Stupid Stainless question

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Few stupid newbeeeeeeeee questions here.When tig welding Stainless what should the settings be? I am welding a 20gauge stainless box and it looks like my dog may have left this behind.Next question is when reading things and they say DC straight, does this mean neg or pos?And final, whats the best way to keep 20 gauge from warping?Thanks for any helpJames
Reply:DC Straight is DC Electrode Negative, typical for GTAW.Thin stainless very nicely responds to a pulsing unit, like my Maxstar 150 STH.  I can't remember the settings from the last time I was doing stainless sheet, maybe 60A?  Butt and corner joints will want less heat than lap joints.
Reply:stainless warps, its caused by the lack of heat conductivity, which keeps the heat in a central location causing the metal to warp.Weld quickly, pull the puddle along.  Fit up is everything when tig welding, and use LOTS OF TACKS.
Reply:One way to help you remember that straight polarity is neg is to remember that the neg symbol is a STRAIGHT line._________________Chris
Reply:Your box probably consists of outside corner joints.  This is the easiest type or weld joint in the world.  With SS corner, fit the joint up square and tight, and put small tack welds every few inches.  Now just apply enough current to get a small puddle, and fuse the seam without adding any filler.The inside of the corner may need some inert gas shielding depending on how much penetration you get, and what you need the box to look like.  You can also try putting a metal backup, a chill bar on the inside of the joint, like a section of angle or a copper bar.  This can help prevent burning though and control distortion, etc.In fusion welding without filler, called autogenous welding, it helps to keep a nice short arc length, 1/16" or less, to keep the arc small and precisely concentrated on the joint, making the narrowest possible weld, and not overheating the surrounding metal.  Travel speed can be very fast if you can hold the torch steady enough.Pretty much what drivethruboy54 said.
Reply:The key to keep it from warping is to us low heat input and weld 4inch areas diagonal from each other im building a dog box out of 16 gauge aluminum diamond tread.  46x40x23 and i took my time and kept welding diognal from each oposite bead and i got her less than a 16th out of square.  open corner joint will lay it in there nice.Last edited by infamousjer; 02-28-2007 at 10:15 PM.
Reply:Here's an easy way to remember polarity Senator = straight electrode negativeRepublican = reverse electrode electrode negative The first three letters are the key !!, Or just memorize one, the other is of course the opposite !