How to remove water stains on stripped tables?

[Linnea Lahlum]

How to remove water stains on stripped tables?

I just stripped 2 tabletops. Both have / will have marble centers, so the area was small. Both are oak. One is vintage and one is modern. I refinish and repair pieces for my own use, rather than make them from scratch (with a few exceptions....like making a top for a vintage base, or vice versa).

The vintage table is Eastlake.The finish came off with no difficulty. The stain did not come off, or at least not much. I had planned to re-stain and match the rest anyway, not change it. It’s a typical reddish golden brown Eastlake color, on the lighter end of the spectrum. Unfortunately there are water stains that have made the wood dark in several spots. A past owner must have used it as a plant stand. The spots look dark brownish grey. The rest of the piece is in such great shape, that I really want to make the top look as good. I just cut a beautiful piece of marble to fit in the center open space.

Following is a photo of it before I stripped it. It was too dark out to shoot a photo when I finished stripping it today. I plan to resume work on it tomorrow. It’s getting cold outside, I want to get this piece done quickly. I have to do smelly / messy processes outside.

I don’t know what the modern table was finished with. I bought it at a craft sale. I had assumed at the time it had a modern waterproof finish on it. It was not expensive. I used it myself as a plant stand, and it immediately got water spots. So maybe it was an oil finish. Finish was natural, there does not appear to be a stain; or if there is, it’s a light one. The water stains on this are more of a brown ring or halo effect. I did not strip the legs or apron as those looked ok. I would not mind staining this one to be darker, as the room where I have it has stains all darker than natural oak. (Though since I did not strip the legs or apron, maybe I should not think about that. Can you stain wood that has an oil finish? )

What, besides sanding, should I do to remove the water stains? I have been reading here about oxalic acid. Long ago I had a really old oak kitchen table I was refinishing. It had large areas of grey staining; I think it had been greatly abused and spent some time outdoors. I tried oxalic acid back then, and the stains did not budge.

Thanks for your suggestions.

[Wayne Lomman]

There are two possible approaches I would be trying. The first one is sanding. This will remove the top part of the stain but probably not enough of it to look good. You could scrape it instead of sanding initially. If you don't have a cabinet scraper, use a wide and sharp chisel as a scraper.

The other approach is careful bleaching. Success depends on your skill level and requires chemical handling. If anyone wants to know how to do this, let me know. I am just a bit hesitant to briefly describe it and have someone get only half the idea and come to grief.

Whichever way you go, if you can get it lighter, you can selectively stain to match the rest of the job. Cheers

[John TenEyck]

Oxalic acid normally will take out black water stains in oak. The product Bartender's Friend contains oxalic acid and works pretty well. I would try that first. If that doesn't remove it all, you can always sand it if it's solid wood.

You can't really stain over a film finish. However, you can apply a glaze over it to change the color, and then a new finish over that.

John

[Linnea Lahlum]

Wayne, I'd like to know. It would be good for my future reference, as long as I keep buying furniture that needs refinishing. I was going out to buy oxalic acid today. I have seen conflicting info on whether to apply a saturated solution to just the stain, or the whole piece. And for how long. One said overnight, and repeat 3 times.

I'm ok with chemicals. I etch copper and brass for my artwork, plus use a lot of patina chemicals on metals.

[Linnea Lahlum]

John, I have Barkeeper's Friend on hand. Are there disadvantages to using it vs. pure oxalic acid?

I am hoping to avoid having to sand deeply, as I have carpal tunnel syndrome. I also don't want to end up with a dip, or to impact the ogee edge (not really visible in the photo). This piece came out looking really good after stripping, except for the stained part. It is solid wood.

With the kitchen table I referenced above, I had to take out a tremendous amount of wood to get rid of the grey areas. And I didn't have carpal tunnel syndrome then.

With regard to the modern piece, maybe I will try glazing. Then it will look like it belongs in that room with the other reddish brown craftsman style furniture. What do I look for in a glaze? For the stripped top on that one I can just use the stain that I used for the baseboards there.

[John TenEyck]

Barkeeper's Friend won't work quite as well as straight oxalic acid, so it takes longer to have the same effect. With either you have to wipe the treated area really well with lots of water to remove both the stains it brings up and the chemical.

