Argon flow query

[ikb]

Having learned to butt weld thin aluminium with Oxyacetylene in the days of B/W 405 line TV and trouser turn ups I have worked my way through Arc and MIG welding on cars and my multifarious engineering hobbies. The appearance of economical PWM circuitry has now enabled me to purchase a TIG machine with which I hope to achieve similar results as Oxyacetylene albeit DC so no aluminium.
Using my suppliers recommended argon gauge and flow meter set up however, I experience an off-putting burst of Argon each time I start a run. I attribute this to the fact that the gauge is factory preset to 2 bar which feature allows a volume of gas at 2 bar to build up in the line between the gauge and the machine solenoid valve. This build up of gas rushing through the torch every time the solenoid valve in the machine opens until the pressure up and down line of the flow meter equalizes. This must waste gas to some extent I guess. This does not happen with my MIG setup where I adjust the flow using the pressure regulator rather than the flow meter valve.
Am I being too sensitive or, as I believe, should I swap the preset pressure gauge to an adjustable type?
Cheers ikb
PS As a newbie I hope I am on the right forum.

 

[slim_boy_fat]

Welcome to the forum fella.

You could try a pea-shooter type regulator in the line after the bottle regulator, cheap and easy to set. Like so http://www.ebay.co.uk/bhp/gas-flow-meter

 

[Richard.]

Having learned to butt weld thin aluminium with Oxyacetylene in the days of B/W 405 line TV and trouser turn ups I have worked my way through Arc and MIG welding on cars and my multifarious engineering hobbies. The appearance of economical PWM circuitry has now enabled me to purchase a TIG machine with which I hope to achieve similar results as Oxyacetylene albeit DC so no aluminium.
Using my suppliers recommended argon gauge and flow meter set up however, I experience an off-putting burst of Argon each time I start a run. I attribute this to the fact that the gauge is factory preset to 2 bar which feature allows a volume of gas at 2 bar to build up in the line between the gauge and the machine solenoid valve. This build up of gas rushing through the torch every time the solenoid valve in the machine opens until the pressure up and down line of the flow meter equalizes. This must waste gas to some extent I guess. This does not happen with my MIG setup where I adjust the flow using the pressure regulator rather than the flow meter valve.
Am I being too sensitive or, as I believe, should I swap the preset pressure gauge to an adjustable type?
Cheers ikb
PS As a newbie I hope I am on the right forum.

Most if not all single stage regs surge at start up before stabilising to desired pressure and they also do this as you get close to emptying the bottle also. Yes it wastes lots of gas especially when doing lots of short runs it practically eats bottles. It also can effect the ability of a "perfect" strike up too as that surge can create a little turbulence for a second effecting the way the HF is carried to the job. Only slight mind and doesn't bother most people. Ultimate solution is a multistage reg. Consistent flow rate every strike and towards the end of the bottle. Initial lay out can be pricey but mine has paid for itself in gas savings a good few times now. Couple this up with a quality gas lens on the torch and you can weld serious quality at surprisingly low flow rates.

 

[ikb]

Thanks for your responses. I have been migging for many years using Pub C02 as in the Pub setup ie. just the gauge and setting the flow empirically. The addition of a flow measuring device maybe would have helped repeat-ability but I got on fine without one. Clearly the pressure and therefor gas volume in the my Mig setup hose is the same as the pressure set by the regulator. Whereas in the TIG setup the 2 bar pressure in is greater than I wish to feed to the torch. So untill the pressure is vented off by the solenoid valve the pea-shooter flow meter is ineffective and there is this sudden venting of the excess pressure at the torch.
When I purchased the Argon gauge and pea-shooter flow meter the picture on the gauge box showed one gauge and I foolishly thought that I would have the same setup as my MIG but with the addition of a flow meter. whereas the gauge on the Pub Gas setup indicates hose line pressure the TIG setup indicates bottle pressure. Had I taken more care in my choice I would have seen the potential problems but it seems that I just switched off my brain and went with the suppliers well meant recommendation. Warning to all maybe!
Richard you seem to be well tuned in to the high level of finesse required to achieve good results and have clearly understood my problem.
Cheers
ikb

 

[Richard.]

