How do you weld two pieces together?

[Trousers]

Hello all. I'm finding this forum very useful. I bought a hobby arc welder recently 100A. My progress so far; I can do nice bead lines on a piece of thick pipe but have been unsuccessful in joining two pieces together.

Do the two pieces have to be mechanically bonded, or bridged, i.e. to form a solid electrical connection between the two pieces to be welded, or is the arc supposed to do that and you attach the ground to the largest piece? So far, the best I've done is to run a bead along both pieces, but when it has cooled and come out of the vice, one of the pieces easily separates from the other with a nice bead line attached to it, and I've run out of practise material.

Is the general idea of good arc welding to make a weld using as low a current as practicable?

Ta, much.

 

[shenion]

Post some pics and say want size metal and rods you are using.

Doing butt or fillet welds takes practice especially keeping the rod within the weld pool and making sure it melts both pieces.

BTW, welcome to the forums

 

[Drains]

Is the general idea of good arc welding to make a weld using as low a current as practicable?

Ta, much.

Hey Trousers.

Do what Shenion says, eg, tell us what you're using - most importantly, what rods, at what amps?.

In answer to the last part of your question - No - you should be using as high a current as practicable. Probably, the main reason your welds are failing is low current.

 

[Trousers]

Thanks for the replies. I'm using 2mm & 1.5mm E6013 rods at about 70A & 50A respectively. This is a bit higher than it states on the machine for those rod sizes. The metal is about 100mm * 200mm & 4mm thick. Don't have any pics at the moment.

 

[Drains]

Now then trousers. Your amps are fine. I guess the next question is did the rods come from machine mart or screwfix? If so, they're cheap (cheaply made, not cheap to buy), nasty and difficult to use. Learn on them and everything else will be easy!

6013s, especially cruddy ones, can be a sod to use. The skill is in getting the metal, not the slag, to do the joining. For a start, move slow enough initially to get a build up of enough metal to join the two pieces(hopefully with the slag on top). You might do a teeny tiny weave - like you have the shakes a bit. That could help. Also, experiment with your arc length (it should be short, even under the slag). Also, try to recognise the difference through the lens of molten metal and molten slag - this is easy with some types of rods, difficult with cheap 6013s with runny slag.

Otherwise - arc is a skill, so practice is required, and plenty of it. You say earlier you have been running beads on flat plate. Just to get a better idea of what you're doing, try running one bead into the next - don't separate them. That will give an angle at the bottom of the last bead which you have to fill. You might get an idea of where you're going wrong if you try that, and it saves steel. It's called pad welding - as if you are building up another layer of metal on the plate. You'll get through the rods, but don't underestimate the value of practice!

Cheers

Si

 

[Trousers]

Many thanks for the advise Drains

I'm getting somewhere now in my attempts to weld. It's not pretty but the welds seem to be doing their job. I have a serious lack of practise material at the moment and I've resorting to chopping things up, so I can weld them back together again. At the start I was practicing on difficult welds like welding different metals, thin metals; tubular rods, nails and such like. Actually, one of my best welds at the start was to weld a big nail to my vice. But, a bit of patience & a lot of practise go a long way.

I think the 1.6mm rods probably are of poor quality. Got them at my local independant tool shop, 85p for ten. Don't know the brand but the bloke said they'd been lying around for years and I wouldn't yet know the difference between good & bad anyway. They are quite difficult to strike and maintain an arc, even at around 80A. But it may just seem that way due to my lack of skill. Those 1.6 rods disappear fast don't they, I guess the smaller ones are more difficult to use for that reason?

The reason I asked about using as low a current as practicable is my welder says to use 40 & 55 amps for 1.6 & 2mm rods resp. but at those settings the rod just sticks or I can't get a strike at all. At around 50-70 or more works well.

Before I go, a couple of questions if you please?

Is the rod size only one factor in determining amp setting? I.e. how does the mass/thickness of the metals to be welded factor into the AMP setting?

Or, how does the metal type of the piece factor into it?

And

Is it common practise (if you have a small setup) to bead one piece, clean it, bead the other, clean then bead between the two for the final weld?

Ta.

