TIG welding aluminum issues, please give advice.

[Georgie]

ok heres what my welding postioning looks like....I think the torch is maybe too big as I see collets for 1/4 inch tungstens in my kit... I feel like its made for a more heavy duty job..


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I think that all im doing wrong is unable to keep the right angles and arc distances throughout the weld sequence....

 

[shenion]

I'd set the control to 50/50 (center) as you are getting some contamination and need more cleaning.

 

[Georgie]

I believe 50/50 is all the way counterclockwise...each mark is 5%..

I THINK...?

 

[Rrunnach]

I doubt much wrong when viewing pics, experiance is lacking, all the pieces will drop in place, once you get your head around welding al/al.

It's not a science after all, although some copy and paste it is!!

 

[Rrunnach]

I've just had another look at what you are welding. Your prblem is, when you close up weld on tube, trapped (expanding) air, is surging out, hence contamination.

Drill a small hole anywhere in tube scalloped out, will eliminate the grief you are having......

 

[Georgie]

Rrunnache, Shenion said the same thing...there must be another way to make it finish off clean without drilling holes....

What do you guys think about the size of my torche?

 

[Rrunnach]

When I was fab/welding ROV's for a global oil & gas player. Parts of thruster brackets were al/al tube, which in turn, were welded to machined al/al solid square section. I had no option than drill a vent hole.

After cooling, I purged tube with argon, then quickly welded up hole, this procedure worked well.

Cheers.................

Ps, nothing wrong with torch.

 

[Wendelspanswick]

You could try drilling a hole in the tube that's not scalloped, it will be covered by the scalloped tube. It might help relieve the pressure.

 

[Shox Dr]

I'd of said those tubes are more than long enough to not bother with a hole: just leave a small area to weld and return when cold, the if you don't hang about it the air inside won't have time to heat up, causing it to blowout

 

[hotrodder]

Guys, many of the pics are of partially welded joints i.e. even without a vent hole the air inside the tubes is not trapped.

I think that all im doing wrong is unable to keep the right angles and arc distances throughout the weld sequence....

That's the biggest problem and not an easy one to fix unless it's mastered on flat plate first. They look better than the ones from the OP and a lot more consistant. Heat control is erratic but a chunk of that will be from running loads of beads one after the other on a small offcut


The red line... looks to me like the filler is bridging the joint i.e. arc length is too long so you get two weld pools which are bridged when adding filler wire.
It looks to me as though the torch angle is being lost as the weld progresses, the wire is melting before it meets the weldpool and the result is the erratic blobs of weld... by the green circle it's spacing which is a classic start point for a crack in service, by the blue circle we've got a contaminated weldpool probably due to the torch angle/filler relationship and a crater

The next two look to be fully welded joints...




While the mess at 11 o'clock could've begun with air inside the tube blowing the weldpool out they look to me to be the result of melting off big blobs of filler wire with the arc and then trying to melt it in. The arrow in the second pic for example doesn't look as though it's pointing at a hole, just a void
If i've 'read' the pics wrong and the mess is from trying to fix a blown out weldpool then you can't just weld over it. All the oxidised mess needs removing first

Balance settings aren't gonna fix what's going here, the pic in post #61 shows plenty of 'cleaning' action from the AC balance settings until the soot at the end of the bead which is from a touch down or melting the wire with the arc

The balance dial is marked from 0 - 10, a setting of 5 might be 50/50 of it's range BUT it won't be 50% EN. Georgie got it right according to what the manual says

These units incorporate a potentiometer to effect a wave BALANCE change. With the potentiometer set in its extreme counterclockwise or "Max. Cleaning" position, the machine is set up for "balanced" wave operation (equal portions of re-verse and straight polarity

Based on similar kit i've used i'd expect the 'sweet spot' to be somewhere between 3 & 8 for AC TIG , as i said before the way to find out is run beads on a piece of plate noting the results at different settings
This is for a Miller Syncrowave so the range of adjustment is different (despite still being a dial numbered 1 - 10) but explains better than the L-Tec manual, page 2... http://www.millerwelds.com/pdf/spec_sheets/AD4-2.pdf

 

[Rrunnach]

You could try drilling a hole in the tube that's not scalloped, it will be covered by the scalloped tube. It might help relieve the pressure.

Waste of time, will achieve nothing...............

