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  1. #61
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    Considering Paul's location I would have thought it standard practice to chew the cap off and drink straight from the long neck.

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  3. #62
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    Ahem...Rednecks and hillbillies to the... nah; Shouldn't go there.

    Just on a point of order, I think it was Rob that brought up the connection .

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  4. #63
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    Ahem...Rednecks and hillbillies
    Banjo territory.

  5. #64
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    Quote Originally Posted by planemaker View Post
    Banjo territory.

    FINALLY!!! someone brought the topic back to woodworking.

    Cheers

    Doug
    I got sick of sitting around doing nothing - so I took up meditation.

  6. #65
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    Quote Originally Posted by derekcohen View Post
    Thanks Stewie. I posted this information at the start of the thread, with the same link. It was the reason I suggested that the abrasive content of Jarrah were mineral other than silica, and more likely to be those creating an abrasive resin.....
    Derek, I wouldn't rule out silica in Jarrah altogether. Leached soils may be relatively low in silicon compounds, but are still likely to contain a significant amount (Luke, you're the geologist, can you comment on this?). As I said before, it's the second most-abundant element on earth. Plants also selectively accumulate some minerals, for reasons that are generally not understood, so you could quite possibly have high silica in plants growing in low-silica soils, & vice versa. The interweb is no help whatever on the subject, one page I found reckons Jarrah has high Si, another says it has "no appreciable silica", whatever that means. Visual appraisal can be indicative, but is far from reliable, and certainly not quantitative. A proper chemical analysis, preferably of several samples from different trees would certainly be a good starting point for settling that matter!

    I'm also a bit sceptical of the 'hardest woods in the world' rankings you find on the interweb - I found several and none agreed. And none quoted primary sources, so goodness knows where they got their 'information' from. I would hope Dr. Ilic's table is reasonably reliable, he would've had access to primary data in his former job. One of the things I miss in retirement is not being able to access journals & suchlike via the uni libraries.....

    Cheers,
    IW

  7. #66
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    Ian, I agree - unless there is something specific to the Jarrah tree that causes it to resist the incursion of silica. Is there a botanist in the house?

    Also that ratings of hardness are unreliable. We have all experienced the variability of the different woods we use frequently. When someone in the USA says to me - in a categorical manner - that he does not find Jarrah difficult to work or that it is hard on edges, then I wonder what sample he has his hands on. I have had Jarrah that works like butter. I have just re-sawn a Sheoak section (for my table), and were the sparks flying as the blade went through it!

    Regards from Perth

    Derek
    Visit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.

  8. #67
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    Ian, I agree - unless there is something specific to the Jarrah tree that causes it to resist the incursion of silica. Is there a botanist in the house?
    Derek; are you forgetting that Jarrah thrives in Laterite conditions.

    Laterite, soil layer that is rich in iron oxide and derived from a wide variety of rocks weathering under strongly oxidizing and leaching conditions. It forms in tropical and subtropical regions where the climate is humid. Lateritic soils may contain clay minerals; but they tend to be silica-poor, for silica is leached out by waters passing through the soil. Typical laterite is porous and claylike. It contains the iron oxide minerals goethite, HFeO2; lepidocrocite, FeO(OH); and hematite, Fe2O3. It also contains titanium oxides and hydrated oxides of aluminum, the most common and abundant of which is gibbsite, Al2O3·3H2O. The aluminum-rich representative of laterite is bauxite. https://www.britannica.com/science/laterite

  9. #68
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    A very interesting discussion
    sorry I can't contribute anything of serious import
    regards
    Nick
    veni, vidi,
    tornavi
    Without wood it's just ...

  10. #69
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    Derek; are you forgetting that Jarrah thrives in Laterite conditions.
    No, I am not forgetting that, Stewie. If you were following what Ian wrote ("Leached soils may be relatively low in silicon compounds, but are still likely to contain a significant amount"), you would have understood my comment - that I wondered if Jarrah could overcome their reputed difficulty in absorbing silica (due to their laserite environment).

    I wonder what Luke has to say?

    Regards from Perth

    Derek
    Visit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.

  11. #70
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    This is older but has a pretty broad scope of species. Unfortunately silica and alumina aren't discussed separately but are lumped together as ash. Not copyrighted.The Chemical Composition of Wood, R.C. Pettersen hilighted.pdf
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  12. #71
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    Ought to be possible to get the data on ash content mineral analysis.
    How about your own CSIRO Division of Forest Products?

