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Few questions:(a)When welding freehand do you always glide your glove on the metal surface or are there other ways or productsto assist with controlling arc length (eg have seen a "TIG finger heat shield" - not sure how good it is) ?(b)I understand that walking the cup is usedmainly for welding pipes - why / any reasonnot to do it in other situations ?(c)As far as I understand you only look at the puddlewhen welding because this is all you need to look at(which also removes associated danger of looking at the tungsten) - how does one gauge whether youare getting too close to the surface being welded (I can'tseem to tell how close to the surface the tip is) ?
Reply:a - ideally, yes support your torch hand / arm as close as possible to the torch without burning your flesh (TIG gloves maintain good dexterity, but are thin!) Sometimes, you can do this on your wrist or finger supported on the work, but at times this can get HOT! (And don't be a "tough guy" and try and keep welding through it... your second or third degree burnt flesh will not appreciate it.) A heat shield can be effective in some scenarios. Other examples are support your arm/hand on a clamp or bracket that is firmly clamped to your work or to your welding table. Yet another example is on the edge of the welding table. Sometimes it helps to position the work on the table strategically, so you get good torch hand support. Yet another example is elbow propped against a leg. It's not very rigid, but better than completely hanging out there in the air all the way from your shoulder (that is about as least desirable situation as you can have.) The more firm you can get your torch hand supported, the more steady you can hold the arc and reduce chances of "tungsten dipping" while holding a tighter arc. BUT - you'll also need to be able to move your torch hand along as the weld progresses. So, try a "dry run" (without arc) to make sure its going to work before lighting up the arc.b - walking the cup moves the torch sideways in a "Z" type weave pattern, instead of straight ahead (like in a straight line.) Any joint could be a candidate that has the same geometry for supporting the cup along the weld bead path. (IE: a flange or flat piece welded to a pipe, a flat welded to a flat in a straight line, etc.) This sideways movement will melt more parent metal, input more heat into the work (in general), and not penetrate as deeply as 'straight line welding' or welding "stringers". Which bead to use depends on how deep your need your fusion to penetrate, how much heat you are OK putting into the metals, desired surface appearance, etc.c - how to tell how close tungsten is to surface. To start off, before you light the arc, you can move in until you actually feel the tungsten touch the work, then just move it a bit back (desired arc length) before lighting the arc. You'll start out OK using that method. As for being able to tell the distance, make sure you are utilizing your binocular vision. In other words, position and rotate your head, position and rotate your torch, and set your tungsten stick-out so that both of your eyes have a picture of the tip of the tungsten and the puddle. (IE: if you close either eye, you should be able to see the tungsten tip / puddle with the other eye.) You can also set your tungsten stick-out, cup type, and torch angle so that as long as you hold a constant torch angle,you have the correct arc length.
Reply:I've been learning how to tig weld since June, and the TIG finger heatshield is absolutely a huge help. I would highly recommend you buy one to try. It is especially handy for out-of-position welding.worth it's weight in gold. |
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发表于 2021-8-31 23:34:25