My Third Piece - A Segmented Bowl with WIP

[Hardenfast]

I have been encouraged by the many contributors here who provide excellent, detailed Work In Progress pictures of their projects to attempt the same myself. Flushed with some level of success with my first project, which was a segmented bowl in various Australian hardwoods, I was feeling adventurous enough to try something a little more challenging.

My brother recently gave me some reclaimed timbers from a renovation he was doing on a 100+ years old terrace house in Surry Hills (Sydney). There were some pieces of handrail section, newel post & balusters which were definitely Australian Cedar, and some sections of stair stringer and tread which were identified as Kauri Pine with the assistance of forum advice.

Anyway, I decided these would be the two contrasting timbers in a segmented bowl, so away I went with no specific plan or shape in mind. First of all I ripped up a couple of the Cedar balusters, but by the time I had cut away the rounded sections there was only a square section of around 25mm x 25mm


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No worries, I was starting to formulate an idea - I would use this in short vertical lengths alternating with the Kauri for contrast to form the centre section of the bowl. To create the round shape of the bowl it was necessary to "cooper" the pieces (ie. narrower on the inside edge) in the same manner a wine keg is made. I played around with a few different angles and then ran the sections of Cedar through the rip saw again creating a tapered bevel, and then docked it into lengths about 80mm long.

To facilitate the bowl shape being wider at the top I had to create a wedge shape out of the Kauri for the alternating pieces. I used a rough wedge cutting jig & cut out plenty of these pieces on the mitre saw, and then starting glueing the pieces together into 4 quadrant segments. Once the segments were dry I fitted them together into the overall round section. I cut up some bigger sections of the Cedar (70x20) from a newel post for 2x horizontal laminations to the top of the bowl. I did the same thing out of Kauri, making the bottom layer a bit thicker (35mm) so I had a bit of "meat" to play with. This was somewhat fortuitous as you will see hereunder.


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Once the centre laminated section had dried I squared off the top and bottom and glued it to the bottom bowl section which was from a solid piece of Kauri. Once dry I stuck this on the lathe by chucking the inside and turned the bottom & outside of the piece, as I figured it would be too deep once I joined the top laminations on. Note the old staple holes in the Kauri at the bottom of the piece:


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I then glued the top laminations on, which had been previously assembled into hexagonal "rings". For the whole process I used only Selleys "Tradesmans Choice" white glue, although I had a little trepidation about the end-grain joint letting go - particularly once I started to thin the piece down. However, no probs whatsoever.

I have run out of picture uploads so will continue in another thread.

[Hardenfast]

I didn't bother with a press to glue the top laminations on - I just made sure they fitted nicely and layed them down layer by layer upside down. I sat a tin of paint on top of the lot overnight while it dried. And there it was:


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I stuck it back on the chuck when dry, using the previously formed base hollow. The Leady lathe I have came with a "split ring" chuck which tightens by hand and only needs a very shallow recess to grip. Unfortunately, the much greater circumference of the piece now (with the top sections attached) - combined with an over-aggressive gouge in the roughing process - caused the bottom grip to break out the edge of the Kauri. Bugger!


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Undaunted, I drilled the recess a little deeper with a Forstner bit, re-chucked it, and off I went again, this time using a little more caution. Man, after the last bowl I did which was out of very dry Bluegum and Tallowood, this stuff cuts like butter! Shaping - checking thickness. Shaping - checking thickness:


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I was a little paranoid about the glue letting go at the end grain joint once the thickness was reduced, but as I said earlier there was no problem getting it down to an overall 6mm approximate thickness.

One more post to follow with finished pics. Hope I'm not boring the bejesus out of you all. By the way, note the nifty chisel rack I knocked up. I bought 2 TV swivel brackets from eBay and have set one up on each lathe cabinet. They can be moved any which-way and are really handy. Not my idea though - I got the idea from somebody here - can't remember who.

[Hardenfast]

It didn't take too long to shape the piece. I really just followed the form dictated by the glued-up layout. I was quite happy with the final outline:


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It probably looks like a lot of trouble to make this, and I guess it was. However, the preparation in ripping up the sections and cutting the wedges only took around 20 minutes and most of the glue-up work I did between other projects, leaving the pieces to dry while doing other things.

