I probably have some change coming and I am by no means near the rocketry authority of the regular posters on this site, but I use the aluminum "foil" tape used on air conditioning units. Sorry, I am not sure of the scientific name of this product. I cut lengths of whatever size is appropriate and "curve" the tape upward toward the shiny side before removing the backing. It's kinda challenging to get the tape inside the tube ( you need to remove the backing BEFORE you insert the tape into the tube ) but once it's inside, I use an old dowel rod to secure the tape to inside of the tube. It's easier if you try this using 2 or 3 strips to cover the inside of the tube. So far, I have not had any burn through on any of my tubes, and it cleans up reasonably well with a big cotton ball and rubbing alcohol.

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Dave
Fire is the leading cause of fire.
Was once SAM#0132