It turns out the Zinsser clear shellac I was trying to use up was made in 2016. The first coat dried to a hard shell in about 30 minutes, after one hour sanded at 320 grit just fine, and the second thin coat took about three days to fully cure.

I found this article at pop woodworking: https://www.popularwoodworking.com/f...s-eye-shellac/

and found a new quart can of clear zinsser at team blue this afternoon that was made on April 22, 2022 unless they have changed the date codes around.

I am planning to bring in shellac buttons and denatured alcohol for future projects, but I really need a finishing/ chemicals cabinet first as I am kinda overdrawn in the shelf space department currently.

If I can put fresh/new shellac on top of out of date slow curing shellac, how long should I wait before I start putting the new stuff on?

The veneer surface I am trying to finish is only about 1/32 thick, I really really do not want to sand back to bare wood unless there is simply no other way.

I am kinda leaning towards doing an exceedingly thin layer of the new stuff so once that is cured the new surface will be 50-50 old/new, and etcetera.

Thanks