Sanding shouldn't be too bad on CT if you use a random orbit sander. You would know better than I, of course. If you do much woodworking it would be a good idea to look into one of the newer ROS specifically made for low vibration. They are a pleasure to use.

Glaze? You can either use a product called glaze, or you can use a gel stain. In most cases, you apply a glaze over a sealed surface. So you might proceed by applying a coat or two of Sealcoat shellac to the stripped piece, sanding between coats with 320 grit, then apply the glaze/gel stain, then another coat of shellac (do not sand the glaze), then your topcoats. There are variations on that, like putting down a dye and or stain to the raw wood, then proceeding as above.

John

[Wayne Lomman]

OK, everyone else, this is one of the more advanced skills techniques. The procedure below is for your protection while doing this. I cannot stress enough the importance of a well ventilated area. DO NOT DO THIS IN YOUR BASEMENT!!!

Linnea, before you start bleaching, you need a well ventilated area. Do not do this indoors unless in a spray booth with good ventilation. Out doors is OK. Just make sure no-one is close by down wind as there will be some ammonia fumes.

This bleaching process will turn timber a brilliant blonde - it works on hair, it works on wood.

The chemicals required are strong Ammonia solution and Hydrogen Peroxide. In Tasmania these are available from a specialist cleaning chemical supplier as they are routinely used for industrial cleaning in food processing factories. When you purchase the chemicals, ask for a copy of the Material Safety Data Sheet (MSDS) and study it so that you are fully familiar with products and the safety requirements for using them. Keep the products separated. Have a couple of small buckets for decanting the 2 chemicals and a few good rags handy.

1. Make sure you are wearing the appropriate protective gear - as a minimum wear fully body clothing, closed impervious shoes, plastic apron, elbow length chemical resistant gloves and a respirator fitted with the appropriate filter cartridge for ammonia gas

2. Set up the item to be bleached and make sure nothing important in the surrounding area can get splashed or dripped on.

3. The item should be already sanded but don't waste too much effort as the grain gets raised by the process and you have to sand it again anyway.

4. pour enough ammonia solution into a small bucket, saturate a rag with the solution and liberally apply it to the job. You need to really wet the whole job down so that it is dripping.

5. Put the ammonia out of the way.

6. Pour peroxide into the second bucket, saturate a rag in the solution and immediately liberally apply it to the job over the top of the still-wet ammonia. Make sure the peroxide is applied good and wet everywhere with no misses.

7. Return unused chemical to the appropriate containers and clean up.

8. Allow the item to dry in a well ventilated area. This will probably take at least overnight but may be longer depending on the weather etc. The full colour will be achieved in this time frame.

9. Once it is dry, sand it to the desired finish and polish as usual. There is no need to be too careful sanding as the bleaching penetrates well into the timber. I don't remember the sanding dust being irritating but still wear a dust mask.

That's all there is to it. Safety is critical. Apart from that, make sure there are no misses otherwise it will be patchy.

Good luck with trying it. I did a whole restaurant full of tables using this method. The tops were bleached oak and the bases were some red colour. It sound terrible and probably was but architects know everything. Cheers

[Al Launier]

John, I have Barkeeper's Friend on hand. Are there disadvantages to using it vs. pure oxalic acid?

I am hoping to avoid having to sand deeply, as I have carpal tunnel syndrome. I also don't want to end up with a dip, or to impact the ogee edge (not really visible in the photo). This piece came out looking really good after stripping, except for the stained part. It is solid wood.

With the kitchen table I referenced above, I had to take out a tremendous amount of wood to get rid of the grey areas. And I didn't have carpal tunnel syndrome then.

With regard to the modern piece, maybe I will try glazing. Then it will look like it belongs in that room with the other reddish brown craftsman style furniture. What do I look for in a glaze? For the stripped top on that one I can just use the stain that I used for the baseboards there.

Just a suggestion if you haven't already taken this precaution. I had carpal tunnel earlier this year & prior to surgery was advised by an occupational therapist to purchase this:
http://impacto.ca/Products/Detail/ST8206.
As I recall it cost $35, but helped a lot, especially when handling vibratory tools like a palm sander.
Good luck with your Carpal Tunnel Syndrome - not pleasant at all.

