gas lens = arc flash

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I'm a relative novice at tig but I'm coming along pretty well and can weld mild steel with some finnese.  I purchased a gas lens kit so I could take a crack at some stainless tubing.  Went to try it out this morning on some stainless bar and as I started to move and add filler I got flashed.  Tried again making certain of my head position and I got flashed again.I grabed a piece of 1/8 mild steel and ran a bead.  Got flashed.  Changed back to standard collet body and cup - no problem.  Swapped back to the gas lens and flashed.Now, my helmet is a northern tool so I'm sure the root cause is some shortcoming of the cheap helmet.  That aside, why is there a difference between a standard cup and the gas lens?  If anything, more tungsten stickout equals less chance of blocking the arc from the sensors.  Anyone with ideas or similar experience?
Reply:Make sure that the larger gas lens cup isn't blocking your helmet sensors (visually).  you may have changed your angle a little bit.The batteries could be getting weak (if it has any)You can weld stainless just fine with a regular cup, especially for practicing.Also, just because a gas lens allows you more stick out, you don't "need" to stick the tungsten out any more than normal.  It is nice for tight areas though.Buy American, or don't whine when you end up on the bread line.
Reply:Sounds like your hood is a piece of junk, but even in "not dark" mode the hood should provide protection against getting flash burned to some extent. Hell even safety glasses go a long way to protect your eyeballs.
Reply:Gas lens have nothing to do with flashes... ...there must be something with you helmet. Whitch helmet did you use ?
Reply:Haha, autodarkening sucks.
Reply:Those HF helmets will do that to you.  You can stick and mig with them all you like but with low current tig they will sporadically drop out on you.  You need a four sensor mask or at least one of the miller digital series with three.
Reply:Never have been flashed with my cheap lid!
Reply:I have done a lot of stainless tig and have never used a gas lens.X-ray welds; load bearing welds; etc and have never had any issues.I understand the reason behind them, but if it ain't broke don't fix it.Yes, you need a ADF that is rated for the amps of the process you are using and it needs to have quality sensors/circuitry.Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:Originally Posted by skelley521I have done a lot of stainless tig and have never used a gas lens.X-ray welds; load bearing welds; etc and have never had any issues.I understand the reason behind them, but if it ain't broke don't fix it.Yes, you need a ADF that is rated for the amps of the process you are using and it needs to have quality sensors/circuitry.
Reply:I have a miller auto helmet (don't remember model) and it has a control for sensitivity. Sometimes I forget to change that when grabbing tig torch and get flashed. Have to turn it up to high sensitivity. I have even been running beads and it will cut in and out and I just have to suck it up cause can't stop. By the way "flashing" is usually associated with actually causing some irritation to the eyes not just seeing a bright light.Millermatic 252Lincoln 175 plusTA 185tswTA 161stlhypertherm pmax 45Victor torchHenrob torchAn S10 for each day of the week
Reply:Originally Posted by SR20steveYou really outta get a gas lens, you'll love it. And with the large gas lenses you can use some huge cups like #12...I don't use anything but a gas lens.
Reply:first thing is to get rid of that POS automatic hood. they have a fail factor. use a convential hood and learn to drop the hood just before you strike the arc. there is no problem with the gas lens.the purpose of the gas lens is to gice a different type of gas flow. with a standard collet body with a ceramic cup attached the gas flows from 4 orfices and is a bit harsh as it leaves the orfice of the cup. the gas lens has layers of micro screening and the gas is bounced around and comes out of the cup orfice in a softer cloud. gas lenses can be used on all materials. the only difference between a gas lens and a standard collet body is the cost of each one.WELCOME HOME TO ALL VIET-NAM VETERANS
Reply:I'm with skelly. Tried a gas lens setup and couldn't tell 2 cents worth of difference compared to a standard cup. I'm sure they have their place, and you should use what works for you, but I'll stick with a standard cup.