Shellac versus French polish

[mjbarnes]

I am reading lots of posts that say shellac cut with denatured alcohol is the authentic finish for Edison wood cases, and perhaps for bedplates as well. This sounds like French polishing. But if so, why has it crazed on so many old cases? My understanding of shellac finishes is that they should remain softly glossy and deep for centuries if the piece is looked after.

[epigramophone]

Although the name appears on the containers, French Polish is actually a process not an ingredient.
The main ingredient of French Polish is Shellac, to which colouring agents are added to achieve the required shade.

[JeffR1]

I am reading lots of posts that say shellac cut with denatured alcohol is the authentic finish for Edison wood cases, and perhaps for bedplates as well. This sounds like French polishing. But if so, why has it crazed on so many old cases? My understanding of shellac finishes is that they should remain softly glossy and deep for centuries if the piece is looked after.

That's the key phrase, "if the piece is looked after".
Shellac is very fragile, it's worst enemy is the sun, moisture, and anything that is alcohol based.

People generally don't look after things at all, when was the last time you lubricated you cars door hinges _ or oiled your bicycle chain, if that applies.

[mjbarnes]

Bike chain I definitely keep oiled -- no point in peddling harder than I need to.

Do most Edison refinishers apply shellac with a brush or with the cloth-in-cheesecloth method?