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- The process of TIG welding involves the arc creating enough heat in the workpiece to form a controlled molten pool of metal.
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00:06 |
This pool is then built up by adding a filler material of our choice into this weld zone to form a bead.
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00:13 |
Unlike MIG welding, we can control the rate at which this filler rod is added into the weld seam because we're feeding it in by hand and have control over the size, shape and look of the final weld.
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00:25 |
Filler rod material, also known as filler wire is available in a series of different diameters starting at 1 mm then stepping up to 1.6, 2.4, and then the larger 3.2 mm.
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00:38 |
The size is going to have a direct impact on the shape of your weld and it'll give you the option to include more or less filler rod depending on your choice of diameter.
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00:48 |
In motorsport, we're generally working with a limited amount of material thicknesses that are on the thinner side so this generally means that it's unlikely you'll need the largest 3.2 mm filler rod for anything under 200 amps.
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01:01 |
Choosing between the 1 mm, 1.6 mm or 2.4 mm rods really comes down to your material and the type of weld seam you want to create.
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01:12 |
For all DC welding with mild steel, chromoly, stainless steel and titanium, the 1.6 mm rod is usually a great choice due to the thickness of the material usually needed for components fabricated from these materials.
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01:27 |
You may find however that using a 1 mm filler rod for welding stainless tube will result in a flatter weld that is less raised than the 1.6 mm filler rod would produce.
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01:38 |
There's nothing necessarily wrong with either and some of this does come down to a personal preference based on the weld finish that you want to produce.
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01:47 |
As a side note, it's also possible to trim a small amount of 0.9 mm wire off a MIG spool and use this for TIG welding extremely small components with the very controllable inclusion of the small diameter wire.
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02:01 |
When welding aluminium in AC however, we usually use the larger diameter 2.4 mm filler rod or even the largest 3.2 mm if we need a bigger bead profile and faster weld speed.
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02:15 |
You've probably heard the term stacking dimes and this has a lot to do with the rate that the filler rod is added to the weld pool.
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02:22 |
Choose a diameter that's too small and you'll struggle to get enough of it into the weld pool.
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02:27 |
Go too large and you'll create a weld that's too big and this might mean that you have to add too much heat into the weld zone.
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02:35 |
A good rule of thumb here is to match the thickness of the material with the diameter of your filler rod.
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02:41 |
Diameter isn't the only thing we need to consider though, filler rods are traditionally packed in lengths nearing one metre long and because we hold our filler rod quite close to the weld pool, the long overhang can disrupt the control we have over the feeding motion so it's common to cut the rod in half with a pair of side cutters before welding.
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03:00 |
Lastly, as the filler rod goes through the manufacturing process, it can pick up oils and begin to oxidise in transport so it's important to give the rod a wipe with some acetone to remove these contaminants before introducing it into the weld pool.
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03:16 |
The strength of the weld is also dependent on the filler rod material you use to make the weld seam.
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03:22 |
There are a lot of different types of filler rod that suit many different material types and we'll go into this in detail as we get into the material specific area of the course.
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03:32 |
In summary, filler rod is available in a number of different diameters and 1.6 mm is usually used for DC welding and the middle ground 2.4 mm is usually used for AC.
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03:45 |
Getting a nicely uniform weld bead is all about how fast and consistent we are with adding the rod into the weld pool and this is something that's going to take practice to get right.
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03:56 |
Don't forget to cut your rod in half as it comes in one metre lengths, simply because this is going to make it much easier to handle when you're welding.
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