Any Idea What Causes This?

[Paul.]

is arc blow only a problem with mma welding? or can it also affect mig/tig??

Yes mig and tig are just as susceptible to DC arc blow particularly in fillets and the root of butt welds, Its rare on AC unless the material has some residual magnetism, which is possible if muggins practice piece is well used, one method of preventing it is to coil the welding return round the workpiece a few times, not always practical with a small job though

 

[aero]

The weld with the depression running along the centre seems to happen with poor technique, I find. Try a bit more of a swirling action as you go along.

If you have the power too low the weld pool can creep in front of the rod (in direction of travel) and then you can get welds with knobbly bits (again so I've noticed).

Go with the simple stuff before getting tied up with other theories

 

[Muggins the Mug]

Thanks for everyone's input there, but I think this is going to have to be a process of elimination. I'll get a fresh piece of steel to rule out arc blow, then try drying the rods to see if that makes a difference. If neither of those work then I'll try changing my technique to see if that works. Removing most of the variables should help, I hope.

Regards,

Ian.

 

[simon718]

Yes mig and tig are just as susceptible to DC arc blow particularly in fillets and the root of butt welds, Its rare on AC unless the material has some residual magnetism, which is possible if muggins practice piece is well used, one method of preventing it is to coil the welding return round the workpiece a few times, not always practical with a small job though

Paul i take it then, in a joint that has to be regularly re-welded (due to cracking or some other form of failure) arc blow can be a problem after a few grind outs and rewelds?? sorry to but into your thread Ian

 

[Paul.]

Paul i take it then, in a joint that has to be regularly re-welded (due to cracking or some other form of failure) arc blow can be a problem after a few grind outs and rewelds?

Its possible, but in my experience arc blow is often cited as a problem when in fact its something completely different, such as poor electrode technique, poor quality, damaged or damp electrodes incorrect amps etc, I have experienced it on heavy fabrication using mags, but rarely at the kind of welding currents we are talking about here,

 

[scarecrow]

, one method of preventing it is to coil the welding return round the workpiece a few times, not always practical with a small job though

Haven't heard of that one probably better than my method cursing

The weld with the depression running along the centre seems to happen with poor technique, I find. Try a bit more of a swirling action as you go along.

If you have the power too low the weld pool can creep in front of the rod (in direction of travel) and then you can get welds with knobbly bits (again so I've noticed).

Go with the simple stuff before getting tied up with other theories

I doubt if it's poor technique snowcat had a pick of one a couple of weeks ago
I had a few rods do it to me switched to AC and still the same problem changed rods and everything was fine
never had any complaints about my technique

 

[Muggins the Mug]

I doubt if it's poor technique snowcat had a pick of one a couple of weeks ago
I had a few rods do it to me switched to AC and still the same problem changed rods and everything was fine
never had any complaints about my technique

I hope I've not got a duff pack of rods as I've used this type before and they seemed quite good. Probably just my poor technique as I've been trying to slow down of the speed of travel and be more consistant with the arc length. Funny thing is, I thought I was improving.

Regards,

Ian.

 

[snowcat]

a couple of other things that can cause it, would be a long arc length or too high current which can again be linked to arc length, but try the plate first, sometimes material can do funny things, then the rods, then work you way through all the other parameters one by one, personally with new plate and dry rods `I think your welds will be much improved....

 

[chrisg3103]

mine have recently started doing this too, probably dosnt help the place is damp as a very damp thing. have some green stuff growing on the far wall, i call it fred

 

[Muggins the Mug]

Those new Phoenix's that I recently bought may have been stored in an unheated shop/storeroom over Xmas, it wouldn't suprise me if they are damp as I've no idea how long the box has been opened for.

Some good pointers there folks, I appreciate the feedback.

Regards,

Ian.

 

[zzr1200]

Some good pointers there folks, I appreciate the feedback.

Regards,

Ian.

Buy wifey a bunch of flowers, give her a kiss and cook those rods for an hour at 150......

 

[aero]

I'm certain the depression in the weld is simple bad technique. I went out and ran off a bead, half of it with a depression in the centre, the rest normal. One rod, one run, no changes except speed and rod angle.

Keep the rod nearer the verticle and the travel speed higher.

I also tried heating the rods up first. It made a noticeable difference (pheonix 6013). I put them in the oven (lucky the g/f was out). I don't have a fancy quiver, but a 12" length of old steel pipe sat directly on the garage heater kept the rods warm.

 

[Muggins the Mug]

Hi aero,

I'm positive that I kept the rods practically vertical during the laying of the bead, perhaps a change in my posture could have caused it to slant without my noticing. I'm going to experiment later this afternoon and will probably trying heating the rods as part of eliminating what happened. I've got some fresh small pieces of steel try out on.

Regards,

Ian.

 

[Muggins the Mug]

Hi folks,

I found a small piece of scrap 5mm plate last night in the back of my cupboard (very small piece). After a quick clean up with a grinding disc, I decided to give my Phoenix 2.5's a wee bash at the usual 80 Amp. Here's the results below...

The appearance is a lot better than the previous effects on the old piece of steel. In fact, it's the best weld bead I've done so far if I say so myself.

There doesn't appear to be any of the lumps and bumps that I've previously experienced, so perhaps it was the old work piece after all. My technique for holding the rod, etc hasn't changed (that I can tell of). The rods haven't been put in the oven as yet, but I will do as a matter of course.

Regards,

Ian.

 

[bawjaws]

looking good the way i tell if its a good weld is if the slag cracks off itself or if it comes off when you drobit on the floor

 

[Muggins the Mug]

looking good the way i tell if its a good weld is if the slag cracks off itself or if it comes off when you drobit on the floor

That's the beauty of it jaws, a 1½ inch strip came off itself and the rest came off with slight finger pressure (through gloves). Now just to work on getting a peeler.

Regards,

Ian.

 

[malcolm]

It it looking much better. Could be worth trying for a couple of joints - I got a much better feel for arc welding after a bit of butt welding. I did find the joint needed to be prepared in the appropriate fashion. Miller arc calculator has suggestions for prep.

I've not managed a peeler yet, though in my defence the welder broke and it's been a bit too cold to go out and fix it .

 

[Muggins the Mug]

Hi Malcolm,

That's my next project when time permits.

Regards,

Ian.

 

[scarecrow]

looking good some rods are better peeler than others a lot of the rods now have easy slag removal they just seem crack and fall off rather than lift up your probably get one you least expect it

 

[aero]

I dug that run out of the bin, ignore the other welds, the top one is the one where I tried to get the same effects as in your pictures. Rod speed and angle.

That was with a 3.2 at the lower end of the amp range. I was seeing if heating the rods before using them made any difference, it does. They strike up and weld much nicer.