Hi Chaps I need some guidance.

In the process of swapping over from a hobby MIG torch to a Euro torch and discovered I can't half squeeze the trigger for gas and fully squeeze for gas plus current because I had to add a gas solenoid control for the Euro torch whilst the gas control valve in the hobby MIG is in the torch.

Is there a control circuit somewhere on the web where I can have one click and hold for gas and 2 clicks and hold for weld. It would also be nice if on release the weld stops but there is post flow.

Searched in vain.

Cheers!

I think what you're really looking for is a pro machine!
1 click for gas, 2 click for wire, I don't know of any machine that gives you that. Can't think why you'd need it either. Although some esab machines do have a slight delay between pulling the trigger and the wire feed starting, gives a slip second of pre flow, but not selectable of adjustable, but that's on synergic machines, and I suspect its more to do with the machine setting itself up for each weld

Post flow on a mig, not really needed IMO, but I think some machines do it, but its not really needed like with tig.
I think by the time you've made all these changes, it'll only be the casing that's original from your machine, you'd end up changing just about everything else inside.
What machine do you have?

[Edited on 9/1/16 by blakep82]

Actually, my cheapo Wolf MIG can do exactly that!! The gas valve opens before the electrical contact closes, so I can run the gas for a second or so before the weld. I find it's quite effective when filling in an angle where the shroud is too big to get in a proper place, a second or so of gas seems to fill the void before the weld strikes. If I just pull the trigger in one it tends to spit.

I could probably just turn the gas up a little bit, but it seems to work well for me.

Cheaper non euro torch welders usually have a manual gas valve in the torch itself rather than a solenoid operated one in the machine. The gas pipe up the umbilical is live all the time once the gas bottle is turned on. The gas should purge when pressing the trigger even if the power isn't turned on.

I expect there is a slight delay/ gap between the gas valve and electrical switch on pressing the trigger that allows the gas to pre and post flow.

A euro style set up only has a switch in the handset which operates the wire drive, the main welding current and the gas valve all at once.

what Brian said ^^^^^^

quote:

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Originally posted by Brian R
Cheaper non euro torch welders usually have a manual gas valve in the torch itself rather than a solenoid operated one in the machine. The gas pipe up the umbilical is live all the time once the gas bottle is turned on. The gas should purge when pressing the trigger even if the power isn't turned on.

I expect there is a slight delay/ gap between the gas valve and electrical switch on pressing the trigger that allows the gas to pre and post flow.

A euro style set up only has a switch in the handset which operates the wire drive, the main welding current and the gas valve all at once.

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You don't need to switch the gas on separately. You are looking for a solution to a problem that doesn't exist.

The wire feed and the gas solenoid switch on at the same time on virtually all MIG welding machines.


There is a peculiarity to the system that does work indirectly as your hobby MIG did.
Because the gas release solenoid is in the machine the pressure builds up between it and the reg on the cylinder before
the trigger is pulled. We will call this the primary line. The secondary line is from the solenoid to the shroud, or gun.

On release the build up of pressure travels up the secondary line as a wave giving the newly started arc instant coverage.

You will hear this as a whoosh that quietens down as the gas flow equalises between gas in the primary and secondary lines.
When you stop pressure builds again ready for the next arc start.


This is assuming that along with the "pro torch" we also have a pro reg and flow meter to match.


HTH
Paul G

(Pro welder)

Again, unsure that you've got a problem, unsure you need a solution.

I have an adjustable pre-flow on my heavy MIG (255TE), no post flow. Neither on the smaller machine (Migatronics 5000 - Euro conversion).
Pre and post-flow is, of course, available and adjustable on my TIG machine, where it is required.

Do you have a special requirement on the MIG, heavy shielding for a stainless/aluminium application? Otherwise, run with what you've got. I can't see you have a problem.

If you're determined to have the pre and post gas function, how's about a foot pedal to open the gas solenoid untill the torch trigger is pulled. Or use a pair of relays? First click operates the gas relay and gives a live for the feed relay on the next click.

I understand your problem. It's probably not something you'd want for a MIG set doing production work on clean steel, but I often end up using the shielding gas to extinguish flames when welding sills and such because trying to blow it out with the mask down never seems to work

I started looking for a two position momentary microswitch for you yesterday but came up with nothing. If there's space in the torch though, I'd look to fit a second microswitch next to the original but offset forward slightly, so that engaging the first switch puts the gas on, then pressing the trigger further engages the second switch that switches the welding current. You could probably implement similar with a second push button on the side of the torch wired to the gas solenoid in parallel to the main switch wiring (but with a diode) that only opens the gas solenoid. Similar to owelly's suggestion, just packaged slightly more ergonomically.

I'm with the OP on this, my Clarke 160 allows gas only and it's a function I like and would also look for if
I were to change machines.

Dubai hotel


I said just pull the trigger HALF WAY

quote:

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Originally posted by owelly
If you're determined to have the pre and post gas function, how's about a foot pedal to open the gas solenoid untill the torch trigger is pulled. Or use a pair of relays? First click operates the gas relay and gives a live for the feed relay on the next click.

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As my Granddad said: Always give the laziest man the hardest job, and he'll find the easiest way......