 

[Rrunnach]

Guys, many of the pics are of partially welded joints i.e. even without a vent hole the air inside the tubes is not trapped.

That's the biggest problem and not an easy one to fix unless it's mastered on flat plate first. They look better than the ones from the OP and a lot more consistant. Heat control is erratic but a chunk of that will be from running loads of beads one after the other on a small offcut

View attachment 35974
The red line... looks to me like the filler is bridging the joint i.e. arc length is too long so you get two weld pools which are bridged when adding filler wire.
It looks to me as though the torch angle is being lost as the weld progresses, the wire is melting before it meets the weldpool and the result is the erratic blobs of weld... by the green circle it's spacing which is a classic start point for a crack in service, by the blue circle we've got a contaminated weldpool probably due to the torch angle/filler relationship and a crater

The next two look to be fully welded joints...

View attachment 35975
View attachment 35977

While the mess at 11 o'clock could've begun with air inside the tube blowing the weldpool out they look to me to be the result of melting off big blobs of filler wire with the arc and then trying to melt it in. The arrow in the second pic for example doesn't look as though it's pointing at a hole, just a void
If i've 'read' the pics wrong and the mess is from trying to fix a blown out weldpool then you can't just weld over it. All the oxidised mess needs removing first

Balance settings aren't gonna fix what's going here, the pic in post #61 shows plenty of 'cleaning' action from the AC balance settings until the soot at the end of the bead which is from a touch down or melting the wire with the arc

The balance dial is marked from 0 - 10, a setting of 5 might be 50/50 of it's range BUT it won't be 50% EN. Georgie got it right according to what the manual says


Based on similar kit i've used i'd expect the 'sweet spot' to be somewhere between 3 & 8 for AC TIG , as i said before the way to find out is run beads on a piece of plate noting the results at different settings
This is for a Miller Syncrowave so the range of adjustment is different (despite still being a dial numbered 1 - 10) but explains better than the L-Tec manual, page 2... http://www.millerwelds.com/pdf/spec_sheets/AD4-2.pdf

There are a combination of errors, but would say, lack of experience is a major factor. Practice will get you sound welds on tube to tube.

Although I am going back years ago and, if I use ROV's as an example. All marine grade alloy, 6mm plate, tube, solid round bar ect.

I had no cleaning action on my old BOC ADR 300, ROV max depth was 10.000 FSW. I never had a dipper on a mega buck ROV.

OP is welding tube, do you all think this cleaning action stuff is really relevent??

Cheers..........

 

[shenion]

I had no cleaning action on my old BOC ADR 300, ROV max depth was 10.000 FSW. I never had a dipper on a mega buck ROV.

OP is welding tube, do you all think this cleaning action stuff is really relevent??

Cheers..........

Your BOC ADR 300 had cleaning, just that it was fixed at the max cleaning setting (AC balance) his machine allows.

 

[Rrunnach]

Your BOC ADR 300 had cleaning, just that it was fixed at the max cleaning setting (AC balance) his machine allows.

Hmmmmmmmm, max cleaning on al/al normally give less pene, or it did on some older type machines.

I do not doubt what you say, but will consult with my plant tech.........

Cheers.......

 

[Shox Dr]

OP is welding tube, do you all think this cleaning action stuff is really relevent??

Cheers..........

Im I reading that correctly?

Not that I have welded at over 230amp in AC I was lead to believe anything under 250amps needs the cleaning side of AC. Over 250ish AMPs DC can be used so has no cleaning

 

[wheresmejumper]

maybe the cleaning isnt the issue here,but the technique

 

[Shox Dr]

maybe the cleaning isnt the issue here,but the technique

As said torch control/rod control is the biggest factor. all the joints in the pictures are post cleaned, maybe to remove the soot etc. None look to have been either wire bushed or scotchbrited. Once you are proficient at tig then you can be a little gun ho'with the pre clean. But you live with the knowledge it will bite you when you least want it to

 

[wheresmejumper]

i asked earlier in the thread,but the op said they werent cleaned after welding.presumed the grainy bead appearance was a minor gas leak then,as there wasnt even one shiny bead

 

[shenion]

He said he's using 5356, I always get a bit of a grainy finish on it. 4043 I get a glossy finish.

As he gets his torch angle, arc length and filler technique up; it will get a bit better but still be dull.

 

[wheresmejumper]

ive only ever used 5356,never had them grainy?