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run along the fin body tube joint and then sprayed with accelerant so it set instantly. I find an old X-Acto knife blade works good for this. I first put a few drops of medium CA on an index card and then dip the knife blade in it and run it along the fin/body tube joint. The fin must be held down tight on the gage block against the body tube as shown in Figure 4 while the CA is applied. Continue holding until the accelerant has been sprayed and the CA is set. It can be done by one person after a bit of practice. Once the CA is set, remove the body tube from the jig. The fin will be perfectly aligned in the vertical or thrust axis, which is what we want. However, it may not be extending perfectly straight out from the body tube. Usually the fin can be moved into the right "yaw" orientation since it was only CA'd on one side. If it doesn't want to stay there, a drop of CA can be placed on the non CA'd side to keep the fin per- pendicular. Figure 5 shows the fin after at- tachment. The sequence is repeated for the other two fins. For the second fin, I usually ro- tate the body tube so the first fin is stick- ing "up." The third fin is a little trickier. To attach it, I had to elevate my jig so the fin on the bottom side will not bump into the table. See Figure 6. This also shows why the spacing of the gage block or other top piece from the edge 12 JANUARY/FEBRUARY 2020 SPORT ROCKETRY Piester and Estes Collection Donors The National Association of Rocketry would like to thank the following donors The Estate of Barbara K. Stine Scott Hala Raymond Maye Joseph Pingree Marc Lavigne William Rainey Paul Reed Earl Hemphill Steve Sibal John Cummings Dewain Feller Raymond Mayes Vince Huegele Jonathan Duke Todd Schweim Douglas Dotson Robert Bernatchez Joe Hinton Gordon Mandell Eric Justin Ted Cochrane Jay Apt Pat Fitzpatrick Robert Hermes Philip Nubel George Stine John Langford Dean Fox Joy Fox Jim Barrowman Christopher Lagemann William Burrows James Pommert Jonathan Rains Trilobyte Systems William Marchant Figure 4. Fin held in place to stay flat and up tight against the body tube. The CA is put in the fin join with the other hand. Figure 5. First fin is attached. Terrance White Dennis Harwell Jonathan Sato Garland Hendricks Stewart G McNabb Louis Giglio Allen Gardenghi Christopher Jenkins John Kitchens Arthur Barber Tim Hegemier Timothy Doll Scott McCreery