How do I cut the tape? Use a 4 inch taping knife. Use it flat on the flat joins. Use the point of the corner for internal joins. We recommend the DELKO® BLADE for the job! Read more about the DELKO® BLADE here. Watch it in action in our clip below. Post navigationPrevious post: What is the best consistency to mix the compound?Next post: I’ve heard the Internal Applicator Attachment is patented and exclusive to Delko® Tools and their distributors – is that true?