Well now. Lots of thanks to Holly Flannaghan, my technician comrade in Geography who has access to a furnace, and also does her research!
This is Alice la Porta’s mould painted with the Aluminium Kiln Wash to stop the glass adhering to the mould. It did more or less work. The mould was unfired and next time we may use an already fired ceramic mould.
I had three grades of glass cullet. Sand, sub-1cm, and above 1cm. We used the sand and sub-1cm cullet on the top to fill up the mould.
Then Holly performed her magic. Over four hours the temperature was gradually raised to around 1000 degrees Centigrade, and then kept there for two hours or so before starting the slow cooling process.
And one day later here we are. The Aluminium Kiln Wash worked but we had to break up the mould to get access to the glass. Once out the glass was actually thinner than I anticipated. The sub-1cm cullet must have had a lot of gaps that it had to fill. Next time we will use the sand only and a slightly higher mould to give the slab more depth.
The glass appeared not ideal. It looked similar to the fused glass blocks produced using Nacho’s kiln. However, once I started to work it I realised that it actually had very good internal cohesion. It flaked well although crumbly.
And this is it. The outcome but also a starting point. We need to adjust the mould size and make sure it’s already fired. Use sand rather than sub-1cm cullet and perhaps keep it at 1000 degrees Centigrade for around four hours before allowing a very slow cool off period.
I am actually super happy with this handaxe. Many thanks Holly!
Today we had an Archaeology Open Day which was surprisingly quiet. Consequently I had quite a bit of free time in the lab on my own. I had also had about five blue glass bottles cluttering up my office for what seemed like ages, and so I added two and two together and came up with a trug of blue glass cullet.
This wasn’t completely out of the blue (pardon the pun). My colleague in Geography, Holly, is in charge of a small furnace and we have discussed the possibility of melting my glass bottles to produce a slab of glass, and Tuesday next week may be the opportunity to do so. However, based upon previous experience I needed a method of stopping the melted glass block adhering to the clay mould. Enter Potters Aluminium Kiln Wash.
The experiment next week is to use the clay mould given to me by Alice la Porta, and use the Potters Aluminium Kiln Wash to form a layer between the mould and the glass cullet to be melted in the furnace. Holly is going to be in charge of times and temperatures, I will be in charge of keeping my fingers crossed.
This is the mould Alice gave me, let’s see how it goes…
I have been off work for two weeks over Easter, and although I have had some work stuff to do, I also have lots of Barmston Beach flint tablets to play with!
From Barmston there does seem to be two different types of flint collected. One type, like the above thin tablet with chalky outer surface seems to be pretty undamaged and works well. This leads me to think the materials on the beach are from two different glacial events or perhaps accumulated from different geographical locations.
Anyway, this was a particularly thin tablet of flint and as such liable to break. As a strategy to avoid breakage I pressed the flint to my thigh. The idea being that this helps by adding my body mass to that of the flint.
Using this strategy the next step was to use a hard hammerstone to ‘turn’ the edge. This involved taking a flake off one face, then turning the tablet over and using the fresh flake scar as a way in to take a flake off the the opposite face.
The sound is really interesting as you can hear when the tablet is resisting the hard hammer blows. Rather than persist and risk endshock and breakage, I would simply go back a stage and made bigger the platform. This approach allowed me to work my way around the nodule turning the edge without any major issues.
I then shifted over to a heavy antler hammer and used the worked edge as a ‘way in’ to take off longer flakes. Because I was pressing the tablet of flint into my thigh I was effectively hitting my leg with the antler hammer, but on the way catching the edge of the tablet and pulling off a flake.
As you can see from each worked face, the longest flake removals are a pretty descent 5 cms or so, but because the tablet of flint was already relatively flat I was mainly creating a cutting edge.
The two aspects I really like about this handaxe is the size (it is pretty big) and the symmetry. As I know how tricky it is to achieve these aspects I believe that this would have also held aesthetic value to a Palaeolithic handaxe maker.
So, the end result is one big, sharp and also aesthetic handaxe. Yesterday I destroyed one flat nodule and made two glass arrowheads as well as making this rascal. In relation to my performance here I think the correct term is that ‘I was cooking on gas!’
