[raticus]

As my first TIG machine that I bought 2 years ago, I bought the featureless Miller Diversion 180. I've had no issues with it as far as welding, but I do have two big issues with it while welding. One is the torch, it's freakin' huge, bulky, and even harder to handle with heavy hoses that make it seem like it's a water-cooled box but it's not (if it was water cooled I wouldn't complain about it). It may or may not be replaceable, haven't gone there yet, would much rather have something like what I use at work, a thin simple CK and lightweight simple braided hose). The second issue, is it has no post (or pre) flow control. It wouldn't be a big deal if they had just set the post-flow to something realistic like 5 seconds, but it's as long as 15 seconds depending on your amp setting. 15 seconds is ridiculous, I'll do a 5 second weld and lose 15 seconds of gas (or rather, 10 seconds if it was set to what I would set it at, at 5 seconds post flow)... and with my little 40 bottle (yeah, yeah, I know... I need a bigger bottle, on the shopping list behind ten thousand other things I need), it wastes a ton of gas. Was thinking of selling the box and buying a different one with actual controls, like flow and frequency as I've made it through the beginner stage and finally getting half decent (on good days), but money is tight (money? what money? I'm lucky to afford car gas to make it to work...). So I'm wondering if I can come up with some kind of homemade post-flow setup (other than somehow convincing the wife to stand there and shut off the bottle valve when I bark out 'close it!' after every weld, but that would take more bribery (i.e. money) than it would take to just buy a new box... lol.. yeah, that ain't happenin')... Anyone have any ideas? Yeah, silly question, but ya never know...

[Oscar]

So I'm wondering if I can come up with some kind of homemade post-flow setup

https://www.arduino.cc/

Are you familiar with stuff like this? If not, are you capable of teaching yourself? That answer to those questions is (likely) the answer to your question.

[Farmwelding]

I agree with that. We have one at shool and sitting there waiting is just such a waste. I don't think it is possible without rewriting the program inside the thing. I don't know what Miller was thinking with the diversion series. Lincoln has their squarewave which is cheaper and Dan do stick, have pulse, AC controls. Miller definitely missed with these tig welders.

[cj737]

The Diversion is an older type of machine. Yes, they're newer models offer more features, more control. But it works damn well.

Postflow is automatically set per amp you weld with. This cools the tungsten as well as protects the weld. You think you're consuming a lot of gas, but depending upon the flow rate, it's really not that much. Another member did a little analysis of postflow for total consumption that illustrates pretty clearly it wasn't even a bottles worth per year of full time welding.

Probably mostly a function of your flow rate, not postflow duration.

[rahtreelimbs]

You could always get a torch with a valve. The first tig welder i bought was a Miller Econotig. It has a 15 sec. postflow. Having the ability to shut the valve off was a simple way of controlling postflow. You want to change the torch anyway.


Try USAWELD.COM......they might be able to help you.

[raticus]

...You think you're consuming a lot of gas, but depending upon the flow rate, it's really not that much. Another member did a little analysis of postflow for total consumption that illustrates pretty clearly it wasn't even a bottles worth per year of full time welding.

Probably mostly a function of your flow rate, not postflow duration.

Correct me if I'm wrong (and I'm wrong often lol), but if my flow rate is 15cfh, then my post flow is also 15cfh. If i weld say for 10 seconds, then my post flow wastes a good 10 seconds of flow/gas with a 15 second pre-set post flow (as I would not need more than 5 seconds of post flow)... Wouldn't that double my gas use? With say a small 40 bottle, 20 is being used to weld, and 20 wasted. Kinda doesn't matter what size bottle, either way, half of the argon is being wasted... Other than welding some really thick material at some really big amps, I can't imagine ever using 15 seconds of post flow. I know some charts will say 15 seconds for 150 amps or so, but I just don't see the use for that much post flow in my limited experience (though I'm usually 125amps or less on most projects)... I work with mostly carbon steel and 6064 aluminum at home, and primarily SS at work (from 20 gauge to 11 gauge usually), and 5 seconds is perfect for pretty much everything.

[Farmwelding]

Yes math will state that if you weld for ten seconds then and your post flow is 10 seconds it is the same. It is just something you may have to live with or maybe try a new torch with a valve which I was curious about with a solenoid that does the gas work. Gas valves on the torch is mostly for scratch start. If the machine is pumping out 15 CFH of gas and you close it does that not build up a lot of pressure that gets squirted out when you crack it open when you light up the next time.

[Oscar]

Well, either you make your own circuit with gas solenoid and program it all.....or just use a gas valve torch. Both will work if implemented correctly.

