The fin marking guide found in the supplies for the Big Bertha rocket is a handy tool for aligning the fins. The following steps detail how to mark the rocket body tube to prepare it for attaching the fins.
3.1. Cut out the Tube Marking Guide located on the Rocket Kit’s provided instruction Manual.
3.2. Tape the LL end of the Tube Marking Guide to one end of the rocket tube and wrap the guide around one side of the Body Tube. Finish by taping the FL side of the Tube Marking Guide to itself (this chosen end will be considered the bottom of the tube).
3.3. Place a mark with a pencil on both sides of each FL and LL line on the Body Tube.
3.4. Remove the Tube Marking Guide from the tube and extend all the lines by setting the tube in a right-angled channel (like a door frame), lining up the mark and sliding the pencil along the guide.
3.5. Put a small mark 4in from the bottom of the body tube on the LL line.