Bandsaw blade question.......

Discussion in 'Woodturning Discussion Forum' started by odie, Dec 10, 2012.

  1. Dean Center

    Dean Center

    Joined:
    May 4, 2010
    Messages:
    456
    Location:
    Bozeman, MT
    It's the arboreal version of Don't mess with Texas.:D
     
  2. Gretch Flo

    Gretch Flo

    Joined:
    Jun 9, 2004
    Messages:
    1,222
    Location:
    Haslett, Michigan
    bk walnut causing dulling of gouges

    I have turned a few (10-15?) pieces of bk walnut-some green and some fairly dried out. I normally use 5 gouges at a time before re sharpening. Haven't really noticed a problem with BW dulling quicker than others. Must be the midwest clay/sand soil!! Gretch
     
  3. robo hippy

    robo hippy

    Joined:
    Aug 14, 2007
    Messages:
    1,868
    Location:
    Eugene, OR
    Hmm, the silica got me thinking about myrtle/california bay laurel. It does dull the tools fairly quickly. Always figured that since the best stuff comes from the coastal areas there was more silica in it than normal woods.

    So, if a wood has high silica content, is that some thing that the tree produces, or some thing that it sucks up from the surrounding soil?

    robo hippy
     
  4. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    I did some Internet searching and found that there are 21 species of walnut. The piece that I got in the Alan Lacer class which was cut locally seems much denser than the walnut that I got in trade from another turner in the northeastern part of the country. The few walnut planks that i have bought were comparable to the lighter walnut. The piece that I got in the class is also much darker in color compared to other walnut that I have seen.

    I have found next to nothing about silica in wood although i know that local white oak (primarily post oak) is moderately high in silica.

    UPDATE: Rather than silica, the mineral deposits seem more likely to be calcium carbonate. That would seem more logical since the ground water in north Texas is quite hard. Apparently most hardwoods can get calcium carbonate deposits. In an urban forest, it is more likely where the water source for the trees is from deep aquifers where the water is hard. However even shallow wells are likely to be hard with a high calcium content due to shallow limestone formations.
     
    Last edited: Dec 20, 2012
  5. MichaelMouse

    MichaelMouse

    Joined:
    May 16, 2005
    Messages:
    3,540
    As you no doubt encountered in your searches, silica has some solubility problems. Wants pretty acid conditions to get into solution. Unless it's in solution, the tree can't transport. Silica is an abundant (#2), albeit weird element. If there's a non-carbon-based life form somewhere in the universe, it's probably based on silica, with silanes that mimic carbon chains. Tree likes it if available, perhaps because of the structural mimicry.

    Calcium, as you no doubt discovered, is more soluble. It'll get into the tree and you'll find it pretty much where you find silica - those places where the water transport slows so that it can combine and stay behind. Calcium oxalate is the poison in a lot of leaves, the stuff of mineral stain in maple, and kidney stones. :mad: Look at that greenish cast in the confused grain under a branch. Probably calcium salt of some sort, likely oxalate.
     
  6. Edward Weber

    Edward Weber

    Joined:
    Feb 20, 2012
    Messages:
    72
    Location:
    Wilton, CA
    Thanks for the more in-depth information on silica and calcium.
    Please correct me if I'm wrong, but all trees are susceptible to either or both of these elements, which can make them more difficult to machine and dull tools much quicker than usual. Which brings us back to Odie's OP, where he had a piece of Goncalo Alves that was much harder to cut than normal. The blank he was cutting may have a very high mineral content due to where it was growing. Also there are two different species of Goncalo Alves.
    Goncalo Alves South American {Astronium fraxinifolium}
    Goncalo Alves Central American {Astronium graveolens}
    One, the graveolens species, is the harder of the two.
     
  7. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    For the benefit of others who may not have been "into" chemistry since high school, a minor clarification should be made. From the early hour of your post at 4:22 AM (or possibly a really late night post :)) and the probability that you were still waiting on Mr. Coffee, it would be most reasonable to assume that you intended to type "silicon" rather than "silica" given that you made reference to the element and not the compound "silicon dioxide" which is the chemical name for silica, AKA sand.

    Maybe there actually are silicon based life forms all around us and we don't recognize it (them) because of the absence of any characteristics that we identify with "life". I think that Dr. Asimov entertained such an idea in "Planets Have an Air About Them".

    Regarding calcium carbonate, I am coming to the conclusion that there is no particular species of domestic hardwood that is more likely to contain deposits of the mineral, but rather, it depends on where the tree grows. Limestone is likely to be found either on the surface or not too far down where a tree root system gets its water around here and in much of Texas. My assumption that post oak and other white oak species contain a lot of mineral deposits is probably because they are the predominant native species of tree around here and not that it is an oak characteristic. It could also be that oaks prefer growing in this type of environment which sort of makes mineral deposits a characteristic of the wood. Likewise, the urban black walnut that gave us fits would be more likely to contain mineral deposits because of where it was grown and not some characteristic of the species.

