We are in the process of cutting a white pine timber frame, and despite our best efforts mildew and blue stain have tarnished our timbers. We have bleached and then sanded the beams to try and stop new growth and minimize the appearance of the stain. I suppose there is not much we can do at this point, but does anyone know any way to reduce the stain once it's there?

One other question - we recently raised and enclosed a timber frame barn, and to treat the beams we used sanding, a mixture of half bleach/half water, then finished them with a mixture of half linseed oil and half gum turpentine. Now, about 5 months later, we are noticing some brown stains that look like water marks. We think it might be from water in the beams coming out (they weren't completely dry). Anyone seen this before?

Hi Chris:
I have had some luck with oxalic acid in solution in the removal of blue stain. When it gets bad though I have used a two part system that I purchased through American Building Restoration This system comes complete with the requisite hazmat paperwork but the parts are concentrated liquid solutions of sodium hydroxide and hydrogen peroxide. Follow the directions and it will work (the guys in the shop that actually applied it were impressed) and it saved throwing some very expensive wood away.
The best bet is to eliminate the stain by seasonal sawing, keeping it out of the weatther and getting the surface below 20% as soon as possible. I also believ the customer needs to be informed that blue stain is not serious problem in reasonable quantities. Sawmills use some fungicides that kill blue stain and some other living creatures to assure no blue.
Regarding the brown stains after raising: not knowing the location of this frame I would suggest using linseed oil only if you add a mildewcide (purchased from your local paint supplier)

Any one else have any suggestions?
Curtis