thinner ally tig problems

[oggy]

Ive been tig welding aluminium for about 3 weeks now. Im getting the hang of welding thick stuff but have problems with thinner stuff. The pics are of the stuff i think ive got the hang of.Using 150amps with gasflow on max 2.4 tungsten & 2.4 rods. Now the thinner stuff involves welding aluminium unions onto about 3mm thick ally. Ive turned the amps down to about 30 amps & gasflow down to 7lpm. rods & tungsten are the same,both 2.4. The problem is that im getting alot of black muck into the welds. should i turn the gasflow back up to max ? ac balance is set at 70% for both jobs.
cheers

 

[mike 109444]

Oggy No ideal about your tigging problem but if you look on your camera for a "closeup" setting usually denoted by a pic of a flower you might find your images come out clearer giving the tigger guys (and gals) a better view of the problem

 

[brightspark]

Oggy No ideal about your tigging problem but if you look on your camera for a "closeup" setting usually denoted by a pic of a flower you might find your images come out clearer giving the tigger guys (and gals) a better view of the problem

cheers for the info on camera

 

[oggy]

cheers for the info but it was taken on a phone. my problem is why is the weld clean on thick stuff & full of crap on thin stuff ?

 

[Llundberg]

30 amps seems way low for 3mm. I use 80-90 amps for 3 mm.

 

[hotrodder]

Pics of the welds you're struggling with would be more helpful than those that are coming out nicely. Preferably in focus

The technical term for the black soot/muck is weld smut, article on it here... http://www.thefabricator.com/article/aluminumwelding/how-to-recognize-minimize-weld-smut The article is more applicable to MIG as with TIG you most commonly see it when the wire has touched the arc/tungsten touched the pool vaporising some ally

30A sounds way too low to me for 3mm as does 80-90 but sooo many things influence amperage and if the transtig is one without digital meters (most of them that i've used were specced without as 'bare bones' versions) then i would trust the numbers even less

I'm wondering if the 2.4mm wire is part of the cause... if the amps are on the low side then the weldpool is gonna be smaller making it easier to touch the arc with the wire before it reaches the puddle or more tempting to try and use the arc to melt the wire. Without pics of the problem it's just guessing though. I wouldn't decribe 3mm as thin personally and unions (in the context of rad necks/automotive stuff) means thicker wall but overall relatively tiny parts to me. Welding say a -6 fitting into something ain't easy when you're new to TIG due to the amount of torch manipulation that's needed to weld small diameter stuff... to get a big enough weldpool for 2.4mm wire it's very easy to end up overmelting the union. You really need to be quick and accurate with some 1.6 wire, at least with the initial tacks

Shouldn't need more than 7 litres/min for most work with TIG... about the only time i'm running more than that is welding something like Ti with a giant gas lens and a #12 ceramic. Typically with ally (and most other stuff ) unless access dictates otherwise i run a #7 with flow rates from 5 - 7 litres/min depending on joint configuration, amperage and the amount of stickout needed

 

[oggy]

Cheers hotrodder the transtig im using does not have a digital readout so i could be using less amps than i think.I shall try & get some pics in focus.
I found doing the filler necks in the out of focus pics not to bad but with the smaller diameter stuff im not getting the( beads )? just a melted mess with lots of (smut) in it . Think i need to turn amps up & move abit quicker ?
I do find going round small diameter unions harder as i have to keep stopping to move the job round.
thanks again

 

[langy]

Cheers hotrodder the transtig im using does not have a digital readout so i could be using less amps than i think.I shall try & get some pics in focus.
I found doing the filler necks in the out of focus pics not to bad but with the smaller diameter stuff im not getting the( beads )? just a melted mess with lots of (smut) in it . Think i need to turn amps up & move abit quicker ?
I do find going round small diameter unions harder as i have to keep stopping to move the job round.
thanks again

Don't look like your feeding enough rod in looking at the neck pics mate

 

[hotrodder]

Think i need to turn amps up & move abit quicker ?

I think there's more going on than just that... As Langy said the rad neck is a bit underfilled and looking at the pics again i'm wondering if arc length is a bit on the long side (maybe it's the super close up pics).
When tacking I have the machine set high enough to give me a weldpool pretty much immediately so that the entire tacking process takes a couple of secs tops. Travel speed on small diameter stuff... i'd say it's more important to keep the angles of attack right than moving faster, unfortunatly keeping up with the change of directions is tricky and takes some time to get to grips with

 

[Piero]

Trust hotrodder and langy to come up with the goods

Very interesting reading guys, its teaching the likes of us new tig welders a thing or two.