    I found only a small mount of information about mineral deposits in wood in Hoadley's book, "Understanding Wood", but nothing related to an association with species. Similarly, the FPL Wood Handbook briefly mentions mineral deposits in domestic hardwoods only from the perspective of workability in Chapter 3:
    Hard deposits in the cells, such as calcium carbonate and silica, can have a pronounced dulling effect on all cutting edges. This dulling effect becomes more pronounced as the wood is dried to the usual in-service requirements.
    I noticed that the current online version of the handbook has been updated with many changes since my 2003 and 2006 editions that I have on my computer -- something else that I need to download and clog up my hard drive.

    Along a similar line of thought, many of the folks from the panhandle area of west Texas never had a tooth cavity because the ground water is naturally fluoridated and not because they are a different species (possibly silicon based :)).
     
    Last edited: Dec 20, 2012
  8. dbonertz

    dbonertz

    Joined:
    Oct 16, 2007
    Messages:
    277
    Location:
    Fort Collins, CO.
    Along this line I have turned some elm, maple and cottonwood that have really stunk up my shop and other logs of the same species that weren't to bad. I conclude the really smelly stuff grew by sewer lines and the others didn't.:D
     
  9. MichaelMouse

    MichaelMouse

    Joined:
    May 16, 2005
    Messages:
    3,540
    At least I was half awake. Coffee was a nice Italian roast to compliment the cinnamon toast, BTW. Silica does have solubility problems, but it is composed of silicon and oxygen.

    As to sewer lines and smells. The willow that cost me several hot, fragrant summer hours with a hatchet and hook to get the roots out of my septic tank smelled pretty much the same under sandpaper as the one that grew out front. I think it has more to do with the amount of water captured in the heartwood and how log it's had to stagnate.
     
  10. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    Bowl of cold mushy cereal here to go with the damp chilly weather. harrumph

    What time is breakfast tomorrow?
     
  11. Wayne Spence

    Wayne Spence

    Joined:
    Jun 13, 2009
    Messages:
    217
    Location:
    Denver, Colorado
    band saw blades

    Silica SiO2 is sometimes thrown around losely. It will precipitate out of solution with no crystalline form and be rather soft. The hard form of it most common is quartz which is quite hard. There are 4 other forms, crystabolite and tridymite, similar to quartz. The other two, coesite and stishovite are high pressure forms found only in metorite impact craters. I have heard but cannot verify that teak from Indonesia is rich in quartz giving a very dulling effect to tools. Now that the USGS has an organic branch maybe they will investigate the chemical uptake and reactions of trees with the soil.

    One other important item. When I lived in Texas we would take a piece of Texas quartz and boil it in coffee all night. Come morning it was soft as a donut and tasted like hambone.

    Correction the correct spelling is cristobalite.
     
    Last edited: Dec 21, 2012
  12. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    Hey, Wayne. how well does the quartz donut wash down with the trail coffee? :D I hear that a dried cow chip is even better than chicory. We Texans are known for spinning a yarn now and then, but I try to keep 'em believable. :D

    Thanks for the information on the various forms of SiO₂. When I looked at the USDA Forest Products Laboratory site I got the impression that the bulk of their research now is to support the lumber industry in areas such as engineered wood products rather than more academic questions such as mineral deposits in wood.
     
  13. John Lawson

    John Lawson

    Joined:
    Oct 12, 2008
    Messages:
    142
    Location:
    Denton, TX
    I would think it would take quarts of coffee to wash down a quartz doughnut...
     
  14. Ian Robertson

    Ian Robertson

    Joined:
    Feb 3, 2010
    Messages:
    111
    Location:
    Tooradin, Australia.
    Home Page:
    I wonder if it would give you Kidney or Gall stones?;)
     
  15. KellyDunn

    KellyDunn

    Joined:
    Jun 28, 2010
    Messages:
    361
    Location:
    Hawi, Hawaii
    Home Page:
    This thread has actually become very interesting. A number of us here in Hawaii ponder many of the blade issues brought up here. The worst wood I have ever put through the bandsaw is Sausage tree. Takes a new blade to garbage real fast. The wood is so nasty it rounds over state of the art tool steel in moments. We have volcanic soil so nothing really nasty in the water. But all of us seem to use the term silica. Something nasty has to be in the wood. Next is Ulu(breadfruit). Both these woods are pretty soft in comparison with say Koa. And very fibrous. And most of us assume coconut palm has piles of silica in in it. Tough on blades and tools. so it seems that sand can not get sucked up into the pores? Do I got that right or am I missing something? Very micro perhaps and then getting lodged like a log jamb? Any one help clarify that? Seems I am reading different answers and ideas.
     
