Practical MIG Welding: Mild Steel
Watch This Course
$199 USD
-OR-
Or
8 easy payments of only $24.88 USD
Instant access. Easy checkout. No fees.
Mild Steel
04.25
| 00:00 | In this set of modules we're going to look closer into the different materials that are commonly worked with in motorsport MIG welding and how we need to treat each one differently. |
| 00:08 | Let's start with the most used option which is mild steel. |
| 00:12 | For clarity, the term mild steel refers to many low carbon steels that are commonly used in motorsport applications. |
| 00:18 | The MIG welder and low carbon steel are a match made in heaven and it's this material that 90% of MIG welders are designed to be used for. |
| 00:25 | To be clear though, MIG welding mild steel still requires good knowledge of part preparation, machine setup and welding technique in order to get the best results from your weld and it's these techniques we'll be focusing on in this module. |
| 00:38 | When it comes to mild steel preparation, although MIG welding certainly doesn't require the clinical preparation that's required for TIG welding, it definitely doesn't hurt. |
| 00:47 | By removing the majority of contaminants like rust, mill scale, oils, paint and other surface coatings, we reduce the chances of any of these contaminants affecting our weld, our health and our safety. |
| 00:58 | The cutting of mild steel can be done with high speed abrasive cutting discs like a chop saw or an angle grinder but the slow speed nature of a cold saw will produce better results. |
| 01:08 | Either way, we need to ensure that the steel is cleaned up afterwards as any type of cutting will introduce contaminants. |
| 01:15 | Setting our machine up to weld mild steel is thankfully a fairly straightforward operation. |
| 01:20 | First we need to select and use the right consumables to work with our intended material which is the gas and our filler wire. |
| 01:26 | As we've touched on already in this course, the majority of material used in motorsport fabrication, mild steel included, will suit either 0.8 or 0.9mm filler wire. |
| 01:37 | After opening up the shielding gas bottle tap and depressing the trigger on the handpiece of the MIG gun, we can set the gas flow rate to around 10 litres per minute. |
| 01:45 | As the machine would have begun to roll out the wire while checking the gas flow, trim it down to a stick out length of around 10mm from the end of the gas nozzle. |
| 01:53 | This will give us our correct stick out length and a nice clean wire tip to begin our weld. |
| 01:57 | With our physical machine setup almost complete, it's time to key in the parameters for our given welding scenario. |
| 02:03 | Remember that each machine will have differences in the way they're set up but the fundamentals of a MIG welder will remain the same. |
| 02:09 | Most machines will either have a synergic function that allows us to input our mild steel specification or at least a setup guide to get us in the ballpark by referencing our material thickness, wire diameter, gas type and amperage or voltage needed for the job. |
| 02:24 | The technique of welding mild steel depends largely on the position that we're welding in. |
| 02:28 | Unlike TIG welding, we have a spare hand for this process and it's common for MIG welders to guide the torch with both hands along the weld joint. |
| 02:35 | This is done in a pushing motion that sees the torch leant over at approximately 15-30° to point the nozzle in the direction of travel and shield the arc with gas. |
| 02:45 | As we weld our mild steel, we need to listen to the sound it's making and visually inspect the weld as it's forming. |
| 02:52 | In 90% of situations for motorsport applications, we'll be using the short circuit method of welding which we discussed in the earlier welding techniques module. |
| 03:00 | This emits a fast crackling sound similar to frying bacon as the wire contacts the weld puddle and shorts out. |
| 03:06 | Diagnosing a weld should be done during and after our welding session. |
| 03:10 | Any air bubbles, craters or discolouring will indicate a lack of shielding gas and will require us to make sure that our bottle's flow is adequate for the task that we're completing. |
| 03:19 | A good looking weld is usually a strong one and visual inspection is important both during and after our weld. |
| 03:26 | A weld that appears very small and sits on top of the part that we're welding will indicate a lack of heat and wire feed. |
| 03:32 | On the flip side, a wide sunken weld can indicate too much heat and may cause problems on the backside due to excessive penetration. |
| 03:40 | Don't forget that we can always double check our welds with destructive testing as we've covered earlier in the practical skills section of this course. |
| 03:47 | To recap the main points in this module, remember that when we're preparing mild steel, all coatings must be thoroughly removed from the material and all cutting surfaces need to be properly cleaned up. |
| 03:57 | Setup and welder settings are fairly straightforward when it comes to mild steel and most decent modern welders will have a synergic function to make things easier. |
| 04:05 | When it comes to the weld itself, we need to make sure to get that nice crispy bacon crackle sound coming from your torch using the short circuit method. |
| 04:12 | Concentrate on keeping our wire stick out even and favour both halves of the material equally. |
| 04:17 | Practice makes perfect and mild steel is the best material to perfect your craft. |
