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21/01/2007 6:02 AM

How to refinish red oak windowsills

Our red oak windowsills that are about 16 years old are in need of a
refinish. The wood is black in some parts which maybe due to the
moisture from the windows. Do I sand the wood until the black
disappears or is there a solvent available that will clean the wood?
Is there any risk in me sanding too much to remove the black? I am
assuming that the black is just surface deep. After I remove the
black, I was going to add coats of clear polyurethane.

Does anyone have any other suggestions on how to make this windowsills
look beautiful again?
Thanks.
Regards,
Sandy


This topic has 4 replies

Jt

"Juvenal"

in reply to "[email protected]" on 21/01/2007 6:02 AM

21/01/2007 4:13 PM


Sandy wrote ...
> Our red oak windowsills that are about 16 years old are in need of a
> refinish. The wood is black in some parts which maybe due to the
> moisture from the windows. Do I sand the wood until the black
> disappears or is there a solvent available that will clean the wood?
> Is there any risk in me sanding too much to remove the black? I am
> assuming that the black is just surface deep. After I remove the
> black, I was going to add coats of clear polyurethane.


Sandy:

Red oak develops black patches and streaks wherever iron and moisture come
in contact with it. The discoloration is probably deep into the wood. If
you try to sand the spots where the wood is discolored, without sanding the
entire surface evenly, you will definately see divots where you sanded
heavily, magnified by the clear poly.

Oxalic Acid wood bleach is the recommended stuff to scrub in to remove most
of the discoloration. Then try a medium brown oil stain such as Minwax
Special Walnut, or Sherwin Williams equivalent, and finish with a satin
polyurathane varnish. This will hide the current discoloration and the
discoloration that will undoubtably continue to occur, as much as possible.

--
Timothy Juvenal
www.tjwoodworking.com

Pp

Prometheus

in reply to "[email protected]" on 21/01/2007 6:02 AM

21/01/2007 9:07 PM

On 21 Jan 2007 06:02:02 -0800, "[email protected]"
<[email protected]> wrote:

>Our red oak windowsills that are about 16 years old are in need of a
>refinish. The wood is black in some parts which maybe due to the
>moisture from the windows. Do I sand the wood until the black
>disappears or is there a solvent available that will clean the wood?
>Is there any risk in me sanding too much to remove the black? I am
>assuming that the black is just surface deep. After I remove the
>black, I was going to add coats of clear polyurethane.
>
>Does anyone have any other suggestions on how to make this windowsills
>look beautiful again?

I've done quite a bit of this, and my best results came from the
following-

First off, sanding is a rediculous amount of work- the old finish will
gum up the paper, and it will take forever. What you want to use is a
cabinet scraper (which is a flat rectangular piece of steel that you
will likely need to mail-order from a place like Lee Valley- most
hardware stores no longer carry them) for the flat pieces, and a
curved contour scraper for the detailed areas- those usually look like
a teardrop mounted on a handle.

Scrape off as much of the finish as you can- that *should* be down to
the bare wood, using even strokes. Pay attention to the grain of the
wood- it will cut better one way than the other. If what you're doing
seems to leave a rough surface, then scrape in the other direction.
If you don't want to buy a cabinet scraper, an ordinary wood chisel
will work in a pinch- remember that in this case, you are not
chiseling with it- you are dragging it along the wood with the edge
facing down. Sharpen often.

Once the scraping is done, vacuum off the sawdust and give it a quick
wipe with water to raise the grain. *Then* sand it- if your scraping
left a decent finish, 220 grit should be fine.

If you still have black marks, get some wood bleach (*not* household
cleaning bleach) and follow the directions on the container. You may
have to repeat several times to lighten the dark areas.

Neutralize the bleach according to the instructions, give it final
sanding, and then apply your stain. (Sherwin Williams "Fruitwood"
looks superb on red oak) After the stain is fully cured, apply your
top coat (usually Polyurethane).

You will probably want stain- even if you bleach a lot, there will
still be some of that black left in the wood. I suggest the fruitwood
because it darkens the grain, and blends that discoloration in really
well, along with having an excellent red color to it.

I would avoid at all costs using a heat gun *or* chemical strippers.
Believe me, I've tried them all- and they just do not work as well as
simple scraping on old finishes.

Good luck!

Pp

Prometheus

in reply to "[email protected]" on 21/01/2007 6:02 AM

21/01/2007 9:10 PM

On Sun, 21 Jan 2007 16:36:43 GMT, Lew Hodgett
<[email protected]> wrote:

>Juvenal wrote:
>
> >
> > Oxalic Acid wood bleach is the recommended stuff to scrub in to
>remove most
> > of the discoloration. Then try a medium brown oil stain such as Minwax
> > Special Walnut, or Sherwin Williams equivalent, and finish with a satin
> > polyurathane varnish.
>
>You could get into a lot of trouble trying to use what I know about
>stains, so let me ask a question.
>
>What is the down side of trying to use a gel stain such as WoodKote for
>this application?

The down side is that it's not really called for. Oak stains so
nicely, there's no reason for a gel stain. Almost any old stain will
do the job without blotching, but some don't look good because they're
the wrong color. (That's all in the eye of the beholder, of course.)

LH

Lew Hodgett

in reply to "[email protected]" on 21/01/2007 6:02 AM

21/01/2007 4:36 PM

Juvenal wrote:

>
> Oxalic Acid wood bleach is the recommended stuff to scrub in to
remove most
> of the discoloration. Then try a medium brown oil stain such as Minwax
> Special Walnut, or Sherwin Williams equivalent, and finish with a satin
> polyurathane varnish.

You could get into a lot of trouble trying to use what I know about
stains, so let me ask a question.

What is the down side of trying to use a gel stain such as WoodKote for
this application?

Lew


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