What do you do when adhesives won’t stick? Generally speaking, there are three or four things that interfere with glue, tape, or other adhesives sticking.
Usually, adhesive doesn’t stick because the surface is too smooth, or it’s not clean enough or dry enough. So the first thing to do is clean the surface with an appropriate cleaner. If the surface is visibly dirty or dusty, glue or tape won’t stick to it. It will stick to the dirt, then peel right off.
If the surface is wet, the liquid usually breaks down your adhesive before it gets a chance to stick.
If it’s not visibly dirty or dusty but your glue or tape won’t stick, the surface could be greasy or oily. A good solvent will take care of that. Clean the surface with a bit of mineral spirits or lighter fluid on a clean, lint-free cloth, and let it dry. This is a common problem with nonporous surfaces like plastic, metal, or glass.
The next thing is to make sure you’re using the right kind of glue. White glue works really well on wood or paper, but it won’t do much on metal. To glue non-porous surfaces, you really have to use a super glue or epoxy. The useful website this to that specializes in giving glue advice for various combinations of surfaces. Enter the two materials you’re trying to attach, and it tells you the glues that work.
If the surface is smooth, you can improve its gluability if you rough it up a bit. Rub the area you are trying to bond with some heavy-grit sandpaper. This gives the glue a bit more surface area to grip to. Be sure to clean the surface after you sand it.
There’s usually one last thing you can do, and you can do this even if roughing up the surface isn’t possible. Clamp the pieces together or place a weight over it until the adhesive sets. Pressure always helps to create a strong, lasting bond. Let it dry for however long the instructions recommend, and your project has a much greater probability of success.