- Thread starter Gizmo.Y
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Barking Mat
Cuddler of hedgehogs.
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That's a gas issue isn't it? Perhaps try 6 or 7 lpm, and I'd use a smaller cup.
However I am not a tig proffesional, but good amateur.
Is your torch screwed together properly?
However I am not a tig proffesional, but good amateur.
Is your torch screwed together properly?
pedrobedro
Man at Matalan
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Too many amps or too much heat turns stainless dull grey. Turn it down or go faster probably.
Filler wire is too thick... some 1.2 or ideally 1.0mm wire will need less amps (thicker wire 'sucks' heat out of the weldpool as it melts. Or the weldpool freezes each time you add wire if the juice isn't high enough)
Amperage depends on all sorts of stuff including travel speed, arc length, maintaining angle of attack and machine calibration; 42A on one machine isn't necessarily 42A on another. Anything from low/mid 30s upto mid 40s is probably the usual ballpark for most with a 1.5mm stainless butt with some 1.0 or 1.2mm wire. Need to be quick and accurate with more juice or the heat input goes up.
Nail angles of attack/arc length (they're related, lose the angle of attack on tube and arc length typically increases) and balance amperage against travel speed and weld colour mostly takes care of itself. Not so noticably on thinner wall stuff as there simply isn't enough of a heat sink. Most of the world deals with this using pickling paste or electrolytic weld cleaning etc. On the internet it's more common to use large cas cups and weld really slowly i.e. pausing every inch or so for the postflow to ensure shiny silver welds for twitface pics [/tongue in cheek]
The pretty colours are virtually meaningless and ain't gonna happen if chasing a full pen butt without a purge... If the back of the joint isn't shielded it'll oxidise and those oxides can be drawn through the weldpool. There'll also be LOF (lack of fusion) defects as the back of the weld cokes/sugars; this is extreme oxidation where much of the chromium has been 'cooked out' leaving the weld less stainless than it should be
If it's purged properly the pretty straws/yellows/blues/purples on and around the weld bead still lower corrosion resistance in many environments as they're the result of a thickened oxide layer. One big exception being elevated temperature service where oxides are gonna occur naturally i.e. no point using pickling paste* to remove oxides and passivate the part on something like an exhaust as the entire thing is gonna get covered with oxides the first time the engine is run in anger
* basically it 'eats' oxides and free iron leaving a passive chromium rich surface. Chromium is very reactive and oxidises immediatly but this time we're talking a microscopically thin oxide layer which resists further corrosion and if/when it's damaged there's plenty of chromium available for this passive layer to regrow as long as there's some O2 about. Weld heat tint is a thickened oxide layer that 'steals' some chromium from just below the surface [/gross generalisation]
Amperage depends on all sorts of stuff including travel speed, arc length, maintaining angle of attack and machine calibration; 42A on one machine isn't necessarily 42A on another. Anything from low/mid 30s upto mid 40s is probably the usual ballpark for most with a 1.5mm stainless butt with some 1.0 or 1.2mm wire. Need to be quick and accurate with more juice or the heat input goes up.
Nail angles of attack/arc length (they're related, lose the angle of attack on tube and arc length typically increases) and balance amperage against travel speed and weld colour mostly takes care of itself. Not so noticably on thinner wall stuff as there simply isn't enough of a heat sink. Most of the world deals with this using pickling paste or electrolytic weld cleaning etc. On the internet it's more common to use large cas cups and weld really slowly i.e. pausing every inch or so for the postflow to ensure shiny silver welds for twitface pics [/tongue in cheek]
The pretty colours are virtually meaningless and ain't gonna happen if chasing a full pen butt without a purge... If the back of the joint isn't shielded it'll oxidise and those oxides can be drawn through the weldpool. There'll also be LOF (lack of fusion) defects as the back of the weld cokes/sugars; this is extreme oxidation where much of the chromium has been 'cooked out' leaving the weld less stainless than it should be
If it's purged properly the pretty straws/yellows/blues/purples on and around the weld bead still lower corrosion resistance in many environments as they're the result of a thickened oxide layer. One big exception being elevated temperature service where oxides are gonna occur naturally i.e. no point using pickling paste* to remove oxides and passivate the part on something like an exhaust as the entire thing is gonna get covered with oxides the first time the engine is run in anger
* basically it 'eats' oxides and free iron leaving a passive chromium rich surface. Chromium is very reactive and oxidises immediatly but this time we're talking a microscopically thin oxide layer which resists further corrosion and if/when it's damaged there's plenty of chromium available for this passive layer to regrow as long as there's some O2 about. Weld heat tint is a thickened oxide layer that 'steals' some chromium from just below the surface [/gross generalisation]
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This more than any other thing is for me the hardest part of tube/pipe. The narrower the diameter the harder. It took me a while to get comfortable and I have to remember to be vigilant or else I lose concentration and the AOA goes and then I'm cutting my toes badly.
