Quote Originally Posted by RichardH View Post
It seems like 1/4" should be plenty, considering what I can push through a hose with an air compressor (even at 50 psi). Poly / braided tubing isn't an option outdoors here - the UV + heat + low humidity destroys plastics. I'll just need to look further than Home Depot to source 1/4" i.d. rigid copper.

In the larger shops you've seen with piped gas, did they use a flow regulator at the back of the machine? That seems to be more practical (and more consistent), even with a long hose.

Cheers,
Richard
Oh yeah, AZ. Not much will survive outside there. Maybe not even aluminum tubing, but there is that and copper refrigeration tubing that will work and can be bent to suit, pretty easy. For sure you will need your needle valve and flowmeter near the machine, or you will have one hell of a startup blast. Some shops just have flowmeters for each machine, others have a regulator and flowmeter, so I guess they are running higher line pressure to get more machines on the same size line. I never saw a line pressure gauge on that system, so I'm guessing. On the ones with just flowmeters they were running 50psi. You need a minimum of 25psi, but most regulators are from 40-80psi. I don't have an Everlast regulator, so I'm not sure what they come set to. A few brands are adjustable for both pressure and flow. I would strive to get a leak-free system if you plan on going that way. If the system bleeds out, then it will most definitely draw in air as it heats and cools. Another AZ specialty. And the amount of argon required to purge all the air out of a tube will surprise you. For welding stainless steel pipe, the specs call for 5 times the pipe volume to purge enough oxygen to get a clean weld with a purge monitor. Argon is heavier so you might want your tube to rise from the bottle to the bleed point. That will help, but it will still take several complete changes of gas to purge all the O2 from the lines. The last thing you need as a new welder is contaminated gas, you will chase your tail trying to figure out why your welds don't come out right. Depending on where your power outlets are, you are still tethered to them, so unless there is some compelling reason to have your bottle far away, or your shop is huge, it seems kinda overkill to plumb for welding gasses, especially for just a few machines, but it's up to you. I will admit that the small size and weight of inverters dwarf a 330cuft bottle, unlike the older transformer machines where the added weight of a bottle was negligible.