 

[FranV8]

Agreed !! Want to see some better pics of Oggy's works so far - looks good for just three weeks on it.

 

[oggy]

Thanks for the help so far. The filler necks were done at 150 amps, If i was to turn it up to say 200amps & fed the rod quicker would that help with the underfill ? underfilled ?Would that be why im getting the odd tiny leak on the edge of the weld ? I have the tungsten sticking out maybe 5mm to help me get under the overflow pipe . Im on the small stuff tomorrow so i shall get some pics up hopefully in focus this time. I had a play around doing some today on some scrap which didnt look to bad . Well to me they didnt

 

[hotrodder]

No need to turn the amps up. You either need to add a little more wire each time you dip or (preferably) add a similar amount more often i.e. don't move the torch as far between dips.

Second pic about 4.30 and again at 6 o'clock is what looks like it could be poorly tied in toes and/or maybe some coldlap at the neck side of the weld. If the leaks occur at these (or similar looking) areas then it could be because you're moving the torch too far between dips.

Can't find any decent close up pics of ally fillets, let alone on small fittings. This is the best i've got to hand which probably doesn't offer enough detail...



The AN fitting is -6 for a very rough idea of scale. The fitting is the round type (rather than the larger hex base) and the leg length of the weld matches the base of the fitting if that makes sense. When welding around them i'm adding smallish amounts wire very frequently i.e. freeze lines are probably overlapping by about 90%. The 'roll of coins' look comes from adding more wire less frequently which can work on small stuff but is more difficult imo as coldlap becomes a bigger potential issue

Get us some in focus pics

 

[oggy]

Cheers for that hotrodder. Ive been doing some smaller stuff today ie welding fittings fittings onto oil cooler's. Im going back in later to do somemore so i shall take some pics hopefully in focus of todays work.
Turned it upto 100 amps for these & seemed to go ok but you will know better than me. Its hard to teach yourself but i wont be beaten

 

[oggy]

Well i got onto doing the smaller unions. tacked them on in 2 places . layed the job flat and tried to weld it on in two goes. started on one tack & welded round to the other, turned job over & done the same again. It's harder than it looks .
Again pics not great it was midnight & lighting not very good sorry

 

[hotrodder]

It's harder than it looks

Yep!
Well it looks you've fixed the weld smut problem so the weldings progressed further than the photography It's gonna take time/practice but looks like maybe you're losing the torch angle/increasing the arc length as you go...

Between the line at 8 o'clock and the one at 4 (especially near to 4 o'clock) it looks to me that the torch has been laid back (increasing the arc length) and is favouring the core. Wire additions have also gotten a little erratic. When working around small diameter stuff it's relatively easy to either end up blocking your view of the weldpool and/or tieing yourself up with the wire depending on body position at the start and how you move. Most people usually find it easier to start with a less natural body position so that they're becoming more comfortable as the weld progresses i.e. you start slightly out of position and move through comfortable (everything right in front of you) to out of position. Hope that makes sense. You can also try bending the end of the filler wire... pros are that you don't have to move your wire feeding hand around so much, cons are that you can't really feed the wire until the bent end has been deposited i.e. you're changing the way the wire is fed as the weld progresses

Watch craters at the end of welds (9 o'clock), either keep the arc moving as the weldpool freezes and/or add an extra dab of wire as you slope out/back off the pedal. They're a classic spot for a crack to propogate from and the dimple can often be a pinhole that leaks although that's more likely with butts/outside corners than fillets

 

[oggy]

Yes its getting better than my camera work I can see what you mean about the arc getting longer. The part of the cooler with the hole in is closer than it looks in the pic. im using a number 5 ceramic & it just fits between that part & the union if im careful. im trying to weld it in two goes so im not stopping & starting so much. Its just trying to keep the angle & the wrist all the same . I have been having abit of a practice today on the crater finish . just remembering to it & not be in a rush to finish .cheers again for ur help

 

[Jim Davey]

This is one of those times where this can be really handy...

 

[norlander]

This is one of those times where this can be really handy

Is it possible to have a link to the specs and prices of those torches without breaking the forum rules??

 

[Jim Davey]

Google I-head from Weldtec, the quality of Weldtec knocks CKs for 6 but you do pay for it.
I'm a Weldtec outlet, you can email me your machine make and model and I'll happily advise prices specs etc.