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Removing old water stains from stripped piece

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  • #503014
    GfB
    Participant

    I have stripped an old sewing table that was passed to my wife a few years ago. The water stains have been there since before we got it, and I’m afraid may be deep, as the table held plants that were watered in place.

    How to remove? The top is veneer, so I can’t just sand to my heart’s content until the stains disappear. I’ve looked up solutions on the web, but most are abrasive based (baking soda or toothpaste), or some sort of oil (mayonnaise, BLO), and I don’t know if these would adversely affect the new stain and finish I’m planning to apply.

    I haven’t determined yet which finish I want to use. Thinking maybe Tung oil over the initial stain, then paste wax.

    #503048
    Ed
    Participant

    See what you can learn about bleaches like oxalic acid. Be careful with them, lungs as well as eyes and skin. If you find one that seems appropriate, learn how to neutralize it and learn whether it can interact with other chemicals to give harmful vapors.

    #504360
    GfB
    Participant

    Thank you Ed.

    I did more research and found out about oxalic acid, but couldn’t find any at my local stores. So on the recommendation of a couple more sites, I tried trisodium phosphate (TSP). After about 5 coats over the day, all but one of the stains are completely gone. The last one is almost invisible, but wouldn’t go away after even a couple more washes. It’s hardly noticeable, so I’m not going to worry too much about it.

    #504547
    Ed
    Participant

    I haven’t used TSP for this purpose. Let me know how it goes, please. Is there a neutralization step after applying it?

    Goes without saying, but you now have wet wood. Let it dry, dry, dry before moving on. When you are out of patience, wait some more. If you will be using water based dye or stain, it’s less critical, but you still want to let it dry.

    A test board to make sure nothing funny happens at the next step is probably a good idea, although you’re fairly well committed at this point… Still, if you see a bad interaction on your test board, you can make another test board and try something else without having to figure out how to undo the bad interaction.

    #504613
    GfB
    Participant

    This is the stuff I used: http://www.savogran.com/pdfs/TSP_PD.pdf

    Neutralization: The instructions indicate to just wash off with warm water, which is what I did. TSP is a base, so I’m guessing some sort of non-wood harming acid?

    I hadn’t really thought about it, but I think maybe I will apply some TSP to a test wood and see if there are any interactions when I apply finish.

    I’ll be happy to provide before and after images of the sewing table, as well as the test wood for comparison. (note: for some reason, I am currently unable to post pics in the forums. I have contacted support.)

    • This reply was modified 1 year, 8 months ago by GfB. Reason: clarify wording
    #514247
    GfB
    Participant

    As an update, I’ve almost completed the piece. It’s been stained, and tung oil applied. I’ve applied paste wax, and am waiting for it to cure before final wiping. There is no sign of the original water stains, and no apparent discoloration. I will upload pics upon completion.

    @ed,
    As a continuation of our discussion on the effects of the TSP, I am testing on a piece of oak. My test is to split the oak into 3 parts:
    #1 soaked in TSP, and left to dry between applications
    #2 soaked in TSP, and rinsed between applications
    #3 no TSP (baseline)

    After applying TSP to #1 and #2, I found that the boards turned green. Since both did, I’m assuming the TSP reacted with the tannin in the wood, and is not a reaction to the rinse water. I will upload result pics.

    #514264
    Ed
    Participant

    @awesomeopossum74 thanks for the follow up. Looking forward to photos. Was the sewing table oak, too? Was your test piece red oak or white?

    #514746
    GfB
    Participant

    This is the finished table. I think it came out very well, considering it’s age and the damage it had. Wife is very pleased, probably the most important.

    Attachments:
    #514755
    GfB
    Participant

    Well, shoot. I guess I never uploaded the “before” image. Here we go…

    Attachments:
    #515025
    Ed
    Participant

    Well done. Very nice, top to bottom. I like the new drawer pulls.

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