Weekend Projects - Art Deco Winged Bowl archive

Friday 23 January 2015

Sue Harker shows you how to make a decoratively shaped Art Deco winged bowl

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When designing a decoratively shaped bowl, such as the one shown in this project, it helps to draw outline shapes and patterns in a sketch pad. These shapes give you a visual aid for how your finished item will look. Once the desired shape has been selected, the profile can then be copied onto a length of timber the correct size. To do this, select a piece of paper the same size as the timber, fold the paper in half and then in half again. Draw a quarter of the profile on one side and cut out. When the paper is opened out, an equal pattern will emerge. The shape is then cut into the blank, before any turning is done. The size of the internal bowl will be dependent on the width of timber being used: I chose a piece of sycamore (Acer pseudoplatanus) measuring 165 x 296 x 50mm, which allows for a reasonable size bowl. Rather than using a square piece of timber, I have used a rectangular piece, which creates two long 'wings'. This makes the turning slightly more difficult, but produces a very pleasing shape. Should you wish to avoid turning uneven shaped timber, this bowl could be turned from a round bowl blank measuring 295mm in diameter and cut to shape once turned.

The decoration I have applied is called 'sgraffito', which is a decorative technique used in pottery, glass and painting. It is where two layers of different colours are used: the top layer is then scratched in to reveal the underneath colour. For this project I have used a black base colour and gold iridescent paint for the top coat. I have used a rubber 'sgraffito' comb, designed for this technique, to scratch a small straight-lined pattern through to the base coat.

To give the decoration an Art Deco feel, I applied some low tac tape in straight lines leading from the edges of the wings to the start of the rim of the bowl, before applying the top coat of paint and creating the pattern. When the tape is removed, solid black lines emerge, which adds to the overall design.

STEP 1

Place your bowl template on a piece of sycamore measuring 165 x 295 x 50mm. Secure in place using pieces of masking tape. You can then draw around the template using a permanent marker pen

STEP 2

The next step, using a bandsaw, with a thin blade fitted, is to cut along the black lines to create the finished shape

STEP 3

You can then drill a hole, the correct size for your jaws into the top face of the bowl blank. Clamp the timber to the pillar drill to hold securely in place while drilling

STEP 4

Mount the timber on the lathe, position the toolrest and secure tightly in place. Stick a piece of masking tape over the toolrest and mark where the edges of the rotating wood start. This will help for positioning your tools for beginning each cut

STEP 5

Cut a spigot the correct size for your jaws. Here I am using a skew chisel laid on its side to create a dovetail

STEP 6

Mark where the underneath of the bowl will be and, working from the outer edge, reduce the thickness of the wings leaving step cuts for the bowl to be shaped - see drawing

STEP 7

When the desired wall thickness has been achieved along the wings, shape the base of the bowl. Cutting from the spigot, with the grain and towards the wings, remove the step cuts produced earlier. Blend the bowl shape into the wings to form a crisp transition. A long-grind 10mm bowl gouge can be used for this

STEP 8

When the shape of the bowl is satisfactory cut a 'V' groove to define the foot. A fingernail-profile spindle gouge is suitable for this and will create a crisply cut groove without torn grain. Sand the bowl section and the solid part of the wings on the lathe working through 120-400 grit abrasives

Sanding the underneath

For the underneath of the bowl start cutting from the outer edge and work towards the centre, leaving step cuts where the bowl shape is to be turned. This will allow the wings to be shaped and cut to the required thickness, while still having the bulk of material left for support. When the wings are the required thickness you can start to shape the bowl - a rough profile of the bowl shape should be evident from the step cuts being left, while cutting the wings. To refine the shape of the bowl, start cutting from the centre, removing the step cuts as you go. Blend the transition between the bowl and wings.

A long-grind bowl gouge is used for this. Start at the foot and using a bevel supported cut, work towards the wings. The tool is then rotated to shear scrape the solid section of the wings. This is done by rotating the flute of the tool towards the wing, lowering the handle to bring the swept-back grind of the tool into contact with the solid section of the wings. The transition from bevel supported cut to shear scraping is done in one fluid movement to create a clean cut. Do not shear scrape beyond the solid section of timber; this section will be hand sanded off the lathe using a sanding block.

STEP 9

Remove the bowl from the lathe and apply masking tape to the sanded bowl section, this will protect it from being scratched when sanding the wings. Using a large sanding arbor or similar, hand sand the wings. This is easier when sat on a flat surface covered with non-slip matting. Sand in the direction of the grain and work through your usual grits ensuring all marks are removed before progressing to the next grit

STEP 10

Mount the bowl on the lathe, using the chucking spigot cut earlier and true up the front face

STEP 11

Remove from the lathe and hand sand the surface, using the same grits and process as for the underside. Paint with acrylic black paint mixed with flow medium. This will produce a smooth coat, which will only need a gentle rub with 1,000 grit abrasive when dry, to remove any imperfections

STEP 12

Mount the bowl on the lathe and cut a 'V' groove, through to clean timber, at a diameter of 135mm. A three-point tool is used for this

STEP 13

Apply strips of 3mm-wide low tac tape running from the outer edges of the wings to the 'V' groove. Stick some masking tape around the 'V' groove to avoid contaminating with paint

