tig welding help

[blighty]

Just got me self a nice new tig welder and have no idea how to use it..... maybe.

right then..
got a DC tig many moons ago and have been having lots of fun with it. last week i got me self a AC/DC to have a go at some Ali welding. Things with the Ali welding arn't going to plan!

i'll go aver the setting the welder has and a short note to say what i have done.

AC/DC set to AC
- electrode (have also tried +)
pre gas 2sec
starting amps (have gone up and down with this and also kept it the same as the main amps)
main amps (40 amps up to 200)
AC frequency (50- 200)
AC balance (30% - 70% .... on 30% nothing happens, 70% the tungsten melts and balls up. i have figured why this happens)
down slope 2 sec,
end amps 40
post gas 5 sec
using pure argon
tip is ground to a point.

when starting the weld the tip is about 1/16 away from the ali. it lights and i get a ball of fire all over the place, then get a lot of little burn marks. after a while i get an area of ali just melts away. this dosent mater what amps i use. with higher amp's it just happens quicker.

what im not getting, (with any setting)is the dark spot, that turns into wight fluffy looking stuff (wight fluffy stuff is the cleaning action) then molten ali.

first pic.
1.5mm (0.060") 1amp per thu and add a bit. started at 70 amp's then tried 40 up to 120.

second pic.
6mm (0.250") one on the left is 100amps, 200amps on the right.

while typing, i have found something about the yellow powder seen on the second pic. they says its not enough gas or the cup is to small. gas flow rate should be 15-20 cfh. min is about 18.

any thoughts would be great as i'm dying to weld two Coke cans together

 

[XD351]

One thing i'm not seeing is the scratch marks from a stainless wire brush ! With aluminium cleanliness is everything so degrease using acetone , wire brush with a stainless wire brush that has not been used on anything else like steel or dirty metal .
It looks like you are holding too long an arc and your stick out on the electrode is too long . What electrode are you using - zirconiated , lanthanated , something else ?
Have a look at a few youtube channels :
Weld .com
Welding tips and tricks .
From the info on these channels you should be able to get your set up close to where you want .
I usually set the clean width and ac balance mid way ( 50%) and tweak it from there . Frequency around 100hz and keep the stick out as short as possible so it keeps nozzle nice and close to the workpiece ,also watch how much you tip the torch over - too much and it will suck air in from behind the nozzle and contaminate the gas shield . You may need a little longer post flow to stop the electrode oxidising , it should be shiny ( usually a blueish colour ) and not dull or frosty looking . If you contaminated the tungsten you will have a bugger of a time with it so either get a new one or snap off the contaminated section ( break it over a sharp edge with a small hammer ) .

 

[bazmak]

Aluminium has an oxidised surface which makes it difficult to weld
You need to wire brush just before welding

 

[vidio1]

Have you seen this guy's videos? http://www.weldingtipsandtricks.com/

 

[mayhugh1]

I'd try something a little less ambitious than welding coke cans together until you get a little more experience under your belt. Butt welding two coke cans was actually part of the final exam in the tig welding course I took a number of years ago at our local community college. Practice running beads on 1/16" or 3/32" plate until you get the hang of it. You didn't mention whether your using high frequency start. On aluminum it's really needed to get the arc started without contaminating the electrode which is what your photos might be showing. And, it should be set to 'continuous'. Also, your electrode should be balled for aluminum instead of being ground pointed. Use pure tungsten electrodes for aluminum. The thoriated (increased emission) electrodes are intended to be pointed, run on dc, and used on ferrous metals. -Terry

 

[blighty]

