Ok, I know this sounds silly. But the more furniture I build, the more acute my concern for wood movement becomes. And that’s appropriate. Here are a few things I think I know about wood movement:
- Small/thin pieces are more prone to warpage than thick pieces;
- Uncoated wood will move more than coated (finished) wood will;
- Wood that experiences frequent changes in humidity will have more movement than wood that has a more stable environment.
Here’s what I know about the coffee stirrers at Starbucks:
- They’re very thin;
- Between the shipment from the manufacturer to the warehouse to the store, and then the exposure to steam from coffee and humidity changes from constantly opening/closing doors, the stirrers experience many frequent changes in humidity;
- They’re uncoated/unfinished;
- I think, but can’t be sure, that the stirrers are made of a softwood.
So, why don’t these things bend like a badly hammered nail? I have found one or two that are bent, but the vast majority are just nice and flat – no warp, bowing or cupping.
Maybe it sounds stupid (and maybe it is), but I feel like there’s a lesson I can learn here. And for those of you who will inevitably say that the lesson is “don’t bother us with trivial things,” please assume I’ve heard your message already. 😉
Yours in curiosity,
Mitch
“I’m always humbled by how much I DON’T know…”
Replies
Mitch,
Is your question focused on wood movement or warping? I don't know that the Starbucks stirrers don't move a lot...have you measured them? Warpage is from internal stress and/or uneven exposure to moisture...never saw just one side of stirrer go in a coffee cup have you? I'd suggest you forget the Starbucks stirrers and apply your questions to toothpicks...great little tools. :)
BG,
You make a great point. I didn't differentiate wood movement, which doesn't necessarily involve warping, cupping or bowing, from warpage.
That said, I would expect such thin pieces to move in a non-uniform way, given all of the changes they experience, and therefore not stay straight and flat. Waddaya think?Mitch
"I'm always humbled by how much I DON'T know..."
Mvac,
I mean, I just don't know. Being it is Starbucks, they probably have a pass from all the powers to harvest old growth timber and keep just the good parts for their sticks. On the other hand I've never collected 100 after use and studied what happened while they dried...it's just not as useful to mankind as studing the drying aspects of toothpicks (they get reused often).
However, I would not conclude thinness by itself is a good predictor of warpage....all those #2 pencils that got chewed in grammer school..not one warped either. :-)
Edited 6/8/2005 12:26 pm ET by BG
Perhaps the lesson is, "Build nothing requiring wood longer than 5 inches"
Roy
Uncoated wood will move more than coated (finished) wood will;
I really hate to do this, but technically, that isn't true... finished wood will move just as much as unfinished, the difference is that the finish slows down the rate of change...
felled, hauled, milled, packaged, shipped, dunked, stirred, trashed....
good resourse management...??
sorry... didn't mean to preach....
Mike Wallace
Stay safe....Have fun
"Uncoated wood will move more than coated (finished) wood will;
I really hate to do this, but technically, that isn't true... finished wood will move just as much as unfinished, the difference is that the finish slows down the rate of change..."
I really hate to do this too, but a slower rate of change is synonymous with wood moving less than unfinished/uncoated wood.
Nitpicker! ;-)
Mitch
"I'm always humbled by how much I DON'T know..."
I really hate to do this too, but a slower rate of change is synonymous with wood moving less than unfinished/uncoated wood.
Nitpicker! ;-)
<thunks... n groans......
no no noooooooo... think about it....it's easyyyyy... unfinished will move every bit as far... it'll just move slower... total movement is exactly the same it's the rate that's different...
hair-splitter.. ;P~~Mike Wallace
Stay safe....Have fun
Hair? And here all this time I thought it was wool. :-)
I guess we can agree to disagree. While a hard coating such as a varnish won't eliminate moisture changes, it certainly will inhibit it substantially - thus the rate of movement is quite slower than with unfinished wood.
This would enable you, for instance, to cut a part to exact length and not assemble it for a day or two without worrying about dimensional changes. If you left it uncoated and had, say, dovetail pins on each end, you could be in a for a world of hurt.
Just a thought...Mitch
"I'm always humbled by how much I DON'T know..."
True over here Indonesian furmiture was in style for a while a few years ago. The only problem was that in Indonesia the wood was stable at about 20% . It didn't matter what finish they put on it when it got here it lost humidity to stabilize at around 10% . That wood moved as much as any going from 20% to 10%..... slower ,but it moved.
The fashion sort of pettered out when buyers began to realize that fixing these peices, to make them useable again, cost more than buying them new.
Philip
You may have solved the great wood movement problem of our time. Just make all your furniture from coffee stirrers. As a bonus you won't need to sleep much. :)
"Just make all your furniture from coffee stirrers. As a bonus you won't need to sleep much."
Hmmm. Not a bad idea, actually, although the laminations would take forever... :-)Mitch
"I'm always humbled by how much I DON'T know..."
I haven't seen miniature finger jointing bits for routers. Maybe it's time to see a patent attorney?
Popsicle sticks too.
"Popsicle sticks too."
