Motorsport Fabrication Fundamentals: TIG Welder
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TIG Welder
06.02
| 00:00 | - We've just covered MIG welding in the last module, but the other common welding technique used in motorsport fabrication is TIG welding which is a much slower but much more controllable option. |
| 00:11 | This is an important skill within the motorsport fabrication industry that allows us to weld ferrous and non ferrous materials with complete precision. |
| 00:19 | TIG stands for tungsten inert gas but is sometimes known as GTAW which stands for gas tungsten arc welding. |
| 00:27 | Unlike MIG welding, there are no provisions for gasless welding in the TIG process. |
| 00:33 | These welders are also available in DC only or AC/DC machines. |
| 00:38 | AC or alternating current is essential if you want to weld non ferrous materials like aluminium whilst DC or direct current is used to weld ferrous materials like mild and stainless steel. |
| 00:50 | AC/DC combination machines are a popular addition to many fabrication workshops and in recent years the pricing and the physical size of these machines has dropped significantly making them much more accessible to the enthusiast market. |
| 01:05 | A TIG welder relies heavily on the use of shielding gas which is released through the TIG torch to protect the molten weld pool. |
| 01:12 | Argon is the most widely used form of shielding gas you'll come across and the amount of argon used is dependent on the setting of the gas regulator which is attached to the argon bottle and adjusted with a flow rate valve. |
| 01:25 | The flow rate is critical to maintaining enough shielding gas coverage during the welding process. |
| 01:31 | Most TIG flow rate valves have a small ball bearing inside a glass tube that has increments that will tell us the flow rate once the gas is running through the torch. |
| 01:41 | When learning to TIG weld, we usually start by setting the flow rate between 7 and 15 litres per minute but this won't always be the case. |
| 01:49 | The reality is that the ideal gas flow will change with each different weld setting, different sized cups, different weld angles, different materials and even welding outside also requires us to make changes to our flow rates to ensure a protection of the weld pool. |
| 02:05 | You might be thinking that we could just crank up the flow rate to cover all situations but it doesn't really work like that. |
| 02:12 | First of all, argon is expensive so obviously we don't want to waste it needlessly by using an excessive flow rate. |
| 02:19 | We also want the strongest weld that we can get so it all comes down to finding the right balance and having the right flow rate. |
| 02:26 | The process of TIG welding is superior to MIG welding in many ways. |
| 02:30 | But chiefly because of the control it gives us over the arc. |
| 02:33 | This allows us to be very precise with where the arc is directed as well as exactly how much heat we introduce into the material we're welding. |
| 02:42 | This is critical for some materials such as chromoly which can become brittle around the weld area if too much heat is inputted into the material during the welding process. |
| 02:53 | A quality TIG welding machine will give us enough adjustability to control our weld irrespective of the material we're welding the thickness of the material or the location of the weld. |
| 03:03 | Without going too far into the specific operation of TIG welding, we're able to adjust many key elements of our weld, not only from the machine but also as we travel along our weld via an optional foot pedal or an adjustable dial on the TIG torch. |
| 03:19 | Having control over functions like pre and post flow of shielding gas, up slope and down slope of weld amps and the speed and frequency of the amperage pulse means that we can manipulate and tune the weld to get the best possible results. |
| 03:33 | This probably seems like a lot of information to think about but you really don't need to go too deep into this when you're just beginning to learn how to TIG weld. |
| 03:42 | A modern machine like our SWS TIG that we're using here has an easy start function that basically gives you suitable settings to get started for the particular material and thickness that you want to weld. |
| 03:54 | From there, you can then switch into pro mode and gain complete control over your machine settings and functions. |
| 04:00 | The operation of TIG welding relies on the tungsten electrode which directs the arc onto our work piece. |
| 04:07 | Tungsten has one of the highest melting points among pure metals at nearly 3500°C and this makes the tungsten electrode perfect for creating the arc and the resulting weld pool in your work piece. |
| 04:19 | The nozzle that surrounds the tungten electrode is most commonly made from alumina oxide and is pink in colour. |
| 04:25 | This nozzle or cup as it's commonly known must also withstand high temperatures in order to direct the shielding gas over the tungsten and through to the molten weld pool and surrounds. |
| 04:36 | When welding materials like stainless steel and titanium, the importance of this shielding gas means that we must fine tune the gas coverage and the way the nozzle directs this onto the arc. |
| 04:47 | For this reason, there are multiple cup designs available that direct the gas flow in various different situations. |
| 04:54 | With a TIG welder, the arc can be initiated by either the push of a button on the hand held torch or a foot pedal on the floor. |
| 05:01 | The reason a lot of fabricators will use a foot pedal is that it allows them to control and adjust the amperage mid weld, without having to take a hand off the torch, the filler rod or the work piece. |
| 05:12 | Depressing the pedal further will increase the amps to increase the heat being generated at the weld pool. |
| 05:18 | You can then back off the pedal and reduce the amps as the material reaches the desired temperature. |
| 05:24 | It's at this desired temperature that our molten weld pool will start to form and we can then begin moving the weld along by adding our filler rod while modulating our amps via the foot pedal. |
| 05:34 | At first, this action may seem a little hard to coordinate but a steady hand and a lot of practice is what's required. |
| 05:41 | Just like the MIG welding we covered in the last module, doing justice to every aspect of TIG welding is beyond the scope of this course, which is why we cover it in detail in our Practical TIG Welding course. |
| 05:53 | If you want to master TIG welding on a variety of different materials then this course will be the perfect addition for you. |
