i think i will need some bigger shields and tungstens

[lotus 30]

Just cranked the tig up to full. welding some 9mm ali chequer plate wow it is fierce and the biggest shield i have got well hot what do i need to get so i am able to weld on thick stuff.
The welder is an old boc adr 300 and as the title it is a 300amp max setting. luckily it was only a 3" run so i did manage it but i did turn the shield gas up.
andy b

 

[Wendelspanswick]

Water cooled torch?

 

[Richard.]

^^^^^ beat me to it.

 

[langy]

Even a WP26 torch will get hot without a cooler

 

[lotus 30]

Water cooled torch?

Yep set all that up a couple of weeks ago WP18

 

[Richard.]

What size tungsten did you use. I'd say 3.2 maybe even 4.0 mm to be comfortable at 300 amps

 

[lotus 30]

What size tungsten did you use. I'd say 3.2 maybe even 4.0 mm to be comfortable at 300 amps

Thats the information i need my biggest is 2.5 which i used and what shield should i use

 

[Richard.]

By shield do you mean ceramic cup or shroud? If the torch is suitable for 300 amps then the shroud fitted should also be suitable. They will get hot and glow but so long as water pressure is sufficient then it won't take long to cool.
2.4 is too small for that current especially on AC. Any form of Dcep loading at those currents will see it ball up inside the cup quickly. Try 3.2 maybe even 4.0

 

[lotus 30]

Thanks very much for the information and yes it did ball up and it was shroud i meant.

 

[Richard.]

On AC I tend to keep it simple and step up every 100 amps so up to 100amp 1.6, 100-200 2.4, 200-300 3.2 and so on. They are rated to cope with higher but this is when I step up.

 

[lotus 30]

Thats me keep it simple

 

[Richard.]

Thats me keep it simple

Me too