CONSTRUCTION FFEATURES OF FURNITURE

UNIT – 4

CONSTRUCTION FEATURES OF FURNITURE –

SHAPING –

Shaping wood is intrinsic to woodworking. Unless you are making tree-shaped objects, a series of cuts is always required. Beyond the basic square, there are a variety of tools and techniques for shaping furniture parts.

The Basics:

·         Hand-shaped parts: Files, rasps, and planes are for shaping everything non-square.

·         Shaped with power tools: Templates, jigs, and fixtures are essential.

Hand-shaped parts: - When shaping furniture parts, most of the time, hand tools are required to finish the job, whether it's scooping out a chair seat with planes or softening an edge with files and rasps. A cabriole leg requires hand tools to blend the transition from the turned leg to the pad foot, and a ladder-back chair requires using a drawknife to shape the spindles. For most of these tasks, power tools can't do the job with the quality and character that hand tools can impart.

Shaped with power tools: - There are many common techniques for shaping furniture with tools available to woodworkers. The tablesaw can cut large-radius cove molding by setting up a fence that guides stock diagonally across the tablesaw blade. And a router can cut any conceivable shape with templates made of plywood, MDF, or Masonite.

CARVING –

Primarily an ornamental treatment today, carving on furniture has its origin in purely practical reasons, such as the need to shed water, prevent dust buildup, disguise joints, or provide softer edges. Similar to molding, which may be thought of as a form of carving, carvings evolved to lessen the chance of damage, either to the woodwork or the user.

Chip carving is one if the oldest and simplest carving techniques used in woodworking. The technique uses a short-bladed knife to cut intricate designs and complicated geometric patterns through a series of triangular incisions in wood.

Relief carving comes in two styles: high relief, which uses deep cuts to decorate a piece with a pattern or design; and low relief, a similar technique with a shallower cut. These techniques can be used in a variety of projects, from chair backs to painting-like wall hangings.

Fretwork is a style of carving that produces intertwining designs. It is done either as a relief carving on a background, or with a coping saw and carving tools to produce a design with open space.

TURNING –

Woodturning is a form of woodworking that is used to create wooden objects on a lathe. Woodturning differs from most other forms of woodworking in that the wood is moving while a stationary tool is used to cut and shape it. Many intricate shapes and designs can be made by turning wood.

There are two distinct methods of turning wood: spindle turning and bowl or faceplate turning. Their key difference is in the orientation of the wood grain, relative to the axis of the lathe. This variation in orientation changes the tools and techniques used.

In spindle turning, the grain runs lengthways along the lathe bed, as if a log was mounted in the lathe. Grain is thus always perpendicular to the direction of rotation under the tool.

In bowl turning, the grain runs at right angles to the axis, as if a plank were mounted across the chuck. When a bowl blank rotates, the angle that the grain makes with the cutting tool continually changes between the easy cuts of lengthways and downwards across the grain to two places per rotation where the tool is cutting across the grain and even upwards across it. This varying grain angle limits some of the tools that may be used and requires additional skill in order to cope with it.

Most bowls, platters and many vessels are face plate turned, while pens, furniture legs, spindles, and some vessels are spindle turned. The method used may differ depending on the shape of the blank and the technique of the turner, and both methods may be used on the same piece.

FLUTING –

Term applied to shallow, hollowed out grooves which are always vertical. They can either run from the top to the bottom of a post, or side by side. Sometimes, the flutes are partly filled by a small, round, convex molding, or bead, and are then known as cabled; this decoration does not usually extend higher than one-third of the shaft.

Fluted legs tend toward a more formal statement that can be very appealing on dining table legs or sofa legs.  Even kitchen island legs can reflect refinement when fluted.  The fluting also reinforces the verticality of the leg and adds a pleasant note of refinement.  Fluted legs are a useful choice when working on projects in which you want to create a historical reference.  They will lend themselves easily to work in which you want the feeling of finer styles of eighteenth and nineteenth century English furniture as a fluted leg would be seen on examples of Chippendale, Hepplewhite and Sheraton pieces.  In order to create a strong sense of these styles the usual wood choices would be mahogany, walnut or cherry.

Another piece that presents attractively with a fluted leg is the standard tea table.  Several styles of drop-leaf table also show very nicely with this style of leg.  Although more usually associated with a square tapered leg, a few Sheraton pieces are known to have been produced with turned and fluted legs.  In particular there is a very fine example of a later Sheraton sideboard that sports this leg as well as some of the sofas produced by Sheraton just prior to the period of Empire furniture.  There are also examples of tri-foot small tables known as candle stands on which the single central support is a fluted leg.

FINISHING –

Wood finishing refers to the process of refining or protecting a wooden surface, especially in the production of furniture. Although staining furniture is optional, applying a finish is essential to protect the wood's surface. Without a finish, wood can dry, crack and deteriorate or -- if exposed to moisture -- swell so that drawers and doors no longer work. A good finish prevents swelling and cracking, protects against stains and enhances the appearance of the wood.

Process:

Wood finishing starts with sanding either by hand (typically using a sanding block or power sander), scraping, or planing. Imperfections or nail holes on the surface may be filled using wood putty or pores may be filled using wood filler. Often, the wood's color is changed by staining, bleaching, or any of a number of other techniques.

Once the wood surface is prepared and stained, the finish is applied. It usually consists of several coats of wax, shellac, drying oil, lacquer, varnish, or paint, and each coat is typically followed by sanding.

Finally, the surface may be polished or buffed using steel wool, pumice, rotten stone or other materials, depending on the shine desired. Often, a final coat of wax is applied over the finish to add a degree of protection.

Types of Finishes:

All finishes can be divided into two categories: penetrating finishes (those that dry inside the wood) and surface finishes (those that dry on the surface of the wood).

Penetrating finishes: - These are easier to apply and leave a more natural look. Surface finishes are more durable but don't look as natural.

Linseed oil is one of the oldest penetrating finishes, but it tends to become sticky in humid weather. Danish oils also fit into the category of penetrating finishes. Tung oil is a favorite among woodworkers because it's easy to apply and leaves an attractive, natural appearance.

Apply tung oil with a rag rather than a brush. Tung oil provides a thin layer of protection that's suitable for fine antiques and other pieces that won't receive much wear.

Surface Finishes: - Although they don't look as natural as penetrating finishes, surface finishes provide more durable protection. They're a better choice for everyday pieces that will receive a lot of wear.

Unlike tung oil, which dries inside the wood, surface finishes such as shellac and varnish dry on top of the wood to create a protective coating.

Surface finishes are applied with brushes rather than rags, and a variety of brushes are available -- each with different attributes. Oil-based finishes may be applied with a natural brush or a synthetic one. Apply water-based finishes with a synthetic brush, as water may cause natural bristles to swell and become useless.

Shellac is a quick-drying surface finish used fairly infrequently today because it isn't very resistant to water or alcohol. Varnishes offer much better protection, and the toughest of them is polyurethane.

Polyurethane varnish is oil-based, so it may be applied with a natural or a synthetic brush.

                                                                                                      by

                                                                                    VIJAYALAKSHMI.N

                                             HEAD DEPARTMENT OF INTERIOR DESIGN AND DECOR