Stop/start without chipping slag

[Rrunnach]

http://www.mig-welding.co.uk/forum/threads/pipe.13654/page-8

I will. View the pictures on his thread i don't see him chipping he feathers top and bottom of pipe where welds mate.it comes down to the skill and habits off the welder.

Ah, Flange Jockey, he sure is one top notch welder.

Back to images: apart from the obvious peeler's achieved on on some runs, how do you know, no slag was removed by use of chipping hammer?

OC, when you sat your driving test, I imagine went about the learning process listening to your instructor. Then sat final test with DVLA examiner, following the guide lines of the then, highway code. Once you have achieved full license, you can do whatever you want after this, burn the highway code, if you wish.

My lads start as novices, down hand on plate, building up various positional welding on plate. Progressing onto 4" pipe, we have them focus solely on 6G/HLO45, which makes my life easier on their final weld test. Lads are allocated 4" grinder, encouraged to use grinder if there is a slag trap, also stop/starts. With my advice to feather back stop/starts on their final pipe test, as their work is also marked on visual to face side. One they have achieved their provisional certificate, they can chuck the book away, if they wish.

Are you stating it is wrong to train up our next generation welding by use of bad practice?

 

[backpurge]

Can someone explain to me the actual benefit of not ensuring 100% that your stop/starts are slag free and also what advantage you get from re starting on top of a cooling slag pool, am I missing something obvious??

 

[oilcooled :)]

I never welded down hand plate in school.all uphill. So i dunno why you teach that first but im sure there's a reason.forgetting about training lads, on site with welding is very different be it plate fabrications pipes tanks whatever. Having the welding up to standard is most important speed and neatness follow joint second and third. If your lads can get to.standard speed and neatness follow. The more experienced a lad comes the more shortcuts he learns and learns the easy way out of situations its a learning curve.. Would u agree the grinder is left down more the better a lad gets.slag traps do need attention with a grinder. My welding is xrayed very regular i do no what im on about.

 

[oilcooled :)]

Can someone explain to me the actual benefit of not ensuring 100% that your stop/starts are slag free and also what advantage you get from re starting on top of a cooling slag pool, am I missing something obvious??

Speed speed speed. Companies expect so many inches per day in a workshop environment.you need to b very fast on a restart that slag will just burn out off the way.

 

[Rrunnach]

I never welded down hand plate in school.all uphill. So i dunno why you teach that first but im sure there's a reason.forgetting about training lads, on site with welding is very different be it plate fabrications pipes tanks whatever. Having the welding up to standard is most important speed and neatness follow joint second and third. If your lads can get to.standard speed and neatness follow. The more experienced a lad comes the more shortcuts he learns and learns the easy way out of situations its a learning curve.. Would u agree the grinder is left down more the better a lad gets.slag traps do need attention with a grinder. My welding is xrayed very regular i do no what im on about.

First of all, I do not doubt you know what your on about.

Of course, anyone, will require less grind time, as their competence builds.

I've also witnessed shortcuts, like butt an shut, all good until weld/s fail. Anyone remember the new Lloyds building, built a few year back, all those weld shortcuts came to light as welds failed.

 

[oilcooled :)]

Welds failing that's unacceptable. But and shut unacceptable. i often wonder about them 3000lbs carbon fittings socket weld type seems like a home place for corrosion to live

 

[backpurge]

Speed speed speed. Companies expect so many inches per day in a workshop environment.you need to b very fast on a restart that slag will just burn out off the way.

Oil cooled, thanks for the reply. Understand where you are coming from but I have to say I don't agree with the reasoning but I suppose there will be some companies where the couple of seconds it takes to knock off the end crater slag is a big financial deal, places I've worked at have always been more concerned with quality than getting welds done 15/20 seconds a metre faster

Everyone has their own techniques they've developed over the years, so long as they don't dip on bombing who's to say what's right and what's wrong

 

[Brad93]

Personally I have a grinder to hand with a cup brush on it few seconds and the end of the weld is cleaned off ready for next rod and saves cleaning at the end before paint etc. If it needs to it doesn't take 30 seconds to feather a tack or a start stop

 

[Richard.]

