Calcedony Prep

Got the glass cooking for a cobalt calcedony.
I've been looking back at the various post notes for working this temperamental glass.
One thing Pete has pointed out is a tendency to lose the colloidal swirls of color due to the normal rotation of the pipe post-gather. His recommendation is a "slap gather". While this is a colorful adjective, I'm not quite sure what it means.
I'd like to have a good strategy for working the glass so I can best evaluate the cooking ingredients and make adjustments accordingly.

So, how does one perform a "slapped gather"?

-or does it take two?

Thanks

[Jordan Kube]

Don't worry too much about it. Anything you can do to manipulate the glass will make it fun. I like to drop some on the marver and then pick it up.

Ahhh...like the Dino Rosen video I watched.

I saw the torso pic you posted. Very nice!

[Pete VanderLaan]

It's really helpful to not stir calcedonia glasses. If you do, they start to turn gray. So "slap gather" is just what it sounds like. Have an interior gather ready, as big as you want and then dip down on the side of that gather, lift up, rock it back and forth unless you like messes, and pull away from the pot. It will show the veining very clearly that way if it's a decent glass. I have seen people get directly above the pot and go straight down in and straight back up getting vertical veins. As Jordan suggests, you can lay out pieces of what ever shape you want on the marver and pick them up. Fred Warren was doing some beautiful work doing that.
I've long suspected that Dino as mercury in his calcedonia. I can't think of anything else that would make it so effective.

But don't stir it. It also likes to be thick.

Thanks for all the help. I feel like I owe it to CW to follow up with my results.

My first attempt was a cobalt mix that failed to produce opal swirls. I am using crystallica and wanted to see if the cullet/squiggles would work without fritting the glass.

I changed things up and made a clear calcedony mix (no cobalt) based on Pete's recipe for calcedony and fritted glass. Huge difference!

I'm loving this glass. My furnace is a custom wire melter in which is housed both my 80 lb crucible and a 17 lb "color" crucible I got from Sundance. I built separate openings for both crucibles. I just dip into the calcedony, pull out the gather and cut the tail with a pair of shears...no turning!

As the glass cools the swirls appear...more heat/cool cycles=more color!

I haven't quite got the red to express very well yet. Any advice to expand the color spectrum would be very welcome.

Thanks again to those who have shared their experiences with this color and especially Mr. VanderLaan.

[Jordan Kube]

Add some copper and you'll really get to see those other colors expressed. Sometimes.