BS Vertical Test Piece

[MM6CMC]

Got a vertical/up fillet to do this week to get my BS "up" certificate - I'm having problems with a wee undercut right along the weld. As I weld, I noticed you can just see the weld pool bubbling, then when the metal builds up, it calms down. Is this what I shouls be watching for? Any other tips?

Thanks in advance guys.

P.S. - got me thinking - how would you do a vertical butt weld, cos that will be the next on my list. (Say 6mm plate)

 

[runnach]

Got a vertical/up fillet to do this week to get my BS "up" certificate - I'm having problems with a wee undercut right along the weld. As I weld, I noticed you can just see the weld pool bubbling, then when the metal builds up, it calms down. Is this what I shouls be watching for? Any other tips?

Thanks in advance guys.

P.S. - got me thinking - how would you do a vertical butt weld, cos that will be the next on my list. (Say 6mm plate)

I'm assuming fillet is 6mm matl. L to R plane 45 degree, vertical up plane, approx 10 degree, again assuming 2 pass run, root approx 70amps max using 2.5 rod, 2nd (cap) run, 2.5 approx 65amp max, make sure you pause at edges as as you progress up the plate, this should eliminate undercut. You can use 3.2 rod if you feel proficient enough?

Butt should be approached using similar method as above, amps will change tho. New tutorials here is a good starting point..............

 

[MM6CMC]

Sorry Runnach, should have said, its MIG. I'll try and confuse you further....

2 60x200x6 plates at 90° in a "T" shape, and the weld is like you say - 10° from vertical. The weld has to be made in one pass with a pause at some point along the joint.

Been shown a couple of methods for this - variations on a weaving pattern as you progress up the weld, the first being to linger in the middle of the joint, then quickly weld to the left and right, before moving up and back to the centre.

The second method I was shown was to linger at the left, move quickly across the joint, linger on the right, then move up.

I'm producing a neat looking weld quite consistently now, but I'm getting a wee black shadow right up both sides of the weld.

Any suggestions/comments much appreciated.

 

[MM6CMC]

Edit:

 

[Delgado]

The first method sounds like a "Christmas tree" style weave, although IMHO lingering in the middle won't give you a very good weld profile, at best it will be way too convexed (flat or slightly convexed is what you're aiming for, unless the WPS, or examiner/tutor in this case, states different)and at worst it'll look like the pigeons have flown past. In my experience that weave pattern works better if you move quickly across the middle and then pause at the sides, filling the undercut. The second method would be the one that I would use unless I was trying to make a big weld in one pass (using the first method you're effectively putting in 2 passes at once), don't be scared to linger a bit more at the sides(count if you need to) and that should take care of any undercut.

You have to do a stop/start half way through a 200mm coupon with MIG? I can understand the logic with MMA or TIG but anyway..... The way that I was taught to weld with MIG was to always run the next bead into the start of the last, "back stepping" if you like, so I would do the top half of the fillet starting from the middle of the coupon, and then start from the bottom and weld right up and into the start of the first bead (maybe grind it back a bit to get a neater and more reliable join).

This is only my advice for what it's worth, and at the end of the day you're going to have to do it how the examiner/tutor says (not worth pi%%ing him off).

Hope this helps, and good luck with the test!

 

[MM6CMC]

Cheers Delgado, never thought about starting in the middle, but I'll give that a try - sounds like a better approach than chasing the heat/weld all the way up the plate.

Is it just a matter of pausing for long enough on the sides to stop it undercutting?

I tried a few different speeds last week, but in fairness, I was gettin g a bit tired and ratty by then.....

 

[runnach]

Sorry MC I was in arc mode when I replied, I should have noticed post was in mig section

Seems like your question has been answered. I'd imagine stop/start will be on one off the 1/3's of plate and, cut at stop/start for macro, then nick break?

Can't say I,ve heard of method as described by delgado, what I would like to add, starting from btm of joint, stop/start at a 1/3 at start or 1/3 from end? Feather (grind) back prior to continuing weld till complete.

I assume your working to BS4872 Pt 1 or 2?

Cheers.......

 

[MM6CMC]

Seems like your question has been answered. I'd imagine stop/start will be on one off the 1/3's of plate and, cut at stop/start for macro, then nick break?

Can't say I,ve heard of method as described by delgado, what I would like to add, starting from btm of joint, stop/start at a 1/3 at start or 1/3 from end? Feather (grind) back prior to continuing weld till complete.

I assume your working to BS4872 Pt 1 or 2?

