Spiral Bowls, part 1

[Lee DeRaud]

Some of you may remember the spiral bowl I posted last December (if not, it's here (http://www.sawmillcreek.org/showthread.php?t=46716))...at the time I described it as a "proof-of-concept" piece. Well, "proof" may have been too strong a word: the next three I tried blew up on me, mostly because getting the rings lined up during the glue-up is trickier than it looks and apparently I got real lucky the first time.

A ggody amount of thinking and experimenting later, I figured out how to make them reliably...here's the first two.

The first one is basically a copy of the original, but much higher quality:
6469164692
Maple/walnut, about 5-1/2"x3".

The second is a more traditional "bowl" shape, same materials:
6469364694

(to be continued)

[Chris Barton]

Oooh, those are very nice! What kind of glue are you using? Also, what kind of finish on these bowls?

Thanks!

[Lee DeRaud]

Oooh, those are very nice! What kind of glue are you using? Also, what kind of finish on these bowls?The answer is "CA"...to both questions.

[Bill Wyko]

Nice work. Great looking design. I'm a big fan of segmenting and your work is another fine example of the many techniques that can be used to create amazing pieces. Again great job.:)

[Mark Pruitt]

Beautiful! Way to hang with it!

[Jason Roehl]

I likey muchy!

[Mike Vickery]

Beautiful work Lee. I absolutely love the first one.

[Jim Becker]

I especially love the first one! Great shape for this particular technique you're using!

[Gary Herrmann]

Nice job, Lee. I've got to try that. I really like the swirl in the first one.

[Cory Martin]

Wow I just can't get over how cool that is!!!!!

[Steve Schlumpf]

Amazing work Lee! Still can't get over the visual effect looking into each of the bowls! Wow!

[Nancy Laird]

Wow! You have been busy. Nice work - you can almost get dizzy looking down into the first one.

Nancy

[Jonathon Spafford]

Those are just beautiful! The top one looks close to perfect! It has an awesome shape and I like how the light swirl gets darker around the edges... that was intentional right?

[Bernie Weishapl]

Those are cool Lee. I really like these. CA finish looks pretty good. May have to give it a try.

[Scott Loven]

I am curious, has anyone ever tried to do a continuous spiral like a barbershop pole or candy cane effect on a bowl? I have never seen one.
Scott

[Lee DeRaud]

Those are just beautiful! The top one looks close to perfect! It has an awesome shape and I like how the light swirl gets darker around the edges... that was intentional right?Sort of. Note that within the swirl swirl, the grain orientation changes from endgrain to sidegrain and back (or vice-versa) as your eye moves across it vertically: each "ring" is rotated about 15 degrees from the adjacent ones moving up the stack. The dark swirl has the same effect, it's just not quite as obvious in the pictures.

I'll post some pictures of the glue-up process as soon as I find the USB cable for my other camera. It makes it a bit easier to visualize what the grain is doing in the finished piece.

[D-Alan Grogg]

Wow, I like them! Good job!

[Brian Brown]

Lee,

These bowls are sooooo cool. Just a question, do you know of any potential problems in the future with wood movement where the grain is changing from side grain to endgrain as it moves around the bowl? These are way too cool to see them come apart or crack down the road!

Brian

[Lee DeRaud]

Just a question, do you know of any potential problems in the future with wood movement where the grain is changing from side grain to endgrain as it moves around the bowl?I doubt it. It's not really a cross-grain situation: any given glue joint is only misaligned by about 15 degrees.

[Lee DeRaud]

Maybe this will clear things up a bit...

I glue up (for example) a piece of 8/4 maple and a piece of 8/4 walnut, and resaw the result into thin sheets (0.12"-0.15" typically):
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It takes two of these 6"x12" sheets for each cone-shaped bowl and four for the more traditional shape...more waste, but still much less than a solid blank.

These are then cut into the rings that make up the bowl blank:
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This picture is the pieces for a 'round' bowl: the rings for a 'cone' bowl are all the same width.

Those X-shaped widgets are jigs made out of 1/8" MDF and keep the rings concentric during the glue-up:
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They end up glued to the blank, but they're easy to break off after the glue sets up.

Here are some completed blanks, ready to turn:
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There are waste blocks fabricated from discs of 1/4" poplar glued to the bottom end for the chuck to hold. I also have a disc of 1/4" MDF with a small hole in the middle: this press-fits inside the topmost ring and gives the tailstock a place to register during the turning of the outside.

Here is a piece of thin stock for the other bowl I posted:
64753

Before anybody asks:
I use a laser to cut out the rings and the gluing jig. I suppose in theory it's possible to do this with a scrollsaw (or some other traditional tool), but it sounds like more trouble than it's worth. There is almost certainly an easier (or at least less high-tech) way to make these, but I have absolutely no idea what it is.

[Lee DeRaud]

I am curious, has anyone ever tried to do a continuous spiral like a barbershop pole or candy cane effect on a bowl?Continuous? I doubt it. But if there are more and thinner layers, the curve will be smoother.

(Am I the only one having flashbacks to freshman calculus thinking about that?)

[Jerry Allen]

Lee,
Just saw this post. Kool!
I had started a similar Corel design (attached) in Jan, 2006, but never got around to trying it. I was intending to use as little .25 thk. material as possible.
Are you getting good usage/efficiency when cutting?
Please post a .cdr (if you care to).

[Lee DeRaud]

Are you getting good usage/efficiency when cutting?The cone-shaped ones are pretty efficient: each one takes two pieces of the 6"x12" (nominal) stock for 21 layers. Using 1/4" slices, I'd probably go with fewer/wider rings, probably work out about the same amount of material. These all use (roughly) 0.15" stock, anything over 3/16" makes the shape look too tall.

