A good ten years since picking up a mig torch, some critique please

[jimbo84]

I've always used stick although I regularly used mig but haven't touched a mig in 10 years.

Came across a cheap one in the for sale ads on here so bought it, it's a sureweld monomig, two settings of 30a and 85a.

Got some new tips and some new wire for it and rigged up an old fire extinguisher for the gas and gave it a go today.

I did notice it would run smooth but then mid weld it would start sounding like a machine gun (can't think of a better way to describe it) which I guess is to do with the hobby style wire feeds not being the best, only seemed to do it on the 85a setting though.

30a, 4th go seemed to be the best, direction of travel right to left

85a first go (5) seemed to be the best then couldn't get it settled after that.

tried a joint, started off badly but settled down to a better weld (85a)

Managed to run the next one much smoother (85a)

and lastly the rig

Any tips and advice gratefully received.

 

[pedrobedro]

Are you steadying your torch with your spare hand ? It looks like your travel speed and aim is wandering a bit.

 

[Ed.]

I am only guessing here but I think that the welder is running out of power, hence I think the reason that it got better as your weld progressed was because the base metal started to heat up, but you get to a point where it hits the duty cycle which limits the power output at the max amps and then it goes bad again.

 

[a111r]

How did you get on with this old set? It's the same, colour aside, as a Sealey Mightymig 100.
Not the easiest of machines to learn on with the torch being permanently live.

 

[tom2207]

its a start ,,, and the welds are getting better too.

 

[arther dailey]

I might be wrong but its probably upside down to just supply gas rather than powder

 

[tom2207]

I might be wrong but its probably upside down to just supply gas rather than powder

the '' straw'' goes right to the bottom , so if its the right way up the outlet would deliver liquid , and then it would have to turn back to gas as the pressure changes , but the wrong way up lets the gas be drawn off at a lower rate ,,
you dont want a low rate with a fire extinguisher ,,,

 

[minimutly]

That welder is ok for sheet work, beyond that it will struggle. Good use of a spare extinguisher though.

 

[a111r]

They're funny old machines. A gas valve in the torch, as well as internally.
They could have fitted a relay to the board to make the torch non-live for the cost of that extra gas valve...

 

[jimbo84]

How did you get on with this old set? It's the same, colour aside, as a Sealey Mightymig 100.
Not the easiest of machines to learn on with the torch being permanently live.

I still use it from time to time and it's ok for what I use it for. It's a pain having the permanently live torch but it is what it is and just have to remember. I've got a proper C02 bottle I use now rather than the extinguisher. It could do with a new liner and torch really but for the few times it gets used it's ok and not spending any money on it

I mainly use my stick inverter and oil cooled. The mig is just for tacking some little bits together that arc blows to pieces.

 

[jimbo84]

its a start ,,, and the welds are getting better too.

Cheers, it's an old thread and I've improved since the thread post.

the '' straw'' goes right to the bottom , so if its the right way up the outlet would deliver liquid , and then it would have to turn back to gas as the pressure changes , but the wrong way up lets the gas be drawn off at a lower rate ,,
you dont want a low rate with a fire extinguisher ,,,

You're correct, when the extinguisher was empty I undid the valve and there was a tube running to the bottom of the bottle.

I have a proper C02 bottle for it now so no freezing issues.