Welding countertop help

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So I have occasionally had a family friend who owns a food equipment installation business ask me to bail them out on getting some countertops and other types of SS equipment welded.  I am a pretty good TIG welder but I don’t have a lot of experience manipulating SS sheet metal to keep it from warping.  I have done about 10 different variations of countertops, dishwashers, shelving, etc… and each time I can get them welded and the grain back pretty good but I want to know how to do without telling where it was joined and making it not look like a crowd doing the wave.  Most of my problem is with butt joints.  Corner, edge, and even the radius part of the front are easy but its the backsplash and the large flat area of the countertop.  If I could get a list of tools, fit-up, technique; like tungsten size, filler size, gap/no gap, homogenous or adding filler, do you try for full penetration, what to back it up with, how long of welds to make, do you cool the weld down after a certain length of weld, etc….What I was told is to get good tight fit-up, put a chilled thick aluminum backing bar to absorb heat and then weld the joint while adding very little filler, let cool, swap out the chilled bar for another while grinding, then polish.I have attached some pics of the mess that I was asked to fix and have before and after pics showing what I got to work with when I arrived to when I left.  One problem was that there was a to of high and low spots to fill and that the backsplash was warper really bad and I got it to pull back a little by adding a lot of weld then quenching. Another issue is that I was told I couldn’t pull the countertop away from the wall, so I couldn’t get behind it to hammer it out.My settings were: 3/32 2% thoriatedAmps anywhere from 25-75Gas 100% Argon at 20 CFH1/16 316L filler Attached Images
Reply:Gee.You say you're a welding inspector?If I hadn't read your post, I would assume that was done with stick.First tip off that you didn't have a clue was the 3/32" tungsten on gauge material.You need to do a LOT of practice on similar material before you continue to futz up peoples countertops.  Frankly, you're so far off, I'm not sure where to tell you to start.Would you "sign off" on those bird droppings?Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:As helpful as ever SundownIII, I take it III means you're the third. Jesus does that mean there's two more like you crawling this earth. Or should that be TrollingSo. you don't say what thickness this top is.  I've welded a lot (too much) 0.9mm that's 20 gauge to you. You need perfect fitup, a 1.6mm Tungsten with a needle sharp point. You don't need that much gas, 10LPM will be fine, a gas lens helps, but is not necessary. And PLENTY of tacks, too many is better than not enough. At 0.9mm amps varied from 20amp for a corner to 35-45 for a lap.Keep your welds short, on long sections, If it's not going to hold water or be seen then 1" is good with a 4-6" gapsA couple of pictures of a canopy hanger. Attached Images
Reply:Originally Posted by SundownIIIGee.You say you're a welding inspector?If I hadn't read your post, I would assume that was done with stick.First tip off that you didn't have a clue was the 3/32" tungsten on gauge material.You need to do a LOT of practice on similar material before you continue to futz up peoples countertops.  Frankly, you're so far off, I'm not sure where to tell you to start.Would you "sign off" on those bird droppings?
Reply:Originally Posted by Shox DrAs helpful as ever SundownIII, I take it III means you're the third. Jesus does that mean there's two more like you crawling this earth. Or should that be TrollingSo. you don't say what thickness this top is.  I've welded a lot (too much) 0.9mm that's 20 gauge to you. You need perfect fitup, a 1.6mm Tungsten with a needle sharp point. You don't need that much gas, 10LPM will be fine, a gas lens helps, but is not necessary. And PLENTY of tacks, too many is better than not enough. At 0.9mm amps varied from 20amp for a corner to 35-45 for a lap.Keep your welds short, on long sections, If it's not going to hold water or be seen then 1" is good with a 4-6" gapsA couple of pictures of a canopy hanger.
Reply:Originally Posted by arcboyThanks Drf255.  Not sure what Sundown's problem is.
Reply:Awe, that's too bad. I feel sorry the "Negative Nancy"
Reply:I am in the same boat.  I need a seam right in the middle of a top.  I have been practicing on some shelves I took out.   Post more when I am home tonight.  Pics and all.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David RI am in the same boat.  I need a seam right in the middle of a top.  I have been practicing on some shelves I took out.   Post more when I am home tonight.  Pics and all.
