Nozzle stick out

[kelsham]

Hi I have been trying to repair some 1931 car rear mudguards, think motorcycle with side skirt on the inside. They are in very poor condition, rust and splits, plus earlier repairs.

I was having problems getting a stable arc, my Clarke 175 was spitting and then burning through, I blamed the poor condition of the metal very thin, and the rust pits that always seemed to remain even after grinding and brushing.

Even using the thin metal technique did not help. I was searching the net for hints and found the suggestion that the tip should extend beyond the nozzle.

My tip was well recessed, I couldnt bring myself to let the tip protrude so i just ground some material off the front until the tip was almost level.

Immediate improvement, what are your experiences?

Regards Kels.

 

[cumbriasteve]

I have read before about the tip protruding and some people swear by it, actually arguing it is the correct set up.... never tried it myself, most of my work is on thicker material so I have no problems with heat etc.

Suppose if its helped you then there is something to be said for it.

 

[Fazed]

I do this at work after been given the tip by an old boy years ago. I thought it was common knowledge?
Most of the stuff I mig is anything from 3mm up to 25mm using a big old lump of a water-cooled torch. For thin stuff I swap to an MB15 and linish a shroud down so the tip is flush or just proud.

 

[kelsham]

I just assumed that the clarke torch would have been supplied with correct settings. I am only a hobby welder, well thats my excuse.

My Clarke 175 has a strange rotary switch on it. If used at low settings it behaves as expected. If I try to weld thicker metal, the switch alters position and it is impossible to alter through the full range. Left for a while and the full range returns. I presume it is meant to do this but there is no mention of such behaviour in the instructions.

Any comments on this.

Regards kels.

 

[mike 109444]

Kelsham your switch sounds a bit strange (not correct?).
Does it look like pic below (mine) because I had similar probs with mine a while back. So took knob off, removed two screws that secure switch asy to m/c and generally cleaned and sprayed with silicon spray. Avoid wd40 because if there are any cracks or brittleness to the plastic that makes up the switch it will chase the crack and cause the plastic to fall apart

 

[kelsham]

Mike, It looks simiiar from the front, what happens is, if I select 6 on the switch and begin welding it will typically switch back to 3. At this time I am unable to switch through the full range of positions. If I leave it it then returns to the full range. Is this what happened to you? I was beginning to think this was built in behaviour.

Regards Kels.

 

[Drains]

Kelsham, don't worry about the stickout thing - won't make much difference. All it'll do is change the way the job gets covered by gas, and how close you can get the tip to the work. In the case of mig, closer = more current, which isn't necessarily what you want anyway.
Sounds to me though like your problem is that the steel is wafer thin, so not weldable.

 

[mike 109444]

Kels when you say "it looks similar from the frount" does that mean you have not seen the back?. The problem I had was that the switch went very tight and would get stuck in position, say 3 and might have been posible to force to turn but I felt that if I had to force it that much it would break, hence reason I cleaned and lubed it. Been good since. As i recall there is a "detent" mechanisam which I think was a ball bearing in to a dibit. I could be wrong as it was a while ago. If yours is flicking, jumping back by it's self then the detent device is not sitting/dropping into place. It will probley be at the square shaft end as in my pic. Worth giving it a light brushing with small amount of white spirit then some very thin oil. When yours jumps back can you not just go backwards ie you have it on 6, it jumps back to 3 then won't go back to 6 but try 3>2>1>0>6 mabe. As this switch carries the power to the primary side of transformer, it has to handle quite a bit of power so will get quite warm in use and probley drys out the orignal lube in switch hence problem. Note there quite expensive if you can find the correct one!

 

[kelsham]

Mike, No I have not dismantled enough to see the back of the switch. I was beginning to think there was some sort of automatic process taking place as the switch will return to 3 on the dial from 6.

Still welds as if on 6. But the switch range is restricted to three positions.

After some time full range of switching is available.

Regards Kels.