Originally posted by shreadvector
I usually apply the tape ONLY to the top portion of the casing that is not full/swollen with propellant - that way it does not shrink and get loose after burning it all up.
Some good advice there.
The adhesive on cellophane tape will (generally) get soft and 'let go' when it gets warm, such as when the motor fires. This can be a good thing if you are using cellophane tape to hold two motors together for staging. It can be a bad thing if you wrapped the motor case with tape to try for a friction fit in the MMT.
Masking tape is better (IMHO) for wrapping/trimming for a friction fit. It is indeed thicker, as someone here noted, but I have never had problems because of the thickness. If the fit is already that tight (without tape) I just use a narrow piece and apply it lengthwise to the motor---there is no rule that says you have to wrap it all around the circumference.
And if I do use tape to get a friction fit, I don't place the tape on or near the back end of the motor. In case you haven't noticed, many of the Estes-type BP motor casings are swollen a bit (in diameter) at the nozzle. This is because of the factory process of stamping the nozzle materials into place, and the bulged back end does cause a noticeable difference in motor fit within a MMT. I tape the front end of a motor case when I have to get a tighter fit.
When you launch with a taped motor, you need to retrieve your rocket and pull the empty motor casing out ASAP. Leaving the motor case in place will allow the residual motor heat to soak the tape, loosen the glue, and possibly lock the empty motor case into the MMT after the thing cools off later. Not good. I am sure that if you ask here on TRF for removal tips, you will get about a dozen answers on how to get stuck motors unstuck.
As you build your models, something to keep in mind is the possibility of stuck motors. I like to reinforce my MMT tubes by (at least) swiping through the insides with a coating of thinned glue, waiting for the glue to dry, and a light sanding until the insides of the MMT tube are nice and smooth. Probably, CA is better for this purpose, as coatings made with water-based glues might absorb a bit of humidity or moisture and glue themselves to a motor case.
And don't overlook the use of motor retaining clips. For a multi-stage rocket, you can still use a clip on the upper stage if it has a single flat tab that bends around the rear face of the motor (the fancy Estes-style clips will have to be surgically altered to remove the little squiggle--- a squiggle-ectomy?) Load the upper stage motor, hold the lower stage motor tightly against the clip, and tape the motors together as usual. This will give you a more positive upper stage retention.
It whould not come out wiht out a good amount of pull. It is easier to get out after firing since it will be warm and it will still shrink a bit. I use plyers to remove them usually.
