Practical MIG Welding: Wire Spool
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Wire Spool
06.49
| 00:00 | Welding wire is one of the most important consumables we use in MIG welding. |
| 00:03 | This comes wrapped on a plastic spool which is then fitted into the MIG welder and attached securely to the spigot that will guide the wire into the drive rollers that control the wire speed. |
| 00:13 | Your MIG welder's physical size will dictate the weight of spool that can be fitted onto the spigot and this will be listed in the manufacturer's specifications. |
| 00:22 | The wire spool will need to be purchased separately to the machine and this brings us to the next few variables, the wire type and diameter. |
| 00:30 | The type of wire we need is dependent on the type of material we're welding. |
| 00:34 | The most common of these is low carbon, mild steels. |
| 00:37 | For steel, there are two common wire types known as ER70S-2 or 3 which is good for general fabrication wire and ER70S-6 which incorporates more deoxidisers to tackle dirty and rusty steels. |
| 00:52 | Both of these wire types have a copper coating that improves the electrical conductivity to transfer the electrical energy from the contact tip into the wire. |
| 01:01 | Stainless steel can also be welded with a MIG welder, but you need to be mindful of the material type you're welding and the type of MIG wire that's available for those different grades. |
| 01:11 | The three most common grades of stainless steel wire are 308, 309 and 316. |
| 01:17 | These wire grades may also have an L designator which indicates that the wire's carbon level falls in the low end of the carbon range. |
| 01:24 | It may also be common to see the SI designator indicating a higher silicon content. |
| 01:30 | This provides more fluidity of the weld puddle and is recommended. |
| 01:35 | One thing to note here is that shielding gas requirements differ between MIG welding stainless steel and mild steel. |
| 01:41 | Higher levels of carbon and oxygen in the shielding gas react with the stainless steel arc, resulting in some oxidation and reduction in corrosion resistance. |
| 01:50 | This means that the maximum level of oxygen or carbon dioxide that should be used as a shielding gas mix for stainless steel is 3% oxygen and 5% carbon dioxide. |
| 02:01 | Now, if we reference back to our earlier shielding gas module, you'll see that Argo shield light falls within this range, but Argo shield universal has 16% carbon dioxide making it possible, but not ideal to weld stainless steel as it'll reduce the corrosion resistant properties that stainless steel was developed for in the first place. |
| 02:21 | Another notable metal that we can MIG weld is aluminium. |
| 02:24 | This is possible to do, but it does come with a few intricacies. |
| 02:28 | The problem is that aluminium is a very soft metal and the difficulty lies in feeding this very small wire through the length of the MIG gun lead where the resistance can easily cause the wire to bunch up and bird's nest at the rollers. |
| 02:41 | To combat this, most aluminium MIG wire is produced from 5356 grade which is stronger than 4043 grade and can feed through the rollers and put up with a little more resistance through the MIG gun lead. |
| 02:53 | Most welding machine manufacturers will also offer a product for aluminium MIG welding called a spool gun which carries a small spool of aluminium wire in the handpiece of the gun and brings a few benefits. |
| 03:05 | First it means that the spool can be easily set up onto the MIG welder without changing your welder's roller settings or wire spool and second, you won't have to worry about contamination into the aluminium wire feeding its way through a torch lead that has had many other materials push through it on the same liner. |
| 03:21 | It's not all benefits though and there are some considerable downsides. |
| 03:25 | The handheld spool can be extremely heavy and difficult to get into tight places. |
| 03:30 | And realistically it's also money that may be better spent on getting a separate ACDC TIG welder if you have a lot of aluminium welding to do. |
| 03:38 | The shielding gas needed for aluminium MIG welding differs from mild and stainless steels too. |
| 03:43 | Straight argon is required and this further drives home the point that it might be better to look into upgrading to an AC TIG for your aluminium welding needs. |
| 03:53 | Regardless of what metal you're welding, we have a selection of wire diameters to choose from ranging from 0.6mm up to 1.1mm. |
| 04:02 | The most common sizes however that we'll see in motorsport applications will be 0.8 and 0.9mm diameter MIG wire which is suitable for material thicknesses ranging from 0.5mm sheet metal right up to 10mm thick plate. |
| 04:17 | Having multiple wire spools for different applications may seem like a good idea, but we need to make sure that we store and protect our roll of wire to ensure that it won't be subject to moisture and corrosion. |
| 04:28 | When buying a new spool of MIG wire, it will be sealed in plastic to fend off moisture for prolonged storage. |
| 04:34 | It's important that you keep the wire sealed in this wrapping until it's ready for use and if you want to swap and store your rolls of wire, then it's a good idea to do so in a dry environment to fend off corrosion. |
| 04:45 | Corroded and oxidised MIG wire can be identified by a dull or dusty finish to the usually bright luster of the copper coating on the wire. |
| 04:54 | This affects the way that the MIG gun's contact tip transfers the electrical energy into the wire, causing the potential for inconsistent welding problems that can be difficult to diagnose. |
| 05:05 | This oxidised wire will also damage the liner of the MIG gun lead and cause wear over time, leading to costly repairs and potential cross contamination should you run a different material wire through the machine. |
| 05:17 | Regardless of what material we're looking to weld, it's important to do our homework when it comes to wire selection, but for the majority of mild steel MIG welding operations like sheet metal floor sections, bodywork, roll cages and any chassis modifications, ER70S-6 will be able to handle it all in either 0.8 or 0.9mm diameter for any MIG welder in the 200 amp range. |
| 05:42 | There are many types of specialised MIG welding spools available for specialised applications. |
| 05:47 | The manufacturer of these spools will list the wire's intended use, machine polarity, material thickness suitability and type of shielding gas that will be recommended in order to get the best results. |
| 05:59 | Do a little research on these before moving forward because buying a new bottle of gas, a roll of specialised wire and the extra setup time may not be worth the expense or effort. |
| 06:08 | Let's quickly cover off the key takeaways before moving on. |
| 06:12 | A welder's physical size determines the wire spool weight that it can accept. |
| 06:17 | Different metals require specific wire types so it's important you properly understand the job that you're doing and know what type of wire you need before ordering. |
| 06:26 | Wire diameter options range from 0.6 to 1.1mm, however 0.8 and 0.9mm are usually the most common that we'll use in motorsport fabrication. |
| 06:36 | Proper storage is crucial to preventing wire corrosion. |
| 06:39 | If a rusty wire is used, the resulting weld can be dull and the gun itself can also be damaged. |
