Replies

1. 
   davamoore | May 14, 2003 04:57pm | #1

   In his book, "Great Wood Finishes," Jeff Jewitt recommends bleaching out stains in wood using three different chemical methods, starting with the weakest and only progressing to the other options if you continue to have visible stains:

   1. Oxalic acid
   2. Chlorine bleach
   3. Two-part bleach

   Each method requires a slightly different procedure, works through a different methodology (e.g., removal vs. lightening the wood) and -- to be honest -- I haven't had a need to try any of them.  However, I know the oxalic acid method has been described here and in back issues of FWW, so you might want to do a search on Knots and the FWW website.  You might also try Jeff's website, http://www.homesteadfinishing.com -- he has a forum and lots of articles, some of which may touch on bleaching issues.

   Be sure to follow the directions to the letter and clean up the wood fully when you're done.  Any residue can cause problems, and there are always safety issues.

   David

   "The world that was not made is not won by what is done" -- Mundaka Upanishad

1. 
   Gretchen | May 14, 2003 06:51pm | #3

    starting with the weakest and only progressing to the other options if you continue to have visible stains:

   Oxalic acid

   Chlorine bleach

   Two-part bleach

   I think the weakest would be chlorine bleach (thus not the order here).  And you must get a fresh bottle of bleach from the store as it weakens when opened.Gretchen

1. 
   davamoore | May 14, 2003 10:20pm | #5

   Sorry, Gretchen, I wasn't being specific enough.  I was referring to Jeff Jewitt's recommendation of swimming pool chlorine bleach, often known as "shock," which is much stronger than regular household bleach.  You mix the powder in hot water.

   I also agree with Howie's assessment, that the black is probably caused by minerals in the water to which the wood was exposed.  My first thought was acid rain or road spray, but I wasn't sure what area of the country we were talking about.

   David"The world that was not made is not won by what is done" -- Mundaka Upanishad

1. 
   Gretchen | May 15, 2003 03:02am | #6

   I will always agree with Howie's assessments--or at least almost always!!  I am about ready to post about spar varnish again--get ready!!Gretchen

1. 
   davamoore | May 15, 2003 03:51pm | #7

   Spar varnish, Iraq.  Spar varnish, Iraq.  Which debate to follow? <grin>

   (And apologies for using the situation in the Middle East in a poor attempt at humor.)

   David"The world that was not made is not won by what is done" -- Mundaka Upanishad

2. 
   longcreek | May 21, 2003 04:16pm | #9

   thank you I had not heard of oxalic acid before and it did an excellent job

1. 
   davamoore | May 21, 2003 07:26pm | #10

   Great!  I'm glad it worked.

   David"The world that was not made is not won by what is done" -- Mundaka Upanishad

3. 
   BiotechBill | May 21, 2003 08:25pm | #11

   Another thing to keep in mind. When using water soluble aniline dyes, use distilled water for the dye AND for pre-raising the grain. I made the mistake of using iron laden tap water once...totally screwed up the project and I had to start over!

   Dr. BillThey would not call it REsearch if you only had to do it once, that would be just search!

1. 
   davamoore | May 22, 2003 12:06am | #12

   Another good point.  Yes, I always use and keep distilled water on hand for these very purposes.  Just swap it in and out of your Homeland Security kit!

   David"The world that was not made is not won by what is done" -- Mundaka Upanishad

2. 
   forestgirl | May 14, 2003 06:19pm | #2

   David's suggestion is an excellent one.  The end grain's going to be the toughest.  "...clean up the wood fully when you're done" refers to using vinegar to neutralize the bleaching solution.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

3. 
   HowardAcheson | May 14, 2003 07:04pm | #4

   Black stains in oak are caused by the minerals and metals in rainwater. The approriate chemical to remove them is oxalic acid. Hardware stores, paint stores or marine stores will general have it. Follow the directions.

   Chlorine bleach will have little affect. It is primarily used to remove dye stain from wood. Two part A/B bleach is used to remove the natural wood color from wood.

1. 
   longcreek | May 21, 2003 04:14pm | #8

   Thank you the oxalic acid worked great