  16. odie

    odie

    Joined:
    Dec 22, 2006
    Messages:
    4,424
    Location:
    Deep in the woods
    Just a note to let those interested know.......I have received the two band saw blades from Carbide, and have not used them yet. I'll continue to use the Timberwolf blade until there is a problem, or until it becomes dull.

    Since that one bowl that gave me so much trouble, and was the initial inspiration for this thread, the Timberwolf positive claw blade continues to perform perfectly. Although not the same species as that one troublesome bowl, (sold to me as Goncalo Alves, but I've got some doubts that it was labeled correctly), yesterday, I roughed three bowls that were well above 30 percent MC. Since starting this thread, I've roughed about 10-12 bowls.....all with no issues.

    I don't know what can be deducted from all this, but this particular Timberwolf blade doesn't appear to be the problem.

    An alternate set tooth blade is the best overall choice for my purposes......

    Thanks to those who contributed to the content of this thread.

    ooc
     
  17. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    I think that the exact mechanism for mineral deposits in wood is still something unanswered ... at least for woodturners. Maybe some one in the Forest Products Laboratory knows.

    I am sure that any minerals would need to be in solution in the ground water in order to be taken up by the roots. In addition to SiO2 being the largest part of volcanic soil, I know from the smell of vents when I visited Hawaii in 1974 that there is also a lot of sulfur so the ground water is probably acidic where these trees grow which I think would help dissolve some of the minerals. Any mineral that can be dissolved to some degree, even if only a very small amount, can amount to something significant considering the huge volume of water that a tree drinks. I believe that most of the water ends up in the leaves, at least in deciduous trees, but I can envision some minerals building up in the wood sort of like hardening of the arteries.

    Anyway, that is my story until a wiser person comes along and sets the record straight.
     
  18. Wayne Spence

    Wayne Spence

    Joined:
    Jun 13, 2009
    Messages:
    217
    Location:
    Denver, Colorado
    bandsaw blades

    Kelly-This is my attempt. The Hawaiian Islands are composed of a rock that is basaltic, about 52 percent SiO2 by chemical analysis. This does not mean that there is a mineral SiO2 in some form that comprises 52% of the rock. It means that there is Si when combined with oxygen would total 52% of the rock. It could be from one mineral or a dozen minerals combined. The magma when ejected cools rapidly and the elements do not have time to segregate into various minerals , the rock is homogeneous, rather like a glass , individual crystals are not visible.

    Now take this rock, grind it up and spread it on your flowers or your tree. Will the tree take up the particulate material or only that that dissolves . I don't know but if it takes up particulate material it will be abrasive just like the rock is abrasive.

    If the rock were granitic it would contain 72% SiO2, some of it in the form of quartz which is quite hard and abrasive.

    Finished - excuse the verbose Odie
     
  19. MichaelMouse

    MichaelMouse

    Joined:
    May 16, 2005
    Messages:
    3,540
    If the plant could somehow push solid material through its vessels, how would it discriminate? It would take in any stray grain of whatever, not just silicates. The mechanism of uptake is known. http://www.eplantscience.com /bota...ficial_elements/silicon/silicon_in_plants.php

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC42876/ et cetera As this article reminds us, we can thank silicon for the first sandpaper - horsetails - which preferentially pick up silicates. Note, also that one of the silicon-loving plants is sugar cane.

    It's only a bit of chemistry to produce our friend SiO2 and others in, as the first article states "nanometric, microscopic and macroscopic dimensions." I'm going to go out on a limb and say that the first two probably don't play a large role in abrading our edges, but the third might.

    I once picked up a few hundred BF of hard maple from a kiln near an iron mine. The trees had grown downwind of the operation for many years, and the surface looked pink. If ever there was a chance to get solids in wood, that was it. Sadly, it was only casual surface dust from the kiln which was located in old concentrator buildings.
     
  20. Bill Boehme

    Bill Boehme Administrator Staff Member

    Joined:
    Jan 27, 2005
    Messages:
    8,139
    Location:
    Dalworthington Gardens, TX
    Home Page:
    This has become a most interesting and enlightening thread that has "evolved" from a bandsaw blade question and I think that we have all learned more about wood in an unexpected way. I have had a few "aha" moments as more dots got connected.

    Odie, I hope that you don't mind too much that your thread has been hijacked, although I have a feeling that you also have appreciated the evolution. In a sense, the subject has not really changed -- it has only delved deeper into what make some wood hard to cut and why does some wood dull cutting edges so quickly.
     

Share This Page