Cheers.......

Runnach, Don't know how the piece will be tested - other than that we've to have a stop/start halfway along the weld, There's been no mention of grinding the weld back presumably because that would mean someone would have to set up a grinder.....

Don't know which part of the 4872 it is either - the best info they could offer was that if I did any welding jobs in future, in the event of any accident/fatalities if I was taken to court, then I could say I was a competent welded as per BS4872.

Sounds a bit far fetched to me - I just figured that if I could knock out test pieces for vertical t-piece and vertical butt weld that I'd be at a good enough standard on the MIG to move on and try something else. (Probably stick )

Thanks guys

 

[backpurge]

Runnach, Don't know how the piece will be tested - other than that we've to have a stop/start halfway along the weld, There's been no mention of grinding the weld back presumably because that would mean someone would have to set up a grinder.....

Don't know which part of the 4872 it is either - the best info they could offer was that if I did any welding jobs in future, in the event of any accident/fatalities if I was taken to court, then I could say I was a competent welded as per BS4872.


Sounds a bit far fetched to me - I just figured that if I could knock out test pieces for vertical t-piece and vertical butt weld that I'd be at a good enough standard on the MIG to move on and try something else. (Probably stick )

Thanks guys

4872 pt 1, Fusion welding of steels
4872 pt 2, MIG and TIG welding of aluminium alloys

With regard being covered in the event of an accident, that is total b****cks, if you screw up you screw no matter what quals you have, it is down to the employer to ensure you are adequately trained/qualified

 

[MM6CMC]

Backpurge - thought as much.

As far as I'm concerned, it's a certificate to put on the fridge with all the ones the wean has from school......

 

[backpurge]

Backpurge - thought as much.

As far as I'm concerned, it's a certificate to put on the fridge with all the ones the wean has from school......

It's always good to have a reference point so you know how you are progressing but if they are wanting you to part with hard earned for it you could probably do a macro yourself and spend the money on something more worthwhile unless you are needing your ticket to use as a reference when looking for work

 

[Delgado]

Can't say I,ve heard of method as described by delgado,

Cheers.......

Hi Runnach,
So you've never heard of "back-stepping" MIG welds? We use that method a lot over here when doing long runs or multipasses that you can't possibly complete without a stop start, due to body position, having to weld through holes that the torch wont pass through in reinforcement plates when welding around things etc, Although I must admit that I only learnt to weld that way over here, maybe it's not done that way in the UK, or maybe it's because I wasn't welding pressure stuff with MIG when I was welding there (the welders that I knew, if you like), I don't know?.. IMHO Apart from giving you neater beads, I would imagine that it gives you more reliable stop/starts, as you're effectively grinding off the unreliable starts of the beads and then welding a hot bead straight into the rest of it.

All the best!

 

[runnach]

Hi Runnach,
So you've never heard of "back-stepping" MIG welds? We use that method a lot over here when doing long runs or multipasses that you can't possibly complete without a stop start, due to body position, having to weld through holes that the torch wont pass through in reinforcement plates when welding around things etc, Although I must admit that I only learnt to weld that way over here, maybe it's not done that way in the UK, or maybe it's because I wasn't welding pressure stuff with MIG when I was welding there (the welders that I knew, if you like), I don't know?.. IMHO Apart from giving you neater beads, I would imagine that it gives you more reliable stop/starts, as you're effectively grinding off the unreliable starts of the beads and then welding a hot bead straight into the rest of it.

All the best!

Evening Delgado,

Yes of course I know of "back stepping" I was referring to another element of your post, I probably read it wrong

My point re; grinding back, MM6......would be attempting a test piece, where ease of access to grind back stop/starts would be a simple task, thus helping to ensure complete fusion. As you state, not many welds are done in ideal conditions, hence back stepping, which in fact one does even when grinding back.

Cheers.............

 

[Delgado]

Evening Delgado,

Yes of course I know of "back stepping" I was referring to another element of your post, I probably read it wrong

My point re; grinding back, MM6......would be attempting a test piece, where ease of access to grind back stop/starts would be a simple task, thus helping to ensure complete fusion. As you state, not many welds are done in ideal conditions, hence back stepping, which in fact one does even when grinding back.

Cheers.............

No worries, I'm not the best person at putting my thoughts into words, but it all makes sense to me

Sure, I see your point and agree, I wouldn't have thought that he/she'd be able to do the test piece in the manner that I explained, although the info might come in handy for them if/when they start welding for real.

All the best!