This week, I decided to use my newly perfected skills on a selection of fancier and prettier glasses. I made more arrowheads than I thought I would this week, so there'll five to cover. One of those arrowheads I will talk about for quite a bit. I also promised in my last blog that I would go over step fractures so I will start with that.
I originally thought that step and hinge fractures were different names for the same thing. However, the research I did said otherwise. This website explained them both nicely. It also goes further in depth with all the math that determines how the material flakes. It surely can explain it better than me as the people that wrote it are professionals. Don't read too deeply, though. I don't want you to find out I misunderstood something or said something wrong.
Either way, I made this beautiful graphic to help demonstrate the idea. I even copyrighted it! Press control and click any image to see a larger version. Anyhow, the right side shows a hinge fracture and the left side shows a step fracture. A hinge fracture occurs when a crack travels along the piece but then diverts to the face of the piece. As such, the flake is smaller and there is this sort of "hinge" where the flake "hinged" off. A step fracture occurs when a crack travels along a piece but then stops. It is the follow-through motion of the flintknapper that removes it. Due to the continuation of the crack, a step fracture usually ends with an area that is off-color to the rest of the material. It is often obvious where the crack ended and how the flake should have looked, and it can sometimes be removed like a hinge fracture. A few can be viewed on the refrigerator glass below.
Here's another beautiful graphic! Mrs. Crews mentioned how a girl somewhere in the country did graphics for her genius hour and gave that one genius hour sheet the girl made to us. Perhaps that is an idea for another genius hour. I doubt I will do any more for this project, though. Again, control-click on the image to see it in a better resolution. I use the word "biface" in the graphic. It is a more proper word for an arrowhead and means that both sides of a piece of stone or glass have been flaked. On a side note, I made the perfect graphic for Kyle, so check out his blog to see it. If it isn't there, then he must hate me.
This one is all about hinge fractures and what to do with them. Note how a hammerstone is pictured. Only percussion flaking, a technique that involves striking the edge of a piece with a stone or antler, can create hinge fractures. This makes sense as I have only come across them while using the copper mallets. Hinge fractures seem to occur because the hammer can vibrate when it strikes the material. Pressure flaking, however, doesn't involve striking the material so no such vibrations can occur.
On my previous blog, I said I thought the ridges seen on a conchoidal fracture occurs as a result of force traveling through the material as a wave. From what I have read, it would appear that I was right.
Here are the five arrowheads this week. Some of you who read my previous blog may be wondering where the spear point is, and I'll get to that. There is a reason for the title of this blog.
This was my first arrowhead of the week, and it turned out rather nice. I had been saving an Old Spice bottle bottom that was thicker and more flat for this week as I wanted to make something better from it. It didn't turn out exactly as I hoped, though.
To start, I got a number of large hinge fractures. This was because I needed to use the copper mallets to prepare the edges of the material a lot. The one on the left was particularity bad. I couldn't remove it using the pressure flaker as shown in the above graphic, so I had to reduce the size of the arrowhead. This may have helped me, though, as I was able to remove all of the flat sections from the glass with the smaller arrowhead. I also had a number of rather thick portions that were difficult to remove. Another problem came when I was notching it. I tried to go for diagonal notches, but the tangs broke off, so a stem was created.
Here's a massive flake I removed from the above arrowhead. Sadly, part of the edge broke, but you can still see how gargantuan it was.
These three tall, dark, and handsome drinks of water were mentioned in the previous post, and I will go over each one individually.
This was the spear point I was making from a piece of refrigerator shelving. You may not be able to appreciate it, but the flaking I was doing was the best I have ever done. You can see how all of the flakes are parallel and extend for a good portion across the face of the glass. I was so marveled by it, that I took three pictures. Unfortunately, the spear point didn't turn out like I hoped.
I had spent maybe about an hour and a half working away at the point when I applied too much pressure on the center and it snapped. This happened to my father with an obsidian point, so I was trying to be wary. We even put extra tarps on the ground so it wouldn't break should it fall on the concrete.
This is the final result. I continued working at the top, or right in the picture, portion of the broken point. I had a nice shape going until an inch broke off. As a result, the finished point is much smaller than I wanted. I did remove all of the flat portions of the glass. Had I not, it would have been very obvious due to the matte finish. The base of the arrowhead is also a little weird. I was going to do side notches, but the bottom was damaged in the process, so I mirrored the pattern. After I finished this arrowhead, I was going to make another from the bottom piece of glass. Unfortunately, it broke and broke until nothing was usable. As such, I am really disappointed with how this turned out.
This arrowhead, made from a sparkly purple glass, was next. It turned out very nicely. I had a different and radical idea to start with, but due to a few bad breaks, I went with this shape. Otherwise, this arrowhead was rather uneventful. There is, however, a hinge fracture on the other side. I didn't try to remove it as I was afraid the tip could break off or the notches could become damaged in the process.
I was incredibly disappointed by this arrowhead. This was the piece of red glass above. The main issue with it was that the red glass was incredibly thin. I should have broken it in half to begin with. Multiple times while working at the glass, it snapped. Eventually, this was all I could make. I mainly feel bad because the materials are my father's, so I don't want to waste them, even if they've been sitting around for a decade.
My final arrowhead ought to be recognized by Kaden as I made it with the bottles he so graciously donated. These were the club soda bottles from chemistry; they were fished from the trash. I scored around the bottom of the bottle and then gave it a good whack. The first one didn't break all that well and was unfortunately unusable. The other two turned out very nicely, and I was able to make the right arrowhead from the flat portion of the bottle base. There were a few extremely small flat sections of the glass that weren't removed, but they were so unnoticeable that I left them instead of reducing the size of the arrowhead. I didn't see this until the picture was taken, but the left edge is uneven. I will probably clean that up later. Another thing to note is the color of this glass versus the refrigerator glass. The former is completely colorless, but the latter has an attractive green tint.
Although I was disappointed with how some of my arrowheads turned out, they were all much better and cleaner than my first arrowheads. I have talked before about how I have used the copper mallets to rough out the shape of the arrowhead. However, I probably won't be using them anymore if possible. They can produce hinge fractures and can leave an edge that is actually harder to work with. If you look at what was going to be the glass spear point, you'll notice how the edge and the face are at right angles with each other. I thought this would make pressure flaking impossible, but it actually allowed me to create larger flakes than I normally would have been able to. Percussion flaking also is more, for lack of a better word, unpredictable. I could strike the material and snap it in half or produce the massive flake you saw above. It also might simply crumble the edge, requiring even more work to prepare it. Nonetheless, I am more skilled now and realize what went wrong with my previous arrowheads.
Another thing I realized is that often you will need to work with and not against the material. I usually have an idea for the arrowhead's final shape, but most of the time, something breaks and a new shape has to be chosen. I am starting to simply work the material until a shape becomes evident; let the material choose its final shape, not me.
I will definitely move on to stone arrowheads next week. I meant to make a number of nicer arrowheads this week, and I would say I succeeded. I have had nearly a month to practice away at glass and will have nearly a month to work on stone. Since I understand the techniques needed and what went wrong in the past, I may end up being ahead of schedule for the next couple of weeks. No matter what, I doubt I will be behind.
A lot of the time, the stone will need to be heat treated before making an arrowhead from it so I will go over that process next week in detail. It's sort of like baking, so perhaps I can collaborate with one of the cooking bloggers. Furthermore, I plan to redeem myself. There are some other pieces of refrigerator shelving I can use and even a fancy piece of obsidian with a golden sheen. Hopefully, I will be able to make a spear point before the end of this project.
No comments:
Post a Comment