Removing Water Spots From a Finish

This article was inspired by a question from Larry. He writes:

I have a question about a damaged finish on antique furniture. My wife’s cousin was cleaning her house and her 3 year old daughter was “helping”. Isabel, the helpful little youngster, sprayed Windex on a number of her mother’s antiques. The Windex, as I’m told, left white spots on the finish where it was sprayed. Being the only woodworker in the family I was solicited for advice. I know that ammonia based products can be used to clean shellac off of brushes and such, so my initial thought was that the furniture was finished with shellac. But, I’m not sure how ammonia affects other finishes such as lacquer and oils. I wouldn’t think that it would damage poly, but I’m 100% sure about that either. Are you familiar with this type of damage? If so, is there an easy/quick fix or does the finish need to be stripped? I’d appreciate any information you could give. Thanks a bunch. Love the web site and videos. They are quit helpful and informative.

Windex really isn’t good for any finish, so its best if you avoid it completely. So what are these white spots? In all liklihood, the water in the Windex is the cause. Water can create a hazy white spot of moisture that gets trapped below the surface. So, what can you do about it? Worst case scenario is refinish. And if these pieces really are antiques, I recommend consulting with a restoration professional before doing anything. On the other hand, if this is just family furniture for daily use, you can try a few things that may remedy the situation.

What Finish Is It?

Before doing a repair, its essential to know exactly what the finish is. You can do spot tests in an inconspicuous area like the underside of an apron, table top, or leg. If the finish dissolves easily in lacquer thinner, you’ve got lacquer. If it dissolves in denatured alcohol, its likely shellac. And if it doesn’t dissolve in either, its probably a varnish of some kind. Check out this video where I use this methodology to determine what the finish is on an old piece of furniture: Refinishing Pt. 2

For a Lacquer Finish

If you know the finish is lacquer, you try to spray the surface with lacquer thinner. A good heavy coat will reactivate the lacquer and might allow the moisture to escape before it once again dries to a hard film. Another thing to try would be to spray a fresh coat of lacquer on the surface. This will redissolve the top layer of lacquer and might get rid of the white spots. If you don’t have an HVLP system, you can use a can of Deft from the big box store if you like.

Now there are also a few products on the market that claim to get rid of white spots but I don’t have much experience with them. In fact, I was just at Lowes yesterday and they sell a pre-moistened rag (probably some sort of oil), that you can wipe over the spots to get rid of them. For $5, its probably worth a shot. I have also heard of a weird trick using mayonnaise. Since mayo is pretty much oil, you can put it on the surface so that the oil soaks through the finish and displaces the moisture. But who knows if it actually works. And to be honest, I would envision you replacing your water stain with a more unsightly oil stain.

For Shellac and Oils

If the finish is shellac, you could try all the same things mentioned above, substituting denatured alcohol for the lacquer thinner. And if the finish is oil-based, you can try a light sanding with 320 grit followed by a light coat of an oil-based finish. Of course, feel free to try some of those off the shelf solutions mentioned above.

What solutions have you found for removing water spots?

Category: Finishing

Comments

  1. Larry (http://) February 6, 2007

    Thanks for the help Marc. I’ll let you know what works.

    Larry

  2. Dick Cain February 6, 2007

    The same thing happened to me quite a few years ago. I made some candle holders out of some 3″ diameter Birch disks, & set them on our Duncan Phyfe dining room table. After sitting overnight, there were 20, 3″ diameter white spots on the table. I didn’t know what to do, so while hesitating for a short time they went away by themselves.
    So possibly in order to rush things along, maybe try a hair dryer on low heat.

  3.  

    A suggestion for Larry (submitted by Doug).
    A couple of years ago, my mother damaged her antique dinning table. She forgot to blow-out the candles on her center piece after a dinner party. Forty-five minutes later she returned to the Dinning room to find the candles had burned down low enough to light the center piece ablaze. In a panic, she poured a big pot of water over it, leaving a very nasty mess in the middle of the table. After the center piece and water was cleared away, she was left with a big white circle in the middle of the table. I was able to remove the white stains by using ground pumice stone, same as you would to rub out a finish. I’ve found that if the finished isnt damaged all the way thru its layers the ground pumice stone will take the stain out. Then just wax and buff the surface again. Experience with ground pumice stone helps, i use a small amount of distilled water as a lubricant. Hope this helps.