Thanks for your responses. I have been migging for many years using Pub C02 as in the Pub setup ie. just the gauge and setting the flow empirically. The addition of a flow measuring device maybe would have helped repeat-ability but I got on fine without one. Clearly the pressure and therefor gas volume in the my Mig setup hose is the same as the pressure set by the regulator. Whereas in the TIG setup the 2 bar pressure in is greater than I wish to feed to the torch. So untill the pressure is vented off by the solenoid valve the pea-shooter flow meter is ineffective and there is this sudden venting of the excess pressure at the torch.
When I purchased the Argon gauge and pea-shooter flow meter the picture on the gauge box showed one gauge and I foolishly thought that I would have the same setup as my MIG but with the addition of a flow meter. whereas the gauge on the Pub Gas setup indicates hose line pressure the TIG setup indicates bottle pressure. Had I taken more care in my choice I would have seen the potential problems but it seems that I just switched off my brain and went with the suppliers well meant recommendation. Warning to all maybe!
Richard you seem to be well tuned in to the high level of finesse required to achieve good results and have clearly understood my problem.
Cheers
ikb

Any time ikb. I've come across it myself on many occasions. It's not as noticeable with mag welding because the general flow rate is around 10-15 lpm on a typical mag set up the surge doesn't seem that great but on tig using half that flow rate (5-7 lpm) that surge is very noticeable. A multistage reg reacts in nano seconds and that surge just isn't there any more. I would bet someone tig welding 1 inch stitches all day would use half as much gas again with a single stager than someone on the same job with a twin. I don't think flow reading measures are going to help here. They will tell you what your using but they won't eliminate the initial surge on start up.

 

[hotrodder]

While a dual stage is reg is in many ways the nicest/most elegant solution most of their benefits can be gotten with a 'gas economiser' either between the regulator and machine or built into a reg mounted flow meter. Saves buying another regulator, will deal with initial gas surge (giving more accurate arc strikes & saving some argon) but won't automatically compensate for variations in flow rate as the cylinder pressure drops however the flow rate typically only starts changing (increasing) noticably every few minutes when using the last dregs of the cylinder

Personally i'm a huge fan of dual stage regs with oxy fuel as they make life much nicer when welding or brazing thin stuff i.e. very low output pressures. With TIG i used a fixed output single stage reg and a flowmeter with a built in gas surge stage
Another way around the initial gas surge is to increase the pre flow time by a sec or so

 

[Richard.]

increase the pre flow time by a sec or so

Which gets around the striking issue but doesn't change the fact the surge is still there and still wasting argon.
Personally To the OP the best way to eliminate this properly Is to add a second stage. How you do this is up to you. Like above you can add a 2nd stage surge eliminator to your reg In the form of a flow tube or you can just go with a 2 stage reg complete. Personally I prefer the complete assembly.

 

[hotrodder]

the best way to eliminate this properly Is to add a second stage. How you do this is up to you.

Agreed. All i was doing was pointing out a few other options cheaper than buying another complete regulator. Surge eliminators/argon economisers range from ~ £30 for a basic jobby to getting on for £100 for something like the GasIQ / Elga flowmeter i use. Dual stage regs probably start at around £100 and go up from there to over £200

 

[Richard.]

Yep they ain't cheap things especially if like me you chuck em out every 5 years.
We like what we like. I'll be sticking with the gasiq dual stage regs.
I use 4 x 30ltr bottles of argon a year. After it's been hooked up to 20 bottles and time for replacement it's bought it self back 3 times over just in gas savings alone. When looked at in this perspective the £160 spend doesn't matter

 

[Richard.]

3 is an exaggeration as I get my cylinders very cheap but certainly twice over no doubt and it would probably be 3 times if i was sourcing my gas else where.