[Linnea Lahlum]

Thanks, Al. I have a brace I never use anymore, but this looks different. I have had to change the way I do things. Rest my pliers handle in a different place in the palm, no longer do the same task for hours, etc. I use my drill press for things most people use a flex shaft for, to avoid holding the vibrating hand piece. Can't vacuum or mow the lawn.

I don't have a palm sander, but was thinking of buying one. Looked at some yesterday, but really need a demo.

I have been dodging surgery for over 10 years, as I'm afraid of losing fine motor control. In metals one has to work to very small tolerances, like using 1 mm burs to cut a seat for a stone.

[Linnea Lahlum]

I did the oxalic acid today, mixing the crystals up with hot water. I don’t think it is going to work on the vintage Eastlake piece. So far, it does not look promising. I had read conflicting instructions: apply, leave on for 15 minutes, wipe off: versus leave on overnight. At first I was excited because I thought it was lightening. But when I went back to check after having to do something else briefly, leaving it soaking, it looked unchanged. Maybe less grey, but still dark brown. I scrubbed with a scotchbrite pad after letting it soak. Second time, I used a stronger solution, essentially a slurry, and left it on for 45 minutes. This was thick enough that it did not dry in that time. No change. Did it a third time, no change. So I put the remaining slurry on, and will leave overnight in the garage.

Interestingly, the brown rings on the modern piece came right off with one application. I could see them fade before my eyes. I did 3 on that one too, as long as I was doing the other. Then rinsed with distilled water.

Could the cool ambient temperature have played a role? The hot water was not hot for long. It is perhaps 65 F outside, and I did it in the sun. After I finished for the day, I read another thread suggesting applying it as a paste, putting a damp rag on it, then putting a warm clothes iron on the rag for a minute.

I am not inclined to do a different bleaching technique on the vintage piece. I will try just sanding next, if I can’t figure out how to make the oxalic acid work.

[John TenEyck]

If the OA didn't remove the stain after what you've already done, I doubt it will no matter how you use it. I think your options at this point are to move on to a 2 part bleach or sand it.

John

[Linnea Lahlum]

Plant Stand 1d.jpgPlant Stand 1f.jpg

I wanted to report back on the oxalic acid treatment. I left it ovenight and the stains still weren’t gone. So, I did the treatment recommended in a different thread (somewhere) of reapplying a thick paste, then laying a damp cloth on, then applying a warm iron. I could tell that was working, as the stain immediately started to be drawn up into the cloth. I did one minute with the iron on the low silk setting, moved the iron, another minute, etc. The vapors steaming upward were pretty bad (I was doing this outside): I had to do it with my head turned to the side. (I was already wearing googles). Rinsed, checked, better: but not entirely. So I repeated, with new OA, fresh cloth, iron on slightly higher setting. With the last repetition the cloth did not change color. Then washed down with baking soda and water. The grain in the affected area was raised alarmingly, but now that it’s dried overnight, it’s not too bad.

I’ll be sanding it next. The second photo shows it after drying overnight. The formerly most stained strip is oriented to the right.

[Linnea Lahlum]

Plant Stand 1d.jpgPlant Stand 1f.jpg

I wanted to report back on the oxalic acid treatment. It took experimentation, but it worked. After the first day of attempts with little improvement, I left it ovenight and the stains still weren’t gone. So, I did the treatment recommended in a different thread (somewhere) of reapplying a thick paste, then laying a damp cloth on, then applying a warm iron. I could tell that was working, as the stain immediately started to be drawn up into the cloth. I did one minute with the iron on the low silk setting, moved the iron, another minute, etc. The vapors steaming upward were pretty bad (I was doing this outside): I had to do it with my head turned to the side. (I was already wearing googles). Rinsed, checked,better, but not entirely. So I repeated,with new OA, fresh cloth, iron on slightly higher setting. With the last repetition the cloth did not change color. Then washed down with baking soda and water. The grain in the affected area was raised alarmingly, but now that it’s dried 2 days, it was not too bad. Its now sanded and ready for staining.