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  1. #1
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    Default varnished wood gone black

    I am looking for advice on rectifying some unsightly woodwork. On the back of the forcabin door the wood under the varnish is going black is there any way of rejuvenating this with sanding and a varnished finish or am I going to end up painting it?

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    Quote Originally Posted by voyager35 View Post
    I am looking for advice on rectifying some unsightly woodwork. On the back of the forcabin door the wood under the varnish is going black is there any way of rejuvenating this with sanding and a varnished finish or am I going to end up painting it?
    Yes, you can sand & varnish. Why not ?
    Dum spiro spero. Cras ingens iterabimus aequor.

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    Default varnished wood gone black

    As above, it's wood that has some damp in it be careful when sanding not to remove the wood veneer also.

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    If the black is really under the varnish you have to remove the varnish.

    Sometimes, though, the varnish is worn and Magic Sponges will turn the black wood back to normal- like magic!
    I may be wrong, but I'm not confused.
    ⛵ Ex-SolentBoy

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    You didnít state if it was veneer or solid wood.....

    You will have to remove the varnish and then gently sand the wood to remove the majority of the black marks. You will probably find that the marks have got into the grain of the wood and will need removing with Oxalic acid or a mild bleach solution.

    Normally if the wood is teak it is a fungus that needs to be removed and cleaned off and it is caused by dampness getting under the varnish.

    Once sanded and cleaned off you need to dry the piece and then varnish using the normally accepted procedures.

    Hope this helps out.

    Tom

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    yoda is offline Registered User
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    Trust me on this I have just done it and it does work.


    Black marks can be rubbed all day, however, and they’ll never come out. The only way to remove them is to remove the finish and then attack the stain. The problem when trying that with a fine antique? By taking off the finish, the value is lowered. On the floor, though, that’s not an issue. In fact, putting a new finish on a hardwood floor actually increases the value of a house. Here’s how to do it: First sand the finish off the wood. Then attack the black mark with bleach. Use a glass jar and an old brush. Pour the bleach into the jar, dip the brush in the bleach, and brush the bleach onto the stain. Let the bleach evaporate for a couple of hours and then come back and apply another round. Let it sit overnight.
    If the stain still isn’t gone, step up the efforts with commercial wood bleach. First, moisten the wood with a damp sponge to allow the bleach to penetrate better. Then mix equal amounts of the two liquids that come with commercial wood bleach. Brush a liberal coat of the mix on the damp wood and let it soak into the wood. In a little while, it should start bubbling. It takes about four hours to see results. Then make sure to neutralize the bleach. Mix two parts water to one part ordinary household vinegar. Dampen a sponge with the mixture, and rub back over the bleach.


    Mine only needed the overnight bleach treatment, I used an own brand 'thick' bleach and just because I wasn't sure I used distilled vinegar. This works, trust me and you don't end up sanding through the veneer. Use a brand new sponge (souring sponge is fine) otherwise residual cleaners end up on the surface. You do need to scrape off the varnish first but I found a decent new scraper made easy work of it. Don't worry about putting bleach where it's not needed as it seems to have no effect in these areas.

    Yoda

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    Quote Originally Posted by voyager35 View Post
    I am looking for advice on rectifying some unsightly woodwork. On the back of the forcabin door the wood under the varnish is going black is there any way of rejuvenating this with sanding and a varnished finish or am I going to end up painting it?
    its either dirt or damp, one you can get rid of with sandpaper the other a new floor panel.

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    Quote Originally Posted by ukmctc View Post
    its either dirt or damp, one you can get rid of with sandpaper the other a new floor panel.
    Black marks like this are very often the beginnings of wet rot, particularly if it takes the form of stains stretching out from a joint along the line of the grain. You may notice a slight fungus-y smell if you sniff close up. It needs to be treated asap, not just cleaned. Bleach will kill surface rot (once the varnish is removed), but a washover with a proprietary rot-killer is better, before you reapply varnish. Be particularly sure to treat the end-grain, where the penetration often takes place.
    Last edited by AndrewB; 04-02-12 at 12:39.

  9. #9
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    Quote Originally Posted by yoda View Post
    Trust me on this I have just done it and it does work.


    Black marks can be rubbed all day, however, and theyíll never come out. The only way to remove them is to remove the finish and then attack the stain. The problem when trying that with a fine antique? By taking off the finish, the value is lowered. On the floor, though, thatís not an issue. In fact, putting a new finish on a hardwood floor actually increases the value of a house. Hereís how to do it: First sand the finish off the wood. Then attack the black mark with bleach. Use a glass jar and an old brush. Pour the bleach into the jar, dip the brush in the bleach, and brush the bleach onto the stain. Let the bleach evaporate for a couple of hours and then come back and apply another round. Let it sit overnight.
    If the stain still isn't gone, step up the efforts with commercial wood bleach. First, moisten the wood with a damp sponge to allow the bleach to penetrate better. Then mix equal amounts of the two liquids that come with commercial wood bleach. Brush a liberal coat of the mix on the damp wood and let it soak into the wood. In a little while, it should start bubbling. It takes about four hours to see results. Then make sure to neutralize the bleach. Mix two parts water to one part ordinary household vinegar. Dampen a sponge with the mixture, and rub back over the bleach.


    Mine only needed the overnight bleach treatment, I used an own brand 'thick' bleach and just because I wasn't sure I used distilled vinegar. This works, trust me and you don't end up sanding through the veneer. Use a brand new sponge (souring sponge is fine) otherwise residual cleaners end up on the surface. You do need to scrape off the varnish first but I found a decent new scraper made easy work of it. Don't worry about putting bleach where it's not needed as it seems to have no effect in these areas.

    Yoda
    Thanks this worked well. Sanding of the old varnish got ride of 90%of black marks and the ordinary domestic bleach got rid of the rest. Trouble is the rest of the interior looks shabby against the door, definitely a job for another day or week or maybe next year?

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