TIG and Stainless - with questions

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I'm in my 4th Saturday of my ACC welding continuing ed class using TIG. It's been a slow go but I'm quickly learning that I'm addicted to it.Yesterday I grabbed some of the scrap that we use to surface on for practice and made a couple trays (thanks to another thread on this site that gave me the idea)......Stainless is much harder to TIG than mild steel. It wants to dance all over the place with just a little bit of heat. That..... coupled with my non-smoothness with laying rod and dealing with the foot peddle at the same time..... I decided to try and weld it up as much as possible using no filler. This way I could go fast. But the fitup was bad, so in a  few spots I had to use filler..... it is ugly..... but they do hold water without leaking!Question is: Can I use a flap disk on stainless to clean it up and make it look better? Is that normal to do on stainless?Here are pics of my first whack at Stainless yesterday......(Warning..... FUGLY pics below) Attached Images
Reply:Yes a flap disc is better than a wheel for cleaning up stainless.   Your goal should be grind before welding not after.   A wire wheel will make it look better too.  If its a real job, stainless wire wheel.   Nice box.  :thumbup:Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by Fexal. It wants to dance all over the place with just a little bit of heat.
Reply:Could also be trying to run too low an amps on too large a tungsten.You have some sugaring from burn thru in the 1st pict on the inside.I can't tell how you set up the joints, but good joint set up will make this very hard or much easier depending on how you did the prep.I made a few notes on your best one even though the picts are not that great.The yellow circled area looks good and should be what you are looking for. Very little color to the weld, and it looks well wetted in. The red area is just a bit too hot, hence the extra color, but no heat marks way out on the plate. Could use some extra filler possibly to help with the heat. Blue areas are definitely too hot even though I can't see the weld. Attached Images.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Thanks DSW! That is very helpful.The Yellow I used filler. I was using 3/32 on 65 amps. I'm still working on pedal control so it is very possible I had the peddle to the metal.The Red area I was using no filler. I was just dragging the torch along and letting the pieces melt together. I was moving fast but steady right there.The blue........ more filler, but going too slow so I burned through, then spent an eternity trying to fill it in.And I didn't clean anything. Just grabbed random scrap out of the bin that happen to fit pretty close.Thanks for the feedback. This is helpful!Last edited by Fexal; 02-19-2012 at 11:43 AM.
Reply:what thickness is the material?stainless should be easier to weld then steel, it almost welds itself if the fitment is good.  I haven't been welding for more then a couple of years, but i have had pretty good success with stainless.  There's a few things you got to do before stainless almost welds itself:1. cleanliness.  Since SS can be welded autogenously, if you don't get rid of dirt, grease and contaminants it will make your bead porous, ugly, or difficult to control while welding.2. fitment.  too much gap will create sugaring.  If the puddle is exposed to oxygen in the air, it will "rust" immediately, so try to keep the gaps between pieces to a bare minimum.  For best result: no gap.  Unless you're running a back purge... (that's another story all together)3. proper size tungsten for the amount of heat you need.  I tried welding 24 gauge SS with 3/32 tungsten.  Not gonna happen with my chops.  But once i switch to 1/16 tungsten, immediate success.  (I bet it's not because my welding "mad-skillz" suddenly got better)4. heat sink.  Even if you have the best of fitment, thinner SS will distort a lot with heat.  Rendering your perfect fitment useless by creating gaps (gaps = bad).  use a block of aluminum or copper behind the weld.  This not only take away excess heat, it also blocks the amount of oxygen exposure on the backside of your puddle.I'm sure there are more things to watch out for, but this is all i know.  good luckhere's an example http://weldingweb.com/vbb/showthread.php?t=68391Last edited by oxy moron; 02-19-2012 at 12:57 PM.
Reply:When everything is right stainless flows like butter.   When its wrong....ANY contamination on the tungsten and I get a new one.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:The Flap Disk....... Makes it like perfect.......For the exception of the guys in the welding shop....... the guys in my department (sales) will think I'm awesome......... I will have them so fooled!!! Attached Images
Reply:If you want something a little more "showy" and sharper edges, when I welded some windshield posts for my buddy with my wire feed and straight argon (not pretty welds but did get penetration) I ground a majority of the weld down with a flap disc then I took the time and finished it with a DA sander and 80 grit.  Nice sharp edges.  Not as rough of finish.  He said he's going to polish them but it's been over a year and I doubt he will.  Probably wouldn't have turned out as nice as they did if I let him finish it, he probably would've just left the welds.  This shows how the post is formed:
Reply:acc is rumored to have a pretty good blacksmithing program, ever wander around those parts? try not to use your flap disks for stainless and carbon, as you'll probably get some contamination, ie rust spots. though flapdisk are made to wear away and expose new abrasive so it may not be a huge concern.  i keep separate everything for grinding steel and ss.   i've found that flap disk and sanding pads almost always take off more material than hard wheels, they dont last as long, but they make for less grinding