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This is a repeat of a post I made to a bicycle building forum - you can find that thread (including a couple of photos) here: http://www.frameforum.net/forum2/ind...opic=2938&st=0
Ok, at this point, this issue has confounded me, the good folks at General Air, my old welding instructor, and everyone else I could think of to ask. Looking for any kind of weird idea at this point - I am baffled.
The symptoms: I'm getting greyish, lumpy deposits on the surface of my tig welds. Glowing embers are visible in the weld pool while welding, as well. Clearly, something non-inert is getting to the weld, but I'm stumped at this point as to what it might be. The arc also has a tendency to wander and is relatively hard to control. Strength of the joint seems unaffected - I've done some destructive testing to make sure. But the appearance is sub-par from what I'm used to doing. See the pictures in the frameforum thread for some of the worst examples. This problem began about 2 months ago for no apparent reason - I've been using the same materials and techniques with no problems since early 2003.
The problem occurs on both my (brand new) Dynasty 200DX and my older 2003 vintage Maxstar 150STH.
Solutions I've tried with no effect, in no particular order:
-Check (no leaks) then replace regulator, all hoses, torch body and parts.
-Replace entire welder (hey, I always wanted a Dynasty anyway...)
-Use different type (ceriated and thoriated), size (3/32 and 1/16), and brand of tungsten.
-Use different gas cups and lenses of all different sizes.
-Change argon flow rate to torch from as low as 5cfh to as high as 35.
-Replace argon tank (multiple times) and try argon from another supplier.
-Replace tungsten grinding wheel with new ($$) diamond wheel.
-Sharpen tungsten to fine point, sharpen tungsten then grind flat, etc. I've pretty much tried every shape of grind you can think of.
-Close all doors/windows and completely eliminate any possibility of drafts (it's notable that I never used to have this problem when welding with a fan running on a hot summer day).
-Use different type/size of weld rod (ER70S and 880t in .035 and .045).
-Use different cleaning procedures (acetone vs denatured ETOH, stainless wire brush vs emory cloth vs scotchbrite vs 3m metal cleaning pads).
-Use different tubes (happens with 4130, everything made by True Temper, all Nova/Columbus stuff that I have, and even old Tange prestige).
-Backpurge/don't backpurge tubes.
-Change welder settings all over the map - from 70 to 120 amps, pulse rates from .5 to 2/second, different background/peak, etc, etc.
-Swap polarity.
-Keep all hoses/lines in warm, dry place for 2 weeks to make sure no moisture is inside.
-Move entire welding setup 10 feet to another location in the shop.
-Clean welding table/replace ground clamp to ensure good ground.
-Probably a few other things I can't remember now.
I've done some sample welds using other equipment at other locations and I have absolutely no issues, so it's not anything about torch angle or technique (and given that nothing about my technique changed in the last 3 or 4 years, whereas the problem started about 4 months ago, I doubt that it's a technique issue).
I'm pulling my hair out on this. Any clever ideas?
-Walt
Ok, at this point, this issue has confounded me, the good folks at General Air, my old welding instructor, and everyone else I could think of to ask. Looking for any kind of weird idea at this point - I am baffled.
The symptoms: I'm getting greyish, lumpy deposits on the surface of my tig welds. Glowing embers are visible in the weld pool while welding, as well. Clearly, something non-inert is getting to the weld, but I'm stumped at this point as to what it might be. The arc also has a tendency to wander and is relatively hard to control. Strength of the joint seems unaffected - I've done some destructive testing to make sure. But the appearance is sub-par from what I'm used to doing. See the pictures in the frameforum thread for some of the worst examples. This problem began about 2 months ago for no apparent reason - I've been using the same materials and techniques with no problems since early 2003.
The problem occurs on both my (brand new) Dynasty 200DX and my older 2003 vintage Maxstar 150STH.
Solutions I've tried with no effect, in no particular order:
-Check (no leaks) then replace regulator, all hoses, torch body and parts.
-Replace entire welder (hey, I always wanted a Dynasty anyway...)
-Use different type (ceriated and thoriated), size (3/32 and 1/16), and brand of tungsten.
-Use different gas cups and lenses of all different sizes.
-Change argon flow rate to torch from as low as 5cfh to as high as 35.
-Replace argon tank (multiple times) and try argon from another supplier.
-Replace tungsten grinding wheel with new ($$) diamond wheel.
-Sharpen tungsten to fine point, sharpen tungsten then grind flat, etc. I've pretty much tried every shape of grind you can think of.
-Close all doors/windows and completely eliminate any possibility of drafts (it's notable that I never used to have this problem when welding with a fan running on a hot summer day).
-Use different type/size of weld rod (ER70S and 880t in .035 and .045).
-Use different cleaning procedures (acetone vs denatured ETOH, stainless wire brush vs emory cloth vs scotchbrite vs 3m metal cleaning pads).
-Use different tubes (happens with 4130, everything made by True Temper, all Nova/Columbus stuff that I have, and even old Tange prestige).
-Backpurge/don't backpurge tubes.
-Change welder settings all over the map - from 70 to 120 amps, pulse rates from .5 to 2/second, different background/peak, etc, etc.
-Swap polarity.
-Keep all hoses/lines in warm, dry place for 2 weeks to make sure no moisture is inside.
-Move entire welding setup 10 feet to another location in the shop.
-Clean welding table/replace ground clamp to ensure good ground.
-Probably a few other things I can't remember now.
I've done some sample welds using other equipment at other locations and I have absolutely no issues, so it's not anything about torch angle or technique (and given that nothing about my technique changed in the last 3 or 4 years, whereas the problem started about 4 months ago, I doubt that it's a technique issue).
I'm pulling my hair out on this. Any clever ideas?
-Walt
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