Wood Spin - Sand in wood? Fact or Fiction?
- Written by Emmett Manley
Note: this is a slightly tweaked encore (think summer re-run) of a 2010 Wood Spin article
At various points in my ten years of woodturning experience, I have encountered the following statements:
- “this wood is full of sand and will dull your saw and tools quickly”
- “since that tree was growing in sandy soil, it will be filled with sand”
- “trees suck up sand”
- “osage orange is full of sand and that is why it is so hard to cut”
Plus, at least a dozen variations on these statements, all authoritatively stating that wood which is hard to cut, and which quickly dulls tools, is wood with a high sand or “silica” content. Please recognize, on the front end, that sand is not synonymous with silica.
Is this true? Or, are we dealing with old woodturners tales and mixed up correlations? I recall one famous scientist who believed, as a child, that tree limbs whipping around caused the wind to blow. It was not until he was ten years old, in the middle of the ocean, and encountering a lot of wind that he realized that his correlation was amiss. But it is certainly true that some woods are much more difficult to cut than others and that some woods will dull tools quickly.
|Harvesting Dead Osage Orange Limbs||Osage Orange Bowl|
In attempting to sort out the issue of sand in wood, I have dug around in all sorts of chemical and botanical sources, including contact with the person perhaps best qualified to provide the science needed to answer the question -- Rob Wallace, Ph,D., botanist and accomplihsed woodturner, Iowa State University. Via e-mail, Rob was kind enough to provide answers to many of my questions and to admit that he does not have all of the answers to this intriguing quest.
Let me provide a list of facts, some of which may raise more questions than they answer:
- Silicon Dioxide (which is quartz, which in small granules is termed “sand”) is essentially insoluble in water or in the aqueous liquid we refer to as sap. If sand was water soluble, we would not have any beaches.
- Sand granules are too large (and too insoluble) to move up a tree via the transport systems which exist in trees This does not happen. There is no sand in a tree except that pressed into the wood by direct contact of the wood surface with sand.
- If sand were in a particular wood, it should be visible to the naked eye when a fresh cut is made in that wood. Certainly visible with a simple magnifying glass. It is not there.
- It is true that sand/quartz is a hard substance: 7 on the Mohs Hardness Scale where 1 is talc and 10 is diamond. Quartz will quickly dull saw blades and tool edges. No disagreement here.
- Sand may be imbedded in logs which have rested on sandy soil.
- All clean woods which quickly dull tools share the property of being dense and heavy. There are no light woods which dull tools. Osage orange dulls tools because it is an extremely dense and hard wood. Ditto for black locust.
- Some forms of silcon are water soluble and can move within a tree’s transport system and some of these silicas can interact with endogenous chemicals and result in deposits of silica compounds. This is not a common situation.
- These deposited silica chemicals are probably (?) not hard crystals -- think more like table salt -- and are not especially dulling to tools. This is a shaky “fact” and subject to modification as the definitive investigations are conducted or uncovered.
- However, over long periods -- many centuries ? -- certain silica deposits can replace the natural wood structures . We call this "petrified" wood but understand that the petrification process is very slow and takes place underground.
|Cutting Black Locust||Black Locust -- Dense and Hard|
So, what is the bottom line? At this point, and based upon what I have learned about sand chemistry and tree physiology, I am convinced that sand/quartz plays no role in the interior of trees relative to serving as an abrasive and thus dulling tools.
However, it remains to be determined whether or not other silicon -containing compounds, precipitated within the wood of certain trees, do play a role in making the wood harder. Certainly petrified wood is very hard, but can you “lightly petrify” wood over a period of a few decades? Remember, too, that the long term pertrification process takes place under ground and under certain climatic conditions.
The definitive studies remain to be conducted; or, if scientists have already answered the question of silica in wood having a significant abrasive effect, I have been unable to locate the information. Unless they have a grant from a chainsaw or timber company, botanists would have little interest in investigating the role of precipitated wood chemicals as related to wood density and abrasiveness.
For those who insist that sand resides in the interior of certain trees, I refer them to no less than Albert Einstein who stated, “if the facts don’t fit the theory, change the facts.” Or to the English scientist, Julian Huxley, who observed, “the great tragedy of science -- the murder of a beautiful hypothesis by a brutal gang of facts.”
August 2015 Meeting Photos
- Written by Chuck Jones
The President's Challenge for the month of August was "Fruit". The winner picked by member vote was, well, ahem, the President himself, Bill Wyche.
