I had a box of miscellaneous parts that I'd bought en mass from someone leaving the hobby. It sincluded some parts I didn't think I'd use, like a one piece molded plastic fin can, motor mount, and engine retainer (18 mm) for BT-60, and a nose cone with a ribbed shoulder that was really a little too big for a BT-60. Then one day I needed something to test a home made propellant, so I took a full length of BT-60; sanded down the ribs on the nose cone, and it still was a really tight fit so I glued it in; cut the tube below the cone and installed coupler; glued in the fin can; added a shock cord by the tri-fold on both ends; and a parachute. I gave it a shot and the motor was a complete failure. It burned nicely but generated no thrust to speak of, and the rocket never even moved.
Later I gave it a paint job with no filling anything. It's still yet to fly. It's name is "Dispensable".
Pictures later.