Removing Ring Marks in a Veneered Table Top

      Refinishing pros offer opinions on how to refinish a badly marred wood-veneer table top. November 12, 2006

I was brought a walnut veneer table to refinish. The original finish was obviously oil, and somewhere in the table's life, someone painted it dark brown. The table has been abused and there were numerous rings on it. The owner wanted the table refinished to the original state, so we stripped the finish off and lightly sanded the top to remove as many imperfections as possible. The table is beautiful, however as soon as we applied boiled linseed oil to the top, the rings came back strong. What step am I missing?

Forum Responses
(Finishing Forum)
From contributor M:
Did you try wetting the top with either lacquer thinner, alcohol, or mineral spirits to see if the rings appear when the wood is wet? If it does, then you are going to have to remove or tone the wood to hide the rings. What coating are you planning to use?

From the original questioner:
Here is a photo prior to us removing the existing finish. I took the finish to bare wood and then rubbed a mix of linseed oil/poly over the wood. Everything looked wonderful until the oil dried. The rings have returned, but are not white. Instead they are very dark. This is a veneer, so I'm hesitant to remove anymore wood. This table is accompanied by 5 studio styled chairs of walnut. I originally wanted to oil and wax the furniture, since the owner doesn't like the look of lacquer or poly.

Click here for full size image

From contributor M:
The table looks like it is solid wood. Have you tried to sand the top down to see if the ring and markings come out?

From contributor H:
Since you have already sanded it, then you only have one real option left. Re-veneer it. From the photos, this table has been used abused and will refuse any further stripping. It may have been sanded already and the person sanding found out what you did and decided to paint it. With what veneer costs and the labor involved, I would suggest to the client a new solid wood top. It will be cheaper and better in the long run.

From contributor M:
I would not give up on the table so fast. He still has some other finishing options. He can try a single bleach like Clorox, or a two component Albino bleaching. He could also try using a tinting toner, stain, glaze, and a shading stain.

From contributor C:
Oxalic acid is your best bet on those dark iron stains. Still, I have to agree that it's pretty much burnt toast. Don't waste a lot of time on her... life is short. How about a really dark finish with just a hint of the grain and natural color peeking through? Mostly black?

From contributor M:
Contributor C, I'm surprised at you, being a long time restorer, and after all the advice you have posted here in the past. I personally think it's a piece of cake, with many options, and certainly worth the time to restore it to match the chairs.

From contributor R:
I agree with the oxalic acid treatment, easy to do, and all but the worst stains should go away. Just make sure you neutralize it thoroughly afterward with baking soda and lots of water. If it is veneer and there are loose spots, make sure you address them first.

From contributor T:
Oxalic acid, brown paint, or giant veneer patch. If you do oxalic, you'll probably need to strip off the finish coat you put on. It will probably take several applications, and you risk lifting the veneer. (If it does lift, you can usually iron it back down.) Do neutralize before you sand down the raised grain - you won't like breathing that dust much. Chlorine and two-part bleaches work on some things, but not dark iron stains.

From contributor C:
Sorry, that looks like some pretty tough cake to me. I'd guess it'll be tougher than flank steak from an old Holstein. Those iron stains are easy to lighten but can be very difficult to remove. With that many that dark and in those big circles... I'd rather strip off the veneer and faux the substrate (even if it is chipboard).

From contributor M:
You need to start by stripping off the oil finish, then wash the wood down with acetone, allow the wood to dry, then sand the wood. Check the wood to see how it looks. You may want to go with a tinting toner and a colored glazed. This is up to you. If you want to try to remove the rings and stains, first try the Clorox bleach. You probably will need a few applications.

If the black stains do not come out, give the oxalic acid a try. It may take out the stains, but then leave lighter spots in those areas. You may need to bleach again. You can use clean water to soak the wood, which will also neutralize the bleach. Allow to thoroughly dry.

Check the table top. If you're happy with the results, then you may just stain and apply your coating. If you're not happy, then I suggest you make up a translucent tinting toner and go from there.

If you need some help, we will walk you through making up a tinting toner. You may not want to go through all that bleaching. If not, just strip it down again, wash it with lacquer thinners or acetone, sand it, and then stop there, and go with a tinting toner. This thinned out color coating will uniform the wood's color with a combination of pigments and coating in each application.

From contributor T:
Okay, I should have told you to bleach the whole top - it will affect the wood's color a little bit and I'm sure you don't want blotchy. Should have also told you to use a fresh batch mixed with very hot water for each application. It's always worked for me. The old, cold stuff doesn't do nearly as well. Rinsing with water will dilute the acid and stop the bleaching but it won't neutralize the acid. This stuff really is an acid and it's best to treat it with some respect. To neutralize you need something like a baking soda solution or I use 20 mule team borax in water - 3 or 4 oz/gal. A TSP solution would also work.