This afternoon I treated myself to two of the larger slabs brought back from Barmston. The flint isn’t as good as I remembered, or the pieces worked so far aren’t. The first one worked well with the hard hammer, but it had a very hard seam in the centre that disrupted the soft hammer blows. That one ended up in the waste flint pile.
The above two photos are of the second flat tablet, and it worked a lot better than the first. I was able to get a good rough out without any major endshock, all good.
And on this side that has worked. The flint fractured approximately according to plan, the edge is sharp and I am happy with the shape.
Flip it over and that’s when you spot the step fractures. That they are all on one side is, I think, something to do with how I work each surface differently, but I am not sure actually how I work it differently.
I think it may be to do with the initial turning of the edge, and by doing so I get a way in, but inevitably the angle is better on one side than the other.
Consequently I get to do all the nice stuff on the good angle side, and then have lots of step fracture action on the other when trying to bring the second face into line but without the suitable angles. That’s my current theory anyway, and fortunately I have quite a few blocks left to play with, and find out if I am right. Watch this space…
I have been making quite a few handaxes recently, but only just detected that I have a style. It occured to me when I saw these two next to each other and recognised how similar they are. Shape and size was an obvious similarity, and so these two can be recognised as the same ‘type’, and that would be cordate, or heart shaped.
However, it is the process, or ‘technology’ that is the real connector and this relates to how I get my initial flakes. We have very large and chalky nodules, as discussed here and these nodules need breaking down into flakes in order to make a handaxe. Flakes have a thick, bulbar ‘proximal’ end, and a thin and sharp ‘distal’ edge at the other. Intuitively, I seem to make my handaxes with a heavily thinned bulbar section on one side, and a minimally thinned distal edge on the other. This method has developed unconsciously, and I have only became aware of it with these two, and then looking at earlier examples.
In the above video you can first of all see the minimally worked ‘distal’ edge, then the more intensively worked bulbar section, and finally the ripples of percussion indicating this was originally the ventral face of the flake. I’m not sure why my body chooses to work the flakes in this way. I will have to make some more handaxes to find out!
I have been collecting glass from the bottle tip for our melting experiment, and along the way found some nice thick pieces.
I was in the lab Saturday working on flint, and so today (Monday) I had an hour or so working on this brown glass base.
It took a while to get into it, and once in I had to sacrifice size in order to get rid of some horrible step fractures.
I used stone, antler and finally a copper pressure flaker to finish it off. It flaked really well and I am happy with it. I also have a nice green piece so let’s see if I can find the time tomorrow as well.
I destroyed two of the large flakes produced last week before I got to this with the third. It is a Neanderthal Bout Coupe, or flat based handaxe, and I like it.
I have had a bit of a ‘John day’ today. First thing I took Bella for a walk to the bottle dump. I found some blue glass fragments and a couple of interesting bottles, but no nice thick pieces.
After a late breakfast of left over veggie Shepherds Pie I went into uni. As you can see, we have some very big nodules, inherited from Alice la Porta. When she was buying them I told her to specify big nodules, as our previous delivery had been largely small ones. I should have said medium size.
Anyway, today I wanted to try breaking one up to see how it would go. I chose what looked like the easiest nodule, with flat sections as ways in. I then proceeded to produce a series of large flakes, and a lot of small debris.
For the breaking up process I used these two hammer stones, and as you can see, I didn’t get off scott free. However, they did their job and I then wanted to make a handaxe from one of the flakes.
All together I had three goes and made two handaxes, and I really like the one made from this flake. I learned from the glass handaxe I made last week, and this time stayed focused on preparing platforms and getting long thin flakes off.
One of the transverse flakes came off nicely but stepped in the centre of the handaxe (see left hand side with brown stripes).
So I did one of my special techniques that I learned from a Bronze Age knapper, and fitted the flake back in. I then whacked it again and successfully removed the step.
If you look at the flake scar on the right hand side you can see the negative bulb of percussion in the centre of the handaxe illustrating the process.