I sanded it up through the different grits to 400, then gave it a quick rub with EEE - followed by one good, heavy coat of Shellawax. Overall size is 320mm diameter by 150mm high. It seems fairly unique in my limited experience - I haven't yet seen another one employing the same structure and techniques.


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I like the segmented technique for a couple of reasons. Mainly because it allows you to be quite creative in the materials used, and you're able to use up all of the stuff that would normally end up in the waste bin. Also, there is far less material to remove once you start turning, as the shape is largely pre-formed and hollowed by the assembly process. Just my thoughts.

So, project number 3 now sits on the dining table. Back to the retaining wall project for me now, for a while anyway. Let me know what you think.


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Regards. Wayne

[Skew ChiDAMN!!]

Nice work. You didn't have any problems with the different density timbers when sanding?

[macca2]

Very nice.

macca

[Hardenfast]

Nice work. You didn't have any problems with the different density timbers when sanding?

Thanks Macca & Skew. No major probs with the sanding process, although as you know it can be a little tricky when one timber is a little softer or differently textured to the another.

One thing I have noted from my previous laminated bowl is that the different timbers can/will move differentially, just a little, even after the piece is finished and sealed. Whilst it was impossible to feel any ridge between the joints when first finished, I have noted that there is now (3 months later) a very slight prominence from one species to the other. It was perfectly smooth when completed.

It can only be felt - not seen - so does not detract from the appearance. Minor point - but a reminder as to the ever changing nature of timber - even when fully seasoned. Atmospheric and seasonal forces at work on a porous, cellular material ad-infinitum, I guess.

Thanks also for compiling my 3 posts into 1, mods. Much better!

[chrisb691]

Nice job Wayne, looks good. :2tsup:

[Wood Butcher]

Thanks also for compiling my 3 posts into 1, mods. Much better!

No probs. It is a good WIP that will be very useful to members.

[Manuka Jock]

Choice job there Wayne ,
I'm not a segmented person myself , but that one , especially the octagonal rim , does it for me . :2tsup:

I like your toolrack too , black with concrete wash huh. :p

cheers ,
Jock

[Skew ChiDAMN!!]

One thing I have noted from my previous laminated bowl is that the different timbers can/will move differentially, just a little, even after the piece is finished and sealed. Whilst it was impossible to feel any ridge between the joints when first finished, I have noted that there is now (3 months later) a very slight prominence from one species to the other. It was perfectly smooth when completed.

I've been told that if you start with a circular base, and build up your laminations from the outside edge instead of "on top of the edge" that this movement can lead to severe cracking or even the failure of the piece. :oo:

Not something I'd know from personal experience, but wouldn't it really you off to lose a piece over such a simple thing?

[Harry72]

Nice work H&F!

[thefixer]

Geez I'm humbled . Magnificent work and bloody good mathematics as well. Top stuff.

Cheers
Shorty

[joe greiner]

Very well done, Wayne. Good recycling effort, and a beautiful finish.

The term of art for your coopering process is also known as "stave segmenting;" not sure if that still applies to shorter staves as you used. Your top rings would gain more structural integrity if each ring were rotated by a half segment with respect to its neighbour, like running bond in brickwork, because of more side-grain purchase and less reliance on end-grain gluing. For your design, this would work with only one ring maintaining its hexagonal shape, as you made it.

Joe

[Sebastiaan56]

Very nice Wayne, something to aspire to,

Sebastiaan

[Rookie]

Beautiful piece Wayne. My BIL asked me to "make something" with some Huon Pine and Blackwood that he bought in a sample pack when touring Tassie. I've been struggling with what to do with it but you have given me a few ideas with this. Thanks.

[Hardenfast]

Thanks for the comments, Gents - all much appreciated.

Joe; stave segmenting? Is that what I did? It actually didn't take too long as I was able to run the full stick along the angled rip saw, and then dock the pieces to length already "staved". I believe that in barrel making the coopers generally do this by hand as their staves are of course bow shaped to suit the barrel. Still, it was an interesting process to work out the angles and and resulting profiles.

I actually considered staggering the laps on the top rings for greater structural integrity as you've suggested, but decided the appearance may be better to have them aligned - as can be clearly seen in the second last photo.

I originally intended to shape the top of the top of the bowl in the round, but quite liked the hexagonal shape as the work progressed so just worked around that. It was a little more work as the hexagon had to be carefully resized for symmetry after the turning process, but I think it really suits the piece.

Wayne