Noob penetration question

[NoelC]

Hi,

I'm using 1mm wall mild steel 16mm box section. I have 2 lengths touching lengthwise parallel to each other and I'm welding along the lengthwise join. My question is what sort of penetration should I be looking for? i.e if I look inside the box section should I see some penetration? At the moment I can run a bead fine along the join but see no penetration. If I put the amps up I get some penetration to the interior of the box section but also tend to burn through. As such I'm a confused newbie.

Many thanks in advance

Noel

 

[hotrodder]

With that type of joint the back of the weld isn't going to look the backside of a butt weld, i'd expect to see heat tint and some scaling if looking inside the tube, maybe with a little bit of reinforcement. To really know what's going on weld up an offcut and cut/break it open however with 1mm wall it's more difficult to get a cold weld with poor fusion than it is to be a on the hot side if that makes sense.

If the weld bead transitions smoothly into the base metal as opposed to looking cold (like a worm sat on the tube) then it should be fine. As they say a picture is worth a 1000 words...

 

[NoelC]

Many thanks, I'm getting some heat tint and the transition looks smooth so I think I'm ok. I guess I got too focused on making it look like a butt weld. Will have another go and see how I get on. Thanks again.