henry Kadzielski
Member
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Good morning Gizmo.Y.
The pretty colours that you are after, are not that easy to obtain and the smaller and thinner the tube or pipe section the harder. It's all related to current and travel speed. If you reduce the current, you spend longer at a point to get fusion and to move the weld pool. Thus more heat input, results in blackened and dull welds. on the other hand by increasing the current it is much harder to control the weld pool and there is a possibility of blowing a hole.
Anyone that has done Tig has gone through this and can appreciate what you are asking. It is however difficult to express in words what is exactly required to be done. Every one welds differently and can achieve the same result, but it is up to what works for you. I have been told this many times when doing my Tig pressure ticket and now I am doing the Mig solid wire pressure ticket. The problem is words don't realy convey what you realy require.
The best option is to get someone that can realy Tig weld (not just those that claim they can) watch him and then he watches you and tells you what you are doing wrong. There are tiny little bits of detail that make the difference in the finish
.
The problem we all have is we just don't know what we don'y know, this mentoring (with the right person)and I am stressing that the right person makes all the difference. If the mentor can weld (be carefull to make sure he can) stick with the one person, two people two different ways, that confuses the situation.
I am currently following my own advice and have one person 'holding me by the hand' through the different positions for the Mig ticket. This one on one is what is making the difference. We have 14 weeks to complete the course at 3hrs per week (12mm plate down hand fillet 3 runs with stops and restarts, vertical up root and weaved cap, horizontal butt 5 passes with stops and restarts and rotated pipe three passes I think, haven't done this yet).
This is for someone that dosen't weld every day, but only when required, so I have been practicing with samples I have organised myself. It is all about the technique and getting it right and unfortunately it takes time (you can't put an old head on young solders) is so true.
You can struggle through on your own and it can be done but it takes time, having help shortens the learning curve greatly
Hope that this helps, as I do feel your pain and have experience and am experiencing this first hand.
The pretty colours that you are after, are not that easy to obtain and the smaller and thinner the tube or pipe section the harder. It's all related to current and travel speed. If you reduce the current, you spend longer at a point to get fusion and to move the weld pool. Thus more heat input, results in blackened and dull welds. on the other hand by increasing the current it is much harder to control the weld pool and there is a possibility of blowing a hole.
Anyone that has done Tig has gone through this and can appreciate what you are asking. It is however difficult to express in words what is exactly required to be done. Every one welds differently and can achieve the same result, but it is up to what works for you. I have been told this many times when doing my Tig pressure ticket and now I am doing the Mig solid wire pressure ticket. The problem is words don't realy convey what you realy require. The best option is to get someone that can realy Tig weld (not just those that claim they can) watch him and then he watches you and tells you what you are doing wrong. There are tiny little bits of detail that make the difference in the finish
.The problem we all have is we just don't know what we don'y know, this mentoring (with the right person)and I am stressing that the right person makes all the difference. If the mentor can weld (be carefull to make sure he can) stick with the one person, two people two different ways, that confuses the situation.
