Explode-o-bowl

[TC Robertson]

At a recent craft show a fellow vendor had an unfortunate lesson in glassblowing. One of their large hollow bowls imploded with a big POW! around 3PM on sunday. The vacuum created inside finally overcame the strength of the glass.
We had a similar exp. with some large fish that self-destructed. Our fix was a tiny hole put in near the base, made with a tungsten rod heated with a ranger and spun. I shared this info with the bomb blowers.
I would be having a tough time sleeping for a while, thinking about all the potential ied,s out there. These folks are in Seattle and have not been on the show circuit long, I think.

Just a public notice about a possible problems for anyone making large sealed pieces. Later, TC :slink:

[John Teeter]

Could you drill a little hole in the piece when it was cold to relieve the vacuum?

or would the vacuum in the piece during anealing induce so much stress the piece wouldn't be anealed incorrectly and the stresses would be "locked in?"

Just curious

:angel:

[Jordan Kube]

It's much faster and easier to do while it's hot with the tungsten.

[Kenny Pieper]

I know some fokes put a thin wire in the hole of an orniment before the loop is applied. After the loop is finished the wire is pulled out leaving a very small hole.

[Barb Sanderson]

Actually TC it happened around 1:30pm and I didn't sell a single glass piece for the rest of that afternoon! The artists in question are accomplished and have been making these bowls for years. The particular bowl in question was using new colors that may have been a tad bit incompatible. Or something else entirely....!

Barb

[TC Robertson]

The next 4 customers we had asked if our glass exploded. They bought anyway, just double bag it please.

I thought a light had blown, or terrorists! I told them their work would be popular in Iraq. Later, TC:rolleyes:

[Pete VanderLaan]

I'm pretty much with barb on this one. It sounds more like incompatibility. Bright reds and yellows?

[Barb Sanderson]

Yes it was a combo of an opaque red and either yellow or orange - a combo they had never done before.

Barb

[Pete VanderLaan]

Bright reds and yellows cannot be made with lead. Cadmium and selenium in the presence of lead make a variety of shit browns. They have to be soda Lime glasses as color rods to achieve a bright clean color. The 30-45 percent lead in most color rod allows for the tolerance level in viscosity that we see in color rods adapting to a variety of clear glass bodies ( see articles by Dan Schwoerer at Bullseye) . The cad sel rods have zip for tolerance. They are short brittle and stiff. The rods are always always always really low on expansion (around 85 L.E.C. from Kugler )and you subsequently get to see an implosion rather than a bust out when it lets go. Also usually more easily achived with hot lights.

It wasn't a hard guess. Best to use Gaffer rod for this stuff if you are working a 96 L.E.C. glass.

[TC Robertson]

That does make sense for their case. My large fish imploding was based on thin walls and too much vacuum. I don't have many compatability problems. Later, TC