From contributor O:
I don't really think that this table is doomed to the trash heap. We're looking at a table that hasn't been stripped or sanded yet. Most of the staining marks look to be surface stains and I think they can be coaxed away with a few solutions of oxalic acid and a sharpened cabinet scraper. I've seen worse surfaces that have been restored back to life and to me, this table looks like a great candidate.

Contributor M, perhaps I'm missing something, but how did you determine that the table was solid versus a veneer? I think the banding is solid walnut, but how about the surface itself? Looking at the cathedral peaks and how they meet the next flitch, I would have thought the table to be veneer.

To the original questioner: I think you have a diamond in the rough, so proceed with caution and post some pictures of the restoration if you can.

From contributor M:
No experienced finisher bleaches part of a top. They do it all at the same time. Hot water is not really needed; in fact, it will only dilute the bleaching chemicals. I never used anything but clean water to wash off the bleach, and never had a reaction. It doesn't have to be chemically neutralized if you thoroughly wash it off, and then wipe the wood dry. I think that info comes from some finishing books, magazine articles, or some manufacturers looking to add another item to the sale. Save your money, use only what you need to do the job. Not every job needs every chemical that is mentioned or sold because that's what some finishers use in their process.

From the original questioner:
Wow! I knew that I would get lots of great info here. I will be removing the oil finish in the morning, but I will take pictures first and you can count on daily updates on this project.

Regarding the veneer vs. solid thoughts, I noticed that some areas, primarily around the banding, have worn through to a substrate. I also noticed that underneath the table, the grain is much different from what is on top. I didn't see any areas where the veneer appeared to be separating from the substrate. Thanks for the advice.

From contributor M:
Looking at the photo, it appears to me to be a solid table. The outside edge looks like a perfect match with the graining on the top surface. If it was a solid top, I would run it through a sander/planer. If it is a veneer, then there are other ways that I would treat it, as I already posted.

From the original questioner:
Here is another view of the table without the two inserts and with a couple of the chairs.

Click here for full size image

Here is a close-up of the banding on the tabletop.

Click here for full size image

From contributor M:
Now that I see a second photo of the table, it looks like veneers. The table apron in both photos looks completely different, as does the wood on both tops. The first photo looked like walnut, the second photo is hard to tell, but it doesn't look like the same wood.

From contributor P:
To determine whether it's veneer or solid, just slide open the table where the leaves go and examine the edge.

From contributor M:
Since the table is veneered, that leaves out the option of running the top through a sander/planer. I'll still go along with first stripping the table top, washing it down with lacquer thinner, and then giving it a careful sanding. Then see what the table looks like. The 3 steps that I listed are needed anyway, whenever you're going to bleach the wood.

From contributor I:
Take the old finish off and sand the crap out of it, carefully watching for any signs of a color change (this would mean you are going through the veneer). Step away from the bleach! I can't count the number of jobs where I have had to go out and repair the finish 6 months later where someone used 2 part wood bleach and then it leaches out of the joints or just makes the finish weak where it wasn't really neutralized and destroyed the acid catalyst in the finish. Yeah, it looks great when it's done and the check clears, but I personally expect my finishes to last longer than that. There is still plenty of wood grain in the picture. My first priority would be to save the table top if possible and a good sanding is risk free if you're careful not to burn through. Also, I have had good luck on rings, after the finish is stripped to bare wood, spraying on a light vinyl sealer and then sanding. I don't know why it works, but sometimes I have been able to even get out sunburn lines that way.

From contributor M:
It's a veneer - how can you tell him to sand the crap out of it? Maybe if you did your own bleaching and finishing you would think differently. My experiences with bleaching are not the same as yours, and many fine finishing shops do it all the time whenever it is needed.

I suggest that the questioner be very careful trying to sand out those markings, or he will have no choice but to re-veneer the whole top. I think I would rather have him deal with a bad bleaching job than have him sand through the veneer, which is quite easy to do. I might just start with toner over the stripped, cleaned, and lightly sanded table top, and then use the other coloring mediums like a stain, glaze, and a shading stain to add a new matching finish.

From contributor I:
I have worked at high end veneer shops most of my life. Please re-read the part of my post about watching for a color change, which signifies going through the veneer. When you reach the point that you make drastic moves like bleaching a walnut top... I would replace the top over bleaching. Toned out, shaded in walnut doesn't appeal to me.

