All adhesive tapes function better when they cover more surface area. Pressed against a broken up surface, discontinuities cause an area deficit, which prevents the tape from making contact. The more rigid the tacky backing, the worse this effect becomes. On coarse surfaces, the issue eases off, but it’s still deemed a bond diminishing influence.
Rough-Surface Bonding Strength
Curiously, coarse surfaces are often preferred when a tape adhesive is applied. The tiny material irregularities aren’t flat, that’s true, but there are plenty of them. Under a microscope, those rough grains look like tiny mountain ranges. They have peaks and faces, which multiply many times over as the microscope scans the material skin. Applied firmly, a malleable tape conforms to those tiny peaks and canyons. That’s a powerful feature. It’s not until those coarse surface outlines break into full-out material discontinuities that the adhesion effect becomes attenuated.
Smooth-Face Adhesion Permanence
If rough grains look like mountain ranges under a microscope, what does a smooth wall look like? Why, its faces are featureless and glossy. It’s easy for adhesive tape to “grip” glossy stuff. The two layers bond and cure instantly. On glass or metal, even on different surfaces, those that switch from one material to the other, adhesive tape anchors itself. However, there are exceptions to this rule. Teflon is smooth, but the fluorocarbon features an infamous non-stick attribute, so adhesives won’t typically cling to this slippery stuff. Bonding action is a problem on some paints, waxy surfaces, and even on some engineering plastics. That’s a chemistry issue, unfortunately.
Overcoming Surface Differences
There are construction tape adhesives that cling easily to concrete or lumber. The versatile backings conform to the coarse peaks and canyons mentioned earlier. However, for bricks masonry, those peaks rise too high. It’s hard to find a product that will stick to masonry, but there are a few high-performance products that can pull off this impressive feat. A flexible tape backing and a thicker than average tacky substrate are both crucial here, so keep those features in mind. Of interest to those who are stymied by a poor adhesion experience, some materials can be roughened by an abrasive pad until the tape adheres properly, but this action really should be viewed as a last resort.
Glossy surfaces require little application energy, for adhesive tapes easily find purchase on flat planes. For coarse surfaces, a conformable tape and thick substrate can overcome the roughness issue. There’s still a point at which the surface roughness and/or discontinuities will hamper the curing process, though. Last of all, there are glossy materials, Teflon is one example, which discourage the use of adhesive tapes.