blue/black pine sapstain

[1938farmall]

I'm working on a new pine project and have dark gray stain that oxalic acid won't touch.  Thought if anyone had a way to bleach it out, this would be the place to ask.  Anyone ever have any luck ?  Thanks, al

[isawlogs]

 
The blue stain will not come out , it is a permanent no matter what you do . I just finished an aquarium stand thatwas made with blue stained  white pine , I wanted to varathan it as is , but someone used a veto and I had to stain it  :   :-\   I findit will give caracter to a none caracter wood .  8)

[Dodgy Loner]

I just wanted to clarify what isawlogs said.  The gray stain on your pine is caused by a fungus and is called "blue stain" because it often is blue.  It's often gray, like yours, though.  I don't know of any way to get rid of it.  It penetrates the whole piece of lumber and will often get worse the more you plane off.

[woodmills1]

as stated that is a blue stain from fungus.  The stain happens when the temperature is above 70 degrees.  Logs more than a week old will stain in the sap wood in hotter weather.  Cut boards that are not stickered will stain overnight in the summer.  Boards will even stain in the piles during hot weather.  The stain is impossible to remove, though it does not effect the strength of the lumber

I have marketed some stained pine as a specialty product......"denim pine"

[Dodgy Loner]

I've found that blue stain will affect pine even during the winter if the weather is humid.  We cut over 3000 bd.ft. of SYP between October and February, and every inch of it has blue stain.  Most of the logs were sawn into lumber the same day they were felled.  Fortunately, the lumber was just for a pole barn.  I would have been pretty disappointed if I had cut it for interior paneling or furniture.