Since getting together with John, Rob and a few others for our regular knapping sessions, pressure flaking has become a bit of an obsession for me-in particular, working pre-cut glass slabs into points of various sizes. Key to this is taking a good first set of pressure flakes, to remove all of the original surface-an end result that is ‘fully invasive’ has become somewhat of a holy grail for me over the last few weeks. To that end, I decided to make an Ishi stick out of a chair leg John donated-a number of the knappers on youtube, including palaeomanjim, seem to use them for their larger pressure flake removals, and the general idea is the longer handle allows more power to be applied, thus removing longer flakes.
The construction of the Ishi stick is very similar to the Ishi style pressure flakers John discussed a few posts ago-I split the lower part of the chair leg, cut a groove for the nail, and carved a collar to locate the copper cap, and another recessed section, which I bound with string to secure the whole thing. Initial attempts to use the Ishi stick were a little shaky, and overall it felt a little odd, as the long handle runs up the forearm and braces the wrist. However, once used to it, it allowed a more controlled application of power, and resulted in some excellent long pressure flakes.
Detail of the Ishi stick at the business end
The Ishi stick (top) and the Ishi style pressure flaker
However, as the often uttered phrase goes, with great power, comes great responsibility. In this case, a responsibility to pick the correct platforms, and a responsibility to control the removal process and avoid unnecessary force. On this first outing of the Ishi stick, it was a lesson I learnt the hard way, breaking every piece I started. But, there is a lesson to learn in every mistake-on reflection, all of the breakages occurred at the same point in the point-making process. I had successfully removed the plate glass surface with the first pass of pressure flaking using the Ishi stick, and I had returned to take a second set off, using the high spots left in between the pressure flake scars taken in the first pass as platforms. I used both the Ishi stick, and the Ishi style pressure flaker for this stage on different pieces, but both resulted in the piece ending in two bits.
Good invasive removals from the blank, but both broke in the middle
At this moment in time, I have yet to decide whether this is because I am putting too much force into this second set of removals, because my technique is exerting too much ‘bending’ force on the piece (exerting a force along the axis of its thickness, as opposed to across its width), or whether the pad I am using for pressure flaking, with a groove to allow a free pressure flake removal, is not offering enough support.
My pressure flaking pad and one of the broken pieces. Is the groove in the pad too big to support a piece this size?
So our next knapping session on Thursday will see a new three-fold approach: 1) Removal of the first set of flakes using the Ishi stick and pressure flaker pad. 2) Good platform preparation (or re-preparation). 3) Removal of second set of pressure flakes using the Ishi style pressure flaker, and a new pressure flaking pad with a smaller groove, so as to offer extra support.
As John said at the end of his last post, I am sure we will be making a few more of these-for me, it’s fully invasive or bust!