Starting flakes on glass

[jonathan creason]

I stopped by the local glass place yesterday and scored 4 large pieces of plate glass (and the guy told me I could have much more).  I've been trying to work on it a little, but I'm having trouble getting decent flakes started on the 90 degree edges.  I end up with a ton of hinges all down the side.  What's the best way to start with this stuff?

[JackCrafty]

Watch this video.  It's a bit grainy but you'll get the idea.  The glass slab in the video is larger than plate glass, but the same principle applies.  You will need to "scissor" the square edge.

---http://www.youtube.com/watch?v=QGT1sU0_NL0&feature=related

[cowboy]

You'll want to stitch the edge on a square cut or broken peice of glass. All that amounts to is taking short steep flakes back and forth off the edge all the way around. Once you do that you'll have platforms along the edges that you can work with. Hmm, may have a pic for example. Found one - stitched edge .

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[Josh]

...then what?    Do you bring the whole edge to below the centerline or do you run flakes alternating sides with the stitched edge?

[cowboy]

Well, on this particular one.. I beefed up those individual platforms, got em just below center and started popping off some good sized spalls with big percussion. Eventually got it worked into a nice big bi-face right before I snapped it in half  . This was just to demonstrate a stitched edge. Would be a little different on a peice of glass and most likely all pressure work depending on the thickness.
  Shannon has a real good tutorial on bi-facing in the how-to section..

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[Josh]

Cool that's where I get confused... Thanks Paul.

[cowboy]

Not a problem . Hmm, digging through these old pictures is giving me the fever .

[jonathan creason]

Thanks guys, that video and pictures helped a ton.