Pulsed MIG welder from China

[Ashley Derrick]

I bought one of these dual-pulse MiG welders (got £50 off) to try silicon-bronze repairs on motorcycle parts using pure argon gas shielding.
The external construction quality looks fairly good but the manual is absolute rubbish.
I have tried some repairs to thin metal silencers with it with Si-Bronze wire and results were good for 1st attempt.
However, neither the manual or the seller can tell me what the function of the third (right hand control knob) is for.
I assumed it was for pulse length but it doesn't have any obvious effect.
Anyone know anything about this unit. The maker is 'ST .. 'Smart Tingo' but no reference to them on the internet.

 

[tigdlo]

Inductance.

 

[Jack Ryan]

Yes, it is inductance. It (usually) sets the dip rate in short circuit transfer mode.

The machine has a power ratings plate but it must be made up. The primary ratings are listed as "I2" and "U2". That probably doesn't affect it's operation but be careful what you touch.

Jack

 

[Ashley Derrick]

Thanks guy .. yes looking at it , there is an inductor symbol underneath the control knob.
Any tips on how I should set this inductance control please? I will be typically be silicon-bronze brazing (pure argon) onto thin (1 to 2 mm thick) mild steel, so the current will be set very low, as it's a 250A machine.
Attached are images of my machine. There is an earthing stud on the back panel ..... should I connect this to a separate 6 mm sq. earth cable back to the consumer unit in my garage? The house is on a modern dual RCD consumer unit..

 

[Ashley Derrick]

This looks useful. https://www.weldingtipsandtricks.com/mig-welding-inductance.html

 

[tigdlo]

Something really doesn't add up in the ebay description and ratings plate of that welder. Are you sure the welder is a dual pulse 250A? How do you turn the pulse off?

 

[eddie49]

I agree with tigdlo, there is nothing apart from the eBay description to differentiate this "dual pulse" MIG from every other generic imported MIG. There are no specifications, and no controls that would alter the width or height of the pulse.

The Earth stud is probably just the ( chewed up ) head of a screw that secures the green/yellow Earth wire on the inside of the rear panel. If the mains cable is 3-core, and if the green/yellow wire is actually connected inside ( some aren't ), no additional Earth is needed.

 

[Jack Ryan]

Any tips on how I should set this inductance control please? I will be typically be silicon-bronze brazing (pure argon) onto thin (1 to 2 mm thick) mild steel, so the current will be set very low, as it's a 250A machine.

I don't do braze welding with a MIG but as a rough guide, start with the control in the centre. Less inductance (increased dip rate) tends to cause more spatter and more penetration. More inductance make the weld pool quieter, less spatter and (perhaps) better wetting. For braze welding, I'd use more inductance. You'll have to try it an see just how much control you have. Otherwise wait for someone who MIG braze welds to comment.

There is an earthing stud on the back panel ..... should I connect this to a separate 6 mm sq. earth cable back to the consumer unit in my garage? The house is on a modern dual RCD consumer unit..

The case should be connected to mains earth already. I would not connect an additional earth either back to the panel or to a local earth such as a welding table.

I suspect the additional earth point is for jurisdictions where there might not be a mains earth.

I don't know how dual pulse fits in either. I have not come across a machine where it was "hard wired".

Jack

 

[GRW]

Sorry to crash the thread.... but can I ask in my ignorance:
1. What is Mig Brazing?
2. How do you do it?
(I thought brazing involved a flame torch and a filler rod with brass in it or summat?)

 

[pedrobedro]

Sorry to crash the thread.... but can I ask in my ignorance:
1. What is Mig Brazing?
2. How do you do it?
(I thought brazing involved a flame torch and a filler rod with brass in it or summat?)

Have a look on millerwelds for a detailed description

 

[Jack Ryan]

Sorry to crash the thread.... but can I ask in my ignorance:
1. What is Mig Brazing?
2. How do you do it?
(I thought brazing involved a flame torch and a filler rod with brass in it or summat?)

There is a difference between brazing and braze welding (formerly called bronze welding). Most people who talk about brazing mean braze welding which can be done with gas, TIG and MIG. It is a process that uses localised heat to form a fillet on the metal to be joined without melting it.

Brazing requires close fitting joints (like sockets) that are heated generally. Then the filler is melted on the base metal and is drawn in by capillary action. This is the same process as "silver brazing" pipe joints but at a slightly higher temperature.

Brazing can be done with gas and TIG welding - the TIG form is almost identical to the gas form where the arc is used to heat the area around the joint.

Both forms use a filler that has a melting point less that the metal to be joined and the metal to be joined is not melted. Braze welding has a puddle, brazing doesn't.

