This is very much a work in progress.

Tools needed:

• One (1) 1/8“ wrench (open-end) (Available in the maint cart)
• Two (2) 1/2” wrenches for work on the MIG gun

Always have two people to change out cylinders; it's useful to have extra muscle, or a spotter.

Cylinders (both full and empty) are stored against the cages behind the metal lathe.

Cylinders in storage must be secured with a chain or ratchet strap.

Cylinders in storage:

• 100% argon
• MIG Mix (25% CO2, 75% Ar)

Cylinders are labeled with their contents. Make sure you are getting the correct bottle.

Do not move cylinders without a cap on the cylinder, securing the valve.

Close the valve on top of the gas cylinder.

If the indicator dials on the regulator show pressure in the system, we must purge the lines.

With the welder unit powered on:

1. Turn down the wire speed and voltage as far as possible
2. Hold the gun far away from the ground clamp
3. Pull the trigger until the dials register no pressure in the regulator.

Cut off extruded wire, coil the gun tube, and stow the gun.

Note: if you have a large amount of excess wire, put it in the box in the powder coat area. The wire is useful for hanging workpieces while powder coating or curing.

With the cylinder valve closed and the lines purged:

1. Find a cylinder cap. (There should be a cap next to the base of the cylinder, but it may have migrated to another part of the welding area.)
2. Loosen the compression fitting on the regulator. (Use the 1 1/8“ wrench.)
3. Remove the regulator. (Move the regulator and the hose out of the way.)
4. Put the cylinder cap on the cylinder.
5. Undo the chain holding the cylinder to the welder.
6. Lift the cylinder off of the welder and onto the floor.
7. Spin the cylinder to a dolly.
8. Bring the empty cylinder to cylinder storage.
9. Secure the empty cylinder in storage with a chain or a ratchet strap.

1. Transport new cylinder from storage to the MIG Welder.
2. Lift the cylinder onto the cylinder shelf.
3. Secure the cylinder to the welder with the chain.
4. Remove the cylinder cap. (Place the cylinder cap on the shelf at the base of the cylinder.)
5. Attach the regulator. (When hand-tightening the compression fitting, keep the regulator supported.)
6. Tighten the compression fitting with the 1 1/8” wrench. (DO NOT OVER TIGHTEN. Use the wrench to tighten the fitting about a quarter turn past finger-tight.)
7. Spray soapy water on the fittings.
8. Open the cylinder valve fully to charge the cylinder. (Use the gray valve handle; it will indicate for the next user that the valve is turned open: red is open, gray is closed.)
9. Inspect the fittings for any leaks. (The soapy water will noticeably bubble in the presence of leaks.)

TODO: add/film a demonstration of soapy water showing a leak?