One thing i'm not seeing is the scratch marks from a stainless wire brush ! With aluminium cleanliness is everything so degrease using acetone , wire brush with a stainless wire brush that has not been used on anything else like steel or dirty metal .
It looks like you are holding too long an arc and your stick out on the electrode is too long . What electrode are you using - zirconiated , lanthanated , something else ?
Have a look at a few youtube channels :
Weld .com
Welding tips and tricks .
From the info on these channels you should be able to get your set up close to where you want .
I usually set the clean width and ac balance mid way ( 50%) and tweak it from there . Frequency around 100hz and keep the stick out as short as possible so it keeps nozzle nice and close to the workpiece ,also watch how much you tip the torch over - too much and it will suck air in from behind the nozzle and contaminate the gas shield . You may need a little longer post flow to stop the electrode oxidising , it should be shiny ( usually a blueish colour ) and not dull or frosty looking . If you contaminated the tungsten you will have a bugger of a time with it so either get a new one or snap off the contaminated section ( break it over a sharp edge with a small hammer ) .

cleaning....
i got some 340 grit then buffed it using a scotch wheel. so i take it its meant to be clean clean and not just shiny clean?

not to sure what the tip is, but it has a red mark on the other end. i'll look at the packet when i'm home latter.

think you right about the stick out. it was about 1/2inch out. the cup i was using was a #6

would you also suggest only using cups and tips just for ali? as i had gone strait from welding mild steal to ali. so the cup was a bit sooty.

 

[blighty]

Have you seen this guy's videos? http://www.weldingtipsandtricks.com/

yep seen him. also Kevin and probably all the others. also seen another guy he's more studio based than filming out of his shed.
he did a top 5 ali mistakes. one of them was exactly what i was getting in the pic i put up. he said it was down to not enough gas or to much. to much touch angle. but mainly contamination.

 

[blighty]

I'd try something a little less ambitious than welding coke cans together until you get a little more experience under your belt. Butt welding two coke cans was actually part of the final exam in the tig welding course I took a number of years ago at our local community college. Practice running beads on 1/16" or 3/32" plate until you get the hang of it. You didn't mention whether your using high frequency start. On aluminum it's really needed to get the arc started without contaminating the electrode which is what your photos might be showing. And, it should be set to 'continuous'. Also, your electrode should be balled for aluminum instead of being ground pointed. Use pure tungsten electrodes for aluminum. The thoriated (increased emission) electrodes are intended to be pointed, run on dc, and used on ferrous metals. -Terry

not to sure if the welder has "high frequency start" but starting wasn't a problem. i'll have a look later. also what electrodes i have.

i've seen the balling thing on weldingtipsandtricks but he also say you can use a point. he was using a ball on an edge and out side corner weld. then a point on an inside corner.

coke cans..... yes yes i know....walk then run. but it would be cool:thumbup:

 

[blighty]

so for tonight.

bigger cup, not so much stick out, clean the ali, ball the electrode, not so much torch angle.

thanks for all your help guys:thumbup::thumbup:

 

[XD351]

Red tip = thoriated - not what you really want as it doesn't like ac .
Try 2% lanthanated ( blue tip) or a zirconiated ( white or light brown tip) - these colours can change with different countries and manufacturers .
With the old type transformer machines you wanted a balled tip but the new inverter welders you want a point like a sharp pencil and knock the very sharp point off as it can melt and drop into the weld pool , you can do this with a small stone or very carefully just touch the tip on the grinding wheel also make sure the grind marks are longitudinal as it helps control the arc and keep it stable . . Your welder will have hf as it has ac and you need it to keep the weld arc going as ac actually stops when the electron flow slows down and then changes direction , dc only machines can have it or not .

 

[blighty]

right then.....

the tungsten I have has "1.6mm 150mm TUNGSTEN 2% THOR" written on the label.

pic 1,
before I started. 1.6mm all nice and clean.

pic 2,
changed the cup from a 6 to a 7. 7 is the biggest cup I have. and the amount of stick out.

pic 3,
1. 1 sec pre flow, 30amp start ramp 3 sec. 70amp main. 3sec ramp down 30amp, 5 sec post flow. 110 AC freq.
2. same settings but hit the ali with the tip.... changed the tip.
3,4,5 was playing with the amps.
6. 125 amps.... just because...
7 change over to DC 80amps. to me DC looks a lot like AC?

pic 4, the welder.

