Mig gas pressure ,what happened ?

[HacksawParticipant @hacksaw]

In August , i sacked off the disposable bottles and changed to Hobbyweld rental bottle . Along with a 2 dial regulator and an adaptor tube to join the small tube on the welder to the regulator . Turning the gas on, the pressure went up to 150 on the left hand dial , and by turning the regulator knob , settled on 10 (litre p. m ?? ) on the right hand dial . All's been good..Last Friday i noticed when turning on the bottle , the left hand needle was barely off the stop , so i've had 6 months welding out of it . Pretty economic..

I only had a small job to do , the right hand dial was still well up near 10anyway .. so i gave it a tweak more and it settled on 12 litres?? pm . Did my job , it worked as it always did ..but i noticed the RH needle creep up further when i stopped ..I squeezed the trigger , it dropped back to 12…and then climbed again . So much so that if the needle stop hadn't been there it would have gone right the way round again. I let the pressure off with the trigger , I didn't turn off the bottle ,got side tracked with something else … and there was a loud pop and hissing ! The end of the adaptor tube had been blown out !! I thought pressure remained constant ??

Did the bottle pressure drop too low for the regulator to work ?

A new bottle today ,and it doesn't do it ….

Edited By Hacksaw on 23/02/2018 18:28:34

[HacksawParticipant @hacksaw]

[Brian Sweeting 2Participant @briansweeting2]

Sounds like you might only have a single stage regulator. The outlet pressure can change as the inlet pressure falls.

A two stage regulator would avoid that problem.

A brief description from Wiki here **LINK**

[HacksawParticipant @hacksaw]

Interesting ! Sounds like i do have a single stage regulator ..

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