I am very pleased with this one, it is large with nice long flat removals. I don’t know if a Homo heidelbergensis knapper would have been concerned about the step fracture, however that process was immensely satisfying for me and gives the handaxe some personality. Happy days.
I don’t normally destroy perfectly functional things in order to make my stone tools, however…I found this nice thick glass ashtray in Oxfam and it reminded me of the glass slabs I want to produce with Nacho.
So £3.99 and 24 hours later I was sat in the lab with a small hard hammer. The glass was really good to work even if it took me a while to get rid of the ‘walls’ of the ashtray.
Like the older glass I am used to, this ashtray glass had bubbles in it. I knew what I wanted, a large ovate handaxe, and my earlier removals, when I had more material were better. I have some nice flakes that will be good for arrowheads at some point.
It looks half decent, is fully bifacially worked (no original surface left) and I have retained a good size. However, it is not my best. Harder to see from the pics is a step fracture ‘island’ on one face. I relaxed a little and went ‘intuitive’, which felt right, but failed to produce descent removals.
I was concentrating more on outcome than process, and in doing so stopped giving each removal the due consideration it deserved. By the time I realised I didn’t any longer have a good way in to remove the steps. If I really wanted to make it into something I like I would lose size, and it would end up like many of my smaller ones that are either made from smaller pieces, or like this, takes me lots of removals to get it ‘right’. Anyway, the hour in the lab was the thing. It’s been a while and it was great.
My understanding of how to hit things has developed not through flintknapping but martial arts. Consequently, this also influences how I teach other people as I find the principles to be transferable. The first issue is cultural, that generally we are taught that hitting is a bad thing, and so we don’t get that much practice. A first step then is to just get people used to hitting flint with a hammerstone and I have previously done a whole two hour session at Chester on just that.
I then move on to a discussion of impact, or kinetic energy. My understanding is quite processual, in that kinetic energy is a result of the relationship between the mass of an object (hammerstone) and the speed it is travelling upon impact. Whilst the mass of your selected hammerstone will be constant, one variable we can play with is speed at impact. If we remove angles and accuracy from this discussion, a high impact speed increases the kinetic energy, and this in turn increases the chances of getting a clean flake removal. To increase the speed of the hammerstone it is necessary to have a relaxed arm, and relaxation comes from a familiarity with the hitting process (see paragraph one). So far, so good.
Anyway, I was at home and most of my knapping gear is at work and I was feeling a little bit stressed and saw a nice tabular piece of material in the back yard. I am 99.9% sure I picked it up at the Mynydd Rhiw site earlier this year, but my problem was that I only had a very large and very small hammerstone to hand, and a small antler hammer that I usually use on glass. None of the tools were ideal but I wanted to have a go, and if my above theoretical understanding was correct, I should be able to adapt my speed of hitting to compensate for the overly large or overly small size of the tools being used.
So that is what I did. The large hammerstone was good for the first stage of cortical removals. As you can see, each of these pieces has between 80% and 100% of cortex on the dorsal face.
The next stage was a little more tricky, as I could have done with a slightly smaller hammerstone and larger antler hammer for the shaping and thinning process. As you can see, these pieces are characterised by around 50% cortical surface and they are generally smaller.
With the final stage I really had to hit the material hard with the small antler hammer. A bigger one would have worked better, but my approach succeeded and I did manage to get some nice soft hammer flakes off. As you can see, these are characterised by minimal cortical surface present.
Anyway, if the material was indeed from Mynydd Rhiw I should have made a Neolithic polished stone axe, but being me it became a small flat based cordate handaxe. This is technically incorrect because the material was originally quarried even though I picked it up from the surface. At one point it had a large step on one surface, which I removed by replacing a removal and using that as a punch to get rid, and it worked really well.
The speed thing does work, but it is hard work, and the intuitive way I normally select the appropriate tool does save me energy. There is more to hitting than this, I deliberately avoided a lengthy discussion of angles and accuracy, however this post does go some way towards exploring and explaining (my understanding of) the underlying complexity of what is generally perceived to be a simple process.
