MIG welding w/straight CO2 advice please

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posted
11 years ago

Mon, Dec 3, 2012 10:10 PM

I just brought home a bottle of CO2. I will be using it instead of C25 mix for steel welding where I can and setting up a manifold for making my own mixes. I already have regulators and flow gauges. One regulator has the proper fitting for the CO2 cylinder. I didn't put the fitting on though and don't know how many CFM was being run through the regulator. At 30 CFM flow will I need to worry about frozen regulators? I can imagine welding outside in the cold and having things freeze up. Besides buying some backflow preventers for the manifold should I make up some type of finned heat exchanger to warm the CO2 as it comes out of the bottle and before it enters the regulator? Thanks, Eric

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posted
11 years ago

Tue, Dec 4, 2012 4:28 AM

I actually prefer it . And yes , on cold days regulator freezing can be a problem . I'm not sure your heat exchanger idea will work , you'd have to get the gas pretty hot to offset refrigeration effect . I just switch over to flux core for outside work . Burns hotter , and no worries about the shield gas blowing away .

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posted
11 years ago

Tue, Dec 4, 2012 11:13 PM

The gas just needs to be kept above the freezing point of water. I prefer using MIG over fluxcore. But you are right, fluxcore is better for welding outside if it's breezy. And usually the outside jobs are on the backhoe bucket or something similar where a few dingleberries don't matter and the weld zone is often dirty. What happens when the reg freezes? Eric

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posted
11 years ago

Tue, Dec 4, 2012 11:36 PM

Mine over-pressurizes . As soon as I notice any frost I stop . I've had it go so high it pegged my flowmeter/pressure guage . Took me a while to correlate that with frost on the regulator . My point about temps was that it's just like refrigerant thru an orifice . And a drop from say 600 psi to around 3-5 is going to chill a lot .