Tig on on thin 4130 tubing

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I am trying to develop tig skills for 4130 tubing (bicycle frames sorta like zank's practice thread).In any case lots of good info in zank's practice thread and also in this article from miller.The following is my most recent effort.  If you have some ideas of things I should be thinking about please let me know.  There is a good chance I just need more time but advice and feed back is also good.  What do you guys think? Is this underfill, overfill, too hot, to cold, etc.  Click on images for full size versions.  Also, more photos on my blog.I cut up the weld and then touched it up on my belt sander for this photo.I am using a Miller 150 STH in pulse mode with a pedal and the amp dial set at 70.  Argon is around 18 CFH.  I am using 1/16" thorated and .035 rod (70S).Thanks for looking and please let me know what you think.
Reply:I think they will hold just fine but now comes the fine tuning..Try a LITTLE hotter and go a little faster..Cosmetics will be needed here because of what it is..Look at any bike frame at any bike shop..Cosmetics.It has to look nice on top of being functional.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:1+ for it looks slightly cold and you not going fast enough.Personally, I'd turn off the pulse, and crank up the dial to 150 and use the pedal. My maxstar is the 150STL and has no pulse setting, so it don't know how well it works, but the pulser on my sync would be useless on this.  Practice, practice, practice.Ian TannerKawasaki KX450 and many other fine tools
Reply:Mark, what wall thickness are you practicing on?I'm as much of a rookie as you, so take this with a grain of salt. One thing that has helped me is to pull back a little bit and increase my arc length. I always heard/read "tight arc, tight arc". I was trying to barely hover above the puddle because that's what I thought "tight arc" meant. I was often so close that when I added rod, the puddle would come up and hit the tungsten. The beads were crowned (convex) and I always felt like I was running cold. One day it kind of dawned on me to increase my arc length a bit. It helped a lot. The puddle diameter increased, the toes of the weld started to blend into the tube wall better, and the beads started to become flat to just slightly concave. It felt like a good step forward. Hope that helps!
Reply:Thanks for the tips!  I am very inspired to get better.Zank, I might be a little too tight as well.  Do you have an idea of how much arc length you maintain?  The Miller article describes arc length as "Less than or equal to the electrode diameter. Generally, the tighter the better, as shorter arc lengths reduce heat input".  My hands still shake a bit so nothing is all that exact for me but I have been holding very tight arcs when I can.  I will try a little bigger arc goal (say around 2 to 2.5 mm).  I read something once that stated a longer arc was in a sense also increasing the heat because the machine will automatically put out a bit more power to jump a bigger gap.
Reply:Oh man, I dunno. I just go by how the puddle looks. One thing I do is prop on the tube with a TIG finger. I then slide along and around the circumference of the tube. This helps keep the arc length consistent as I go around the joint. I still have to adjust my torch angle as I go, but my distance stays pretty steady.
Reply:Ya, i should get a TIG finger, I keep burning my hands even with light gloves.  As to your earlier question I don't know the thickness of the tubing because I am using scrap from another frame builder.  I think most of the stuff is around .8mm.I did a little bit more practice today with the aim to be a little hotter and faster as per Zapster.  I am concerned about cosmetics but also safety, and durability.  All three would be great but really safety is the #1 goal followed by durability and below that cosmetics.For safety, I figure it is key to have proper bead side with no undercutting or under-fill but I don't have a lot of example of weld cut away shots.  There are some in the practice thread you started.  Your welds have a bit more filler material and in general that seems safer.  I don't yet know what is ideal but I think I may be underfilling.Next time around I will be working on trying to make the puddle a little bigger and trying do more of pushing the filler rod in rather then just moving the torch along the wire.
Reply:I would concetrate on appearence and stop wasting time and material by cutting up your weld samples .  If the bead isn't visually appealing to you then there is no point in going any further to investigate if its a good weld.  You should be able to weld another tube on the same sample and get in more practice.
Reply:ive been welding on chromoly tubing alot lately... id try 1/16 70s2 rod and turn the amps up a bit if using the pulser. the thicker rod seams to help the appearance and also it seems to keep the HAZ down a bit.
Reply:febikes, I never got to the free cup, free elbow, uniformity of the really good TIG welders so I've always relied on making some sort of steady-rest to get at least my forearms anchored.Zank mentions a TIG finger or finger stall, but here are a few sketches of some pipe clamp steady rests. I don't have as much reach or access with finger stalls so I concentrate on resting my arms to get a little more steady on the work.These allow me to keep some decent arc gap control, even though they won't work in every single tube job, I use this method with aluminum hand rails and other small saddled pipe work.just a pedestal to clamp the work on top of, then a bunch of furniture clamps to make a quick change rest system.lots of different ways to make a fixture like this, and if I were doing bike frames I would take time to create a fixture that allowed good weld access to each joint with only one or two frame resets?If you're not one of the guys, like Zap or Zank, blessed with "brain surgeon hands" and have shaky hands like me, then a nice positioning fixture is just the tool to get the quality of welds you want.Here's a bigger rotisserie type fixture I made since I'm just to old, fat and inflexible to weld inside a skiff.  I can still get the job done, I just have to get the work in a position that I can reach and steady rest my arms!  Whatever tools it takes to get the job done.cheers,Kevin Morin
Reply:Kevin big thanks for the drawing and photos.  I will be making a similar setup for my shop.