Advice PLEASE FOR NEWBY

[Easyrider]

Hi Guys

First attempt on alloy with a tig .... ok on flat plate but i had to repair a alloy post .. doesn't need to look A1 but did notice something straight away

ok .. set up (post is 3mm onto a 5mm flat plate)

1st picture external edge 145 amps, tip (2.4 filed to point) set about 5mm beyond shroud .. (to help me see it) .. 12 LPM argon
Not too much drama but in the next picture it was an internal corner where
it seemed to be getting to the top abd bottom ok but not right at the join ..
got much hotter and i rinsed a whole filler rod on about a 50 mm length weld.
Good penetration but looks horrendous. Tried to lenthen the tip out of the shroud but it really didn't like that.

 

[Easyrider]

Comon guys ... is there anyone who has struggled with an internal corner like this ??
must be a neater way to do it ... i'm a complete beginer to TIG so not sure which way to go ...............

 

[hotrodder]

Your arc length could be too long (arc fans out putting more heat into the sides rather than the root of the joint) and/or not hot enough- fillet weld typically requires more amps than an outside corner, especially on aluminium. Problem with cranking the amps up on something like the part pictured is that your welding to an edge which'll disappear fast given the chance, not an easy one for a first go on aluminium. Preheat would've helped

 

[Easyrider]

Thanks hotrodder ..... im going to practice a few of these and to preheat what does one normally do ..??

 

[simon718]

a mapp torch should do fine to put a bit of pre-heat into it

 

[hotrodder]

Yeah. Flame, oven, even use the arc itself in a pinch. It's a good idea to at least take any 'chill' off with anything except thin Al sheet/tube. Aluminium conducts heat way better than steel so initially you need to throw more at it. Unfortunatly it also has a melting point much lower than steel so once the part is heat soaked you've got to haul ass or lower the juice. Preheat it first and the effect is reduced

This effect is much less noticable on larger fabrications. Thin stuff quckly settles down heat wise, thicker things with a lot of mass... sometimes you have to stop and add more preheat as it's radiating it away faster than it's being added.

 

[TheJoker]

...you've got to haul ass or lower the juice...

This could be taken out of context... Well put. A pedal is good for "lowering the juice" when you can't "haul ass". (I'm still very much learning - and I don't have much alu to weld, at the moment ).