t file deeply into the corners of nail walls during preparation or finishing filling. This causes a breakdown of the natural nails at the stress area and promotes stress cracking.
Do file gently straight down along the side of the nail wall to smooth the natural nail or enhancement product. Gradually angle the file using more pressure just below the stress area to create the desired shape.
Don’t file too fast because it can create heat and hurt. Never “saw” back and forth at sidewalls or cuticle areas. This can cause redness to appear on the nail plate.
Do file using the following method to achieve smoothness: Draw an imaginary line down the center of the nail surface. Holding the file at a 45° angle to the line, use small, curved, downward strokes to make your way down to the free edge on the right side. Repeat on the left side. Use a softer file for smoothing over the cuticle and sidewall area from the cuticle down toward the free edge in one direction.