Jack

 

[GRW]

There is a difference between brazing and braze welding (formerly called bronze welding). Most people who talk about brazing mean braze welding which can be done with gas, TIG and MIG. It is a process that uses localised heat to form a fillet on the metal to be joined without melting it.

Brazing requires close fitting joints (like sockets) that are heated generally. Then the filler is melted on the base metal and is drawn in by capillary action. This is the same process as "silver brazing" pipe joints but at a slightly higher temperature.

Brazing can be done with gas and TIG welding - the TIG form is almost identical to the gas form where the arc is used to heat the area around the joint.

Both forms use a filler that has a melting point less that the metal to be joined and the metal to be joined is not melted. Braze welding has a puddle, brazing doesn't.

Jack

Years ago (so my recollection is sketchy) an older mate used to braze repairs to his cars.
He had a couple of "pencils" in holder's, which I think ran off his arc welder?
You'd set the points a short way apart, so you'd get an electrical arc flame, then he'd use the flame and a brazing rod to make the join.
Looked very Heath-Robinson & unsafe - but seemed to work well enough.

 

[Matchless]

Years ago (so my recollection is sketchy) an older mate used to braze repairs to his cars.
He had a couple of "pencils" in holder's, which I think ran off his arc welder?
You'd set the points a short way apart, so you'd get an electrical arc flame, then he'd use the flame and a brazing rod to make the join.
Looked very Heath-Robinson & unsafe - but seemed to work well enough.

Carbon arc

 

[Jack Ryan]

Years ago (so my recollection is sketchy) an older mate used to braze repairs to his cars.
He had a couple of "pencils" in holder's, which I think ran off his arc welder?
You'd set the points a short way apart, so you'd get an electrical arc flame, then he'd use the flame and a brazing rod to make the join.
Looked very Heath-Robinson & unsafe - but seemed to work well enough.

Yes, (twin) carbon arc can be used for brazing.

Jack

 

[Ashley Derrick]

Thanks for your additional replies/comments. I bought this welder mainly to repair Japanese bike exhausts, mudguards etc. I often silver solder repairs but for exhausts you really need high melting point braze. I decided against oxy-acetylene as the bottle rental/gas is expensive and I don't feel comfortable using on domestic premises, for safety reasons. The beauty of MIG brazing it is that you can build up the repair and then grind back .... if you then find a pit in the finish you simply put another run of weld over the pit without flowing the original braze. I tried this welder on a Honda down-pipe as soon as I receiver the welder and the 1st repair I did looks great and the chromers were very pleased with it. To have this kind of repair done professionally, by the chromers (usually subbed out) is very expensive.

Not sure what do to determine if it is a twin-pulse machine. I find it very difficult to converse with the seller via email but I go from Hull to Leeds every week so I could also drop by the seller's premises, which is in Halifax.

I am an electronics engineer so I have storage scope/Hall-effect current sensor /data-loggers etc. Would I see the twin pulse or lack of it.from a scope-test waveform trace .

The machine came with aluminium wire and I have not tried that yet. What are your opinions of the weld posted on the listing and attached?

 

[tigdlo]

Yes, a scope will tell you what you need to know, if you google dual pulse mig waveform or similar, there are many examples. Probably best do this before contacting the seller as then you will know for sure what you have.

I don't know what dual pulse mig welded aluminium looks like, even if that's a perfect example doesn't mean it was made by the same model welder as yours.

Please keep us updated and post the scope readings if possible.

 

[Ashley Derrick]

Yes I will post findings with scope.
I also have this TIG machine and I want to try TIG brazing with silicon-bronze filler rods/pure argon. I bought a Furick ceramic #10 setup for it but not had the time to try it out yet.

 

[Pigeon_Droppings2]

The beauty of MIG brazing it is that you can build up the repair and then grind back ...

I've used it quite a few times on my kemppi mig...it's handy for repairing door skins as it keeps the heat down.

Have done a few pitted coolant pipes and has worked well on those too. I tend to use it on more delicate repairs (non structural stuff).

 

[500e]

I use it to repair enamel signs, less heat keeps enamel damage down

 

[eddie49]

Please be aware that the output of even a "straight DC" inverter MIG can be a spiky PWM waveform, as seen Post #9 of this thread:

MIG welder torch voltage - general question

I've been using my Uptime160 MIG for a while now and it's working fine (slightly erratic welds recently but solved with a new tip). After reading threads about voltage, amps and wire speed I decided to test the welder to see what the controls actually control and what the voltage is at the tip...

www.mig-welding.co.uk