A Welding Problem – Steel Type?

[Grindstone CowboyParticipant @grindstonecowboy]

Many years ago, our local welding supply place fitted an old CO2 cylinder with a proper valve and a regulator for me and will still refill with CO2/Argon. I cobbled up a connector from regulator to the thin nylon tube on my Cebora Mini-Mig. Much cheaper than the disposable cylinders. Have never tried flux-cored wire so can't help there.

The best advice I got was "If it sounds like bacon, it's OK. If it sounds like sausages, there's something wrong."

Rob

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Nigel, how long and what size cable is your spur to your workshop? as this can make a lot of difference, because a long run on a small cable will have a significant voltage drop at the socket end with a heavy load like a welder. It is about 20M from my consumer unit to the consumer unit in my garage, but that is served by 10mm sq. armoured cable, and I don't get any voltage drop problems. Maybe you need to get a new supply fitted anyway.

Regards Nick.

[Nigel Graham 2Participant @nigelgraham2]

Nicholas –

Thank you. As it happens someone at work did give me a short lesson in MIG welding one day, but not long after that the company decided it was more economical to sell the welding plant and bring in a contract welder, rather than have the occasional welding done by someone still employed anyway! So that was a one-off lesson.

I also have some training-materials written for welding and fabrication courses However, although that brief lesson and those books give me some background, I appreciate it also needs much practice and a very steady hand even just to put a ridge of weld metal along a bit of scrap plate.

What is the difficulty with flux-cored wire? Does it need an especially steady hand to maintain the right gap for the tiny bit of flux available to work properly?

'

Grindstone –

I don't have the advantage of a friendly local welding supplier who can refill bottles for me, but a quick search once I'd found the right name, shows the nearest Hobby Weld agent is not very far away.

That culinary tip's new to me! I know the sound should be steady and fairly quiet but I must admit I've never really thought about the acoustics of bacon and sausages.

'

A good question, Nick (Farr) -.

There is an RCD labelled "Shed" in the panel by the meter, in the home's front porch, but nothing to tell me the rating.

The cable down the garden looks armoured, by a very short section exposed across a path between the lawn in which it is buried, and the house wall. It goes through the wall into a junction box. I do not know the armoured cable size but the continuation upstream looks like 13A flex. Hmmmm. It vanishes into Goodness-knows-where, but my suspicion is an otherwise-isolated twin socket below the kitchen work-top. Very Hmmm.

At a guess, there is a good 20m of cable involved; possibly nearer 30. The house and garden are not very large but the cable has to follow walls etc.

My thought was to run a new cable but in conduit along the garden wall. I don't know the circuits in the shed but I'd replace with a surface-mounted ring-main for the sockets with a spur for the lighting (l.e.d. strips).

====

As far as the metalworking goes, I have largely worked out an alternative assembly so it is not welded and can use that steel that prompted my original question. It is fine for bolted, screwed-in or rivetted work, and indeed as candidate material for some of the engine components.

I have accumulated much off-cut and re-work scrap I could practise on. Some of it is steel box-section (ERW tube), 50 X 50 X 3mm, maybe only 2.5mm, and I know that can be welded.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Nigel, there are many regulations about running cables out to sheds / or any outside areas now and they have to be signed off by an approved electrician and I think your local council has to be informed somehow, so it is best to seek an approved person for advice.

Regards Nick.

[duncan webster 1Participant @duncanwebster1]

Unless you want to weld thin stuff a stick welder has a lot going for it. No expensive gas for starters. I've replaced my simple transformer with an inverter job. Not only does it make better welds, I can pick it up, old bones not good at heavy weights.

The other essential as others have said is lots of practice. When I was doing a lot the slag used to follow me off like a banana, not any more.

[Nigel Graham 2Participant @nigelgraham2]

Nicholas –

Yes, I know all domestic wiring is covered by assorted regulations, so I had always intended to do the donkey work myself to the specifications, and engage a professional electrician to test it and connect it to the distribution panel.

Why councils though? What's their interest?

My work-place employed a small group of electricians versed in all sorts – domestic 240V 13A. industrial 3-phase, shipboard wiring which is a speciality of its own, American 110V/60Hz supplies and converters…. Then along came a raft of new rules that said they were not able to wire their own homes! (Well, they could, but would still have to pay to have it admired – by someone with far less experience than theirs.)

'

Duncan –

I appreciate welding requires a heck of a lot of practice to acquire. Most of the welding I have done over the years has been simple stick work, wherever possible setting the work so it is always downwards, but I have never discovered the proper relationships between steel thickness, rod size and current.

My physical problem is having always had wobbly hands that wave a long electrode's end around like a reed blown in the wind; hitting the work a long way from the joint, sticking the rod to the steel, unable to maintain steady gaps and speeds. Someone suggested I cut the rods in half, but that flakes the flux off.

The other difficulty is that the lack of practice becomes self-fulfilling. Firstly, by preventing any welds that transfer or share the component's loads, so limiting one to welds only lightly stressed if at all, whose failure is merely inconvenient and appearance unimportant. Further, producing only jagged rows of rough "glue" blobs separated by slag, deters one anyway.