Excellent point!
But how come no one's answered my question? Doesn't it make sense that these items are primed for both movement and warpage?Mitch
"I'm always humbled by how much I DON'T know..."
I love coffee but don't buy it at Starbucks due to the fact that you usually have to wait in line behind some college chick trying to pay for a $4.99 Mocha Latte with an over-the-limit credit card. Right behind her is a fey, pampered, metrosexual dude with about a million and one instructions for how to prepare his green chai,...I'll have an aneurysm if I have to wait that long to get a cup of coffee,....by the time I get it I won't need the caffeine,...But my guess, if I had to speculate, is that part of the "experience" for paying 3 or 4 bucks for a cup of coffee, is that you get non-warping wooden stirrers. Next time you're in there you might want to snag some and use them for small straightedges,... kidding,..Ed
Are you serious -- there is actually a Starbucks in Mississippi? The times they sure are a'changin.
There's known to be two sushi restaurants in Jackson, MS - some Navy pilot compadres of mine used to go, occasionally. Myself, I gave it a miss - I've already consumed my lifetime quota of sushi from living in California and Japan.
I'll take a stab...
At a factory in xyz developing country a zillion labourers paid $.12 a day are picking out all the stirrers that show signs of internal stress relief as they travel down the starbucks conveyer belt.
After the trouble sticks are picked out both sides of the "lumber" will experience changes in moisture content at the same rate (and nearly the same internally).
So if it's flat after milling, it should stay flat.
No expert as I've done all my carpentry with popsicle sticks not stirrers. (Popsicle stick bridge competitions in Engineering class)
Andy
Nice question. Perhaps they move, but you don't perceive it. For instance, an 1/8" cup in an 8" board is easily seen. The proportionate cup in a stirrer which is 3/16" wide would be only 3 thousandths.
Let's look at your assumptions;
* Small/thin pieces are more prone to warpage than thick pieces;
Not true. A frequent cause of warpage is the uneven distribution of moisture. The thinner the wood, the more likely and the faster the wood will be at equal moisture content throughout.
* Uncoated wood will move more than coated (finished) wood will;
Again, not true. Moisture, or the reduction in moisture is the cause of warping. And, a finish will not stop watervapor migration--only slow it down. If the wood is equally finished on all sides, the moisture will still be equal and there will be little or no warping.
* Wood that experiences frequent changes in humidity will have more movement than wood that has a more stable environment.
True but that's just a truism. It's like saying you will get wetter if you jump in the pool than if you don't jump in the pool. The number of changes in relative humidity does not make wood any more unstable. It just moves more frequently.
Now, let me say that there are species of wood that will warp more than other species in reaction to changes in moisture content. Beech is the king of unpredictable reactions as it expands and contracts.
Also need to differentiate between stability and warping. Stability is generally defined as the relative magnitude of expansion/contraction as the moisture content of the wood changes. Warping is the bending/twisting of the wood as it expands and contracts. Some woods just quietly expand and contract and do not warp. Others warp as the expand and contract.
Howie,
"* Small/thin pieces are more prone to warpage than thick pieces;
Not true. A frequent cause of warpage is the uneven distribution of moisture. The thinner the wood, the more likely and the faster the wood will be at equal moisture content throughout.* Uncoated wood will move more than coated (finished) wood will;
Again, not true. Moisture, or the reduction in moisture is the cause of warping. And, a finish will not stop watervapor migration--only slow it down. If the wood is equally finished on all sides, the moisture will still be equal and there will be little or no warping."
As I replied to BG, I think your observations about the difference between "wood movement" and "warping" are spot on. I will say that many of the books I've read from respected authors (don't make me find the references) have said that thicker wood is less likely to warp. That said, the notion that water vapor dissipates from a smaller, thinner object at a faster and more even rate makes sense.
As for the coated/uncoated argument, I think you make my point, in that I would equate wood "moving more" to wood "moving at a faster rate." But again, as you point out movement doesn't automatically mean warpage.
So, I think the only logical conclusion is that those stirrers are made from a wood that typically remains stable in service, even with expansion and contraction. Assuming that's right, that helps me to focus not only on construction details that allow for wood movement, but on the specific characteristics of certain woods (as in your Beech example) that may have a tendency to warp more with expansion and contraction.
Thanks for the analysis. Sometimes the most trivial things can produce some important insights.
Best regards,Mitch
"I'm always humbled by how much I DON'T know..."
Why does Pepto Bismol give you a calico-colored turd?
Charlie,
Where does the white go, when snow melts?
Cheers,
Ray
Ray, my wife will be packing and shipping your stuff tomorrow. Sorry again for the delay. I had to take a short trip earlier this week on some family business.
Chas.
Hey Chas,
Not to worry, take your time.
Regards,
Ray
...silly question..where do you think the white clouds come from..duh!
White clouds live in different place than Black ones..
If we got along there would be no rain!
I think they all are made with a torsion box construction...
LOL. Of course, the obvious conclusion... :-)Mitch
"I'm always humbled by how much I DON'T know..."
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