[clavius]

There are lots of ways to do this, but if you want to do it without altering the guts of your machine (and voiding the warranty, risking damage to the machine or getting electrocuted, etc) a completely external solution is possible but will be the more complex approach. You need a solenoid "upstream" of the one in the machine, and a way to sense when the machine opens its internal solenoid so that it can open the one you added at the same time, and then a way to sense that you are no longer asking for welding current, and using that signal to close your upstream valve after your desired post plow time.

This will not change your preflow at all, you are stuck with what the machine provides.

Another approach is to just totally bypass the internal gas control and build one that routes the gas around the welder, and picks up the necessary signals to know when to open and close the valve.

And while none of this is overly difficult if you are familiar with such stuff, it is not trivial to do if you are not. And doing this will cost some non-trivial money unless you are good at scavenging stuff like this.

If you are willing to alter the guts of your machine, it gets simpler in some ways, but requires a bit more planning and understanding the innards of the welder.

I have a Lincoln SW200 that has this same trait. It is a bit annoying. I was planning to do something like this (I deal with industrial controls like this as part of my job) but have come to the conclusion that it is just not all that big a deal for the amount of welding I do. By my calculations cutting my longest post flow in half saves me about 5 cents/weld at what gas costs me. I may still do it at some point, but don't all that much feel the need now.
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[Poland308]

Simple solution. Just run the gas line external of the machine and get a torch with a gas valve.

[MarkL]

Correct me if I'm wrong... Kinda doesn't matter what size bottle, either way, half of the argon is being wasted...

You're correct, I had the same concern with my Lincoln SW200. It runs for 12sec when I'm at 120A, which is a common setting for what I do. I pay approx $.01 per minute of argon flowing at 15cfh, that varies a factor of two either way depending on whether I go to airgas on my own and get one tank, or whether I give it to my friend who's a welder and he takes it some place cheaper that he goes to. So I stopped thinking about the extra cost. It's not harmful to the environment, there's already a lot of argon in the air.
I think the benefit of some extra postflow far outweighs the cost of having too little. Heat damages tungsten, which is expensive. Heat damages the torch and torch components, and it degrades the electrical conductor in the torch. If I had a water cooled torch I'd be much less concerned, but with an air cooled torch I've decided to be OK with using the extra argon.

[exnailpounder]

Correct me if I'm wrong... Kinda doesn't matter what size bottle, either way, half of the argon is being wasted...

You're correct, I had the same concern with my Lincoln SW200. It runs for 12sec when I'm at 120A, which is a common setting for what I do. I pay approx $.01 per minute of argon flowing at 15cfh, that varies a factor of two either way depending on whether I go to airgas on my own and get one tank, or whether I give it to my friend who's a welder and he takes it some place cheaper that he goes to. So I stopped thinking about the extra cost. It's not harmful to the environment, there's already a lot of argon in the air.
I think the benefit of some extra postflow far outweighs the cost of having too little. Heat damages tungsten, which is expensive. Heat damages the torch and torch components, and it degrades the electrical conductor in the torch. If I had a water cooled torch I'd be much less concerned, but with an air cooled torch I've decided to be OK with using the extra argon.

Mark...where are you from?...we live close...near Joliet here.

[MarkL]

Mark...where are you from?...we live close...near Joliet here.

I'm near St Charles, in unincorporated DuPage county. I had a friend in Plainfield, so I used to get down that way a fair bit. I don't like going down Rt 59 through Fox Valley Mall area anymore, it's so built up it's crazy busy.

[MarkL]

I pay approx $.01 per minute of argon flowing at 15cfh...

I went back and checked my numbers, this number is not correct. The correct number is: I pay between $.04/minute and $.15/minute for 15cfh flow.
That's based on refilling an 80cf tank for $13 if my welder friend takes it with all his tanks to some place that only works with contractors, or $50 if I take the tank over to Airgas where I bought the tank.

The source of the mistake is that I looked at the wrong figure: the cost for each 12sec of postflow is $.008, and I rounded it off to $.01, but mistakenly thought it was the cost per minute.

[raticus]

my issue isn't the cost, it's the hassle or running out of gas in the middle of something and having to drive to the gas supply store to get another bottle (especially on weekends when I'm doing projects and the gas supply place is closed)... of course having a tiny bottle doesn't help but even if I had a good sized bottle i'd still be pissed that i ran through it twice as fast as I needed to

yeah if I could switch to a torch with a valve that would help but be annoying.. I work with a little scratch-start box that we take to off-site repair or install jobs that has a torch with a valve, and I constantly forget to turn it off (and turn it on)... hate the thing

i do have some old nitrous solenoids i could rig up... hmmmm...

[Oscar]

So what are you gonna do?