OK so two questions spring to mind from this discussion so I'll ask them here rather than start a new thread :
1. It seems to me that both MMA and MIG welders are basically a current source, with a 'ground' clamp, and an electrode which is either a plain welding rod in a holder (MMA) or a more sophisticated "cable" which carries a gas supply and a conduit for the welding wire (MIG). So, if you're designing a MIG machine to sell, it is almost trivial to make it also do stick by providing a simple connector for an MMA cable, taking this from the current source before it gets to the MIG connector. Why don't more manufacturers do this ? Rohr seem to, and R-Tech, but it's not as common as you'd think. I'm looking for a "first welder" and I want to start with MMA to get the basics into my head, but like the idea of being able to do MIG later.
2. AC versus DC. Leaving out clever stuff like aluminium, people talk about loving traditional transformer technology, for reliability and simplicity - which is presumably AC - but also rave about the controllability and "lovely arcs" on DC with the newer inverter boxes. I've seen people put simple high-current rectifiers on the output of buzz boxes but that's not really DC is it - it's rectified AC, kind of 100Hz pulses. So, (a) is DC actually nicer to weld with, or it is just that DC usually means inverter which is more controllable; (b) does AC limit you in any other ways, and (c) does simply rectifying AC actually improve anything, and (d) Some people put large capacitors onto rectified AC but this sounds a little bonkers to my basic electronic brain because they're a completely uncontrolled current source and you could get truly huge current spikes across an arc. Are large inductances a better bet here ?
Apologies for the list, just trying to sort out all the Qs buzzing around my head !
Oh, and does this site have any sections for hooking up people looking for a day's one-to-one hands-on instruction, with people looking to provide that for a suitable sum ? feels like that would be a good thing to have !
Richard
1. It seems to me that both MMA and MIG welders are basically a current source, with a 'ground' clamp, and an electrode which is either a plain welding rod in a holder (MMA) or a more sophisticated "cable" which carries a gas supply and a conduit for the welding wire (MIG). So, if you're designing a MIG machine to sell, it is almost trivial to make it also do stick by providing a simple connector for an MMA cable, taking this from the current source before it gets to the MIG connector. Why don't more manufacturers do this ? Rohr seem to, and R-Tech, but it's not as common as you'd think. I'm looking for a "first welder" and I want to start with MMA to get the basics into my head, but like the idea of being able to do MIG later.
2. AC versus DC. Leaving out clever stuff like aluminium, people talk about loving traditional transformer technology, for reliability and simplicity - which is presumably AC - but also rave about the controllability and "lovely arcs" on DC with the newer inverter boxes. I've seen people put simple high-current rectifiers on the output of buzz boxes but that's not really DC is it - it's rectified AC, kind of 100Hz pulses. So, (a) is DC actually nicer to weld with, or it is just that DC usually means inverter which is more controllable; (b) does AC limit you in any other ways, and (c) does simply rectifying AC actually improve anything, and (d) Some people put large capacitors onto rectified AC but this sounds a little bonkers to my basic electronic brain because they're a completely uncontrolled current source and you could get truly huge current spikes across an arc. Are large inductances a better bet here ?
Apologies for the list, just trying to sort out all the Qs buzzing around my head !
Oh, and does this site have any sections for hooking up people looking for a day's one-to-one hands-on instruction, with people looking to provide that for a suitable sum ? feels like that would be a good thing to have !
Richard