 

[Drains]

Is the rod size only one factor in determining amp setting? I.e. how does the mass/thickness of the metals to be welded factor into the AMP setting? Or, how does the metal type of the piece factor into it?

The two main factors to current choice are rod size, type and make (most manufacturers will recommend current for their own brand, different flux coatings and metal compositions will require different currents); and welding position. This is very important! You can use a much higher current on downhand (horizontal) welding, than you can on, for instance, vertical up welding (the same goes for mig), as you have gravity to contend with. The hotter the liquid weld metal, the slower it cools to solid. Metal thickness is a relatively minor consideration, except on very thin stuff where you may have to get the amps as low as you can to keep a stable arc.​

And

Is it common practise (if you have a small setup) to bead one piece, clean it, bead the other, clean then bead between the two for the final weld?

No. There is no requirement to "tin" a weld. Clean the metal first if necessary, set up the appropriate prep (gap and angle), and fire away. More than one bead may be required (see here and here for more than one bead)​

Ta.

You're welcome!​

 

[shenion]

I had a cheap 110A welder. It needed to be set at 90A to run 1.6mm rods and 110A for 2.0mm. These have a low operating voltage and are notoriously overrated.

1.6mm rods are difficult even with good rods. There is more slag then metal being deposited. 6013's need a higher current and a very short arc length. These burn with the metal near 2mm up inside the flux coating. So, dragging them is about the right arc length. I drag them, the difference is huge on keeping ahead of the slag.

I have a few different 1.6mm rods. Some are very hard to use in corners or bridging any gap as there is so much slag that cools way too fast.

I am seeing more places carry 7014 rods. They are much easier to use and can be run like the larger rods with a "stadard" arc length. I had a tube of them and love them for thinner stuff.

On the cheap buzz box I had, the 2mm rods are easier to use. I'd look for some name-brand 2mm rods to practice with.

 

[Trousers]

Again folks, I appreciate the responses. Will keep practising. I do intend to actually make something once I'm confident enough.

 

[darthmojoe]

if the job is falling apart then your amp is set to low, 100amp is only good for thin sheet steel really get some scrap and start on the highest setting if you only have a home diy style welder,, good luck

 

[Trousers]

Ta for that darth. I know I have a small setup (and maybe even derided on some welding forums ) but it's all I need for all the work I'll be doing. But. What would a larger, say 250A setup give me that a 100A setup wouldn't anyway; if you only need 70A for 2mm rod and I have 100A at my disposal? I'm told it's a greater operating voltage, though my understanding is that this makes it easier to strike and maintain the arc. So for learning, I suppose, it's not such a bad idea to start on a small machine.

A ? please.

Apart from penetration, is a E6011 weld stronger than a E6013 one, or is it the penetration capabilities that make it so?

 

[zardoz]

E6011 make a fierce arc and are good for burning through rust, dirt, (even paint, though not reccomended) this makes them a top choice for agricultural welding done on farms etc, where looks are not important. They are also good for welding downhill.

forceful arc that results in deep penetration and good metal transfer in the vertical and overhead positions. The electrode is usually used with a whipping or stepping motion. This motion helps remove unwanted surface materials such as paint, oil, dirt and galvanizing

 

[Trousers]

Ta Zardoz. Well, what a difference a good rod makes (kudos Drains, this was your first thoughts on the subject). Up until today, I've been using poor quality rods, but today went out and bought some good quality 2.5mm 6013 rods and some black steel. The first thing I noticed was it is a lot easier to use and the weld strength is far superior to the crap electrodes. I'm getting some good results now .

Quite a lot of views for this thread eh?

I think my little welder has performed marvellously for all it is and the price I paid; hasn't cut out once.

Terra for now

 

[Feet 'n Inches]

6011s: are those the cellulose rods - good for vertical down - hold a stable arc with no chance of the slag overtaking, and with good penetration?

 

[Trousers]

Yes, I think they are feet 'n inches. They're raving about 6011 and 7018s over at http://www.weldingtipsandtricks.com/stick-welding.html They say 6013 are only good for practising and amateurs. But as I'm welding 2mm tubular steel now, I'll stick with the 6013s; they seem to be working well.

I think farmers and the like prefer them as they have good penetration and are good for getting through rust and dirt. EDIT: (as zardoz has already said)