I had the misfortune of re-kiting an overbuilt Proton Disruptor to the point of salvage, oh well.
I wanted to recover the aluminum ring base of the motor retention that was epoxied to the MMT with JB Weld.
I cut the rocket apart to free several parts I wanted to recover.
The baffle came out fine and with a little sanding would slide right into another rocket.
The aluminum machined ring that is JB Welded onto the MMT was cut away. Slowly I began to use a carving knife with a nice point to cut away the cardboard and then clean out the grooves that are machined into the ring. Good Swedish steel vs. aluminum, the aluminum lost and came up with the JB Weld.
200 grit cleaned away any remaining JB Weld and left the inside smooth.
Now clean and smooth was good and bad, so I roughed up the inside of the ring with some 60 grit. I test fit the ring on a 24mm MMT to see how much metal was lost and the ring was
now over sized for the 24mm MMT. The 60 grit had put some scratches on the inside of the ring to grip the epoxy but it would not line up correctly being so loose.
My solution was to add some thickness to the end of the MMT. One layer of 3 x 5 index card was just right with a thin smear of wood glue to glue it to the MMT. It took up the space created by the loss of old epoxy and aluminum. After the wood glue dried and the one layer of index card was now part of the MMT, I test fit the ring, it was snug but allowed rotation of the ring on the MMT.
It is now JB Welded in place and ready for duty. The inside of the MMT was flush with the rings opening, not intruding into the path of the Motor body.