to gas lens or not to gas lens.....

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I have had a break from welding for a couple months and have more starting - so I decided to refresh my self.  Remembering that inside corners were still giving me trouble I picked that to practice.    I cut some strips of 1/8 3003 about 1 inch wide to use.   I strted with a 3/32 tungsten(thor)  and a gas lens and a large cup (#9)  -  max current 170A, 70% en ,and 3/32 4043 rod.   about 12 cfh argon.  When I tried starting arc I get a lot of dirty looking junk on the surface which prevents the puddles from being wet and clean and shiney- I can see the crap forming on the surface as soon as the arc starts.  Does not happen on flat work.   I noticed a couple of times that after the weld the tungsten was cobalt blue- which told me it was getting oxygen somehow.   So I cranked the gas up to about 16-18 cfm and that helped the blue tungsten but the starting puddle - while better was still not properly clean.Took all the front off my torch and put on a non-gas lens front and screwed on a small nozzle (about 3/8 id on end)  and still used the 3/32 tungsten.    Used least stick-out to reach the vertex.  gas at about 15 cfh - all other parameters the same.   Kept the tip of electrode down less than 1/8 from work- attempting 1/16 -    the resusults were like nite and day.   The puddle started pretty well without so much drama- and the bead was beautifully shiney and clean with nice crisp texture (not overheated) - WAY better than the gas lense.   I mentioned this once before and everyone laughed at me- but it seems like the gas lense and 90 degree inside corners dont play well together.   The lense seems to work well on flat and outside corner but not on inside corner.   Has anyone else come to this conclusion ?I know some people dont like the lenses and some do.  Laugh if you want but thats what I found........Tim
Reply:I would say the closer to the work you can get the cup the better..the inside corner and big cup wasnt the best solution if you could fit a small cup much closer, the dirt was probably from the surface not cleaned enough or far enough away from the weld and junk got pushed into the weld area, switching lense no lense would depend on the project. as other threads here have shown the tungsten bent for getting into tight spots, all comes back to practice and what your comfertable with. what works for one person may not work for another...Of all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...
Reply:Bad comparison.The whole issue stems from "arc length", not type of lens.Did you even try using a smaller "gas lens cup"?One of the main reasons for using a gas lens in the first place is that it gives you the ability to extend the tungsten further out from the cup and still maintain gas coverage.Also, on an inside corner, the gas is "more confined" (disperses less) so you can generally turn the flow rate down a bit.As is so often the case, the inexperienced welder would rather blame the equipment, rather than the true problem.  The weldor.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:A number 9 cup would typically like to run 20 to 23cfh of argon. More with helium.As mentioned earlier, a smaller gas lense cup would be in order. The only other thing that could compromise the gas flow would be fouled screens. Have a good day.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Im with Sundown on this one ,Whilst most people would think  to turn the gas up a bit when increase your tungsten stick out to maintain coverage, I have had success with reducing it , not much but a bit.I suspect this has to do with setting up turbulence on an internal corner.I have never used a Gas Lense , cant comment on them.A good guess is better than a bad measurement
Reply:I'm with shovelon, large nozzles require higher gas flow.  The #9 nozzle has 2.25 times the area of the 3/8 (6) nozzle you ended up with.  If you apply the same techniques to a gas lens ... cup size, stickout and arc length, I think you would achieve the same results with the same or lower gas flow.Dynasty 300DXSmith He/Ar gas mixerMM350PHobart Handler 120Smith LW7, MW5, AW1A
Reply:I think I tried a small gas lens cup too - but I cant remember the result- must not have been great.I can rule out arc length as it was the same for all the welds.  When i was using the big cup gas lens at about 12 cfh I noticed a small soot ring on the work on the far side of the cup.  I then turned it up to about 15-18 cfh and the ring disappeared.   I dont think there is a major surface dirt issue - maybe a combination of not enough gass for the cup size and some kind of swirl going on down in the corner.  I can weld all day long (and have) with that big  gas lens cup operating at 10-12 cfh in the FLAT position.  Starts clean -welds clean - nice shiney bead.I get the feeling that a narrower column of gas with the small cup (and the cup is closer because its narrower) is getting more gas in the corner where the action it than the big one is .   I will try the smallest gas lens cup compared to a similar size regular cup. sorry sundown- dont understand what you ment by  "bad comparison" -   and I dont get what you mean by "arc length"  as my arc length was the same for all.    I am just trying to systematicly weed out each variable one at a time untill I hit the one which causes the problem.   Thats how I learn things when there is no one beside me watching me that I can ask ( which is all most all the time)I will give another report with what happens between the smallest cups gas-lens/no gas-lense.Tim
Reply:Originally Posted by jethroI think I tried a small gas lens cup too - but I cant remember the result- must not have been great.I can rule out arc length as it was the same for all the welds.  When i was using the big cup gas lens at about 12 cfh I noticed a small soot ring on the work on the far side of the cup.  I then turned it up to about 15-18 cfh and the ring disappeared.   I dont think there is a major surface dirt issue - maybe a combination of not enough gass for the cup size and some kind of swirl going on down in the corner.  I can weld all day long (and have) with that big  gas lens cup operating at 10-12 cfh in the FLAT position.  Starts clean -welds clean - nice shiney bead.I get the feeling that a narrower column of gas with the small cup (and the cup is closer because its narrower) is getting more gas in the corner where the action it than the big one is .   I will try the smallest gas lens cup compared to a similar size regular cup. sorry sundown- dont understand what you ment by  "bad comparison" -   and I dont get what you mean by "arc length"  as my arc length was the same for all.    I am just trying to systematicly weed out each variable one at a time untill I hit the one which causes the problem.   Thats how I learn things when there is no one beside me watching me that I can ask ( which is all most all the time)I will give another report with what happens between the smallest cups gas-lens/no gas-lense.Tim
Reply:I would say the closer to the work you can get the cup the better