Making a Fire Ball
Words: Neil Turner
Photos: Suellen Turner
Some years ago I made a hollow carved sphere like the one shown here and was asked if I could make another for a collector. This provided an opportunity to talk through the process used to achieve the final result.
Make a template for the sphere
When turning a sphere, the most crucial thing to bear in mind is that it has to be a sphere. To assist with this fundamental aim, make a template out of any thin material, in this case, 3mm MDF. The easiest way to do this is to cut out a 210mm diameter rough round shape on the bandsaw. I marked the centre with a centre punch, and then drew a 160mm diameter circle with a compass.
Using a faceplate with some sort of friction drive, hold the MDF circle in position with the tailstock and then true the outside with a parting tool. Use the same tool to part off the ring with the marked circle acting as a guide. If you divide the ring into thirds and then cut out one you now have your template.
Turn the outer form
Place a piece of timber with the grain direction running parallel to the bed, larger than the diameter and longer than required between centres, in this case, black fleck jarrah.
Using a roughing gouge or bowl gouge with the tailstock in support, turn off the corners and create the spigot the shark jaws 70mm diameter and 28mm long. Don’t turn to your required diameter; this will be done when it is remounted in the chuck. I often just use a skew chisel in a scraping position to tidy the spigot and slightly undercut the surface that contacts the jaws when tightened, providing maximum holding potential.
1. Mark a line 80mm from the tailstock, then another 80mm on the other side of centre.
Remount the blank in the chuck fitted with shark jaws, use the tailstock to locate the timber on the face of the jaws, then tighten the chuck. Using the template turn the outside diameter and true up the tailstock end with a parting tool, mark a line 80mm from the tailstock end, then mark a line 80mm on the other side of the centre line (photo 1).
We have now defined the limits of the sphere, with a parting tool remove to a depth of 85mm on the waste side of the line nearest the chuck; the reason for leaving this much material is we have to hollow the sphere any smaller would lead to vibration during this process.
Turning the sphere
2. Working from the centre line, turn the sphere with a bowl or spindle gouge.
We can now turn the sphere with a bowl or spindle gouge, removing material from either side of the remaining middle line work in stages (photo 2).
3. Check your progress with the template and keep the line in the centre.
Checking with the template as you go, remove the tailstock from time to time to assess the diameter from the end. The aim is to have the line remaining in the middle (photo 3). Lightly sand if required.
When piercing any hollow form, the most essential requirement is even wall thickness. A way to achieve that is to drill some depth hole in the sphere – the problem is where to drill the holes?
4. Use a 3/4" twist bit and to drill a 150mm pilot hole.
The sphere will be covered in a fire form pattern. Drawing a section of the shapes will allow you to drill depth holes in areas that will be removed. Draw a flowing line from the bottom to the top of the sphere.
This line creates movement for the drawn flames to follow. Using a 5mm drill with some tape or other measuring device set at the required depth of 6mm, drill two or three holes within each flame. With all the holes drilled, remove the tape and drill one of the holes deeper to 10mm. This helps indicate when you are getting close to the correct depth. Drill a pilot hole 30mm diameter as deep as the drill will allow. I revert to a 3/4" twist bit and drill to a depth of 150mm (photo 4).
Supports and hollowing tools
The piece of timber I’m using is longer than required however a steady is an excellent option to support the sphere during the hollowing process. Mine is homemade with skateboard wheels and it works well.
You can use a range of different hollowing systems – at the end of the day it’s what you’re comfortable with or what your budget will stand. My tools were made many years ago, and I still haven’t found anything that is better. For me, the most crucial feature of a hollowing tool is a small 3/16" high-speed steel cutter and heavy tool shafts to minimise vibration.
5. Initial hollowing at the top was with a Vermec tool.
The outrigger stops the tool from rotating, and the cable tie is used as a depth indicator. Tool cutting height is an essential component of deep hollowing. The tool rest must be set so the cutters are cutting above centre in case of a catch, in which case the tool will tend to fall out from the wood.
6,7. Other hollowing tools were used as required.
Initially, I use a Vermec hollowing tool to remove the wood from the top of the sphere (photo 5), then change to my other tools depending on where I’m hollowing (photos 6, 7). Remove the shavings with a blast of air. Achieve wall thickness as you proceed to the bottom of the sphere, using measuring devices to check your progress. It’s a slow process. To finish the inside, use a larger round scraper in a negative rake position using light cuts.
Sanding, first inside
Sanding inside is a must because we will see inside when we pierce through the wall. I use some Vermec sanding tools to make the job easier working through the grades from 120 to 400.
With sanding completed on the inside, remove the steady if you haven’t already and then bring up the tailstock. If available, place a large centre in the 30mm hole and finish turning the sphere using the template as a guide. You can leave a small spigot 50mm in diameter and 10mm longer than where the sphere ends for some material to carve small feet, then part off with the parting tool.
Draw the flames
8. Use an ink pen to draw in the rest of the flame forms.
The next step is to draw the remaining fire forms using the same process as before with two more curving lines with the flames following the lines, eventually filling in the entire sphere with flames. I tend to use an ink pen as pencil will often rub off with the continual handling during the carving process (photo 8). You can also now mark the position of the feet with a 120° template (photo 9).
9. Marking the the position of the feet with a 120° template.
Carving the flames
10. Start each flame by drilling a 5mm hole.
Carving starts with a 5mm hole drilled in all the fire forms. This makes it easier to use a spiral cutter driven in a flexible cable to remove the bulk of the waste. You can use the spiral cutter to drill the hole, but I find it very slow, and the cutter may wander around (photo 10).
11. A 4.8mm square cylinder cutter was used at 20,000rpm to refine the flame forms.
Don’t carve the flames at the very top of the sphere. They will be finished last because it’s easy to break off the flame tips while sanding the rest of the sphere. With the basic shape now cut out, start to refine the fire forms and feet for the base, with a 4.8mm square cylinder cutter used at 20,000rpm (photo 11).
12. Using a 5mm round bur to shape the bottom of the flames.
Accentuate the bottom of the flames with a 5mm round bur used at 20,000rpm (photo 12).
13. For the pointy tips of the flames, a 1.2mm Krauser bur was used.
14. Rifflers also come in handy for further refining the forms.
The tips of the flames need to be made sharper. I’ve been using a 1.2mm Krauser bur at 35,000rpm for this with some success (photo 13). I use these burs in a micromotor machine, a fantastic tool with almost no noise or vibration. A riffler is used to refine the overall shape and sharpen the tips of the flames (photo 14).
The most time-consuming part of the procedure is sanding. This is however the most important part of the whole exercise as here we’re trying to create movement and the seamless interaction of the flames.
15. A small shopmade sander with velcro applied was used to commence the sanding process.
I have made a small 25mm sander out of a silicon carbide rubber polisher by applying some velcro to the bottom and the top. This allows me to power sand using velcro-backed paper 180 to 400 grit (photo 15). The bottom of the flames can be sanded with
a flapper sander. To stop the paper flapping about, you can use a small rubber O-ring to hold the paper in place. It works beautifully, better than the tape I used to use (photo 16).
16. An O-ring works well to secure abrasive paper to a flap sander.
Everything has to be finished before carving the final flames at the top. Use jewellers magnifiers to see the flat facets which need to be removed during the sanding process. You have to support the flame tips during the carving and sanding process around the top.
I use 30 per cent satin spray lacquer to finish these pieces because it is easier to apply than oil which would be a nightmare to remove from all the crevices.
This is a challenging project, but the reward is a unique piece of art.
Neil Turner is a wood artist who lives in Stratham, WA. See www.neilturnerartisan.com.au