Inlaying With Semi Precious Stones
Thursday 01 April 2010
Patricia Spero inlays a walnut Chinese style bowl with semi precious stones
The Chinese have been using semi-precious stone inlays and carving on their furniture since the early Qing dynasty of the 17th century, when the trend was more towards decorative and luxurious furnishings. The Japanese also used mother of pearl and ivory inlays in flower and bird motifs on 18th century cabinets.
I decided to make a bowl using a 255mm (10in) walnut blank with pedestal, and then inlaid the centre with an oriental design of lotus flowers and butterflies. For this I used crushed semi-precious stones in a variety of colours. As walnut is a dark wood, the inlaid colours had to be bright in order to show up so I opted for turquoise, azurite, malachite and amber. I also had some accents of powdered brass, quartz, calcite and alabaster. Light wood such as sycamore (Acer spp) allows more freedom when choosing your inlay colours.
Choose a walnut blank with dimensions as follows: maximum diameter 240mm (9 1/2in), width of rim 12mm (1/2in), height of bowl 80mm (3 1/8in), diameter of base 82mm (3 1/4n), diameter of neck 60mm (2 3/8in), inside depth 30mm (1 1/8in). Next, turn the inside of the bowl using a 13mm (1/2in) bowl gouge
Once the bowl has been turned, sand and finish it in preparation for the inlaying process
Pick a design you like and ensure it is copyright free beforehand. Then, gradually enlarge the chosen design using a photocopier and make into a stencil using a Presto handpiece or Dremel. Burn through the paper to make your design
The finished cut-out design should look like this, depending on your individual choice of pattern. You must decide here how large you want the individual flower petals and ensure you keep some wood between them to contain the different colours
Secure the stencil to the centre of the bowl with masking tape, and draw through the holes to transfer the design onto the wood. Do not use a pen or a hard pencil to do this, as lines made with these will make a permanent impression
Remove the stencil from the bowl to reveal the design. Use a Presto hand piece, dental drill or Dremel with a fine burr to outline the design
Cut out the petals using a thicker burr, and continue until the whole pattern has been outlined
Now that the outline has been completed, the bowl is ready to be inlaid
To make the stones useable as an inlay, first crush them using a 25mm (1in) steel rod on a metal tray, with a piece of plastic drainpipe to contain them. You need to do this on a firm surface such as the lathe bed. Some of the stones are softer than others, so don't worry if you are left with some small pieces of stone rather than a powder as you can use the larger pieces first and then fill in with the finer powder
Wnen you have finished crushing the individual stones, they should look like this in terms of powdered consistency
Before starting to apply the stones, cover the surface with a coat of wax to prevent the glue from staining the wood. Then fill in the design on the bowl with the coloured stones and fix the powdered stones with thin cyanoacrylate. Fill in one petal at a time and then glue it to stop the colours mixing together. Keep the bowl in the chuck at all times, as it will need to come off and on the lathe for sanding and for adding extra stones
Once you have inlaid all the powdered stone and filled in all the gaps, the bowl is ready for the initial sanding
When you are satisfied with the inlays, power sand the surface with 80 grit sandpaper. You will need a coarse grit to cut through the stones and smooth them, so do not worry about sanding the inside of the bowl before you inlay it. Finish by hand sanding any overspill or glue marks. You will probably find that you have to redo some of the inlays as the stones often fall out, or there are holes that need to be filled with very fine-ground stones. Next, sand the inside of the bowl through the grits from 120 to 600, using sanding sealer between each grit, and finish by polishing with a liquid wax
Fit the bowl on a large button chuck and reshape the foot to make a smoother line with the rest of the pedestal. This is then sanded and polished with wax
When the sanding and polishing is finished, the bowl is complete.