Wood Finishes – Oil and Polyurethane
- on 08.22.08
- Woodworking Finishes
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Finishing a Cherry Table
After finishing a small hall way table made out of Cherry. I looked for a different way to finish it. I considered using an oil stain and a top coat of Polyurethane, but decided that I didn’t want to hide the beauty of the wood, so that was out. So after several false starts, I found a method that works well for me. The finish is a combination of Tung Oil Linseed Oil and Polyurethane. The method is not quick, but I think the end effect is worth the time spent.
I used a three step process to apply the finish to the Cherry table. After I finish sanding the project to no more then 150 Grit, I gave it a thorough cleaning with Naphtha. Naphtha will not only clean the surface better then a tack rag, but will give you an idea what the finish will look like and will also highlight any glue that remains on the surface.
I only sand to 150 grit at this point, because I have found that sanding beyond that point closes too many pores in the wood. If you examine the sanding process, you will see that as you sand, you are closing the pores on the wood.The higher the grit number of paper, the smaller pores you close. If you close too may pores in the wood, the finish will not penetrate into the wood. So stop sanding at 150 grit.
I then apply a seal coat to the project using a 50/50 mixture of Tung Oil and Linseed Oil. Tung Oil will dry to a hard finish, while the Linseed Oil will add the special depth to your finish. I have found that neither oil works particularly well when used alone). Wipe off any excess and allow to dry for several days.
Now sand the project again to remove any impurities in the finish. I use wet/dry sand paper about 300 grit, and Tung oil as a medium. Flood the surface with the oil and then sand, making a slurry with the oil and the residue. Thenn clean the project again with naphtha and apply a 50/ 50 Mixture of Tung Oil and Polyurethane. Allow to dry for 1-2 days.
Sand once again with a finer grit wet/dry sandpaper, normally about a 400 grit this time, use the Tung Oil to once again make a slurry. Clean the entire project once again, with naphtha. Then apply a top coat of 100 % Polyurethane. The end result will be a beautiful finish you will be proud of.
Visit Rockler.com for a good selection of all of your finishing needs.
 Boiled Linseed Oil |
 Minwax® Fast-Drying Polyurethane |
 Minwax® Tung Oil Finish |
 Norton 3X Sandpaper |
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Good information here! Hope you can help. I want to switch a solid walnut dining table top from polyurethane (30 years young but worn) to tung oil without stripping or disturbing the original stain finish that matches other related pieces. Is this possible? I note you suggest mixing tung oil and polyurethane.
Thank you.
Susan
Hi Susan, First I want to thank you for you kind words about our site. I am afraid that if you were to attempt to touch up the finish without removing the top coat of polyurethane, that your new finish would just peel off. Oils, such as tung Oil are designed to penitrate into the wood, while Poly is designed to seal the top. so your new finish would just set on top of the poly.
The only thing I can suggest is to use a mild paint stripper to remove the top coat of poly. I would NOT sand the top off as that would damage the stained finish you want to keep. I would check that this process works by appling the stripper to the bottom of the table where it will not show. After the stripper has worked its magic, I would use a Plastic putty knife and mild scotch brite pads to remove the old Poly. Dont use anything metal as that can damage the finish. Clean the entire project with Napha to remove any stripper left on the surface.
To re finish, I would apply a coat of Tung oil to the table, and let it dry for several days. The I would seal that with a 50/50 mixture of tung oil and Poly. If you want further protection, then you could add another coat of poly.
Please let me know how you made out on this. I would loe to know what you decided.
After reading the article, I just feel that I need more information on the topic. Could you suggest some more resources ?
Hi Vince, What kind of information do you want to know? I don’t know of any published information to recommend. I learned the technique from David Marks, a renowned woodworker, but have never seen it discussed anywhere else. I can tell you from experience that it works well.
If you’d like to discuss this further, contact me at jerseywoodworker@gmail.com. I’ll be happy to give you any information I have.
I want to use this technique, but only have 5 days. Is there a step that can be skipped?
Clay: I have tried to hurry this process along, only to be very unhappy with the results. Even if you are able to control the temperature and humidity levels in your shop, drying times are what they are. What I found is that if you try to apply another coat before the previous one completely cures, the prior cut will tend to come off the project in little balls of finish. So, I guess my answer would unfortunately be , NO you cant skip any of the steps.
Question?
I had a raw piece of cherry wood made into a stool.
I first used linseed oil. And then polyurthane within 2 hours I spray the poly on it. The poly is not drying. Did I use the polyurethane to early?
If so how can I remove the poly and not harm the wood.
The polyurethane is less then 2 days into drying if it will even dry.
Thanks!
Art
Art, Man I feel for you, because I have been there. The bad news is I don’t think your stool will ever dry. Sorry. It will not dry because the coat under the poly is not dry. An oil finish needs several days to completely dry. A good rule of thumb is to wait at least 5-7 days after applying an oil finish before applying an over coat.
I know this because I have done the same thing as you, only I waited three days before applying an over coat. The results were the same. Sorry to tell you the only fix is to remove the poly and oil finish and start over. I would not use sand paper to remove the poly as it will simply gum up within a few minutes. A cabinet scraper will work much better. When the scraper starts to build up, clean it with paint thinner.
After you have removed all of the finish, wash your project with naptha, let that dry for at least a day before you start to build up the finish again.
If you have decorative edges on your project, try cleaning then with a nylon pad similar to the ones used in the kitchen. Soak them in paint thinner to help dislodge the uncured poly.
Good luck, Please let me know how you make out.
Is there a substitute for Naptha?
I just dyed a project with a 2 lb cut of shellac with some aniline dye in it. The finish got ahead of me and built up in a few areas. -’d like to “sand” it down without disturbing the dyed wood.
Could I just use denatured alcohol and steel wool?
You can use Mineral Spirts in place of Naptha. I just perfer the Naptha.
Rather then trying sand paper and Alcohol. I would suggest a good cabinet scraper. use the Alcohol to keep the scraper clean
Question??
Found your advice too late…I sanded 2 mid century dining chairs to raw wood and already used Linseed oil (2 parts mineral spirits/1 part linseed oil)and love the color. It has been 24 hours since and the wood looks very dull. I don’t want a shiny finish or anything near shiny, but will a polyuerthene in satin give it a slight sheen? The wood is beautiful (Not sure what kind), but the current finish isnt doing it justice. Do you have any recommendations?..
Thanks!
If you want to use Poly, I would recommend that you wait until the chairs are completely dry and then select a satin finish poly, Stay away from the gloss finish,as this ends up looking more like plastic then wood. Be aware that some poly’s will over time “Yellow” your finish. Another option would be to use a lacquer finish instead of the poly. Which ever finish you select, I would suggest that you apply it to the underside of the chair to test the finish before you cover the entire chair. That way of its doesn’t work for you, you will have a lot less sanding to remove the finish. let me know what you decide and how it works out.
What kind of lacquer finish should I use? How will this finish be different than the poly? Thanks for the advice!
I would use Deft Lacquer, either spray or brush on application. The finish will build better then a Poly finish will, also will not yellow as the poly tends to do. You will need several layers of either finish, however the lacquer will dry quicker than the poly, so you can apply the next coat sooner. as you apply coats besure to sand the previous coat before applying the next one.