 

[blighty]

Red tip = thoriated - not what you really want as it doesn't like ac .
Try 2% lanthanated ( blue tip) or a zirconiated ( white or light brown tip) - these colours can change with different countries and manufacturers .
With the old type transformer machines you wanted a balled tip but the new inverter welders you want a point like a sharp pencil and knock the very sharp point off as it can melt and drop into the weld pool , you can do this with a small stone or very carefully just touch the tip on the grinding wheel also make sure the grind marks are longitudinal as it helps control the arc and keep it stable . . Your welder will have hf as it has ac and you need it to keep the weld arc going as ac actually stops when the electron flow slows down and then changes direction , dc only machines can have it or not .

can having the wrong tip make that much difference? cos' at the mo seeing that there seems to be no difference between AC or DC i'm beginning to doubt the welder.

I will get some electrodes you suggest and some bigger cups.

 

[XD351]

The electrode choice has more to do with its ability to handle the extra heat that is generated in the electrode when on ac , on dc the electrode is neg and current flow is from electrode to workpiece so the electrode stays cooler but on ac it is half one direction half the other so it heats the electrode up more .
Do you know the composition of the aluminium ? Not all types are weldable so maybe try a piece you know whats in it .
You will know if it is running on ac or dc by the noise , ac buzzes while dc is quiet . If you change the frequency you will hear it as the pitch of the buzzing will get higher as the frequency goes up .
Remember you have ac frequency and pulse frequency - one controls the frequency of the arc and one the other the rate it switches from full power to base power and back again or a weld pulse .
One other thing is switch over the leads so your electrode is positive and try it on ac with the ac balance at 50% , if it improves the welding your machine is not getting a proper ac waveform . You can weld alloy on dc electrode positive ( sort of) but it isn't pretty , the current flow going from work to electrode helps to bust up the oxide layer but it is murder on the tungsten and only something you would only do in extreme desperation .!
I wouldn't recommend that someone learning to weld aluminium or setting up a new machine do it on 1.6 mm thick material , i would start them off with 1/8 or 3mm as it s more forgiving and melt through is less likely . Have you tried this machine with dc and mild steel or stainless ? Also are you sure you are getting a good gas flow to the torch and that your regulator is putting out the gas flow you have dialled in ? Are you using the type with the little floating ball that indicates flow or an old mig type with dual gauges ? The First type is preferred as it is more accurate / controllable
Try a longer up ramp as it will give the arc more chance to clean the metal and maybe keep the amps down to 50 or 60 amps so you can take a good look at the cleaning action , even if you don't get a weld pool you should be able to see the oxide go white and break away from the metal leaving a nice shiny clean surface that is when you up the amps a little at a time until you get a nice clean pool . You can use the 2t/ 4t function to do this as well but it will be easier for you to look that up on youtube than me trying to explain it here - i use a pedal these days so i can hang there cleaning all i want then up the juice and weld away .
Remember you don't wire brush the surface once a day , you do it then weld immediately as the oxide layer starts building up immediately - the less cleaning the arc has to do the better !

 

[blighty]

composition of the ali. the 1.6mm bit would of been 6082 the thicker bit 6061.

the noise does change when i go up and down on the frequency, haven't tried pulse yet.

I tried swapping the wires over the other night. got the same result, but didn't cnge the ac balance. will give that a go tonight.

I have tried it on mild steel and apart form my crappy welding skills turned out ok.

the bottle has the mig type dual gauges. i do have the first type. i could try and fit this to the bottle.
as for gas flow. i can hear it coming out after the click in the welder. plus i blew smoke in front of the cup, so there is gas coming out. as to how much and if it's to what i set it to i couldn't say.

as for cleaning. everything was set up ready to go. i then cleaned the ali and went to the welding bench. about 2 min between cleaning and welding.

for a lough, i'll film it. ill rig something up that will hold the touch. that should take stupid me out of the equation.