'

The task that initiated my question was the boiler-mounting brackets on my third-scale steam-wagon's chassis, an application I certainly do not want to fail. After realising I cannot weld them (the originals were probably pressed or cast) I scrapped them and will replace them with simpler versions cut from heavy angle. Each could do with a reinforcing web, and I might try welding those because they are in compression and the welds only hold them in place.

[Paul KempParticipant @paulkemp46892]

Nigel,

Going on your description of your welds and it's a bit difficult without seeing them (and you in action) and taking some of your other comments re the relationship of current to rod size I would say a lot of your issues are technique. First off for the size job you are describing I would suggest some 2.5mm 6013 rods. For those in quarter plate you want to be up around the 85 / 90a mark. 6013 are good general purpose rods, ideal for down hand (horizontal) you don't need to weave them or play with any patterns just draw the rod along the joint in a straight line and steady correct speed. What is the correct speed, that depends on the job and the size of the fillet you want but 6013's are high slag so if you go too slow with the wrong rod angle you will get inclusions. Position the rod midway between the two plates for a fillet (45 degrees) and tip the holder forward of the weld about 10 degrees.6013's will run EP negative or positive so you only have to decide the current. If yours is an old AC transformer then up the amps a little. If you are getting blobs with mig then your wire feed is likely too slow and if you get slag then you don't have enough gas. If you are using old rods of unknown provedence treat your self to a new box, you may have got some exotic rods there that are more finicky!

good luck.

Paul..

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Nigel, running a new cable out to your shed may come under the notifiable regulations The Regulations Explained so that is why I believe you should seek the proper advice from a trustworthy professional.

Regards Nick.

[Nigel Graham 2Participant @nigelgraham2]

Paul –

Thank you. I do have two or three packs of rods and I think one set is a "special", or rather not for mild steel, though I have put those aside somewhere. I'll look at the ones by the welder to see what grade they are.

I think it is far more my unsteady hands and limited experience that are the real problems though. I find it very hard to keep the electrode moving steadily and at a steady height, especially when it is still full-length, and striking the arc is very much a matter of luck.

The welder itself is nearly new, a SIP model, but probably a simple transformer only.

'

Nick –

I'd only be replacing old with new. The shed was wired by a previous owner, but recently enough for the modern colour codes. The part that worries me is inside the house, where the armoured cable emerging from the under the the lawn changes in a junction-box to what looks like 13A flex.

Mind you, by raising some cut floor-boards in the under-stairs cupboard gives me a view of grey PVC cables and polythene barrer water-pipes merely dangled across the full width of the 4-foot high void under the dining-room. Not very encouraging but despite being a caver so far I've not plucked up the courage to squeeze down the gap others obviously thinner than I have used, to I clip everything up properly.

In my previous home I erected a 6' X 4' shed as workshop but installed its lighting and power cables as two cables were all in conduit but connected in the kitchen by 5A and 13A fused respectively, standard 3-pin plugs with rcds. If anyone spotted them, they were protected extension-leads. No-one did, not even the estate-agent or viewers when I sold the home.

Others here have suggested voltage-drop problems but my machine-tools run happily enough on 1HP 3ph motors with VFD controls. I don't run the welding sets flat out but I might be better using them just outside the kitchen door, where I can plug them into the sockets there.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Nigel, you may only be replacing old with new, but in this case it may be regarded as a partial rewire, which is in the list in the link I posted.

Regards Nick.

[Nigel Graham 2Participant @nigelgraham2]

Thank you Nick.

It seems a grey area though "notifiable" work in planning-authority terms does not include outbuildings in England. It included them in Wales. Though a rewire is, wherever it is.

Really it looks as if best left alone then. The wiring was installed by or for some previous owner, not me; and the only work I have carried out was to replace a broken lamp fitting.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Nigel, I think there are a lot of grey areas and I'm glad I wired my garage before all these rules came into being.

Regards Nick.

[Nigel Graham 2Participant @nigelgraham2]

I think that was the case with my workshop. The cables are above a ceiling that was in a poor state, evidently some years after being slung up. I replaced the ceiling and lined the walls, but fitted removeable panels over the cables.

The cabling and plumbing in a large void under the house floor, do not inspire confidence by the way they are merely slung across the space with only cobwebs to hold them up.

[mgjParticipant @mgj]

I did once have a problem with a SIP that was difficult to control.

Turned out I was using .6 mm wire rather than the .8 for which the machine was intended (though a .6 tip was supplied with it) . The controller card didn't give me enough feed, even at maximum, so it kept burning back. You could weld, but it wasn't great, and I could never balance feed and amps properly.

Might be worth checking, because the right wire restored normal service perfectly.

 

Edited By mgj on 03/06/2021 12:49:58

 

Edited By mgj on 03/06/2021 12:51:50

[Nigel Graham 2Participant @nigelgraham2]

That's a thought – wire diameter.

It feeds well enough so I put the problems of over-feeding or melting back down to my inexperience, still the much more likely!

I'll see if I can obtain a manual for the machine, though. (It came to me in a decidedly "pre-loved" state.)

[Author]

Posts