CO2 extinguisher converted

Date 06-28-2007 02:20

All right guys,

I only weld on the weekends in a hobby capacity and never on anything "Critical." I bought a 10# co2 from my local Welding gas supplier to use as an emergency air fill while offroading. A few weeks later I recieved a free 15# co2 fire extinguisher from someone I know. I want the small 10# for the truck due to size and of course the 15# would be better for welding. Until now Ive been using self shielded FCAW but Ive wanted to use GMAW on occasion. SOOOO I dont believe the gas supplier will fill the fire extinguisher as they use an exchange program. The extinguisher place I go to for work purposes could convert the valve and fill the extinguisher. Bottom line --- is there any noticable difference in the quality of CO2 from these two suppliers? I remember from my food service days there was a food grade and a welding grade CO2. ANY problems you see here, any suggestions? Infrequent Hobby welding ONLY.

By cmays

Date 06-28-2007 02:39

I dont think the benefit is going to out way the trouble and the potential for injury. The cylinders you get from the welding supply are made to hold extreme pressure and abuse. The fire exstinguisher bottle is a thinner walled lower pressure bottle. I think that it has to do with the gas form under pressure of CO2. To get CO2 in a gas form for welding purposes it has to be under extreme pressure. For fire exstiguishers you dont have to have the CO2 in complete gas form. I cant exactly remember what the reason was for but I do know if you put both cylinders next to eachother you can obviously tell the difference in the two.

By RANDER

Date 06-28-2007 02:55 Edited 06-28-2007 02:58

Thanks,

Some detail on the extinguisher. Military CO2 fire extinguisher. 30lb empty and fill with 15lbs CO2. Not your KIDDE fire extinguisher. Looks a sturdy as a welding gas cylinder without taking a UT or accounting for material of construction. Got it from an EX-NAVY guy. WAAYYY_EX. Dont know who he got it from (Dont ask dont tell) Last Hydro date 01/67!!!!!! Yes it will have to pass hydro before filling. The CO2 should be stored in a liquid state as with the welding gas so I didnt see a problem there. Henry what do ya think?

By JA

Date 06-28-2007 03:20

i think you should just get yourself a small bottle of C02 from the welding supply store and lose the fire extinguisher.....(for shielding gas anyway)...

By DaveBoyer (*****)

Date 06-28-2007 04:47

You May not even be able to change the valve, as it would be just by chance that it would fit, and I doubt any gas company would do it if it would fit. Without the proper ownership paperwork that extinguisher if marked as Govt. property will probably be confiscated by any gas company You show it to. this happened to someone I know with a welding tank purchased from Philadelphia Navy Yard at auction and resold without the papers. As far as the gas itself, Yes I think it would work, kind of a moot point.

By RANDER

Date 06-28-2007 13:44

Good points. They said they could put the valve in. Who knows till they see it? Brother where I work I dont think many people care about any kind of papers. Yeah its just a thought as I dont really need the extinguisher. However if both cylinders are designed to hold liquid CO2 under pressure I cant see a reason why there might be a boom. Its really a matter of changing out the valve as I see it. Maybe ill just keep it for those "small" Bonfires at the campground.

By DaveBoyer (*****)

Date 06-29-2007 03:33

IF the valve would fit and if it will pass hydro it should work in theory, as the vapor pressure of liquid CO2 is the same weather it is in a welding tank or an extinguisher. Most gass companies won't mess with anything like this due to liability problems. I have an old CO2 extinguisher I made into an air tank. It is about the size of a SCUBA tank. The valve on that is much larger than a welding tank. YMMV [Your Milage May Vary]

By CWI555

Date 06-28-2007 04:50

don't mean to be a smart A** but it sounds like the makings for a big boom.