Reply:Maybe I wouldn't have been so critical if you hadn't started the post with "I'm a pretty good tig welder...".   Then you tell us you're trying to do this repair with a 3/32" tungsten.  I don't know many "pretty good tiggers" that jump right into a job without having developed the technique and skills on scrap before they take on a project like this.Here's a couple things you might consider:Fitup is critical.The two pieces should be aligned and a small autogenous tack weld should be used every couple inches to maintain alignment.  An aluminum backing bar can help here.Going back and filling in the gaps with additional tack welds is the next step.  Don't overheat the two pieces.Once the parts are tacked up securely, you can use a lay wire technique to fill the seam.  For this, I'd recommend using .035 filler (no larger than .045).  The lay wire technique involves keeping the filler at the leading edge of the puddle (not dipping).  Amps need to be set high enough that you get a quick puddle (keeps the heat from spreading out) and you need to move pretty quick.  The lay wire prevents the "high spots" you would get with dipping your filler.  Speed of movement will depend on the welder.  This is where the practice on scrap comes into play.For this job, I'd recommend a 1/16" (or smaller) thoriated tungsten, sharpened to a point.  You'll also need to maintain a "short arc length".Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Yes back it up with copper if you can lost of clamps and keep the heat input LOW no I mean really LOW NO lower... The wave form is from TOO MUCH HEAT and no place for it to go. Tack small tacks no filler about 6" apart letting the part cool to ambient between tacks.  Once tacked and cold start welding small sections about 2" or so skipping around and never letting the part get so hot you cant lay your hand on it anywhere.
Reply:Originally Posted by SundownIIIMaybe I wouldn't have been so critical if you hadn't started the post with "I'm a pretty good tig welder...".   Then you tell us you're trying to do this repair with a 3/32" tungsten.  I don't know many "pretty good tiggers" that jump right into a job without having developed the technique and skills on scrap before they take on a project like this.Here's a couple things you might consider:Fitup is critical.The two pieces should be aligned and a small autogenous tack weld should be used every couple inches to maintain alignment.  An aluminum backing bar can help here.Going back and filling in the gaps with additional tack welds is the next step.  Don't overheat the two pieces.Once the parts are tacked up securely, you can use a lay wire technique to fill the seam.  For this, I'd recommend using .035 filler (no larger than .045).  The lay wire technique involves keeping the filler at the leading edge of the puddle (not dipping).  Amps need to be set high enough that you get a quick puddle (keeps the heat from spreading out) and you need to move pretty quick.  The lay wire prevents the "high spots" you would get with dipping your filler.  Speed of movement will depend on the welder.  This is where the practice on scrap comes into play.For this job, I'd recommend a 1/16" (or smaller) thoriated tungsten, sharpened to a point.  You'll also need to maintain a "short arc length".
Reply:Looks like you did a repair that made it useable thats what counts. Backing bars are great when you can get them in there, if you have the option definitely use some. As mentioned before fitup is critical, but its not a perfect world in the field so work towards practicing ugly joints once you get the good ones down. If you plan to do more stainless kitchen things work on your polishing as well as the welding.I Have no problem using 3/32 tungsten it works fine for me, but .035 would be preferred over 1/16 for wire.
Reply:Hello arcboy,I would start by clamping heat sinks as close to the weld seam as possible, if possible (so you can still get a cup in there).  Thick aluminum bar/flat stock works well, the thicker the better.  Since copper is pretty much a precious metal these days you probably don't have any readily available.  The bars are not only used to draw heat out of the material, but also to keep it flat/straight.  I like to "sandwich" the material with bars using a clamp on each end, or to a table with bars on top.When it comes to welding it, small autogenous tacks (because your fit up is that good) every inch should suffice.  Personally, I would "back step" the weld about every inch or so (don't start on the tacks), cooling between restarts.  I like to use compressed air or a water squirt bottle to completely cool.  Here is a counter top I built for my home from 18 gauge 304 (I suggest 16 gauge or better), there's a seam near one of the sinks, a trained eye will find it. Attached Images
Reply:I really like that! did you make the sinks too?