I always cut my binding thread longer than 18"...more like 45" (yes, really). I thread the beginning end and knot the just cut end, frequently rotate the needle between my thumb and forefinger counter to the direction the thread is twisting, and move the needle down the thread every few inches to prevent it wearing through. The result is no tangles, no knots, no fuss...with no thread slicker added. It's worked for me for decades, don't plan to change anything now.