seen any non-keyhole plasma welders ?

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Has any one ever seen a plasma welder which DID NOT use the "keyhole"principle to weld.   It looks like the keyhole is barely different than a plasmacutter - maybe just using innert gas instead of air.  ( I am sure I am GROSSLYoversymplifying that !!!!! )My point was the keyhole welder seems to use a relatively high velocity andconstricted nozzle to form a very penetrating and tiny forcefull stream of plasma.I am thinking of something more soft and fuzzy, like an Oxy flame .........An enquireing mind.....????????Tim
Reply:Yes, it was one of the slickest welds I have ever seen. The arc start was so smooth it was amazing. Unfortunately, the unit was smaller mainly gear towar 1/4" and under. if I had a precision sheet metal shop or machine shop, it is definitely would be at the top of my list.
Reply:I worked with Thermal Arc plasma welding systems in automated welding of automotive components.  We did all our welding in the "conduction" mode, like TIG, versus the "Keyhole" mode.  I have not done keyhole plasma welding, but I know that the same equipment can be used for keyhole or conduction mode.  You generate the keyhole with adjustment to the electrode position within the torch, and with plasma gas flow adjustment.  Thermal arc has a tool to gauge the proper setback of the tungsten from the copper orifice tip.  For conduction mode welding we set the tip of the tungsten flush with the outside surface of the copper orifice tip.From what I've read, keyhole plasma can be pretty sensitive to set up and may be limited to automated setups.  Thermal Arc used to produce a gas flow controller to allow the gas flow rate to be ramped up at the start, and ramped down at the end, to transition into and out of keyhole mode.The primary reason we used plasma versus TIG in automation was that the plasma welding system allows you to maintain a small 10 amp pilot arc between the tungsten and the copper orifice tip which allows the welding arc between the tungsten and the workpiece to be started instantly  without any high frequency.  High frequency can cause problems with computer controlled automation.Thermal Arc has a rather thick guidebook on plasma welding, I can't find it on the web now, I think you may have to call and order it.
Reply:Sounds interesting !  I will look on the thermal arc web site and see what they showfor products. !Thanks, Tim
Reply:Yeah I've used them before. Personally, I was never a huge fan. We used them in manual applications at a huge sheetmetal factory. Always had problems with the arc jumping to the basemetal before the torch got close enough to the weld resulting in marks outside the weld area which was a huge problem on brushed stainless. This happened at the beginning of the weld and pulling the torch away at the end. Might have just been because none of us knew how to set it up properly I dunno. Always annoyed the hell out of me. They are also expensive to maintain.  Dropping the torch was a HUGE deal lol. They are a wee bit more expensive than tig torches. When it did work properly it was pretty sweet.
Reply:Originally Posted by i4sillypwrYeah I've used them before. Personally, I was never a huge fan. We used them in manual applications at a huge sheetmetal factory. Always had problems with the arc jumping to the basemetal before the torch got close enough to the weld resulting in marks outside the weld area which was a huge problem on brushed stainless. This happened at the beginning of the weld and pulling the torch away at the end. Might have just been because none of us knew how to set it up properly I dunno. Always annoyed the hell out of me. They are also expensive to maintain.  Dropping the torch was a HUGE deal lol. They are a wee bit more expensive than tig torches. When it did work properly it was pretty sweet.
Reply:Originally Posted by PassengerSounds like you were welding in conduction mode, not keyhole.Conduction is very much like a soft tig arc, but more stable and controlled, however with high speed pulse tig you can get better penetration than conduction plasma, keyhole however, at least for full penetration is king.
Reply:Originally Posted by i4sillypwrYeah I know Dave :P We were talking non keyhole plasma  I never liked conduction plasma but that's just my opinion.
Reply:Originally Posted by i4sillypwrYeah I've used them before. Personally, I was never a huge fan. We used them in manual applications at a huge sheetmetal factory. Always had problems with the arc jumping to the basemetal before the torch got close enough to the weld resulting in marks outside the weld area which was a huge problem on brushed stainless. This happened at the beginning of the weld and pulling the torch away at the end. Might have just been because none of us knew how to set it up properly I dunno. Always annoyed the hell out of me. They are also expensive to maintain.  Dropping the torch was a HUGE deal lol. They are a wee bit more expensive than tig torches. When it did work properly it was pretty sweet.
Reply:Originally Posted by DesertRider33Did you not have a remote control to turn the weld power on and off?  What you describe sounds like welding without a remote, which would be annoying to me too.
Reply:We had a robot mig at my old job too.  Interesting machine as it was an ac output powersource, never seen an ac mig before that one.  Very boring to run it though, I'd rather manual weld any day than run a robot.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op