 

[ikb]

Thanks for that folks my decision is made. While I have a U.O.L. degree in bodging I do believe that certain tasks deserve the best possible chance especially when Mandraulics are involved in the process. I am back to the supplier Monday sharp at opening time to swap my single stage Reg for a double.
ikb

 

[ikb]

Update:
Went back to the supplier this morning armed with an explanatory diagram of the two scenarios and their engineerwhile stating that most people get on fine with the factory set single stage setup, agreed that it may not be suitable for welders new to MIG or those wishing to do the finer work. So the gauge was changed and I am already producing welds better than with the TIG. I have to say that I am extremely pleased with the service provided by the supplier.
IKB
PS I don't know whether it is the done thing to name the supplier.

 

[eSCHEn]

As long as you don't work for them or have any ulterior motives then please do name them. It's always nice to know where you can get good service from

 

[Richard.]

Pics ????

 

[ikb]

1/ After reading previous posts regarding the cost of Dual stage Regulators I was pleasantly surprised when "upgrading " from a single stage. I found the supplier - United Welding Supplies - very helpful and look forward to dealing with them in the future.

2/ I have recently read how to post an image but can't find it now. Trying to maintain minimum media presence on line I would prefer not to get involved with anything "Cloudy" or similar to Photobucket if possible. My first job with the new machine is to build a welding trolley which will hold the new TIG and the argon bottle and I will send an image of my joints when finished.
Cheers

 

[Richard.]

Yeah don't use photo bucket and like as the images don't stay and often don't come up at all. An apple or like device is the easiest way. Just hit upload file and take the photo.
Which reg did you go for in the end. Glad it's got you sorted.

 

[ikb]

Yeah don't use photo bucket and like as the images don't stay and often don't come up at all. An apple or like device is the easiest way. Just hit upload file and take the photo.
Which reg did you go for in the end. Glad it's got you sorted.

The new regulator is a Victor GF250-40-BS3. It does exactly what I had expected i.e. no spurt at commencement and works with the low pressure gauge around the middle of the "MIG" segment of the dial, the the "Peashooter" gauge being more or less redundant although OK as a double check. I admit to have nothing to compare it with but so far so good. I don't know the country of origin but To put it into perspective I read someone on a forum ranting on about my Stamos 250 WIGMA being cheap Chinese rubbish when it says made in poland on the box. Plus when I was at the supplier I noticed a large consignment of boxes identical in every detail to the box mine came in and they don't stock Samos. In my book as in media products much of the circuitry is common and it is just as efficient to manufacture good stuff as it is to manufacture rubbish. As a hobby customer I am very pleased with what I got for my money. Obviously if I were welding helicopter rotors or skyscraper cranes I might be a bit more fussy.
Cheers

 

[Appyasme1]

To be fair, quite a bit of stuff with 'made in usa' or 'made in england' these days actually means 'assembled from chinese parts'...

That said, even if it is 'cheap chinese rubbish' does that really matter if it works well enough to keep you happy?

I was a great non believer of Chinese products,we might not like it, but their products are being used in our machines whether we like it or not.Amphenol plugs,made in the USA,assembled in China

 

[Richard.]

The new regulator is a Victor GF250-40-BS3. It does exactly what I had expected i.e. no spurt at commencement and works with the low pressure gauge around the middle of the "MIG" segment of the dial, the the "Peashooter" gauge being more or less redundant although OK as a double check. I admit to have nothing to compare it with but so far so good. I don't know the country of origin but To put it into perspective I read someone on a forum ranting on about my Stamos 250 WIGMA being cheap Chinese rubbish when it says made in poland on the box. Plus when I was at the supplier I noticed a large consignment of boxes identical in every detail to the box mine came in and they don't stock Samos. In my book as in media products much of the circuitry is common and it is just as efficient to manufacture good stuff as it is to manufacture rubbish. As a hobby customer I am very pleased with what I got for my money. Obviously if I were welding helicopter rotors or skyscraper cranes I might be a bit more fussy.
Cheers

Victor gas equip is known for been very good. You'll do just fine with that. Once you get it hooked up to the tig welder I would suggest you use a flow meter or pea shooter to set your flow. The scale on these reg clocks is very course and quite often inaccurate. Best to set it with a floating ball.