Reading gas flow / Regulator or Torch?

[carlos420uk]

Having recently invested in a 200amp AC/DC Tig I have been having a lot of fun learning the process. With the machine (R-Tec Tig 201) I got a "Cheap" style dual gauge regulator along with a flow meter to take a reading at the Torch. Now my question is which should I trust as correct? As when the flow meter on the Regulator reads 6-8lpm the flow meter at the torch reads way over that. Vice versa if I set the gas flow from the Torch the regulator basically reads 0 flow rate.

Common sense tells me that the regulator is wrong and the flow meter is correct (I hope!) but thought I'd ask just to check as I am on my third "Midi" size Argon bottle already and I've only had the machine 3 weeks

Thanks in advance,

Carlos.

 

[hotrodder]

Of the two the flow meter is the one to trust or at least the more trustworthy. The (lack of) accuracy of dual gauge regs is legendary as while the output gauge may be calibrated in flow you're actually adjusting output pressure when setting it. Rtech regs have come up before too... i'm sure we've had at least a couple of threads where it turned out the dual gauge reg was under reading by crazy amounts i.e. so far out inaccurate would be an understatement

1 midi cylinder a week... i'm guessing 20 litre rather than the smaller 10 litre ones? How much welding and what pressure are they filled to? With shed loads of practice and all the post flow time that comes with lots of stop/starts when learning it's possible but still sounds excessive unless you're getting in a few hours a day and using cylinders that are only filled to 137bar

I've no idea how accurate cheapnese pea shooter style flow meters are but there's so little to them they should be okay? I would say try lowering the flow but if you're only just starting out it may hinder things as you're less likely to recognise the symptoms of flow being a tad on low side

 

[carlos420uk]

Cheers for that, your right the regulator reads waaay out in comparison to the flow meter.

I have an account with Energas and the bottles are filled to 250bar iirc, I'm using the next size down from largest they do which they call a Midi. I have been putting in a bit of practise the last few weeks but the 1st 2 bottles I used had the flow set at the regulator so I think I have been massively over doing the gas tbh. I'll have to see how long this new one lasts.

I assume you get porosity and contamination if the flow is too low, but what are the signs that it is set too high?

 

[FranV8]

Frequent trips to your gas supplier!

I think also the weld run starts to look odd due to excessive turbulence. But I may have just made that up. Try the Miller website.

 

[Seano]

along with a flow meter to take a reading at the Torch. Carlos.

A flowmeter to take a reading at the torch.....? are you using a mig peashooter as a flowmeter for your tig...?

 

[hotrodder]

I assume you get porosity and contamination if the flow is too low, but what are the signs that it is set too high?

Yep but initially the symptoms can be on the subtle side or at least easily confusable when first learning and contaminating things through tagging tungstens etc. Flow rates that are too high can cause the same problems in that turbulant flow can, in some circumstances, 'draw' in air. With a butt or fillet weld on sheet/plate you have to be wasting a lot of gas to get problems, with outside corners/small diameter tube the geometry of the part encourages the argon to flow away and the usual reaction of turning the gas up when shielding problems arise typically makes things worse.

If you search the TIG forum for 'gas lens' you'll find some pics using smoke to visualise how the gas flow looks through a conventional collet body versus a gas lens set up. Note that gas lenses aren't something that makes a 'night and day' difference, they are better but they are also bulkier and the gauze screens are easily damaged/blocked when learning and constantly contaminating tungstens i.e. you don't need to rush out and buy some, at least not yet

 

[carlos420uk]

A flowmeter to take a reading at the torch.....? are you using a mig peashooter as a flowmeter for your tig...?

It's the same as one you would use on a mig torch but it's for pure Argon / Tig instead. It actually came included with an Argon gas saver kit (Gimmick imo) that I got chucked in with the welder as a sample. I don't use the gas saver as it leaks, but the flow meter has been handy.

 

[carlos420uk]

Frequent trips to your gas supplier!

I think also the weld run starts to look odd due to excessive turbulence. But I may have just made that up. Try the Miller website.

Do you mean that the weld will look more like <<<<< instead of nice rounded little U shaped beads? I realise that having the torch at too great an angle causes this but does too much gas flow compound the issue by blowing on the liquid puddle too hard?

Will have a look on the Miller site, Cheers.

 

[carlos420uk]

Yep but initially the symptoms can be on the subtle side or at least easily confusable when first learning and contaminating things through tagging tungstens etc. Flow rates that are too high can cause the same problems in that turbulant flow can, in some circumstances, 'draw' in air. With a butt or fillet weld on sheet/plate you have to be wasting a lot of gas to get problems, with outside corners/small diameter tube the geometry of the part encourages the argon to flow away and the usual reaction of turning the gas up when shielding problems arise typically makes things worse.

If you search the TIG forum for 'gas lens' you'll find some pics using smoke to visualise how the gas flow looks through a conventional collet body versus a gas lens set up. Note that gas lenses aren't something that makes a 'night and day' difference, they are better but they are also bulkier and the gauze screens are easily damaged/blocked when learning and constantly contaminating tungstens i.e. you don't need to rush out and buy some, at least not yet

So basically the standard collet bodies and cups create a whirlwind type gas flow that can drag in air via venturi, whereas a gas lens gives a linear flow at the trade off of using more gas?

 

[hotrodder]

Sort of... the more laminar flow that gas lenses provide make them less sensitive to things that can mess with shield quality- part geometry, drafts, tungsten stick out. For a given cup/ceramic size you don't need to turn the gas up with them but doing so can improve shielding sometimes.

 

[langy]

I use Gas Lens's and only have my flow meter set at 6 lpm

 

[justmental]

i have just got some of these in the post today and what a difference they make.
money well spent.

 

[Seano]

I use Gas Lens's and only have my flow meter set at 6 lpm

Do you just use the ceramic cup lenses Steve, or the ck type Pyrex lenses ?

 

[langy]

Do you just use the ceramic cup lenses Steve, or the ck type Pyrex lenses ?

Ceramic Sean, I've never found any suppliers for the Pyrex ones, do you know anyone that keeps them ?

 

[justmental]

found this just now hope it helps

http://www.rapidwelding.com/dynamic/Category.aspx?c=CK3GASKITS&o=0&zl=3&sq=4

 

[langy]

found this just now hope it helps

http://www.rapidwelding.com/dynamic/Category.aspx?c=CK3GASKITS&o=0&zl=3&sq=4

They ain't cheap are they !!! I might get one though to give it a try

 

[Seano]

They ain't cheap are they !!! I might get one though to give it a try

I've never been sure if they just fit ck torches or most wp17's, do you use any particular manufacturer of gas lenses, have heard some bad news about iffy meshes....we have some at work from starparts I think and the 1.6mm one, the hole in the center is anything but round....I know it is only for centralizing the tungsten, but crap quality imo.

 

[justmental]

i have orderd this one
http://www.rapidwelding.com/dynamic/DisplayItem.aspx?c=D3GSXXXP&zl=3

 

[Seano]

i have orderd this one
http://www.rapidwelding.com/dynamic/DisplayItem.aspx?c=D3GSXXXP&zl=3

But will it fit a non ck torch ?

 

[justmental]

soon find out will let you know Seano if it does