GTT Bobcat Torch

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Glassworking




Hive13 Equipment
List of All Documented Equipment
HV0058.jpg
Owner/Loaner: Hive13
Hive13 Asset Tag: HV0058
Make/Model: GTT Bobcat (google)
Arrival Date: December 2019
Does it work?: yes
Certification Needed?: yes
Contact: Kevin M
Floorplan: Hot Crafts Area
GTT_Bobcat_Torch.png



About this Item

This is a small, single stage glassworking torch.

Plumbing for Single Stage Bench Torch

The GTT Bobcat Torch and Nortel Minor Torch are plumbed independently to their own bottles with thier own regulators and flashback arrestors per the diagram below.
Single Stage Torch Plumbing Diagram

Operation

Lighting the Torch

This torch is setup as the Right Small Torch on the bench, Be sure to identify the gas bottles which are connected to this torch by the labels on the hoses.

  1. Check that both valves on the torch itself are shut (clockwise to shut, red is propane, silver is oxygen)
  2. Check that both Regulators on the bottles are backed out/reduced to minimum pressure (counter clockwise to reduce pressure)
  3. Open the gas bottle valves, crack open slowly till pressure shows on gauges and then open fully so that the valve is firmly backseated to prevent gases from leaking at the valve stem.
  4. Adjust the regulators for each gas so that the outlet gauges read 5 PSI for the propane and 10 PSI for the Oxygen (clockwise to increase pressure, note that pressure will not decrease till the torch valves are opened)
    1. Do not light the torch unless both propane and oxygen gauges indicate between 3 and 15 PSI.
  5. Ensure the vent hood is ON any time the torch is lit.
  6. Using the striker, light the torch by striking near the tip of the torch and slowly opening the gas valve (only gas, no oxygen) til the flame ignites and is sustained.
  7. Adjust the gas till the flame is approximately 5-6” long using the valve on the torch.
  8. Check the gas regulator outlet pressure. Adjust the gas regulator til the outlet pressure reaches 5 PSI. Adjust the torch gas valve intermittently while adjusting the pressure regulator to maintain the flame size at 5-6 inches.
  9. Slowly open the oxygen valve to introduce oxygen to the flame. The flame should brighten from yellow to white and blue, increase the oxygen flow till the yellow and white portion of the flame shrinks into 7 small white “candles” at the torch tip.
  10. Check the Oxygen regulator outlet pressure. Adjust the Oxygen regulator til the outlet pressure reaches 10 PSI.
  11. Using the valves on the torch, adjust the oxygen and gas till the 7 white “candles” in the flame are 6-9mm (¼” to ⅜”) long. If the candles are rough or sharp looking with yellow streaks, increase the oxygen or reduce the gas til the tips of the candles are nearly smooth and white, with the slightest bit of fuzzy yellow at their tips.
    1. The blue portion of the flame beyond the candles should be uniform blue without streak or gaps.
    2. If there are dark streaks or gaps in the blue portion of the flame, and the torch is hissing loudly, This is an oxidizing flame. Decrease the oxygen or increase the fuel to reach neutral.
    3. If there are yellow/white streaks in the blue portion of the flame, or the whole flame is yellow/white, this is a reducing flame. Increase the oxygen or decrease the fuel.
    4. A picture of a neutral flame is below.

Neutral Flame

Shutting Down The Torch

  1. Turn off the torch using the torch valves. TURN OFF OXYGEN FIRST, THEN PROPANE.
  2. If you plan to keep working, you may leave the gas bottles open and the lines pressurized to relight the torch without re-adjusting the gas system. However, if you plan to stop for more than 15 minutes, please continue the following steps and depressurize the gas lines.
  3. Ensure the vent hood is ON during gas burnout.
  4. Firmly shut the valves on both the oxygen and propane bottles.
  5. Without opening the bottle valves, light the torch using only the propane, and allow all the propane gas to burn out of the lines.
  6. When the propane only flame goes out, close the propane valve on the torch.
  7. Open the oxygen valve at the torch to release the oxygen from the lines.
  8. Close the oxygen valve on the torch.
  9. Turn both regulator knobs counterclockwise (decrease) as far as they will go to relax the regulator diaphragms.

Lampwork Safety

Safety Glasses

  • Didymium glass or polycarbonate safety glasses are required for anyone sitting at the torch working soft glass (Phillips 202 or Phillips Sodium Flare Poly lenses)
  • UV blocking safety glasses or film glasses for any observers
  • Hot glass can crack and pop as it cools, so eyes must be protected from flying shards
  • The torch generates significant UV light that can lead to eye damage if not filtered by appropriate eye protection
  • Soda lime glass generates a very bright flare when inserted into a flame that can cause eye damage if not filtered by appropriate eye protection

Fire/Flame Safety

  • If anything related to the gas bottles, gas lines, torch, or flame seems wrong or there is unintended fire, IMMEDIATELY shut the bottle valves on the oxygen bottle and propane bottle.
  • Always wear short sleeves or roll up long sleeves.
  • When starting the torch, always light the torch with propane only, then add oxygen to the flame. When shutting off the torch, always turn off the oxygen then turn off the propane.
  • Never reach into, in front of, or across the flame.
  • Always ensure the torch is securely mounted to the table and the mount pivots are tight, with the torch pointed at an upward angle.

Hot glass and tool safety

  • Any hot scrap glass bits should be placed in the water filled cullet cup so that hot shards are contained as they cool. If molten glass falls on the table or floor, pick it up with tweezers and put it in the cullet cup
  • Place hot glass rods on the rod rack to cool, not on the table top.
  • Always place tools and glass rods on the table or rack with the hot end away from you so that you do not accidently grab the hot end when picking them up

Fumes, Vapors, and Ventilation

  • Always have the vent hood on when using the torches. Reducing or oxidizing flames generate unsafe combustion products, so keep the flame neutral as much as possible.
  • Certain glasses and colors contain unsafe heavy metals and oxides that release toxic fumes when molten. While most standard colors release so little as to be safe, take extra caution with specialty colors advertised as high silver or uranium bearing, vent hood use is mandatory for these glasses.
  • There is a process for coloring finished glass pieces called metal fuming. This process involves placing heavy metals directly in the flame which vaporize and deposit on the workpiece. Use extreme caution if you choose to do this, vent hood use is mandatory.
  • Powdered glass and glass dust can cause silicosis (which is like a bad lung cancer that forms around particles in your lungs). Vent hood use is mandatory when working with powders, frits, or enamels, or when breaking glas rods and tubes.


Asset Tags

Asset # Description Owned by
HV0058 GTT Bobcat Torch Hive13