Flintknapping Glass — Arcturus Primitive Skills Institute
“Working glass is both a challenge and a joy. At Arcturus, we teach that patience, clean strikes, and good habits are the foundation of every successful knapper. Don’t expect perfection at first—expect to break a lot until your hands learn the rhythm of conchoidal fracture.”
Safety First
“Glass is unforgiving. Protect your eyes with wraparound safety glasses, and your hands with snug leather gloves. Long sleeves and sturdy shoes are non-negotiable. Glass throws razor flakes and dust—so wear a mask and work outdoors or in good ventilation. Respect the material, and it will respect you.”
Choosing Your Glass
“Start with bottle bottoms, cullet, or slag glass. These are affordable and predictable. Avoid tempered or laminated glass—it won’t fracture the way you need it to. A clean, slightly convex blank is your best friend.”
Tools of the Trade
“Your billet is your voice. Use antler or copper for soft percussion, and a smooth stone if you need to spall off larger pieces. For refinement, a copper-tipped pressure flaker or antler tine will let you shape and sharpen edges. Always abrade your platforms—strong edges make strong flakes.”
Preparing the Blank
“Detach the bottle bottom cleanly, then strike near the edge to create palm-sized spalls. Aim for 6–10 mm thickness. Look for convexity and avoid flaws. A good blank sets the stage for everything that follows.”
Core Techniques
• Platform prep: “Grind the edge until it’s dull and sturdy. Keep your platform angle around 60–70°. This is where flakes are born.”
• Percussion reduction: “Strike lightly, just inside the edge, with inward-and-down energy. Let the flakes run across the face.”
• Pressure flaking: “Seat your tool slightly inboard, push and snap downward. This is how you refine symmetry and sharpen edges.”
Making a Simple Arrowhead
1. Square and abrade the edge — “Strong platforms are the key to reliable flakes.”
2. Form a bifacial preform — “Alternate faces, keep it lens-shaped, thin to 4–6 mm.”
3. Outline the triangle — “Nibble with pressure flakes, keep both faces convex.”
4. Thin the midline — “Use soft billets sparingly; stop when flakes run clean.”
5. Refine edges and symmetry — “Alternate pressure flaking, abrade often, keep the edge centered.”
6. Shape the base and notches — “Square the base, notch with careful pressure. Balance is everything.”
7. Final sharpening — “A few gentle flakes give you a keen edge. Don’t overwork—glass is quick to chip.”
Troubleshooting
• Hinge fractures: “You struck too close or on a weak platform. Build convexity, abrade more, strike inward.”
• Crushed platforms: “Your edge was too sharp or thin. Grind heavier, use a softer billet, lighten your strikes.”
• Overshots/snaps: “Too much force or too thin a midline. Ease up, preserve thickness, keep faces domed.”
Practice Wisdom
“Start with larger blanks—they forgive mistakes. Watch experienced hands, mimic their rhythm, and take notes on your own strikes. When flakes stop running, don’t force it—re-prep your platforms. Flintknapping is a dialogue with the stone or glass. Listen carefully, and it will teach you.”
“I am practicing this ancient art, and like you, am merely a student forever seeking to hone my skills. Hopefully I will see you in the wild!”
Learn more at survivalschoolmichigan.com