the SFSU studio

documents

• hot-shop code of safe practices (John Leighton)

processes

Wifi access in the studio:

• SSID = Glass (it's hidden - you'll have to type it in)
• WPA2 encryption
• password = !!Glass!!

circuit breakers

Sometimes these get turned off by mistake. Here's some of the most commonly-needed ones:

• The grinding wheel and the blower over Nate's locker: breaker 2B in room E176, which is to the left of the bathrooms by the back door.

furnaces

Charging the furnaces

 

• During the week, the charge can start in the afternoon between 12 noon and 3pm. Start earlier on the weekends.
• Turn up the furnace to 2250° (top black mark).
• Once it's heated up (about 45 minutes), charge 2 bags and keep at 2250°.
• To charge: turn the air down to the low black mark; put on a respirator; load the bag(s) into the metal chute; slide them - quickly - into the pot; turn the air back up to the top mark.
• When the mound is about 2 or 3 inches high (30 minutes to an hour), charge 3 more bags.
• Keep at 2250° until the mound is 2 or 3 inches high again (roughly an hour).
• Top off with 3 more bags or top off and keep at 2250° for another hour or so.
• Rake flat and turn up to 2350°.
• Leave at 2350° overnight to cook.
• First thing in the morning turn the furnace down to 1900° to squeeze for 6 hours.
• Check for seed in the afternoon; if all is good turn up to blowing temperature (~2100°).

Notes:

• do not let the furnace get above 2400°!

Relighting the furnaces

How do you know if a furnace has gone out? Look for one of these:

• If both furnaces have gone out due to a power outage, then the silence in the studio is deafening.
• If the temperature readout on the controller panel is below 1800F, see if the furnace color is orange instead of the normal soft yellow - that's likely a problem.

If the furnace temp is below 1000F, call Nate, Mike or Jim.  The gas valve needs to be turned down significantly so that the furnace doesn't come up too rapidly causing more damage to the crucibles. Otherwise, here's how to relight a furnace:

1. Make sure the blower next to the furnace/glory hole control panel is turned on.
2. VERY IMPORTANT: turn the air control valve for the furnace all the way up and leave it there for a couple of minutes. (This makes sure there's no gas in the burner.)
3. Plug the pedal cord we use to start the glory hole into the appropriate furnace socket. Unplugging requires a slight counter-clockwise twist and the opposite after plugging in.
4. Press the pedal until you hear the pop of the restart and the soft wooshing sound of the burner.
5. VERY IMPORTANT: if the sound is unusually loud or pulsating, turn off the furnace and go back to step one. This is a symptom of backburn where the flame is not forming correctly; it causes the burner to get extremely hot, potentially damaging it.
6. Adjust the air valve so the  needle on the guage is slightly above black mark, so that the furnace will come up to normal working temperature (~2100°) again gradually.

If the power/gas goes out

If there's a majorelectrical or gas shutdown, you want to trap all available heat inside the furnaces so they don;t cool down to omuch. (That could crack the pots.) So first:

1. Close the furnace doors. Caution: don't open them again!
2. Cover the exhaust holes with frax.
3. Call the instructor (Nate), plus Jim and Mike, because its unlikely that we'll all be available.
4. Rig up some lights: the emergency lighting system is only godd for a short while.
5. Move everything out of the way: the room gets pitch black dark and you'll bash your shins moving around in there.
6. If you can trap the heat, then you've got about 2 hours to get torches and propane set up for the long haul.  Don't stick torches in right away because the doors fit very well: if the exhaust holes are covered, the furnaces actually stay hot for a pretty long time - if you don't open them to peek.
7. If the outage lasts longer than this, rig up some propane torches, and try to keep the temperature up.
   

historical record

2009.08.09 #1 furnace rebuild