TIG welding aluminum issues, please give advice.

[Georgie]

Hi all,

Ive got a l-tec heliarc 306 welder. Ive been trying at welding 1 1/4 x 1/8 wall pipe. I did a few runs, then stopped and started to run beads on 1/8 thick plate.

I use a 3/32 thoriated,
Argon 12-13 cfm
AC - On
Soft Start - Off
High Frequency - Continuous
High Frequency Intensity - (potentiometer) Max


Balance - tried it all.. made these with about 7 on the potentiometer
Amps - Set to high, i think at about 130. (the potentiometer doesnt have a precise gauge on it, what should i do to read the amperage more accurately??)

Also im using the pedal,


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Here is the back side


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One thing I notice when watching videos like this http://www.youtube.com/watch?v=cwB4PESPAlI is that in the video, while welding, the arc coming from the torch to the work is always constant and smooth whereas mine is always flickering. It only goes steady and smooth when I push the pedal to the max...and suggestions??


Thnaks!

 

[Lawnmowerboy]

It would help to clean the ally off properly with a decent stainless wire brush and some acetone ( not perfumed )

 

[Georgie]

yeah I already did that that's how I made is welds. What cup size should i use?

 

[shenion]

Thorated tungsten will not have a smooth arc on AC. I'be used them on aluminum at times as they handle heat well.

Get some pure or lanthiated tungstens for best results:

http://www.millerwelds.com/resources/articles/tungsten-electrode-guide

 

[langy]

Hi all,

Ive got a l-tec heliarc 306 welder. Ive been trying at welding 1 1/4 x 1/8 wall pipe. I did a few runs, then stopped and started to run beads on 1/8 thick plate.

I use a 3/32 thoriated,
Argon 12-13 cfm
AC - On
Soft Start - Off
High Frequency - Continuous
High Frequency Intensity - (potentiometer) Max


Balance - tried it all.. made these with about 7 on the potentiometer
Amps - Set to high, i think at about 130. (the potentiometer doesnt have a precise gauge on it, what should i do to read the amperage more accurately??)

Also im using the pedal,


print screen windows xp


how to take a screenshot on a pc


photo storage

Here is the back side


image uploading site

One thing I notice when watching videos like this http://www.youtube.com/watch?v=cwB4PESPAlI is that in the video, while welding, the arc coming from the torch to the work is always constant and smooth whereas mine is always flickering. It only goes steady and smooth when I push the pedal to the max...and suggestions??


Thnaks!

Wrong tunsten for aluminium, you need the white tipped, this is why your arc is unstable, I use 2.4mm tungsten, also gas is too high, I use around 6 with a gas lense.

 

[Georgie]

ok guys, did some more tig this week end. started to practice on the actual pipe im going to be using for this build. 1 1/4 x 1/8 wall thickness. Notched some pieces and tried some welds.
AC
140 amps at gauge, controlled remotely by pedal
13cfm
this time lathinated to a point. points about 4 mm long.
soft start - OFF
balance 70% penetration


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this is what the tungsten looked like after all those welds


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i then decided to take a hammer to the welds just to see how they would last. not sure if I should be disappointed. put it in the vice and beat the **** outta it via BFG.


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the middle joint(butt weld?)


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Do you guys think these welds are strong enough for a roof rack??(carrying canoe,tent etc...)


today took the lathinated tungsten, broke off the tip, and re-ground it to a point. switch the high frequency from continuous to start. put the amps up to 180, switch from AC to DCSP and attempted a (fillet??) weld in some 316 SS 1/4 plate.

And forgot the bloody machine on "panel" rather then switch it to "remote" while using the pedal. its amazing how ss is so easy to make a puddle..

anyways enough yapping, on with the pics..


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when i ended each weld and fliped up my helmet, each weld was glowing yellow/orange! is that normal?

 

[carlos420uk]

It looks to me that you are getting pepper / contamination in your welds. In the picture that you show your torch and Tungsten there is no White insulator in-between the torch head and the cup. If your welding without that fitted then I would say that's probably one of the problems, as you will be drawing air into the Argon stream.

 

[Georgie]

thanks carlos, went to the local welding supply store and picked up that bushing. gonna try a few welds and see what the difference is. OHH, I also picked up a gas lens...


So, does anyone have an opinion on the strength of my welds? are they strong enough for a roof rack?

 

[hotrodder]

are they strong enough for a roof rack?