My take on this has to be with the majority. It's certainly not to tell folk they are wrong. I am not an mma pipe welder but I used to do a lot of big installations of wear plates and classifier blades etc on big mills in cement plants and it was all mma rutile and basics 3G positional. The jobs had dead lines but rework would cost more time than crator feathering. It all adds up I understand that and I'm sure if you've got them consistently through X-ray then your technique is a good one. I've seen long arc starts over the slag on a tail done well and it's a recognised way in the field of doing it without a grinder. We didn't do it. We had a grinder and 10 seconds feathered the tail and restruck tight arc an inch back over.

 

[premmington]

I never get round the fact, slag inclusion is the enemy!

I try not to weave, I just lay stringers down.

I always chip back or grind out weld stops.

I do allot of MMA welding and very little MIG.

But if time and the amount of weld KG down is the only factor.

Maybe the job should be geared up for MIG?

 

[PTvor]

I think there's no getting away from that this is basically a dodgy technique.

 

[Paul G]

It's horses for courses lads. Let me try to draw a parallel.

Lets say you are doing an oil change as part of the preparation for a race.
The car is a '62 Lotus 20, one of those gorgeous cigar shaped race cars in BRG with yellow trim.
You would strip, clean, and carefully inspect every component & gasket and do all this in an almost sterile environment.
Time means nothing.


The tow car that pulls your pride and joy hasn't had a birthday for ages, A Ford Mundaneo with 150k on the clock.
You've got a half an hour before tea so a drop of 710 and a filter won't do any harm. After all, it has got to get you to the "Ring."


Get my drift ?


Paul G

 

[PTvor]

Yes but if you do that you know it's a bodge on something that doesn't matter. The OP is trying to perfect this to the stage where it isn't a bodge, but I think it's of its nature a bodge and I can't see it saves that much time. It works but it takes a lot of effort to hammer the slag off. There are likely to be other problems like the duty cycle of the welder and the leads, earth clamp and electrode holder and slag inclusions.

All sorts of tacky welds which are hit and miss or have huge wormholes are doing something they are good enough for, tacking two bits of steel together to prop up a fence which the wind has blown down and so on, but that's not the point.

 

[oilcooled :)]

What many people don't realise is that as long as the slag isnt an inclusion stuck in a gap that you need a grinder to get it out.the heat of the welding will burn 100%of it out of the way. A welding inspector told me that.

 

[Richard.]

What many people don't realise is that as long as the slag isnt an inclusion stuck in a gap that you need a grinder to get it out.the heat of the welding will burn 100%of it out of the way. A welding inspector told me that.

I'm a welding inspector qualified to cswip 3.2 and that's a bold statement to put forward. While the theory of it is true if it's not trapped it will burn out its not the case 100% of the time. You CAN create a trap on start up from exsisting slag. I'm not saying there is not a technique to eliminate the risk because I'm all too familiar with a long arc strike and I've seen it work many times by skilled guys that can judge very well what they can get away with. Mma welding is a self shielding process where slag is designed to remain where you've been not where your going. Everybody can do something enough times to to gain muscle memory and achieve good results like backing out of the driveway and some short cuts (like only using your mirrors) pay off 99% of the time.
I'm not saying your wrong. It's just not "correct" practice. It's been a while since I've obtained any upto date codes so I cannot say for nowadays but it wasn't acceptable back then to weld on top of slag despite the methods/short cuts used to clear X-ray/macro In the field.

 

[premmington]

I'm a welding inspector qualified to cswip 3.2 and that's a bold statement to put forward. While the theory of it is true if it's not trapped it will burn out its not the case 100% of the time. You CAN create a trap on start up from exsisting slag. I'm not saying there is not a technique to eliminate the risk because I'm all too familiar with a long arc strike and I've seen it work many times by skilled guys that can judge very well what they can get away with. Mma welding is a self shielding process where slag is designed to remain where you've been not where your going. Everybody can do something enough times to to gain muscle memory and achieve good results like backing out of the driveway and some short cuts (like only using your mirrors) pay off 99% of the time.
I'm not saying your wrong. It's just not "correct" practice. It's been a while since I've obtained any upto date codes so I cannot say for nowadays but it wasn't acceptable back then to weld on top of slag despite the methods/short cuts used to clear X-ray/macro In the field.

If someone is going to "burn" my welds after I have done them! I will be cleaning the stops out before restarting after a stop.

Even if it is DIY job we are talking about, for the best chance of weld to be successful. Cleaning up the weld surfaces pre welding and cleaning up the weld stops is always best practice.

I have had the same debate with a time served pipe welder, he re-strikes at speed into a hot weld with a long arc.

While he has had over thirty years welding day in and day. I have not!