I am currently following my own advice and have one person 'holding me by the hand' through the different positions for the Mig ticket. This one on one is what is making the difference. We have 14 weeks to complete the course at 3hrs per week (12mm plate down hand fillet 3 runs with stops and restarts, vertical up root and weaved cap, horizontal butt 5 passes with stops and restarts and rotated pipe three passes I think, haven't done this yet).
This is for someone that dosen't weld every day, but only when required, so I have been practicing with samples I have organised myself. It is all about the technique and getting it right and unfortunately it takes time (you can't put an old head on young solders) is so true.
You can struggle through on your own and it can be done but it takes time, having help shortens the learning curve greatly
Hope that this helps, as I do feel your pain and have experience and am experiencing this first hand.
langy
langys rodshop
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Too many amps, too much gas, too much filler bud, I use 1mm filler on that, gas saver on 5lpm, 35-40 amp but I use a pedal, then you will get pretty colours
I missed the gas flow yesterday, as said turn it down a bit... tube is akin to outside corners in that the shape of the part kinda encourages the argon to 'flow away' making it one of those less is more deals a lot of the time
As eCHEn said keeping up with the constantly changing AOA is one of the harder aspects of tube butts to get. Weld freeze lines are the tell tale when the torch isn't rotated enough to maintain them as the weld progresses
You'd be better off practicing on some cheap ERW mild steel tube IMO... yeah, stainless welds slightly differently but devolping the muscle memory is one of the key things, do that on mild steel tube and the switch to stainless should be fairly painless
As eCHEn said keeping up with the constantly changing AOA is one of the harder aspects of tube butts to get. Weld freeze lines are the tell tale when the torch isn't rotated enough to maintain them as the weld progresses
You'd be better off practicing on some cheap ERW mild steel tube IMO... yeah, stainless welds slightly differently but devolping the muscle memory is one of the key things, do that on mild steel tube and the switch to stainless should be fairly painless
Richard.
Member
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One thing that's fairly obvious from looking at those heavily sunken freeze frames right on the end is that you have started to go down hill and Gravity has taken over. Don't do this. However you are supporting the tube you should not be going much past 12 o'clock.
They are way too wide for the tube thickness which suggests a combination of extended arc length, too slow on the travel (caused by filler thickness no doubt chilling the pool) and a touch too high on the current.
SS really requires such a tight arc. I'm talking 1mm for nicest results.
After all this is done and said my top advice would be aim to weld it properly. Use an inside purge and look for a sound weld rather than shiny and colourful. Those will come as a natural part of the process once you have the rest of it right. If you don't get your desired finish just buff em up silver. As hotrodder said the whole system will be covered in heat tint after a couple of punches near the red line so it makes no difference. But welding it in a manner to try and purposefully achieve them could effect the weld soundness which will result in a come back (no self respecting welding wants one of those).
They are way too wide for the tube thickness which suggests a combination of extended arc length, too slow on the travel (caused by filler thickness no doubt chilling the pool) and a touch too high on the current.
SS really requires such a tight arc. I'm talking 1mm for nicest results.
After all this is done and said my top advice would be aim to weld it properly. Use an inside purge and look for a sound weld rather than shiny and colourful. Those will come as a natural part of the process once you have the rest of it right. If you don't get your desired finish just buff em up silver. As hotrodder said the whole system will be covered in heat tint after a couple of punches near the red line so it makes no difference. But welding it in a manner to try and purposefully achieve them could effect the weld soundness which will result in a come back (no self respecting welding wants one of those).
Well here we are guys. This exhaust was given to me Tacked up with a MIG, the fitup was not amazing, plenty of gaps. But didnt want to break it up to improve the fit up. I also stepped down to a 1.6 tungsten, previously using a 2.4. I made due with the 1.6 Filler
40 Amps
Number 8 Cup
Roughly 6-7LPM
1.6 Tungsten (Blue)
1.6 Filler (308L)
Not perfect, but an improvement.
40 Amps
Number 8 Cup
Roughly 6-7LPM
1.6 Tungsten (Blue)
1.6 Filler (308L)
Not perfect, but an improvement.
langy
langys rodshop
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