  13. #72
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    Quote Originally Posted by rob streeper View Post
    This is older but has a pretty broad scope of species. Unfortunately silica and alumina aren't discussed separately but are lumped together as ash. Not copyrighted.The Chemical Composition of Wood, R.C. Pettersen hilighted.pdf
    Rob

    That's an extensive set of data, although the tables starting around p82 should potentially give up some secrets. Nothing specifically on Australian timbers except that Eucalypts do get a mention under the S. American list. Such trees grown out of their native habitat probably perform slightly differently. Plantation timber also performs differently and is normally an inferior timber compared to forest grown.

    Much, if not all, of the chemistry side of things left me foundering, but I tried to make sense of the ash component. I couldn't! Do you have any comments to add on the data?

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  14. #73
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    Not at the moment. I've been planing and sanding sugar maple shelf blanks all day in the heat (40o+ peak). I've downloaded a set of academic papers on the subject but I'm too crispy at the moment to be inspired.
    Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.

  15. #74
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    Quote Originally Posted by derekcohen View Post
    No, I am not forgetting that, Stewie. If you were following what Ian wrote ("Leached soils may be relatively low in silicon compounds, but are still likely to contain a significant amount"), you would have understood my comment - that I wondered if Jarrah could overcome their reputed difficulty in absorbing silica (due to their laserite environment).

    I wonder what Luke has to say?

    Regards from Perth

    Derek

    Derek; then you may want to consider that silica is not the only possible candidate to the wear resistant properties within Jarrah and other WA timbers that fall within the same category. Laserite soils contain high levels of Iron Ore and Bauxite. There are a number of minerals within these 2 types of ores that may or may not be contributing factors.

    https://www.britannica.com/science/goethite
    https://www.britannica.com/science/hematite
    https://www.britannica.com/science/titanium
    https://www.britannica.com/science/gibbsite

    Good luck with your witch hunt Derek.

  16. #75
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    Sorry for the delayed reply. I'm out on a (geology) field job

    I should preface this with the fact that I'm having to recall some deeply tucked away material here, so, my standard disclaimer reads:

    "It is my understanding that..."

    The presence of Silicon in the Earth's crust is, for the most part, the result of the fact that Quartz is so abundant in the Earth's crust. Quartz is SiO2, with the O being Oxygen, which is the most abundant element in the crust. I think Oxygen is about double Silicon, and then after that there's a big gap between Silicon and whatever comes next.

    Quartz is the primary constituent mineral in most intrusive (cooled under ground as opposed to ejected into the atmosphere by volcanism) igneous rocks, and I believe that the majority of Australia is fluvial or marine sediment overlaying intrusives, so you could expect to find it just about everywhere. The foremost exceptions would probably be rainforests, where the trees are likely rooted primarily in highly organic soils overlaying mineral soils, but it's still going to be there in droves, as is exhibited by the Silica content of rainforest trees like Queensland Walnut.

    The term "Lateritic" and "Laterite" is taking me back about ten years to one of the hardest classes I ever took, which was Soils. I had to use Google to refresh my memory and, of course, I ended up on Wikipedia. It sounds like these are soils that are rich in Iron and Aluminum, but low in Silicon. It doesn't, however, say that they are void of Silicon. I'd be willing to bet a cold beer that once you take away the primary constituents of a laterite you'd likely be looking at an assortment of odds and ends that was dominated by Silicon. So Jarrah DOES have access to Silicon in its native soils, and probably more than enough for it to draw it up into itself.

    If you had a location where Jarrah was growing in a more quartz-rich soil, then it would likely increase the volume of Silica in the wood.

    Also, Stewie, to say that a soil contains ore is a misuse of terminology. Ore is any rock from which a mineral is extracted by humans. It's not really an ore until we want to go get it, in a sense. If humans ceased to inhabit the Earth, then "ore" would cease to exist, and if there were bits of a rock type which could be an ore (like Bauxite) in a laterite soil, it wouldn't matter because the minerals would be bound up in the rock structure and not readily accessible by the tree.

    I'm not sure if that was even remotely helpful to the discussion... but I think it's an interesting one. I also don't think it's a witch hunt, and I'm glad you brought it up, Derek. Whether we find an answer to the question or not, the whole point of this website is for a bunch of dudes to chat about wood, so: Mission Accomplished.

    Cheers,
    Luke

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