  4. Alex Blate April 12, 2007

    Marc:

    Thanks for the excellent content! I really appreciate your no-nonsense perspective on woodworking. I’m an engineer by day and a decidedly amateur/hobbyist woodworker by night/weekend; lacking the freedom to apprentice or train with a master, learning from articulate and down-to-earth experts like yourself is a tremendous asset.

    Now, to my comment… Real mayonnaise, as you say, is mostly composed of oil; if oil were the only thing you needed to remove the white rings, then the “folk remedy” would probably be to just apply vegetable oil to the stain. So unless Helman’s or Miracle Whip have started giving woodworking advise, there is something deeper going on. :)

    Let’s look at what else is in Mayo… Real Mayo contains vegetable oil, eggs (mostly yolks), and an acid, such as lemon juice. It may also contain flavor enhancers such as salt and commercial products will contain some preservatives. Some products that claim to be Mayo are really just fancy industrial chemical concoctions, so who knows what’s in them.

    Now, eggs, particularly the yolks, are powerful emulsifiers. This means, as you know, that they contain molecules which are capable of bonding to both water and oils. Soap is another emulsifier, but doesn’t taste nearly as good :) Compared to soap, the lecithin in yolks is much a weaker emulsifier, but it does the job.

    I would speculate that real mayonnaise, applied to a water stain, would be able to “cross” or penetrate the lacquer and absorb the water; subsequent cleaning with furniture oil would probably wipe any mayo residue away. It makes sense to me that it might work, though I haven’t had occasion to try it.

    One point is that you would have to use a “real” mayo — one which contains eggs, oil, and not much else. Many products in the supermarket are not true mayo. You could also make your own; Joy of Cooking’s recipe is quite good. If you’ve never had fresh, home-made mayo on your favorite sandwich, you haven’t truly lived. Just remember that its shelf life will be short, so keep it cold until use and dispose of any unused portion after a few days.

    Another advantage of home-made mayo is that you know that it hasn’t been pasteurized, which, AFAIK, would reduce the lecithin’s emulsifying juju.

    :)

    Alex

  5.  

    Hey Alex. Thanks for all that helpful info. Guess I should tell you my other favorite way to spend my time: watching Food Network. :)

  6. Todd May 14, 2011

    Marc,
    I am hear to tell you that Mayo does work well at removing water marks from wood. My first experience was at my girlfriends house at 17 and leaving a glass ring on a coffee table. I was scared to death and her mom reasured me that it was okay. She appeared from the kitchen with Miracle Whip and it is just as good for this as it is on a sandwhich.

  7. I see this is an old issue (last post from May 2011) but I just had a similar thing happen here but the cause of the white spot was unknown. The table is a shellac finish and I took an iron and a towel and went over the spot a little at a time and slowly the spot began to disappear. All toll it took about five minutes and the white was totally gone. The table still needs to be refinished and once I’m better versed in french polishing I will tackle that but in the meantime it looks a lot better.

  8. I realize this thread is getting a bit long-in-the-tooth by now… but I found the thoughts very helpful in my quest to rid our dining room table of a white mark caused by placing a hot dish directly on the surface. The finish is a highly polished lacquer.

    Over a couple of days I tried using different oils, Vaseline, etc – no go. I then moved to the hair dryer approach for about 10- minutes, and the cloudiness seemed to improve slightly. Ah ha.. heat!

    I ended up using a clothes iron (like CraigA above), set to medium heat (no steam), and a double thickness of terry cloth as a barrier. In retrospect I think it would have been wiser to use something smoother, but it turned out not to be an issue. I applied heat for about 20 seconds… took a look and flipped the cloth over, heated, looked, flipped, etc. It took about 10-minutes, but all the cloudiness eventually disappeared. Note that there was not much improvement for the first 3- or 4-minutes, so be patient if you try this. In the end, I was left with a slightly dulled surface, but I think that a few minutes with some ultra-fine automobile compound will easily bring up the shine.

  9. Lannette Huberty January 11, 2013

    Back in the 1940’s my parents had a vintage piece of furniture with a built in radio and storage. The top of it would, every so often, get a water ring on it. Because I was fascinated with the method they used to get rid of the stains, I always volunteered to do the job. They would save up cigarette ashes then I would moisten them right on the stain and rub good. It seemed to work well to satisfy my parents that I did a good job.

    • Jim Spanogians July 22, 2013

      Try toothpaste! The gel won’t work.

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