 

[mayhugh1]

Your photos show you're not getting an arc started. You should try balling the electrode and make sure your high frequency is turned on to continuous. These are basic requirements for welding aluminum. The arc will extinguish at every zero crossing of the welding current ac waveform if you're not using continuous high frequency. It's purpose is to keep the arc going during these times. Your machine has high frequency starting - the manual will tell you how to turn it on. Also, balling the electrode is needed to equalize the emission between the electrode and workpiece and the workpiece and electrode. A pointed electrode will bias the emission to one direction which is fine for ferrous metals, but you need the ac cleaning action provided by the bipolar waveform for aluminum. Using a pointed electrode on ac will bias the waveform baseline and greatly reduce the oxide cleaning. Also, once the electrode is inadvertently bumped into the workpiece under power, it becomes contaminted and the emission balance is upset until the electrode is re-formed. The thoriated tungsten electrodes are for ferrous metals and a pointed electrode. The thorium increases the emission from the electrode to the workpiece. For ac you want just plain tungsten to, again, not affect the emission balance, although this is really only a small effect to worry about you get the rest under your belt. Learning to tig weld aluminum involves a big learning curve especially if you're doing it alone. In the 12 week class I took, only two students out of 7 really got the hang of it. Everyone was making beautiful welds in steel, however. - Terry

 

[petertha]

I don't own a TIG yet. My vast experience amounts to exactly one continuing ed evening course at a Tech college, so take FWIW. Any chance that your ground is not as 'groundy' as it could be? One of the guys in my class had some unexplained smoky looking bead segments for a while when he was tacking. I wasn't part of the instructors dialog but seems to me it got solved when they figured out he was doing something different - using the bench vise that was loose on the table or maybe related to the ground clamp itself. I'm not sure how to test for this other than clamp to the material directly?

This link has some potentially similar welds? Same suggestions others have volunteered here. I wanted to add on the grounding issue another guy was having problems with how the electrode was (not) being tightened in properly, the collet maybe? But you mentioned getting otherwise good welds in steel?

https://talk.dallasmakerspace.org/t/tig-welding-settings-configuration-issues/24896/8

 

[joco-nz]

Blighty,

as suggested get an AC/DC grade tungsten - I use Zirconiated Tungsten for Ali welding (https://www.boc.co.nz/shop/en/nz/boc-2--zirconiated-tungstens-boc5030). You could also try some rare earth grade stuff that is supposed to be good for Ac and DC currents. Personally keep it simple and use the "tried and proven" stuff.

I used a #7 or #8 cup for most of what I am welding no matter if Ali or MS. It seems to work pretty well. I only drop down a cup size if trying to get into small corners or if running low on gas and I'm prepared to chance my arm with less wiggle room re gas coverage.

As noted on an Inverter rig sharpen the tungsten to a point then slightly blunt it. At higher amps a balled tungsten will likely be the way to go but for any on around 3-4mm ali or less you shouldn't need to get into that game.

Don't get into pulse or any of the other crap until you have the basics under control.

Do you have a pedal to control amps or is (and your text reads this way) it all preset at the machine and you just stop/start from a switch on the torch? I can tell you that when I moved to a pedal control of the amps when welding with TIG it was like night and day. On MS its not so bad as you have such a wider heat band to operate in. On Ali it is VERY fussy and the heat band you have to operate in to get the weld pool but NOT blow through is much much tighter than with MS.
If you don't have a pedal then have you used the Miller welding calculator to help set you amps?
https://www.millerwelds.com/resources/weld-setting-calculators

If you are able to do/post a video on your attempts that might give us some ideas on what to suggest next.

Cheers,
James.

 

[blighty]

thanks for the post guys, all good stuff:thumbup:

still waiting for the new Tungsten to turn up. cant try anything till it gets here.

 

[joco-nz]

All good. You can chuckle at my learning process on ali if you like while you wait:
http://www.homemodelenginemachinist.com/showthread.php?t=25880&page=54

and soon you will be welding stuff up like (and probably better than this) http://www.homemodelenginemachinist.com/showthread.php?t=27455

Cheers,
J.

 

[blighty]

I remember reading that post. probably one of the reasons i thought i should get me self and AC tig.

funny thing is, i don't have any jobs that need ali welding at the mo:wall:. lots of steel and some copper coming up. It's now a mater of principle. it was designed for welding ali and by the power of gray skull , it WILL weld ali!!!