Estes Mk-109 Stingray Build Part 2 Engine Mount

Check for any molding tabs or burrs.
I'd never get this ring against the tube if this tab were left on.

Notice how the raised tab fits into the upper notch in the blue tube.

 The instructions are a little vague about where to apply the plastic glue.
Plastic glue is typically messy and will leave long "strings" when you pull the tube away from the applied glue.

The instructions show the glue applied to the ring. If the ring were pressed into the tube, the glue would ooze out around the outside of the ring.
I decided to apply the glue inside the tube edge. With the ring pressed into the tube, the glue stays inside the tube.






Have some Q-tips handy to pick up any excess plastic glue. It'll get everywhere!