I have an oak table that needs resurfaced unfortunately I don’t know what existing finish is
How do I know what finish to use and what prep. I should do.
To find the existing finish, you can use acetone on a cotton swab and apply it to the wood. It’s shellac or varnish if it turns sticky, and polyurethane finish, if it beads. If it’s lacquer, the lacquer will completely dissolve.
After the acetone test, if your applied area becomes sticky you can apply denatured alcohol on a cotton swab to distinguish between shellac and varnish.
Varnish takes a long time to respond, whereas shellac dissolves quickly. You can use Ethanol if you don’t want to strip oak of the existing finish completely, then what finish you use will depend on the finish currently on the wood.