Dacite Spalled In Half

When we met I handed him the rock and after a brief examination he said “I’m not sure this is obsidian, but let’s open it up and see what we’ve got here”. He selected a baseball sized hammerstone and placed a leather apron over his thigh, then layed the rock on the side of his thigh and with an arched swing, struck the rock’s edge with a downward blow. After a few strikes, the stone split open the full length of the rock. He said “oh… this is dacite… similar to obsidian but different. Dacite is a volcanic rock that has cooled under salt water and it works differently than obsidian”.

Not too surprising, different materials require different tools to achieve the best results. A gritty-surfaced hammerstone worked best in this case but a hardened dogwood billet works best for harder stones like quartz and rhyolite. The effectiveness of the tool has to do with it’s surface contact time during the strike.

Dacite Flake

After having observed the reduction of the first half of the rock I now have the remaining half of the rock to work with to apply what I have learned from his demonstration. I expect that exciting times as well as frustrating times lie ahead but I’m sure that they will be rewarding in my quest to master flintknapping skills.

Before And After Break

You may have seen a popular craft idea that makes drinking glasses out of glass bottles. The method uses a string tied around the top edge of the bottle body, soaked in alcohol, then lit with a match or lighter. When the flame burns out either cold water is poured over it or the bottle is dipped in a container of cold water. The contrast in temperature causes a fracture that “pops” when it breaks along the string line. The edge is then sanded or ground smooth. (The top part could be used as a funnel.)

My particular application of this method was employed to break out the flat sides of a square bottle in order to use the glass for flint knapping a knife blade. I initially used some jute twine to tie around the side of the bottle but found that the burn time was not long enough so I retrieved a shoe lace that was thicker, thus enabling a longer burn. That did the trick. I was able to break off the remaining sides in similar fashion.

As illustrated in the photo, I placed the bottle in a bread pan in order to contain all liquids, whether it be spilled alcohol from wetting the string or the water that is poured onto the glass after the string burns out. I used “Heet” gasoline anti-freeze as my fuel (obtained from an auto store/department). It is methyl alcohol that burns clean and comes in a yellow bottle with a long neck. I poked a small hole in the foil seal that allowd me to carefully pour the fluid onto the string that was placed on the bottle.

I also have a technique in tying the string. First I tie a small slip knot loop, then I roll that loop over the remaining line. The first loop when tightened cinches onto the main line to make a very stable but adjustable large loop around the glass. Make sure that the string loop when tightened contacts the glass surface.

Final note: the flat pieces of glass from this bottle are quite thin so I am needing to learn a more delicate way to knapp the glass but then that’s part of the fun!

There are different methods to remove the bottle bottoms. One interesting method used for small 12oz. bottles is by using only your hand as illustrated in “Popping Off Bottle Bottoms By Hand“. Larger bottles become progressively more difficult and I have yet to break out a 40oz. bottle.

For larger sizes I find that a metal rod works well. My friend uses a steel chisel or punch, blunt side down, inside the bottle and shakes it up and down while his thumb covers the top. I prefer to use tire irons and rebars to poke it out. In the past, when I have used a tire iron, I would place the blade parallel with the seam at the bottom to strike it. However, I found that it was easy to punch small holes in the process that could jeopardize the removal. Recently I discovered that I could rotate the blade slightly, say about 15 degrees inward or so and the bottoms would break out quite consistently in a single piece.

Should you have the need for glass, bottles are easily obtained from trash or recycle containers and you can try these techniques for yourself. It’s wise to wear eye protection and perhaps sturdy gloves too. Don’t forget to pick up any glass shards left behind when you’re finished.

Although my survival skills span both modern and primitive, I chose to demonstrate the primitive skills throughout the day to compliment the historic air set by the teepee. My initial demonstration was given to a group of Boy Scouts using the bow and spindle fire method to start the campfire for the day. A little later I was excited to demonstrate flint knapping for the first time. for this craft I showed the traditional tools used by indigenous peoples, but I also showed the counter-part tools made of modern materials.

I always enjoy meeting folks who stop to chat. I have often learned new things that often turn into articles that I post. As usual, I try to replicate or apply what I learn from others to validate it and add insights for clarification. Although W. Kerr Scott Reservoir has only one 50th Anniversary, they offer great programs and provide wonderful facilities for organizations and individuals throughout the year. You can learn more at: http://www.saw.usace.army.mil/wkscott/index.htm

I’ve always maintained that indigenous people would have used Bic Lighters if they were available, but, alas, they used the resources that were available to them at the time. As I watched a circle of flint knappers at work, I noticed some of the materials that they used. Although I saw some antlers traditionally used as billets, most used modified copper capped pipes that had been weighted with lead. Although there was obsidian piled in a box, I also saw some white material that was unfamiliar to me. I asked what the material was and the response was “John” stone… which was the porcelain from broken lids of toilets (or “Johns”). One knapper said that, outside of the wilderness, you could always find this resource to use. I also saw some arrowheads that were knapped from beer bottles.

It pleases me to see primitive skills kept alive while incorporating modern materials and resources. It’s the gift of ingenuity that helps us to adapt and survive. By continual practice and evaluation, we can improve and build our skills to better prepare us for emergencies and challenges that may lie ahead.