gas flow

[p0689109]

I am in the process of starting to learn to Tig weld. I have most of the gear. The one thing that I am stuck on is the gas rates. The regulator I have bought has two dials on it. The outlet indicates in psi but I need to be able to set the flow which I believe is rated in cubic feet per hour(cfh) Is there a direct relationship between the psi outlet figure or do I need to purchase an inline flow meter? Or do i need to be conscious of both? I am mainly going to use the machine for replacing mild steel panels on a classic mini first and then a MG Midget. So the metal thickness is 1mm/0.040in. I am going this route as I have not been able to get on with mig welding. The machine I have at the moment is gasless and I believe that for this purpose i would have been better off with gas mig. In the past I have always stick welded but as there are a lot of panels to replace I wanted a neater finish with hopefully less grinding work to do! Any help would be much appreciated.
Cheers, Michael T

 

[GrahamGKD]

Hi Michael,
I may be wrong but as I understand it, even if you have the dual gauge arrangement and the second gauge is calibrated in litres per minute, the second gauge is just a pressure gauge and gives an indication of flow based on an assumption over the restriction in gas flow through the system.


I bought one of these for my set up.

 

[shenion]

If the reg gauge is calibrated in PSI on the output side, it does not have a restricter installed.

My Hobart gauge says on the dial "calibrated for 0.029 orifice". The output fitting looks plugged but it has the small hole.

Sounds like yours was designed for lab use or is supposed to use a separate flow meter.

You can pick up a flow meter like this one. It will be much more accurate than the dial type.

 

[p0689109]

Thank you both for the info. I had my eye on the flow regulator you both suggested. What is the correlation between cubic feet per hour and litre per min then?
Regards, Michael T

 

[shenion]

10 LPM is about 22 SCFH.

 

[p0689109]

Thanks for the conversion.