I have used this alignment guide for several years and find this tool an invaluable addition to my model rocket took box. Fins can be attached to the tubes with ease. You will need to apply your glue to the fin surface being attached to the tube and on the fin line itself, allow the glue to get tacky before attaching the fin. The time frame for getting tacky will depend on the type of glue you are using. This alignment tool works every time with the 3 and 4 fin alignments. It is very important to read and understand the instructions for use of the tool. The tool is easy to use. Since the alignment tool has both the 3 and 4 fin configurations, it would really be nice if Estes rockets would design a fin alignment tool for the 5 fin configuration. I work with a group of boys that are building their first rocket and this fin alignment tool has been very useful and timely.

I had the old Estes metal fin alignment guide about 30 years ago. That one was rock solid -- more sturdy and precise than this one. However, this one does have some advantages, such as the included engine spacer for centering your rocket. And it is a *lot* easier and more accurate than doing fins manually. I did four stars because it's not quite as solid as the old metal one. But it still extremely useful, and recommended for anyone who plans on building more than a couple rockets.

i ordered this unit after making some rockets by marking them with a door frame. This makes the job very easy. you don't need to mark them at all. just place the tube on the guide and attach the fins. very easy. it can be smart to attach the launch lug before you do the fins.