MCW Feb. '14 Program
Feb 20, 2014Public
Photo: Program Chair, Mike Colella, introduces our demonstrator for he evening, Mr. William Peirce.
Photo: Bill is a craft artist in the DC area specializing in building wooden vessels from boards, and he is here to tell us all about how he does it.
Photo: This is a laminated board, made by gluing up pieces of two wood species, that has been cut on a band saw into specially-angled concentric circles.  With a simple reorganization, it will become a vessel with a parabolic banded pattern, as follows.
Photo: Bill first discusses the basic band saw cuts.
Photo: The key to the whole process is the careful design of the angles of the cuts.  The bottom of each segment has to be the same diameter as the top of each next inner segment.  The individual angles (not all the same) of the concentric cuts determine the incremental slope of the bowl wall.
Photo: Bill begins the transformation from 2D to 3D by moving inner segments underneath...
Photo: ...where they magically support each other to become a manifest vessel!
Photo: This is how it "stacks up".
Photo: Bill learned how to make "bandsaw bowls" from a 1983 article in FWW by Peter Petrochko.  He notes that a current, well-known practicioner of this type of work for lathe-turned objects is Michael Mode.  Here, Bill further discuses the effects of varying angles of the band-saw cuts.
Photo: Bill glues scrap pieces on the edge of the boards before he puts them through the planer.
Photo: Here's the biased, band-saw entry point needed to get the saw blade inside to cut the periphery of the next successive ring.
Photo: Bill glues the segments together, first clamped in pairs.  Then those groupings are glued and clamped until all layers become a raw vessel form.
Photo: Bill then sands the vessels to shape, inside and out, using this sanding mandrel held in a drill press.  As woodturners, we would put the raw vessel form on the lathe at that point, much as would be done with a standard segmented glue-up.  In our case, the vessel would have to be round.  Bill can cut his vessels into various shapes, including kidneys, which he would only be able to do with his sanding methods.  He begins at 36 grit and works up to 400.
Photo: Here's an example of a kidney shape.
Photo: The segments may be from a single, solid board, in which case Bill may try to underplay the existense of the bandsaw entry kerfs, leading to a bowl like this that emphasizes the basic, natural grain patterns of the board, ...
Photo: ...as seen here being examined by Marge, ...
Photo: ...or the kerfs may be highlighted with a contrasting wood, as in this complex example laminated from multiple wood species.
Photo: One of the quirks of this method is that, if the pattern is lined up on one side, it will be slightly misaligned on the other. Splitting the difference leads to a stair-stepped pattern which may or may not be desired.
Photo: Gluing in alternating layers of a contrasting wood between segments separates the edges of the pattern in such a way that the human eye-brain combination completes smooth curves for the ascending pattern, as in the vessel in Bill's right hand and not the one in his left.
Photo: The patterns that can be created are as endless as ones imagination.  A simple board glued up with a light half and a dark half can yield this kind of bowl when the rings are successively rotated 180 degrees.
Photo: Of course, glue ups can be very complex, with many small pieces glued together to form a board with patterns...
Photo: ...such as this one.
Photo: Lots of time can be spent experimenting with glue ups in all sizes and shapes.
Photo: Interesting optical effects result.  Is this 2D or 3D?  Does it matter?