Timber Framers Guild

Blue Stain or "how do I chisel when I got the blues"

Posted By: Roger Brown

Blue Stain or "how do I chisel when I got the blues" - 02/13/02 05:59 PM

I would like anyone's advice or opinion on blue stain (on pine).

Obviously, winter cut trees that are taken directly to the mill and then stacked properly are good preventatives for reducing the likelihood of blue stain. I have not yet experienced blue stain but am having a frame milled as we speak and wanted some opinions - my timbers will not see a kiln:

1) I have read that blue stain cannot form under 72 degF. Anyone had experience different?
2) Can blue stain appear later after sawing? Example - if I cut in winter and still have stacked when it gets warmer, can blue stain occur? (I am in Texas, the land of 60 deg temperature swings).
3) Has anyone used any preservatives after sawing. If so, which one(s) and how did you apply and what were the results.

These forums are great info sources from hands-on experts and are invaluable. Thanks for help!
Posted By: Mark L Surnoskie

Re: Blue Stain or "how do I chisel when I got the blues" - 02/14/02 03:18 AM

The fungi that causes blue mold, which in its initial stage doesn't effect the strength of the wood, can be controlled in a number of ways. Temperature as the other fellow suggested to is one control. Growth stops below 40*F and above 105*F. Oxygen deficiency stops it and moisture content below 20 % or above the saturation point also stop it. Sapwood is what the fungi thrives on because of the carbohydrates stored in the cells, so its not so easy to stop. You can chemically inhibiting the fungi. Borate salts (Borax) kills the fungi. There are commercial solutions that can be sprayed on such as YardGuard, Timbor etc. These can be obtained from log home supply places like Canadian Log Home Supply (1-800-746-7773)or contact a local sawmill and ask what they use to dip their lumber in to prevent staining. Hope this helps.
Mark Surnoskie
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