Diamond Rim Bowl archive

Tuesday 20 April 2010

Nick Arnull creates this stunning diamond rim bowl from a piece of English sycamore using various power carving techniques

Gallery

When discussing my next group of articles with Mark, he saw this piece on exhibition and said, "I want that piece for an article." So this month I am going to keep him happy.

This piece is part of a group that, today, I refer to as 'The Geometric Series.' This group of work is one that is still evolving.

I think one of the hardest elements to overcome was that of confidence when doing the initial carving and sometimes knowing where next to take the piece. Sometimes the idea starts as not very much at all: it could be referred to as a seed of an idea that needs to be nurtured and developed, and maybe you even need to wait for a eureka moment to happen.

With this group, I also gained some inspiration from the work of Al Stirt and Hayley Smith.

For this project, as well as the turning tools, you will need an Axminster multi-tool, or equivalent, a reciprocating power carver, as well as a range of acrylic-based finishes.

Tools used

10mm (3/8in) long-grind bowl gouge, 6mm (1/4in) spare-grind bowl gouge, French-curve bowl finishing scraper, 12mm (1/2in) round skew chisel, 6mm (1/4in) parting tool and 10m (3/8in) point tool

Step 1

For this project you will need an English sycamore blank measuring 255 x 50mm (10 x 2in). Mount the blank on the lathe and, using a 10mm (3/8in) long-grind bowl gouge, remove the material to create the desired shape

Step 2

Use dividers to mark the diameter of the spigot that will hold the bowl in the chuck when reversed

Step 3

Using a 6mm (1/4in) parting tool plunge into the blank outside the line and create the spigot for your chucking method

Step 4

Using the 10mm (3/8in) long-grind bowl gouge remove the excess material and blend the surfaces together

Step 5

Refine the bottom of the spigot and dish it out - this will make the piece more attractive and also more stable when placed upon a flat surface

Step 6

Use a 6mm (1/4in) square-grind bowl gouge to refine the shape and try to achieve one continuous cut

Step 7

Using the 10mm (3/8in) long-grind gouge true the edge of the blank

Step 8

Using a round skew chisel create a dovetail on the outside edge of the spigot to match your chuck. Now use the round skew as a scraper, rotated to approximately 45 degrees to allow you to shear-scrape the outside of the bowl. Note: this is an advanced technique

Step 9

Reduce the lathe speed and sand with the abrasive of your choice

Step 10

Seal the surface with acrylic sanding sealer - multiple light coats are always best at this stage

Step 11

De-nib the surface of the blank using fine wire wool

Step 12

Ebonise using acrylic matt black spray paint. Again, light coats are best, then allow the piece to dry naturally

Step 13

Cover with acrylic satin lacquer and then allow to dry

Step 14

Remove the piece from the screw chuck, mount in the chuck and true the rim of the bowl flat

Step 15

Sand the piece flat using a hard-faced sanding block

Rim layout

Step 16

The rim is marked out using a black watercolour pencil. You will also need a 255mm (10in) diameter disc/template to allow you to create the arcs that will create the diamonds. Mark three lines 5mm (1/4n), 60mm (2 3/8in) and 65mm (2 5/8in), then, using the point tool, score two of the lines - these will create the start and stop cuts for the power carving. Do not score the innermost line - this is where the bowl will start/finish. This is very important for that defined look to a piece, as it will frame the carved and decorated area

Step 17

Using the indexing head divide the rim into 24 with the toolrest set on centre to ensure the lines are perfectly radial. At this point, transfer the chuck and the piece to the carving clamp. Set the clamp at a comfortable angle and height

Step 18

Set the template between the radial lines and then continue to draw them in

Step 19

Now set the template to the left and the diamonds will appear. You can shade in the areas to be textured and this will help avoid any potential mistakes

Carving and texturing

Step 20

When carving I use a power gouge - there are several on the market - mine is a Ryobi tool, which I have had for many years, it is fitted with a Flexcut V gouge. The key to good detail is to always keep it sharp. Carve the first line to the right starting on the outside and working in to the centre. Try to get one smooth flowing movement without any changes in the direction of cut

Step 21

Now carve the second line to the right - I find this a little more difficult. Here you can see the previous geometric design simply carved, with no added decoration

Step 22

Using a flex-shaft rotary tool fitted with a rotary hand-piece and a very small good quality round burr set at the slowest speed, place your hand comfortably in the centre of the piece and begin to create a figure-of-eight random texture to relieve the remaining panels. Take great care not to damage the carved edges

Step 23

With all the texturing finished it will require some cleanup - this is sensitively completed using a radial sanding brush fitted to a standard rotary drill. Pulse the motor, as it will keep the bristles softer than if run at speed

Step 24

Here is the finished uncoloured piece. At this stage take some time, look for any mistakes, and if needed, refine them to produce clean edges and detail

Step 25

Using a hard-faced sanding block and fine abrasive gently sand the face with the grain. Keep the block absolutely flat or the edges will become rounded

Step 26

Using a soft long-haired bristle brush apply multiple coats of liquid acrylic black. When the black is dry remove it from the carving clamp and return it to the lathe spindle

Step 27

Seal with acrylic satin lacquer and apply multiple coats to the rim at this stage. Rotate the piece by hand, and as you do so this will allow good and even coverage

Turning out the centre

Step 28

At this stage you must ensure that your tool control is spot on. There is no room for error when making the entry cuts at the edge of the inner bowl. Remove the centre of the bowl working out to the line made earlier to define the edge of the bowl, using the long-grind 10mm (3/8in) bowl gouge

Step 29

With a freshly sharpened French-curve bowl scraper refine the inside of the bowl - gently does it here. Use only the lightest of touches and it will do the job for you

Step 30

Sand the bowl but be very careful at the intersection between the rim and the inner bowl. This needs to be kept crisp and does not want softening as it will lose its definition

Step 31

Shear-sand the bowl and this will remove/disguise any radial sanding marks there may be

Step 32

With the sanding complete seal, de-nib and lacquer the bowl with multiple light coats, then extend the spraying to cover the rim to produce one even surface. Allow the bowl to dry for about an hour before moving on to the next stage

Step 33

Apply burnishing cream to the bowl whilst it is stationary. Do not get any cream over the top edge, as it is not very easy to remove. The bowl is now complete

Step 34

A close-up view of the bowl rim


Woodworkers Institute

Tagged In:

Bowl , Nick Arnull , decorative , rim

Glossary Rollover a term to view its definition

Bowl Gouge , Parting Tool , Skew Chisel , Spigot

Handy Hints

1. When sanding, reduce lathe rotation, as is necessary.
2. Do not use old or tired abrasive - it is false economy.
3. Use a shear sander to disguise any radial sanding marks made when you are hand-sanding.
4. Use water to raise the grain before final sanding
5. Use a soft watercolour pencil when marking out to avoid disappointment at a later stage.
6. Always sharpen your tools when taking a final cut.
7. Try adding a secondary bevel to your gouges and see what difference this can make to your turning.
8. Allow adequate time for coats of lacquer/sealers to fully dry.
9. Use multiple light coats and build up the layers.
10. Use burnishing cream to give differing types of refraction/shine to your work and include these in one of your pieces.
11. Do not be content with the finish as it comes out of the can - experiment further
12. When creating carved areas do not settle for sub-standard details. Take your time and do your best.
13. Check all detail before applying colour to the piece. If needed, refine.
14. When creating decorated pieces use the cleanest timber you can

Diagrams Click an image to enlarge