Hello, I have a couple of older fountain pens Mabie Todd, Wahl, and Waterman that have loose sections. One is BCHR, the others are celluloid. The section with the nib and sac are loose and you can easily turn them in the body or worse they can slide out with a little pressure and or come off with the cap being unscrewed and get stuck in the cap.
I've read that in the olden days they used shellac but I don't want to make servicing the pen difficult. Especially on 70-90 year old pens that are now more brittle and delicate.
Would a drop of shellac vs shellacking the whole section that fits in the body firm it up?
What do you recommend?