The traditional sealant for use under a n oil finish is "Garnet Shellac" usually Garnet French Polish Polish with about 25% more Alcohol added. More modern sealers are in the photograph my first choice is the Shellac sanding sealer, with the Cellulose version for no added colour and very rapid drying.

[Linked Image from i.imgur.com]


The only lessons in my life I truly did learn from where the ones I paid for!