Things You'll Need
Nylon thread and nylon cord are very popular items when it comes to making jewelry. However, it is extremely difficult to tie a secure knot with nylon thread. However, a simple and handy trick can make your nylon thread knot as secure as any other knot possible, and nearly impossible to undo later.
Clip one end of the nylon thread to the clipboard. This will hold the thread securely. Make sure that you give yourself at least 5 inches of thread to work with. Even if you do not ultimately need this much thread, allow yourself this much leeway while tying your knot. You can always trim it off later.
Tie your knot just as you would any other. The nylon thread is slippery, so you will need to pull each part of the knot tight. The clipboard will hold one end, so you will only be responsible for keeping one end tight. If you are tying something like a hook to the end of the thread, then loop the thread through the hook, then tie a standard square knot. If you are just tying a knot, then loop the thread over and around itself to form your square knot.
Heat the knot slightly. Continue to hold the knot tight with one hand. You will have pulled the thread taut between your hand and the clipboard. With the other hand, light the lighter and pass it quickly over the knot three times. Do not slow down or allow the lighter's flame to actually touch the nylon thread. If you do so, the flame will melt through the thread and permanently destroy your knot. However, if you simply heat the knot slightly, the thread will stick together so that your knot is melded in an unbreakable bond.
Let the nylon thread knot cool. Do not pull the knotted thread tighter once you have heated it. Simply remain exactly as you are for about 45 seconds while the thread cools. If you pull on it, the heated thread may stretch and break. However, once the knot has cooled it will not slide apart again as nylon thread has a tendency to do when the knots are unsecured.
Always use a lighter or any flame under qualified adult supervision.