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I am currently installing oak window frames into brick masonry. I am experiencing severe leaching from the open grain of the frames which is staining both the stone and brickwork surrounds. Is this preventable? Does this process have a natural course to take? If so how long? How do I remove staining from adjacent masonry. Is this a case of the natural tannin in the oak bleeding out? I would welcome any advice or assistance.
 

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Oak will be

a poor choice of material for this application unless you have it fully encased in a thick film of sealer like polyurethane. My guess is that you are dealing with tanic acid staining your masonry. Apparently something in teh mortar has activated the reaction.

Ed
 

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I don't know much about masonry, but there maybe some iron in the mortar or the bricks themselves. This is reacting with the tannic acid in the wood. Try to remove it from the bricks with oxalic acid. In the future, you need to seal the ends of the wood too. Although, oak isn't the best choice for exterior work anyways. You can buy oxalic acid at most good woodworking supply stores. They come in a crystal form and need to be mixed with hot water. Allow to cool and apply. Try a small spot first in case it discolors the brick/mortar too. It may be best to just leave the dark stain. If you have light colored bricks, it may not matter. Afterwards, rinse several times with clean water and neutralize with a water a baking soda solution mixed in the ratio of 1 quart H2O to 2 heaping tablespoons of soda. Rinse again with clean water.
 
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