The rounder shape takes about twice as much (four pieces), leaving a handful of waste disks that could probably be reused for something else. Again, with the thicker stock, I'd leave off the top couple of layers, which would let me do a bowl with three pieces, but the leftovers would be pretty useless.

(Oh, and the reason I use 6"x12"? Bandsaw tops out at 6" of resaw, so that's the limit on bowl diameter. Laser is only 16" wide, so 6"x18" won't work, and 6"x6" just makes life harder than necessary. If I were going to do a lot of these, the first glue-up and resaw step would be on 6"x24" or 6"x36" chunks.)

[Lee DeRaud]

I had started a similar Corel design (attached) in Jan, 2006, but never got around to trying it. I was intending to use as little .25 thk. material as possible.Just took a look at your file...

The original bowl I did last year was done with half-rings glued up like your example on page 2 of the drawing...and blew up three more trying to duplicate it. The glue-up step gets incredibly fussy and very intolerant of tiny variations in stock thickness and glue squeeze-out. And making each ring in more pieces would be even worse.

The solution is either to glue up full rings made from pre-laminated stock (what I did) or glue/true/turn one ring at a time like a "traditional" segmented turning. If I had the patience for that, we wouldn't be having this conversation. :p

[Jim Stoppleworth]

Beautiful bowls ---------Here's hoping the "to be continued" will be a tutorial.:)

Jim

[Jerry Allen]

Thanks Lee.
I had replied from page 1 of this thread and did not notice page 2 which is pretty obvious.
I still have some wood thins I got from George P. for last years ornaments and thought they would make good candidates. According to what you are saying here, I should laminate first and resaw. Got to think about that. I hate doing more work than is necessary. However, that may be faster that trying to glue lots of small pieces and getting them flat.
Based on what I've read on various forums and my experience with CA, I would be hesitant to use it for a bowl. I've had a few cedar and cocobolo box joints come apart under stress, whereas, I've never had aliphatic resin glues come apart using cocobolo and paduak on laminated wine stoppers. Course wine stoppers are small and have a lot of glue surface. What's your take on that?
I might try to do something with the designs from page 1 of my previous post using George's wood thins. Very efficient for up to 5.6" dia.

[Lee DeRaud]

I still have some wood thins I got from George P. for last years ornaments and thought they would make good candidates. According to what you are saying here, I should laminate first and resaw. Got to think about that. I hate doing more work than is necessary. However, that may be faster that trying to glue lots of small pieces and getting them flat.
Based on what I've read on various forums and my experience with CA, I would be hesitant to use it for a bowl. I've had a few cedar and cocobolo box joints come apart under stress, whereas, I've never had aliphatic resin glues come apart using cocobolo and paduak on laminated wine stoppers. Course wine stoppers are small and have a lot of glue surface. What's your take on that?
I might try to do something with the designs from page 1 of my previous post using George's wood thins. Very efficient for up to 5.6" dia.Using George's thins, I was able to make thin sheets without resawing: rip them in half down the middle, stack up the halves and joint one edge, and glue them up in "two-tone" sheets. Clamping is obviously the hard part with stock that thin. And they'll need a pass through a planer or drum sander afterward. Having done it both ways, I'd say the glue/resaw/plane-or-sand sequence shown here is less work if you have a decent bandsaw.

You do get some interesting grain reflection effects just using solid rings of a single species, depending on how much difference there is between endgrain and edgegrain. Again the key to that is offsetting/rotating the rings during the glue-up.

As far as the glue goes, I suspect the problem you had with cocobola and cedar was due to the oil in the wood. The CA works fine if you use the thick stuff...and plenty of it: I averaged almost an ounce per bowl on the batch I did last week. The main issue with the glue-up is that you have 15-20 glue joints and a limited amount of available clamp pressure. The glue jigs I make help with that by keeping everything lined up and providing a place to put the clamp.

[Lee DeRaud]

Please post a .cdr (if you care to).Provided as-is, use at your own risk, some assembly required. Anybody trying this, please read this thread completely and look at the pictures. Also note that the resizing required for the glue jigs to handle different stock thicknesses is somewhat unintuitive.
65953
65954
I hope I don't end up regretting this...

[Jerry Allen]

Thanks Lee.
Hope you don't regret it either. Those with bandsaws and scroll saws should have no trouble. I would anticipate the same format requests as on the laser forum. Anyone could manage without it by reading the entire thread.

That's one hell of a lot of CA!

Still working on cleaning up/organizing my shop and learning to sharpen better. Finally after 4 years I'm getting some great edges. (I get side tracked a lot) My favorite tools are the ones I made from files and tool steel bars and rods from Emco. Other favorites are the drill bit extension using 2" concrete nails ground to various shapes and the various Sorby hollowing tool bits that I mounted on tool steel rods.

[Lee DeRaud]

That's one hell of a lot of CA!I may have overstated it a bit: the 4oz bottle I opened on Monday still has about 20% left in it. Then again, that's not counting the thin CA I use to finish these things. :p

But having two or three of these things blow up on me has made me a bit anal about getting 100% coverage and gap filling. If I was making them any bigger, I'd probably think about switching to a slow-set epoxy.

[Frank Howell]

Beautiful work! I'd get dizzy just trying to glue something like that up.

[Joseph Peacock]

WOW!!!!!!!! That's wild! Yet Very,Very good!:D ;) :cool: