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Motorsport Fabrication Fundamentals: MIG Welder

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MIG Welder


00:00 - Welding is often a critical part of the motorsport fabrication process as it affords us the ability to join metals together, providing a lot more flexibility around the type of fabrication projects we can tackle.
00:12 Boiled right down, the term welding refers to the base metal becoming molten and creating a weld pool before fusing together as it cools and this is different to other methods of joining metals together like soldering or brazing.
00:26 There are two main methods of welding that we regularly see in motorsport fabrication, MIG and TIG.
00:33 Both of these welding techniques have their pros and cons and the best option will come down to the specific welding job you're considering as well as the material that you're working with.
00:43 We'll start by discussing MIG welding here which is the cheaper type of welding machine and it's also easier to master compared to TIG welding.
00:52 MIG however is still a completely viable welding option for us though and is flexible enough to tackle the majority of motorsport fabrication tasks.
01:01 MIG stands for metal inert gas and is also sometimes known as gas metal arc welding or GMAW.
01:10 It relies on the welding machine feeding wire from a spool through the hand piece and onto the work piece to create an electric arc when the trigger is pulled.
01:19 This electric arc creates the heat required to melt the parent metal and produce a molten weld pool, allowing the work piece to be fused together.
01:28 The speed at which the welding wire is fed is adjustable as is the heat of the weld via the voltage settings.
01:34 This allows the machine to be adjusted to suit different thicknesses of material, ensuring a strong weld with good penetration.
01:42 The key to a good weld is a combination of setup, technique and the machine settings.
01:48 Regardless whether you're using a MIG or a TIG welder, it's essential that the molten weld pool is protected from atmospheric air in order to prevent oxidation which results in a weak, porous and ineffective weld.
02:01 MIG welders are available in two forms that achieve this aim in different ways, gas and gasless.
02:08 Gasless means that the welder won't have a provision to shield the molten weld pool by the use of an external supply of inert gas.
02:15 Instead, the gasless welder uses a flux cored welding wire that creates the gas shield needed to protect against oxidation during the welding process.
02:25 Although these welders can be effective, they really aren't well suited to motorsport fabrication and you're much better off with a gas MIG welder.
02:32 These are much more flexible machines that provide a more consistent and higher quality weld.
02:38 In a gas MIG welder, the inert gas consists of a mix argon and carbon dioxide.
02:44 Inert by definition means that the gas used remains stable and doesn't undergo a chemical reaction under welding conditions.
02:52 This inert gas is provided by a bottle that's available from your local welding supply store and the flow of gas is controlled by a screw on regulator.
03:00 Once the bottle and regulator are attached to the welding trolley, we can then set the regulator and proceed to load in the wire spool and these spools are available in different materials, including mild steel, stainless steel and aluminium and also available in different thicknesses ranging from 0.7 mm all the way up to 2.4 mm.
03:19 The correct material and thickness will depend on the material that you're welding and the specific welding job.
03:26 MIG welding is widely used in motorsport fabrication because it's quick and it's effective.
03:32 It's two to three times faster than TIG welding due to the nature of the automatic wire feed and the higher welding temperature.
03:39 Now if you've just noticed that aluminium is an option for a MIG welder and have thoughts of laying down nicely stacked dimes on your alloy fabrication projects with a MIG welder, then you're going to be disappointed.
03:51 While yes a MIG welder can weld aluminium together, the finished weld is nothing like the result that can be achieved from a well set up TIG.
03:59 MIG welding of aluminium is usually used in high volume production tasks where the speed of the MIG is key, such as boat building or architectural projects.
04:10 MIG welding is also much more forgiving when we need to weld in areas that are difficult to clean thoroughly or have layers of material with a sealer or rust in between them and this also allows you to get away with poorer fit up between parts.
04:24 It's not ideal but a MIG can fill quite sizeable gaps which would be difficult or impossible with a TIG welder.
04:31 Larger jobs like welding up framework for benches for example is also the job for a MIG welder.
04:37 We often get asked what welder should be purchased when you're just starting out.
04:41 And this really depends on what work you're looking to do with your welder.
04:44 Most fabricators will use both MIG and TIG welders equally but you can't beat a well set up MIG welder for speed and versatility.
04:52 If you only have the budget for one welding machine, then a MIG is probably the best option however it will mean you're limited when it comes to welding some materials like aluminium.
05:03 Doing justice to every aspect of MIG welding is well beyond the scope of this course and is instead something we cover in our Practical MIG welding course which is well worth checking out if you want to hone your MIG welding skills.

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