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Tools/TIG/induction: Difference between revisions
→TIG welder induction (TIG Mode) Level 1: general updates
imported>Stever (more gas on stainless) |
imported>Stever (→TIG welder induction (TIG Mode) Level 1: general updates) |
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** The weld zone must be immaculately clean
** Cleaning the weld with solvents
*** Acetone is recommended, pure alcohols like IsoPropanol or Methanol will generally work, Meths or white spirit will not.
*** NEVER Chlorinated solvents like brake cleaner (Phosgene risk)
** Remove all solvents and cloths when done because of fire risk
** Avoid even touching the weld zone once it's clean
* Clean area for earth clamp
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*** Others are available for special job but these should cover 99.9% of welds
** Selecting a suitable diameter (diameter 50%-100% of work-piece thickness, checking chart on welder)
** Grinding a suitable point, 30 degree point, blunted tip if running higher currents
** Picking a suitable
** All fittings on the torch are hand-tight only, no tools allowed
* Torch
** Picking a gas cup from the table on the welder and fitting it, what the cup numbers mean
** Using a suitable back cap, access and clearance issues, silicone grease is needed
** Setting stick-out
** Power button on torch
*** Option of using pedal control later but for now stick to the button
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** Securing the large cylinder
** Connecting cylinder
** Open the valve slowly
** Setting suitable gas flow rate using both bottles using the table on the welder, but consider situation of weld
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* Parameters set using the middle section. We're using DC (Electrode negative), no pulse, HF-TIG in 2T mode. Back and Forward controls step through the parameters that are relevant to the selected mode
** Using the chart on top of the welder to pick settings
** If the chart isn't helping then use the following guidelines. Use all the %age changes that apply to your work, e.g. if you're doing an inside corner on
{| class="wikitable"
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! Basic Current !!
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| Inside corner || +10% current, -20% Gas flow
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| Outside Corner || -10% current, +25% Gas flow
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| Stainless Steel || -10% Current, +20% Gas flow
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** Preflow - Time in seconds, is used to establish coverage of shield gas before the arc is ignited. How much to use will depend a little on what you're doing but 0.5-1.0 seconds is usually reasonable for steel
** Hot Start - This is an extra very short pulse of current used to help establish the arc, this is IN ADDITION to the base current, so you don't need very much, 5A-20A is normal
** Base Current - This is the normal weld current that will be used for the entire weld, check the chart for an initial reasonable setting for your job. Think carefully about this one, it's your biggest factor controlling heat buildup in the weld. If you go too high the weld will overheat, but it'll ALSO overheat if you go too low because you'll have to slow down too much.
** Downslope - This is how long the welder spends backing the current
** Post-Flow - This is how long the gas stays running after the arc has stopped in order to keep the weld and especially the tungsten shielded as they cool down. It will depend on how large your weld is, huge welds might need as much as 15 seconds, a small weld with a small electrode might only need 3 seconds. We'll be using 5 seconds as a middle-of-the-road setting but you might need considerably longer on stainless steel. You must keep the torch pointed at the weld throughout the post-flow period and also note that if you press the trigger again during post-flow the arc will re-ignite instantly!
|| How to set the arc parameters
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* Overalls are required for UV protection
* We have special TIG gloves that are much lighter and less stiff than normal welding gloves which can be used because TIG doesn't generate very much radiant heat or spatter. These gloves are made of goatskin or pigskin and are specifically reserved for TIG welding and must not be used for anything else
* Depending on the welding current you may want to use shade 9-12 on the welding helmet. All settings will save your vision, you're just adjusting for best visibility. If you're used to MIG/MMA then go one setting darker than you normally would for this current. Make sure the mask is clean, dirty lenses will make this a lot harder than it needs to be.
* You may see people online welding without overalls or even without gloves. They can get away with this because of the low-spatter nature of TIG welding. DO NOT DO THIS - They are probably wearing SPF-1000 sunblock and have developed a tolerance over years, they'll still probably wind up getting skin cancer from it! Cover all exposed skin at all times while welding.
|| Using the right PPE for TIG welding
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| How to actually execute a weld ||
* Proper position of self
** TIG can be used in all standard positions, but over-head is rare and difficult as there's a tendency for the puddle to fall out onto you.
** Holding TIG torch in your dominant hand and the filler rod in the other hand
** Getting a comfortable position, sitting down if possible
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** TIG requires precise, steady movement, so it's very important to be comfortable and able to move freely while doing it.
* Proper position of torch, direction of motion
** Ideally we'd hold the torch perfectly vertical but if we did that we wouldn't be able to see what we were doing or feed in filler rod, so we normally use a push angle of 10-30 degrees. More perpendicular torch position will usually result in a better weld but consider your movement, access, and vision, angles 45 degrees or more WILL NOT WORK PROPERLY.
** Pull welding with TIG is not a thing, don't try it, but it is sometimes possible to back-track a very short distance (no more than the puddle width) in order to move the puddle around and get full fusion.
** Correct distance of the tip is only 1x-2x the diameter of the electrode you're using, and needs to be maintained very steadily. Maintaining this distance properly is the single most challenging thing about learning to TIG weld and will have the biggest effect on your weld quality
** The tip must never touch the weld or the filler rod, in fact it should never touch anything if you can help it! Even the slightest contact will require you to re-grind the electrode. With Steel this isn't too bad as you'll only loose the small section that touched, with other metals you may wind up having to grind away as much as 10mm of the electrode to restore proper operation.
* How the pool forms under the electrode, angle of the arc and how it directs the pool
* Taking the pool "for a walk"
* Moving patterns, circles, arc, steady, stepped
* TIG welding is nearly silent when done correctly, the proper sound is a very faint hiss or buzz when using DC, and a slightly louder humm or whine when using AC or pulse mode, there should be none of the popping or crackling sound associated with other welding techniques. There should be practically no sparks or spatter, if you're seeing any of them at all, you've not cleaned the work well enough.
* What I'm going to do now is to demonstrate how the TIG welder forms and moves a weld puddle, I won't be adding in any filler rod at all to keep things simple. This is usually called "reflow" welding and is the easiest TIG technique.
* [Demonstrate walking a puddle along a bit of thick material]
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| Arc too long || Puddle is slow forming, arc sounds/looks like a flame, heat zone very large || Having the arc too far away is causing the voltage to go too high and meaning the heat is spread over too wide an area
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| Arc too short || Puddle is tiny, pool rises up to touch electrode || Having the arc too short focuses the heat onto too small an area which will make it hard to join workpeices, the short arc causes the pool to actually dome upwards and move towards the electrode. When the tip touches if it gets stick don't try to break it free, stop, let it cool, take the tungsten out of the torch then snap it off the work
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| Angle too steep || Large flame-like arc, elongated puddle, difficulty controlling filler rod || The steep angle causes the arc to spread out sideways and fail to remain directly under the point of the electrode, the heat spreads too far down-weld of the torch changing the puddle shape and the plasma jet tends to melt filler rods before they can get to the pool.
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