Foot Pedal for a MIG (Why Not?)

[malcolm]

From reading shenion's thread (but not wishing to hijack it)....

MIGs always seem to start cold with increased weld build up, then work just right for an inch or two, then as the metal heats up you have to speed up or the weld gets too hot.

TIG gets around this issue with a foot pedal to control the amps on the fly, but I've not seen any MIGs with voltage control.

Is it a technically difficult thing to do? And if not how might someone go about wiring the foot pedal from their TIG into their Portamig so it would work on all the voltage settings?

 

[snowcat]

I have a remote head to control volts and wire speed, but this is just a handheld with pots on.

 

[Drains]

Mig gets around the issue with technique. Sounds like a hassle to put a pedal onto mig, for all sorts of reasons. Mostly cos mig is fast. Set it up right, travel right (for cold starts and penetration). You can move around very quickly with mig, and it's highly positional in a way that tig isn't. (not when you bring speed into the equation). A pedal would be a PITA.

A pedal might be appropriate with very thin materials I spose... It would take as long to learn pedal technique as it would to mig weld properly, I reckon.

Not saying you can't Malc . Not sure about your settings though!

 

[snowcat]

yes mines just to save going back to the machine thats all, its just handy if your in an akward position and want to go from a flat to vert for example cant see much need to change the volts or wire once your runing though.

 

[malcolm]

I might have a look - Was thinking about all the wires in to the transformers might make it a pain, though tackling the job on the other side of the switches might work. Should only take a rheostat. Will have to take a lookie inside and see what can be botched.

I reckon it could be useful for some jobs. And where it's not useful if the welder works as normal when the pedal is unplugged then no harm would be done (apart from risk of electrocution and explosions maybe).

 

[Drains]

Definitely interesting to give it a go.

Easier - rig up a pedal that does the wire feed. Will do the same job more or less - changes the amps instead of the volts, and much more straightforward.

 

[malcolm]

It's fun to experiment, though it's a shame I sold the old Clarke last week - that would have been great to muck around with. Might see if I can have it back.

This whole volts/amps thing still messes with my head. Would be interesting to see if altering the wire speed alone would do what I'm thinking, or whether the volts are the thing. Or whether altering both with the auto adjusting wire speed would be the thing. Who knows, but surely worth a play.

 

[Hitch]

Two of our machines have a remote adjuster, for current and adjusting the arc.
Two of the migatronics had a thumbwhel on the torch wich could be used to fine tune the wire speed for various positions etc. Thats virtually the sane effect i suppose.

 

[shenion]

Footpedal might be interesting. The knob on the gun might be better. Crawling under my Jeep and trying to use a pedal could be comical

I will be trying to fab some kind of footpedal. There are $20 footpedals for sewing machines on ebay. May get one take the circuit out and use the pot and my own circuit.

I have a circuit in mind to use a standard low-power pot instead of the 150 watt rheostat the beast uses. It also uses oddball connectors that have probably not been made in 15 years. Have 6-pin Jones connectors/sockets on order. Will use it for the wire feed and tig footpedal.

The wire feeder has a 25' cable. I'm thinking of adding a current knob on the feed unit. The beast is in a far corner of my garage (next to breaker panel); moving the feed near the work and running back and forth to adjust the current is not gonna be fun

 

[Ratty]

Thats virtually the sane effect i suppose.

As opposed to the mad effect?

 

[Hitch]

ooops

 

[rtbcomp]

The way I see it is that the voltage on most MIGS is set by quite large steps, once you've set the voltage fine adjustment is done by the wire speed.

I'd be inclined to experiment with a circuit that adjusts the speed slightly around the setting on the panel. It could be as simple as another pot connected in parallel or series with the existing one, depending on the circuit.

 

[Alex]

I think TIG is better for difficult angles like welding tube to tube as you get a chance to move and position your arms, with MIG once you start you got to keep going at a steady pace or your weld appearance will suffer.

I do dislike the initial build up on cold metal with MIG it doesn't look very good.

Has anybody considered a TIG type arc with a filler wire drive at a button press, so you start a TIG arc then press a button and filler wire feeds into the pool, let go of the button and it stops.

 

[bronze]

I've seen some mixed answers but didn't really catch anyone saying exactly this:
At work, I use a welder with adjustment on the "pistol" (is that what you guys call torch?). I made a drawing to illustrate (using paint):
The arrow, of course, points to where there are two buttons to change amps (and voltage and feeding, the welder is a synergy device).

 

[shenion]

My Airco has a "Start circuit" that operates as follows:

1. There are two power settings on the unit: start and normal.
2. The start setting is used at first. Then when an arc is detected, it waits about 1/3 second and then switches to the normal setting.

It is great for arc welding, rods will not stick at start. It is a current setting instead of voltage. It is required for MIG as at the normal setting, the wire will hit the work and then the whole wire will glow red and drop off. The start helps the initial arc to get the short-arc mode working.

It might work for MIG to have 2 voltage settings. But I would worry that the wire would quickly burn back to the tip at start at even a small increase of voltage.