This week’s Ask The Craftsman Question comes from Johnathan.
“How can I tell what type of finish is on my wood floors?”
Johnathan, get out your chemistry set and I’ll show you how to determine the different types of wood finish. The process is fairly simple, you just have to test in a specific order because certain solvents will dissolve several finishes while others will only dissolve one type.
Make sure to do this test in an inconspicuous area since you will likely be dissolving the finish off your floor.
Test #1 Is it Wax?
Put a couple drops of mineral spirits, naphtha, or turpentine on the surface you want to test. Let it sit for a few seconds and then rub it into the area. If the finish dissolves, congratulations, you’ve got a waxed floor! If nothing happens, move on to the next test.
Test #2 Is it Shellac?
This time apply a small amount of denatured alcohol to the finish and do the same process. If the finish dissolves, this time then you can be assured you have a shellac finish. If nothing happens it’s time for the next test.
Test #3 Is it Lacquer?
Go get some lacquer thinner and apply it to the finish and see what happens. If it is lacquer, the finish will dissolve pretty quickly. If nothing happens… you guessed it, next test. Warning! If you haven’t done Test #2, lacquer thinner can also dissolve shellac and make it sticky and soft. Test with denatured alcohol before moving on this test.
Test #4 Is it Water-Based?
This time we’ll try Xylene. Let it sit for a bit longer than the others and then wipe it off. Xylene won’t completely dissolve water-based finishes, but it will soften them and make the surface sticky. If nothing happens…the you have oil-based polyurethane.
Hope this helps! Just remember that you MUST do these tests in the specific order listed otherwise you may get false positives for the wrong finish. Good luck!
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
6 thoughts on “How To: Determine Different Types of Wood Finish”
Will this test work on teak furniture that has been stained with water or other liquids?
The test should work on teak. Just be sure to test in an inconspicuous area of your furniture.
The Craftsman Blog Team
This post is so structured and good! One question is lacquer thinner the same as paint thinner? In most of the DIY shops they sell thinner but i assume they are paint thinner.
Does it make a difference what the finish is if the floor will need to be sanded anyway? Should the finish be stripped before sanding?
If the floor is going to be sanded then there isn’t much difference.
This is an amazing post!! I have been wondering what the finish is on my wood floors and now I know what to do. Thanks for answering this question!