[p4spares]

hi all,
it's some weeks i'm stuck in a problem i'm not able to solve. i'm an hobbist and i'm trying to improve.
i'm trying to realize a project in mild steel, 3mm thick. the design use a piece of square tube 40mm that match a 40mm plate. you can see it in the picture.

20190112_163813.jpg (44.67 KiB) Viewed 381 times

i dont have any problem with the corner fillet in the opposite side. 110amp, 2.4 tungsten, 2mm filler. furick 12. works like a charm.
when i try to weld the corner in the picture... same seetings, same gas, same tungsten extension.. disaster. a lot of porosity.
i also have problem on find the best approach for this tight space, if start welding from the corner to the center or vice versa. i tried several approaches.. and i cannot say i found one better than the other.
i'm pretty sure if i remove this little lip with grinder i will get an acceptable result, but i would like to improve.... learn what to do in this kind of situations.
any help is welcome!
thanks,
David

[LtBadd]

David
With that cup you should be fine, what is the gas flow rate?
Maybe because of the inside corner, being confined and trying to see, you end up hold too long of an arc??

[p4spares]

hi Richard, thanks for answer.
my flow rate 15.5 l/mn, around 26 cfh. i tried to increase it to 30 cfh. result was slightly better.
today i dd another test. i used 2 flat bars this time, 3mm thick, 3mm gap from the border (as in the part i have to weld). i lowered amp to 95, maybe a bit too hot... but worked well without porosity.
probably you are right, uncomfortable position + tight area make me keep a longer arc.
David