Carved Hollow Form archive
Monday 19 March 2012
Andrew Potocnik turns and carves this hollow form which features an undulating profile that is then placed on its own turned and carved stand
One idea leads to another and another, which consequently leads to a whole new direction in terms of projects. Then a series of ideas fuse to create an altogether new piece; that's the cyclical nature of how my ideas develop over a number of years. All along the way, I have no concept of where these ideas will lead; I just go with the flow and wait to see what the final outcome will be, and sometimes I just sit back in wonder of just where that initial idea led.
This time I had some ideas sketched on paper for a flat hollow form which had a carved undulating profile as the key feature - something like a marine manta ray swimming in the ocean - almost like a bird in flight. I also had a vertical hollow form that I'd made which was carved on the outside to create deep flutes, inspired by memories of some of Marc Ricourt's work that I had seen some time ago.
I hadn't envisaged the two overlapping until one of those magical moments of divine intervention, or a couple of glasses of fermented grape juice, when the penny dropped and all became clear - what a contradiction of terms - and my mind went off in a flurry of creativity, setting me off in search of the right piece of wood that would allow this idea to be converted into reality.
Tools used: Articulated hollowing tool, scraper, swan-neck tool, 10mm (3/8in) bowl gouge, parting tool, wide fluted carving tool and tight radius fluted carving tool
My favourite stock standard timber is red gum (Eucalyptus camaldulensis) which is the dominant hardwood of my local area. It is a dense timber of about 900kg/m3, lovely to turn and I consider quite easy to carve. Start by mounting a blank on a scroll chuck and tailstock and trim it down to size
Turn the underside of the eventual bowl shape, including a tenon so it can be held, once reversed
I have several scroll chucks but I find a Vicmarc is the most versatile. Grip the blank by the tenon at the base of the form; you can now shape the upper surface of the bowl
Once shaped, you need to determine the opening to suit the overall dimensions of the bowl
And now for the hollowing; I use a variety of tools but an articulated hollowing tool is the quickest and most versatile for getting right into the undercut and out towards the perimeter of the bowl. At this stage, you just need to rough the interior. Final work will be completed once you know how much wood is left after carving the flutes
It is now time to start carving the surface. Mount the workpiece and chuck onto a carving clamp and carve the major divisions so you can later do the filling in...
â€¦you can add more detail as the piece progresses...
â€¦and more detail. I like to use Flexcut carving tools; they fit my hand so nicely and they're comfortable to work with
Here you get an idea of how deep the flutes are and how you need to vary the depth
Return the piece to the lathe and refine the inside using a Kelton hollowing scraper. You could use a variety of tools at this stage. I've encountered homemade tools with outrigger supports, some with flexible depth indicators. Nobody has devised the perfect tool, as far as I can tell, so go with what you feel most comfortable using. With a clear idea of how much timber is left after carving, you can now take the thin walls of the form down to about 3-5mm (1/8-5/16in) depending on the depth of the flutes
To sand the inside of the form I resorted to fairly rough sandpaper - 80 grit - to even out imperfections in the form and prepare it for the usual progression I use 120, 180, 240 and 320 grit
Heavy sanding leads to breaking through the turned form and exposing areas where carved flutes have gone deep into the walls. This is a good thing in this type of work because one of the overall aims is to make the carved flutes a feature on the bowl's opening. This aspect will be developed later in the project
Next, to reverse the form and shape the underside you need to turn a stepped carrier for the piece...
...then mount the form between it and the tailstock...
...trimming the spigot and base to a smooth curve before sanding it through to 240 grit
Carve flutes into the base working roughly in quadrants of the form. Place a sand filled cloth bag under the bowl to protect it and allow for it to be placed on any angle that makes carving more comfortable
The next step is to saw off the small stub left from turning
...so the final stage of carving can now be completed
Using a range of files, including jeweller's files, file the flutes at the perimeter of the form to create a jagged edge. This can easily be completed with sandpaper wrapped around various sized dowels
The same needs to be done to the opening of the form, leaving the ridges between flutes to stand proud and protrude towards the centre. All of the carved work needs to be left un-sanded ready for sandblasting
Mask the inner sanded area off to protect it from stray abrasive in the next stage
I use a somewhat small commercially available sandblasting set up and garnet abrasive which is quite coarse and works well on hard timbers. To finish the sandblasted wood darken the ridges with a hard black stain...
â€¦which is then wire-brushed to 'soften' the transition between raw and darkened wood. You then need to apply several coats of finishing oil to the outside surfaces of the vessel
You can create a stand for the piece to raise it from the display surface. Turn a small, tapered, hollow, cylindrical shape in a scroll chuck. Part the stand free and reverse it onto a carrier...
...and attach it with heat sensitive glue to finish the bottom
Here is the finished cylinder, ready for carving
You can now carve the flutes that are deep enough to break through the cylinder. Wire-brush to roughen the surface, before finishing it in the same manner as the hollow form