tacks/starting a bead on joints

[smashweld]

what exactly are you aiming for when getting a bead/tack started on alu joint? prob any metal actually

getting fairly comfortable with joints once they're started.....but getting the first bit of filler in to get it going is a bit of a lottery.....rod balling up but puddle formed/metal getting way too hot, blowing holes

should you try get a pool going between both pieces right on the join or just as close to the join on one of the parts then try get it flowing in to both pieces (near the root) once there's some filler added?

 

[Brad93]

You’re not hot enough if the rod is balling

 

[smashweld]

cheers, thinking about it...don't think it was as much of a problem before starting to use the pedal.....will experiment with that

 

[Richard.]

Never introduce filler until you see a shiny pool develop on 1 or both sides of the joint.
This should happen almost instantly.
You should be tacking up hotter than you would weld at. I’d say 25-50% hotter.

 

[angellonewolf]

^^^^^^ is that the same for mig ? tacking ?

 

[smashweld]

does the torch or welder heating up have any effect on the arc stability? or how shiny the weld ends up? is that why people use watercooled torches or is it just because the torches get too hot to hold comfortably?

 

[Richard.]

No it shouldn’t do providing you use the torch and tungsten within its current capabilities. If you apply more current than things can cope with you will cause the tungsten to ball excessively or wreck your lenses in which case this can cause stability and shielding problems.
The idea behind water cooling is to allow for bigger current levels, reduce torch size dramatically and give your consumables an easier life. With water cooling you can use up to 250-300 amps through a wp9 size torch. Impossible with gas cooled torches.

 

[smashweld]

ahh, I see. oh well at least i can rule that out... prob just lack of consistency with technique but I seem to get best results at the start of a practice! after changing the tungsten after the first error it goes downhill

any tips on getting the spacing wider? I can't get he pool to move along further without it going to a crescent shape..
some of the better ones yesterday..

 

[Richard.]

any tips on getting the spacing wider?

More filler per dab but dab less frequently as you move

 

[smashweld]

cheers Richard...maybe use larger dia rod too? been using 1.6 on the 2mm sheet and 2.4 on 3mm box sections

 

[smashweld]

more questions....

too much heat seems to be causing the dull looking welds was getting...but...tried an outside corner weld and it came out much shinier than most if not any weld/bead I've ran before. why? likely causes?

also only way I can get that 'stack of dimes' defined look is jumping ahead of the puddle, waiting for it to form and add filler...doesn't take long to form but goes against what I've read/watched about pushing the puddle along. thought?



the poor arc stability that I thought could be caused by the torch heating....now think it's due to not grinding/cleaning the tungsten properly after a dip...used some 180 and 240 discs to get them nice and shiny/smooth(er) after grinding this time and had far less problems


all these were with the pedal set to 120 max...not sure but I'd say pretty close to max when welding, 100 maybe