(click image to enlarge)
- Chuck Jones, Cherries, Dye & Acrylic Spray Chuck Jones, Cherries, Dye & Acrylic Spray
- Jerry Dawson, Pepper, Dye & Paint Jerry Dawson, Pepper, Dye & Paint
- Jerry Dawson, Banana, Dye & Paint Jerry Dawson, Banana, Dye & Paint
- Bill Wyche, Apple Box, Paulownia, WOP Bill Wyche, Apple Box, Paulownia, WOP
- Giley Wright, Apple, Paint Giley Wright, Apple, Paint
- Paul Reed announcing the winner, Bill Wyche Paul Reed announcing the winner, Bill Wyche
- Challenge winner, Bill Wyche Challenge winner, Bill Wyche
- Nick Matos, Lidded Container, Cherry & Maple Burl Nick Matos, Lidded Container, Cherry & Maple Burl
- Nick Matos, big Leaf Maple Burl, Poly Nick Matos, big Leaf Maple Burl, Poly
- Jerry Dawson, Dust Collector (art), Banksia Nut & Walnut, WOP Jerry Dawson, Dust Collector (art), Banksia Nut & Walnut, WOP
- Jerry Dawson, Ash, WOP Jerry Dawson, Ash, WOP
- Randy Pitts, Paulonia, Shella Wax Randy Pitts, Paulonia, Shella Wax
- Randy Pitts, Persimmon Randy Pitts, Persimmon
- Rick Stone Rick Stone
- Rick Stone Rick Stone
- Rick Stone Rick Stone
- Russell Wright, Spalted Silver Maple, Behlens Russell Wright, Spalted Silver Maple, Behlens
- Giley Wright, Lidded Box, Walnut Stump, Master Gel Giley Wright, Lidded Box, Walnut Stump, Master Gel
- Mark Bateman, Pecan, WOP Mark Bateman, Pecan, WOP
(If any of your pieces are identified incorrectly please contact the writer.)
Demonstration by Rick Stone
The guest demonstrator for the August meeting was Rick Stone from the Mid-South Woodturners Guild. Rick's focus was kitchen utensils. In addition to actually making a spoon and a couple other items, Rick showed a wide array of jigs and special chucks for making the utensils, as well as lots of good tips and techniques. We very much appreciate Rick traveling from Memphis, hauling enough tools and jigs to fill an average shop, and sharing his knowledge with us.
Photography by Jerry Dawson
Yellow Bellied Sapsucker, Friend or Foe?
- Written by Emmett Manley
Without keeping you in suspense any longer, the answer is... it depends. For the woodturner who does not make a living selling timber, this beautiful member of the woodpecker family can add some dramatic embellishments to his woodturnings. However, in the past, the tree farmer and the lumber dealer have considered this bird a serious pest. Other woodpeckers also have caused problems but this little sapsucker especially likes to drill a ring of holes in trees and then return to a favorite tree, or trees, to keep drilling and keep the sap flowing. These holes are usually about 5 mm in diameter and extend through the bark and several mm into the sapwood.
Why do sapsuckers like to drill holes in trees? Their name is a dead giveaway as tree sap is a favorite food of these birds. They also feed on the insects attracted to the sapwells and which may be stuck in the drying sap. Unlike most woodpeckers, the sapsuckers are migratory, spending the winter in the southeast, then move back north when sap begins to flow and insects fly. Hummingbirds are also attracted to sap wells where they feed both on the nectar and insects.
Although dozens of species of trees may be attacked by the common yellow bellied sapsucker, mockernut hickories (our most common hickory) is a favorite. Other hickories, birches, most maples, and sweet gums are also commonly tapped. These trees yield lots of sweet sap and, as woodturners, we know how pleasant it is to work with these non-irritating woods.
Well, what’s the problem with sapsuckers? The problem, to the lumber dealer, is wood damage. Some trees may be attacked to such an extent as to gird the trunk or a limb and kill that tree or limb. Or slow the growth. Or, and this is the primary concern, to introduce “iron streaks” in the form of dark brown areas, even inclusions of bark and decay. The term “iron streaks” was coined before it was appreciated that the color and wood weakness was the result of woodpecker introduced fungal activity. These fungal streaks may be localized or extend many feet down the tree trunk as the tree grows. Individual trees may become favorites of individual sapsuckers and such trees can be highly degraded over a period of years. The iron streaks often weaken the wood and they certainly add colors which may not be desirable in wood used for flooring, cabinets, etc.
There was so much concern by lumber dealers in the early 20th century that it was proposed that yellow bellied sapsuckers be eliminated. Forestry publications provided formulas for making your own strychnine paste to place on sapsucker holes. It was recognized that a lot of hummingbirds and warblers would also be killed but this was believed to be acceptable collateral damage to rid the forest of sapsuckers. Fortunately, this effort failed and now the ornithologists tell us that there is a good population of these little beauties so they are in no danger of extinction.
Let’s assume you are a woodturner, not a wood dealer (and this seems a safe assumption for most of the readers of this article), and the perspectives change. It is a fortunate woodturner who possesses mockernut hickory wood well colored by streaks subsequent to woodpecker attack. By matching the diameter of your turning to the location of the “iron streaks” it is possible to incorporate the colors into your product. See accompanying photos for woodturned examples, all made from mockernut hickory trees which had been attacked by yellow bellied sapsuckers.
Once again, the efficient (lazy?) woodturner has enlisted a force of nature to provide embellishments that compare well with those produced by artificial means: air brushes, burnings, paintings, texturings, etc.