Sunday, April 25, 2010

Sculpting Chairs Part 2 Start with the Hard Lines and a Rasp

Part 1 - "Lines, Shadows and Curves, Oh My!" contained some exercises to help train and improve your sculptor's eye. Let's put the rasp to wood in Part 2 and see what flows from the event.

I see chair sculpting in four phases:
  • Construction
  • Hard Lines
  • Soft Lines
  • Transitions
During the construction phase you make the chair's parts and join them using the band saw, table saw, lathe and other tools. Many of the hard lines are formed by this construction phase which ends with parts joined to each other. But most of these hard lines need to be transformed or sculpted so they form a flow from one part to the other. That is the topic for this article.

Where do I begin. Pick up a tool and see what happens. We are back to the fear problem unless we just jump in
and take a chance. Is everybody going to be good at it? No! There isn't a to risk in comparison to many things we endeavor to do, but a lot to gain by trying.

First find a model for comparison. In my newest "Build A Maloof Inspired" Instructional bundle I do a video segment comparing and contrasting the Maloof Inspired Low Back Dining Chair roughed out, assembled and ready to sculpt and a finished chair. In the comparison I draw what I refer to as topographical lines on the chair to show the way surfaces transition in various radii
to join other surfaces forming hard and soft lines. I used a white pencil on walnut to show these contours. For your own project a mental compare and contrast with a picture of the object you are sculpting would be of great benefit.

When I am unsure of finding my chair's shape in the roughed out parts, I prefer to sculpt my prototypes with a rasp. I use Auriou rasps and the number system I will talk about relates to them. The lower the number the more coarse the higher the number the finer. The Auriou's are hand stitched meaning their teeth are set by hand making that are totally random void of a pattern. The result is that they leave a much smoother cut which will not be furrow or tear-out if the rasp is used correctly. They also have teeth right up to and along the edge,allowing the sculptor to get into corners and crevices. They are a much harder cut on your wallet in that they average $100+ for each rasp. A set of 3 rasps I recommend will take care of a great many of your needs and is available at Highland Woodworking. There are other choices. Sam Maloof used Nicholson's patternmaker's rasp. They are the best of those not hand stitched.

The first rasps I grab are the combi flat #5 on one side #9 on the other and a big #10 cabinetmakers rasp that is curved on one side and flat on the other and comes to a point. cabinetmakers rasp. Work with how they cut on some long scrap. Use big muscles and make long sweeps focusing on holding the rasp at 45 degrees to the length of the piece of wood while pushing the rasp along the length . Do not saw with the rasp. When the cut is cleanest you have found its best working angle. Look at the rasp's teeth and push the teeth in that direction.

While making long sweeps you will be establishing a flat. When I round over a surface with a rasp, I mentally divide the surface into a series of contiguous flats and then join them with flats until they appxoximate a radius that pleases me.

Start with an arm. How do you want the outside line of the arm to flow? Is it going to provide lift is it going to have a sweep and in what direction? A way to answer this question is by deciding whether the flow for the chair from any point of view is going to be generally up and back (uplifting) or down and back, etc.

Are there lines that will flow from the front leg through the arm. Is there a line which will continue into the back leg?

Start with the big rasps, using sweeping, big muscle strokes. Work on it until it smiles at you!

Remember the best tools in your kit are patience, persistence and attitude!

Part 3 will explore the use of a grinder to transform and establish the hard lines when you know where they are and you want to get there in a hurry!

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