Depends what you want to put on the roof rack. Good enough to survive in the longterm, not so much. They'll fail from fatigue, possibly very quickly as there's cold lap, inconsistant partial (barely any) penetration, lack of fusion, LOTS of porosity* and crater defects. The weak point in ally welds should be the HAZ (heat affected zone) next to the weld when doing BFH tests and the BFH isn't very useful i.e. some people see the damage that needs to be done to get things to break and think something like 'great, i had to squash the tube before the weld broke' therefore it'll be fine. OK for a piece of lawn furniture, useless when it comes to fatigue life which is what causes most things exposed to cyclic stress to fail


* porosity in ally welds is the result of hydrogen which is soluble in liquid Al but not solid i.e. it's dissolved in the weld pool and then rejected as the weld freezes. Fixing the torch should improve things but if you had a serious gas shielding issue the tungsten would have gotten oxidisied too and become discoloured rather than remaining clean and shiney

when i ended each weld and fliped up my helmet, each weld was glowing yellow/orange! is that normal?

Most metals change colour with heat and glow once 'properly' hot hence terms like red hot, white hot etc. The tungsten is glowing white hot while welding for example and the primary reason behind post flow is to protect the tungsten from oxidising as it cools down. Oxidiation at high temps is what causes the range of pretty colours that most welds end up with- ally is one of the few that doesn't change colour

Read the tutorials (link at top of the page), pay special attention to the section on arc length which is also covered in this thread http://www.mig-welding.co.uk/forum/showthread.php?t=7862 and another here which follows the OPs progress with arc length on tubing http://www.mig-welding.co.uk/forum/showthread.php?t=23592&highlight=arc+length

 

[Shox Dr]

Welding faults aside. Not a material I'd be using for a roofrack. The continual twisting of the vehicle and the buffeting form the wind will cause stress fractures.

I'd be using thinwall steel toob, and IF you want it to look like ali, get it Hot spary coated in Aluminium

 

[Drains]

13cfm? Are you sure? That's about 360 litres per minute, when you should be using about 6 or 7. Even 13 lpm will probably give you porosity as the surrounding air gets sucked into the gas stream.

 

[shenion]

13cfm? Are you sure? That's about 360 litres per minute, when you should be using about 6 or 7. Even 13 lpm will probably give you porosity as the surrounding air gets sucked into the gas stream.

13 SCFM is 6 LPM and is what i normally run.

 

[langy]

13cfm? Are you sure? That's about 360 litres per minute, when you should be using about 6 or 7. Even 13 lpm will probably give you porosity as the surrounding air gets sucked into the gas stream.

I mentioned it in post 15 but the OP seemed to ignore it

 

[Georgie]

Well its a little too late for that. I paid 200$ for 85 feet of that tubing, so, I'm gonna have to use it! I did some welding last night with the ceriated tungsten and gas lense and that bushing. With the traditional collet style and bushing the cup seals well againts the bushing, but with tge gas lense theirs a verry tinny gap, maybe .5 mmm. Anyways, the results were great, i will post pics later on todat.

 

[Georgie]

Ok guys just noyiced the posts about the CFM, i will take some pics of my gauge and machine so yall get an idea of what im running.

 

[hotrodder]

It'll be CFH rather than CFM... as Drains said 13cfm is ~ 360 litres per minute, not gonna happen and if it did there'd be icicles hanging off the reg and probably a dead (suffocated) body unless outside/huuuuge workshop [/tongue in cheek]

13 cfh would be about right being ~6lpm, if it turns out the thing's calibrated in lpm then halve the flow as said

There's an additional gasket/insulator or a different one used with 17/18/26 size torches when fitting a gas lens, part # 54n01

 

[Georgie]

OK heres the machine im using:

L-TEC Hiliarc 306 Delux


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Ok so the values I gave were wrong, it IS CFH!

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Here is the torch with the bushing, the new cup for the gas lens seals well against the bushing on this side...


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But on this side I have a gap


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This was my first pass of the night,

ceriated 3/32
CFH 13
Ac
150 amps at the potentiometer, controled by pedal
Gas lense
Balance at about 60% penetration


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And i tried slopdown time on this pass


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-What kind of machine do I have?? Square wave, sin wave, balanced wave or all three in one?

-Is the gap a problem on the cup?

-How do I tell what size torch I have?
im going to make a few more test with the pipe befor I proceed to build my rack... I'm scared about what hotroder said...I need this thing to be stout!

 

[wheresmejumper]

have you wire brushed it after welding?

 

[biffa]

As you've got a gas lens now you still require another white bush

 

[Georgie]

No, i only brushed it befor welding..

The bushings are different from gas lens cups to traditional cups?