STEP 14

Apply a thick coat of gold iridescent paint mixed with flow medium to the surface and using a sgraffito comb, scribe a crisscross pattern into the paint. This removes the gold paint revealing the black base coat and creates a pleasing pattern

Colouring effect

For this paint effect I have used Jo Sonja acrylic paints. I used black for the base coat and iridescent gold for the top coat. Both have been mixed with flow medium, which 'waters down' the paint without it losing its viscosity. The thinner paint allows you to achieve a smooth, flat finish. Once the base coat is dry, sand gently with 1,000 grit abrasive, this will remove any blemishes. Clean the surface with tac cloth and apply some 3mm-wide low tac tape in straight lines from the outer edges to the cut groove. The tape needs to be securely adhered to the surface to prevent seepage; however, should seepage occur, this can be easily touched up with black paint once the finished pattern is fully dry. Apply some masking tape around the 'V' groove, pushing the edges into the groove; this will stop the gold paint from soiling the groove.

Iridescent paint is milky in appearance, only showing its colour when applied to a dark surface. If applied thickly this milky appearance remains. For the sgraffito technique a thick coat of paint is required and to prolong the working time requires mixing with flow medium. Apply to one wing at a time and create the crisscross pattern with a rubber sgraffito comb. The comb removes the wet paint, leaving the base coat showing through. Allow the paint to dry thoroughly before removing the masking tape to reveal crisp black lines.

When trying a new painting technique it helps to practice on a scrap piece of wood to help you perfect the technique before applying it to your turning. If you don't like the pattern or choice of colours you can black out and try another combination.

STEP 15

When the paint is dry, remove the masking tape to reveal the black lines. If any gold paint has seeped under the tape, this can be touched up

STEP 16

Next, remove the centre of the bowl leaving a 2mm wide ring of black paint at the rim. A 10mm standard-grind bowl gouge is used for this. Create a small cove leading from the ring of black to the start of the bowl. Sand the bowl centre using the same grits as before

STEP 17

With the bowl still on the lathe and with the spindle locked in position, hand sand the edges of the bowl. This will remove excess paint and also smooth any bandsaw blade marks. Work through all the grits using a sanding arbor for support. Try to avoid rounding over the edges at this stage

STEP 18

Remount the bowl using your preferred method and remove the chucking point: Here I am using a vacuum chuck, which allows the taildrive to be removed giving better access to the foot

STEP 19

To finish the bowl, apply several coats of finishing oil. The finished project should look something like this


Woodworkers Institute

Tagged In:

Sue Harker , Weekend Projects


Diagrams Click an image to enlarge

Information

TIME TAKEN & COST
Time taken: 3.5 hours
Cost: Approximately £7
TOOLS REQUIRED
3mm parting tool
10mm standard-grind bowl gouge
13mm standard-grind bowl gouge
10mm fingernail profile bowl gouge
12mm flat sided, skew chisel
Three-point tool
ADDITIONAL TOOLS
Jo Sonja acrylic paints and flow medium
Sgraffito comb
Finishing oil
120-400 grit abrasives
Rotary sander
Battery drill with sanding arbor fitted
Large sanding arbor/block
PPE: facemask, respirator/dust mask and extraction
TIMBER REQUIREMENTS
A piece of sycamore (Acer pseudoplatanus) - 165 x 295 x 50mm

Health & Safety

It is very important to be aware of where your hands and arms are at all times when turning a rectangular piece of timber.
The toolrest needs to be secured tightly, allowing the wood to rotate freely. Ensure your fingers, hands and arms do not hang over the toolrest at any time. Always rotate the wood before turning on the lathe to check it does not catch the toolrest. The speed of the lathe should be as fast as the lathe will allow for this amount of imbalance: the lathe should rotate the wood without vibration. I ran my lathe at 1,500rpm; however, the speed of your lathe may vary. Always allow the lathe to stop rotating on its own or use a flywheel to stop it, if you have one. You should never try to stop the lathe by getting hold of the rotating wood, especially when the timber being turned is not round.
Place a piece of masking tape or similar on the toolrest and draw a reference mark in line with the longest part of the timber. This will help with locating the starting point when taking cuts. Position your bowl gouge slightly to the left of the reference mark and gently feed into the timber. The bevel of the gouge should be gently rubbing along the surface of the wood. Once the cut has started, travel along the toolrest slowly in a smooth movement, this will create a flat surface. If you apply too much pressure to the cut, the tool will bounce and prevent you from cutting efficiently

Handy Hints

1. The winged bowl shape proves difficult to sand. When the timber is rotating, there is a lot of air between the solid timber wings. This space makes it unsafe for attempting to sand while rotating, so sanding either off the lathe or with the spindle lock secured will be required. Use a sanding block of some description to help maintain a flat surface and try to avoid rounding over the edges. The inside and outside of the bowl can be sanded with the lathe rotating using your usual sanding method, taking care to stay within the solid sections
2. When applying oil to your work, take it into an environment that is as dust free as possible. Coating in your workshop at the end of a turning session will result in the very fine particles of dust in the air settling onto the wet oil and this will create a rough surface, which will require re-sanding before another coat can be applied
3. When sufficient oil has been applied and it is totally dry, the centre of the bowl can be buffed using Tripoli compound on a bowl buffing mop, and the underneath and wings can be buffed using a buffing wheel should you wish