After teaching hundreds of hours of welding classes at TechShop I have found that students have a hard time remembering some of the steps to get the machine set up. This instructable is to serve as a guide for people that have passed my TIG welding class but need a bit of a refresher on how to set up the machine.
NOTE: This instructable is not meant to replace the TIG welding SBU at TechShop Menlo Park, it is merely here as a supplement for those that have already taken and passed the class.
Once you have set up the machine properly you are one step close to welding a watertight cube like the one in the picture!
Step 1: Getting Ready to Get Ready
1) Get the welding cage open. If you can find a staff member roaming the shop ask them to open the welding cage. If you can't find anybody, the front desk will be happy to page the appropriate staff member for you.
2) Grab the TIG kit, a pair of TIG welding gloves, an auto-darkening helmet, the TIG calculator, a cleaning brush (specific to your metal) and any other things that you need to complete your TIG welding project.
3) Fill in the tool check out form on the clipboard. Make sure to check the TIG box before filling out the tool checkout.
Step 2: Calculating Torch Parameters
The TIG calculator is relatively easy to use. It works like a slide rule, you align the black mark with your metal thickness (for example: 1/16"), your welding joint (for example: fillet), and your metal type (for example: Aluminum or Steel).
Tip: If you don't know what your welding joint type is, there is a poster above the high voltage safety switch (the thing that looks like a giant circuit breaker) that shows the different types of joints.
Once you figure out your metal type, thickness, and welding joint type the calculator will tell you the proper:
-Gas cup orifice diameter
-Filler rod diameter
-Current type and amperage range
-Gas type and flow
Step 3: Assembling the Torch
2) Screw the correct size collet holder into place on the front of the torch (the end with the white stripe). The rounded end of the collet holder should be pointing forward.
3) Slide the correct size collet into the back end of the torch. Insert the collet with the slotted end facing forward so that the rounded edge of the collet meets the rounded edge of the collet holder.
4) Screw the back end cap onto the back end of the torch (the end WITHOUT the white stripe). Be careful to avoid cross threading as the back end cap threads are made of a harder material than the internals of the torch. You may be charged for damage to the torch if you are deemed responsible.
5) Screw the gas cup onto the collet holder. The rounded end of the gas cup should make contact with the white stripe on the TIG torch.
6) Insert the correct size and type of tungsten into the torch. See notes below.
7) The radius of the opening of the gas cup designates your tungsten stick out. If the opening of the gas cup is 1/4", your tungsten should stick 1/8".
-Make sure to use the GOLD band tungsten for AC welding and ORANGE band tungsten for DC welding applications.
-AC welding does not require that you grind your tungsten. If you leave a square edge on the end of the tungsten it will turn into a ball during AC welding.
-for DC welding, make sure that all of your grinding marks are running in the same direction--parallel to the tungsten-- in a straight line. The length of the cone (the section that is ground to a point) should be double the diameter of the tungsten.
-the collet and collet holder need to be the same size as your tungsten.
Step 4: Plugging in and Turning on the Machine
2) Make sure the high voltage safety switch (it looks like a circuit breaker) is switched off.
3) Plug the machine in to the high voltage socket.
4) Once everything is plugged in, turn the high voltage safety switch on (TIG machine on/off switch should still be OFF).
5) Now that the breaker is in the ON position, it is time to turn the machine on.
Safety Tip: Make sure to get the machine plugged in using the proper order of operations. We have increased the safety of the set-up process by using the high voltage safety switch system. There should be no voltage applied to the system until all leads are plugged in.
Step 5: Tank Opening and Setting the Gas Flow
2) Stay clear of "the danger zone" (also make sure nobody is walking or standing in the "danger zone"). The regulator should be facing away from you so that if it blows out you will not get hit by it. You should be standing in the same spot as where the camera is being held for picture #2.
3) Open the bottle with your hand on the side of the valve. Never open the bottle with your hand on top of the valve! Open the bottle all the way.
4) Set the bottle to the proper flow using the recommendation of the TIG calculator. Or you can set it to the "house" level of 15cfh.
-Make sure the bottle is in the appropriate pressure range. It should be somewhere between 250psi and 2200psi. If it is outside of this range (either above or below) find a staff member to assist you.
-Be very careful opening the bottle, the top valve of the bottle and the regulator assembly can both come flying off with enough velocity to injure or kill. Make sure that nobody (including yourself) is standing in a dangerous area.
Step 6: Machine Display Instructions
Tip: We can look at each parameter by pressing the left right arrows and we can adjust the value on the display with the knob. You can also see that the units are highlighted behind the number being displayed. Also, as we cycle through the program (with the right/left arrows) you will notice that the LED will change its location on the display. When the LED is in the black box (to the left of the capital A) we know that we are adjusting something that happens while the machine is welding. When the LED is lit up to the right of the black box it is showing us something that happens after the arc shuts off. When the LED is to the left of the black box we are looking at something that happens before the arc is started.
2) Set your maximum amperage according to the TIG calculator.
3) Set your gas post flow. It should normally be 8 seconds unless you are welding material that is 1/8" to 1/4" in which case your post flow should be 10 seconds.
4) Verify your gas pre-flow. It should be 0.1 seconds.
5) Verify your hot-start. It should be set to 20 amps.
6) If you are going to weld with DC power, the machine is ready. If you are going to weld with AC, press the AC/DC button so that the AC LED is lit up.
Step 7: Set the Ground Clamp
Make sure to clamp to something that is free of paint and rust (or anything else that can cause a poor connection). Be sure to check the cable and the clamp for signs of wear. If any problems are noticed with the clamp or cable please find a staff member to look into it.
If this is the first time you have set up the equipment by yourself--or if you are unsure of your set up procedure--please find a staff member to verify that you have the machine set up properly before striking your first arc.