Welcome! Forums General Woodworking Discussions Finishing White stains in sanding sealer

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  • #311972
    James Savage
    Participant

    I’m finishing an Ash wall unit I’ve made from Paul Sellers book.
    I’m using Liberon sanding sealer then plan to apply wax paste to a light sheen.
    The first coat went on with no problems but when I applied the second coat of sanding sealer it has dried with white stains, I’m not quite sure why as I have used this finish successfully before. The temperature is 14C in my shed so it can’t be temperature related.
    I’m guessing I will have to rub down until the stain has been removed then re apply the sanding sealer.
    Does anyone know why this has happened please so I can avoid it in the future?
    Thanks in advance.
    Jim

    Jim - Derbyshire.

    https://www.youtube.com/watch?v=xqF49Zwmzs0

    #311979

    I assume your “sanding sealer” is shellac? If so, what is the humidity in your shed? Shellac can turn whiteish in high humidity. That is what happens when you set a wet glass on a side table that has been finished with shellac and when you lift the glass, you can see a white ring where the glass was. Usually the whiteish will disappear when you let the table top dry or in your case, take your wall unit to a low humidity area.

    Located in Honeoye Falls NY USA. The Finger Lakes region of Western NY.

    "If you give me 6 hours to fell a tree, I will take the first 4 to sharpen my axe" Abe Lincoln

    #311984
    Philipp J.
    Participant

    I have heard a very similar story from a local Cabinetmaker also stains in finished surfaces, turns out one of his workers had gotten a new hand cream and some ingridient of it, not sure what, left residue on the surface where she touched the work and after applying finishes it left stains.

    Granted im not certain if that can happen with sanding sealer but its something to keep in mind, also if you use pressurized air to clean surfaces after sanding alot of the cheaper compressors do actually leave some oil residue in the air they blow out which can also result in stains.

    Not sure it will help you but it might, Regards Philipp.

    #311988
    James Savage
    Participant

    Thank you for the replies, certainly something to think about.
    Funnily enough it has been a very wet day here in Derbyshire and my shed is unheated so no doubt the humidity would have been higher. I’ll bring the unit inside and see what happens.
    I’ll keep an eye out for hand creams also, I do get very dry, cracked hands so put cream on regularly so it’s a possibility I could be contaminating the surface.

    Jim - Derbyshire.

    https://www.youtube.com/watch?v=xqF49Zwmzs0

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