Quote:
Originally Posted by ratdude747
for TIG, a trick I was taught once was to put the (pointed) end of the tunsten rod (make sure it is the "green" kind, not orange or red) about .25" INSIDE the porcelain gas shield...
also, for TIG, make sure you are set to AC, not DC if you are welding AL.
For any metal or welding type, be sure to use a wire brush to get the weld areas as oxide-free as possible... having an angle die grinder/drill with a wire brush makes this a lot easier.
Last, for TIG, this is kinda a basic thing, but make sure that you use the correct filler rod. for butt and inner angle joints, the thickness should match the thinner of the two edges being welded. for lap and outer angle joints, no filler rod is (generally) needed; sometimes it helps to "cheat" and use a bit of filler rod to get the puddle started.
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Any benefit to pulling the tungsten into the nozzle? Maybe just to keep a new operator from dunking it in the puddle?
FWIW I prefer thoriated tungsten (Red, also radioactive!
avoid unless you have vented grinding equipment!), lanthanated tungsten (orange), or zirconated tungsten (silver), over pure tungsten (green) for welding aluminum. Pure tungsten is a bit old-school and definitely not the best way to do it IMO as someone who earned an AWS welding certification in Al TIG.
Wire brushes, particularly non-stainless steel brushes, have a very nasty habit of making aluminum and other non-ferrous metals very dirty if used in weld prep. One must also ensure that stainless steel brushes are designated for one material only, i.e. aluminum, steel, or titanium, and that they are not used on a different material. I have always preferred abrasive sanding discs for aluminum weld prep because they don't contaminate the base metal, even if they're used on a different material. Though AC welding current (for AL) will break through the oxide layer as it is, and a break-arc technique will clean out even the toughest oxide deposits like anodized surfaces. Just be sure a good degreaser is used BEFORE and AFTER any brushing or abrasive prep.
In thinner sheet metal you could probably get away with just making a fuse joint for lap and outside corner welds. However, you run the risk of under-cutting the base material and causing a weak joint and some nasty stress risers. I would be very careful about specifying the right weld bead for each joint knowing that fuse joints are prone to under-cutting.