From contributor R:
From a refinisher's point of view, this table looks pretty typical, from the late 50's, 60's or early 70's. Veneer over plywood, or if it is later, veneer over particleboard, or early MDF if you will. Most of this will come out with the stripping, and if not, then oxalic acid/rinse. When the finishing process is completed, any faint traces of these stains that are left, you can consider character. The transition between before and after is so great your customer will be thrilled. I would look at the long straight edges of the table (where the leaves meet) and determine what's under the veneer - solid wood, plywood, or particle board. If it's particleboard, which it probably isn't, you run the risk of the stripper and water (oxalic acid solution) swelling the particleboard on the edges and where the veneers meet.

From contributor T:
Any progress to report?

In the picture below, the wood (pine) was wire brushed and stained with an iron oxide solution as a sample for a designer who wanted a weathered look. It's the same stain that the questioner faces. On the left, full strength Clorox that was allowed to work for 30 minutes. In the center, a strong solution of fresh, hot, oxalic acid that worked for 3 minutes. On the right, old, cold (but saturated) oxalic solution which worked for 6 minutes. It's hard to tell at this resolution, but the stain is not all gone under the cold solution. If I had let it work longer, it would probably be gone.

I learned this the hard way a long time ago while removing water stains from several bedrooms of oak flooring - the solution didn't work as well when it got old and cold. I also rinsed this job down well with water and when it dried, started sanding. 'Twas then I got this burning sensation in my throat and lungs and learned (again the hard way) it's better to neutralize with a good alkaline solution.

It's as simple as hot water holds more "stuff" in solution and since it's "stuff" that does the job and more is better, hot is good.

Click here for full size image

From the original questioner:
Still working on it. I decided to go this route. I removed the oil/wax finish and then sanded the veneer (definitely veneer) to remove as much of the stain as possible. I'm a novice, but even novices can form opinions (albeit sometimes wrong ones). I decided that what contributor M wrote made a lot of sense to me. I wetted the top with mineral spirits and the rings came back. Not wanting to remove any more wood, I've decided to tone the wood.

From contributor B:
You don't have a difficult problem here. I have done this many times on tables, dressers and such. Strip the table again with a solvent wash stripper. Next wash it with lacquer thinner or acetone, although I like the thinner better as acetone evaporates faster. After it is dry (the following day or at least a couple of hours later), lightly sand the top to make sure you have a clean surface.

Dissolve as much oxalic acid as you can in warm water. Warm water will dissolve more crystals than cold. Use an acid brush or equivalent and put the oa on the dark rings - they appear to be iron stains, which are a result of water being in contact with metal, then contacting the wood, which contains tannin.

Keep rewetting the areas and while doing this, take a rag and wet the entire top with the oa. The oa works when wet. This should take 30 minutes or so. Go back later and do it again, then wait till tomorrow and see what you have. Do not have a draft on the surface while doing this, or it will dry too fast.

You may have to do it again. I do not believe you will have much luck with Clorox (sodium hypochlorite) or with the two part bleach (hydrogen peroxide and sodium hydroxide-lye) in this case, although both have their uses in finishing.

You do not need to neutralize the oa. Just wipe the top with a clean wet rag before resanding or the dust will choke you. This will get it as good as you are going to. Any further blending will have to be done with stains, toners, and such.

From contributor N:
These sorts of rings are a routine occurrence in refinishing, and they can be summed up succinctly: white rings mean that the finish has been affected, and dark rings indicate that the finish has been completely compromised and the wood is now affected. Clearly, the table is veneered; the presence of a crossband is a dead giveaway. The table, although attractive, is by no means a masterpiece worthy of extensive consideration, and sanding out the dark stain is probably in order. I have met with mixed results using bleach, and as another poster has stated, the by-product of the bleaching process tends to linger far past the projectís completion. Sanding, if undertaken judiciously and conscientiously, will easily bring this table back from the brink. Iíve tackled dark heat stains in veneer far more severe than the ones pictured without affecting the timbre (I couldnít resist) of the piece. Bear in mind, however, that the darker the stain, the deeper will be its penetration.

From contributor B:
This should not be a problem to restore! Re-strip using a good stripper; not a water wash, but a solvent wash. Then wash it with lacquer thinner. Lightly sand the top with 180. Then, and most important, get some oxalic acid, dissolve as much as you can in some warm water; use glass, not metal. Put the acid on the dark spots only to start, use a small acid brush like we use for glue application. Get the spots wet. Keep dabbing it on for 5-15 minutes. At some point, wipe the whole top with a rag wetted with the acid, then reapply the acid to the spots. You may have to do this for a day or two. The last step is to rewet the entire top with the wetted acid rag. The spots will go away. After a couple of days and the table is dry, clean it off with water only - no need to do any type of soda wash or anything else but water and a rag. If you do not clean off with water, the dust from sanding will take your breath away, but it will not affect the finish. Clean it with water anyway. While the top is wet with water, that is what it will look like when you put coating on it. Wetting is your test to see if the wood is clear of spots and rings. Have fun and charge accordingly!

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