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Thread: Dark blue to black stains on fresh cut lumber.

  1. #1
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    Hoosier National Forest, Bloomington, Indiana
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    Dark blue to black stains on fresh cut lumber.

    Hello. I'm new to this forum as well as milling my own lumber. I've been an avid woodworker for awhile, and still have much to learn and experience, and recently made to decision to start milling my own lumber. I heat with wood, live in the wooded area and am surrounded by State Forest. Dealing with wood is nothing new.


    Running a sawmill, well now I'm defiantly a newbie.


    I bought a Wood-Mizer LT 15 Start. About as manual a mill as there is. But I could afford it and that's the end of that discussion. I had a stack of logs ready: Red Oak, Ash, and some almost curly Ambrose Maple.


    I started noticing some dark blue to black stains on my lumber. See: https://photos.app.goo.gl/o7eDj5MJBQXXutmE7


    It was leftover from the saw dust (mush) after a cut. I think I had too much water coming out on the blade. The stains correspond to the dust patterns between boards. I have turned the water down and do see less of this now. It looks to be only surface deep and on pass with the planer it'll be gone.


    Is that something experienced sawer are familiar with and if so is my water set too high?


    Thanks in advance.

  2. #2
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    Nino, I have never seen boards stained that much from my LT-15. I can't imagine the amount of water making a difference but I usually run my pretty low. Maybe milling in the heat? (I usually mill in the winter)

    What species of wood?

    JKJ

  3. #3
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    Hi John,

    Thanks for your reply. I'm mostly saw this staining on some Red Oak. It was a new blade and the coloration made me think of the way machining steel can stain. I guess that's my current theory. New steel, too much water and yes, it's been really hot here too.

    Are there reasons for milling in winter vs summer? I just got the mill, so I'm just having too much fun and sawing everything I have laying around

    Here's another photos later in the day. Some of the odd 3x3's show the same staining.

    https://photos.app.goo.gl/Vy8ug1ontnYshLUx5
    Trying to cut true in my woodworking and in life.

  4. #4
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    Quote Originally Posted by Nino Cocchiarella View Post
    Are there reasons for milling in winter vs summer? I just got the mill, so I'm just having too much fun and sawing everything I have laying around
    Some of my reasons: It's more comfortable in the winter (our winters are mild) - it's easier to keep warm than it is to cool off when it's 90! When it's cold bugs (mosquitoes, gnats, yellow jackets, etc) that annoy me are gone. Less problem with ticks so I tend to chainsaw and skid logs in the winter. Felling trees and milling when it's cold minimizes some insect infestation - when cutting some maple logs once I witnessed powerpost beetles flying in and landing on the wood (by the scent, I presume). Discoloration due to fungus is more likely and faster in warm and hot temperatures. Holly I've cut in the winter stayed much whiter than in the summer, same with maple. Prof. Wengert (woodweb) says the quicker you cut and dry wood the less color change due to oxidation; when it's warm the time is very short. Seems to me wood tends to dry and check faster when it's hot.

    And one big reason for me - spring, summer, and early fall are so busy here on the farm with garden, fields, livestock, raising poultry, and managing the honeybees! (And travel and outdoor domestic projects - our family manager likes to stay inside when it's cold.

    Sawing short woodturning blanks using a 2x lumber for a support:
    sawmill_blanks.jpg

    I bought my mill is late fall a dozen years ago so my first experience was in cool and cold weather.

    I don't saw much oak. I understand some people don't use any water/lube with oak. Maybe the staining is the reason, don't know.

    JKJ

  5. #5
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    oaks have a good amount of tannins in them and they when get contacted with ferrous metals will stain fairly quickly . I have seen a stain mark from just letting a raw saw blade sit just for a few minutes in damp oak , But the stains do not migrate to deep and can be planed or sanded out after some drying time.

  6. #6
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    Thanks John and David, I learned many useful things.

    I agree about summer activities in the garden and the bug problem. Winter is when I get the most time in the shop to make just because of that.
    Trying to cut true in my woodworking and in life.

  7. #7
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    I'm new to bandsaw milling, too, and have seen the same blu/black stains. After I turned down the water I got much less of it.

    John

  8. #8
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    John,

    I tried that today with on Maple I had left to cut and indeed that really helped.

    So, another question to the experienced folks out there: What level of water is best? I'd bet it depends on species.
    Trying to cut true in my woodworking and in life.

  9. #9
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    Darned if I know. I wonder if you need any water at all when cutting green hardwood logs. Pine and sappy stuff, sure, but I really wonder with hardwood. To answer your question, I'm running a drip, drip, drip flow onto the blade now, not a continuous stream. The 3.5 gal tank is still half full after milling 200 or 300 bf of 4/4 lumber.

    John

  10. #10
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    Quote Originally Posted by John TenEyck View Post
    Darned if I know. I wonder if you need any water at all when cutting green hardwood logs. Pine and sappy stuff, sure, but I really wonder with hardwood. To answer your question, I'm running a drip, drip, drip flow onto the blade now, not a continuous stream. The 3.5 gal tank is still half full after milling 200 or 300 bf of 4/4 lumber.

    John
    Someone on the WoodWeb said he never used lubricant for oak.

    I do what you do - a drip.

    Pine saps up the blade no mater what I do. I periodically clean it (from behind the saw) with a long screwdriver held against the running blade. Maybe something like Pam would work.

    JKJ

  11. #11
    Ash is a sticky hardwood, and you need lube to cut it, or the stuff sticks to your blade.

  12. #12
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    That's not been my experience with ash, Jim. I've cut about 1500 bf of white and brown ash with my mill now. It cuts just like oak. I run just a drip of water and am not sure any is needed. Maybe it's different in your locale.

  13. #13
    Depends on how fresh you cut it.

  14. #14
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    Quote Originally Posted by Jim Andrew View Post
    Depends on how fresh you cut it.
    Ah, that could be it. I'm cutting trees killed by the EAB so fresh is fresh dead, at best.

    John

  15. #15
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    we were caught up in the pine beetle disaster 12 years ago or so and the wood was made quite brittle and had blue staining or streaks thru it . I heard that it was because of the fungus the beetles carried. And that happened so fast it was amazing and sad. All that wood and the best thing to do with it was to burn it , to interrupt the bugs life cycle.

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