C25 argon cylinders pros and cons and shelf life question

Hi all,
I have been welding with a flux core wire and finally decided to
upgrade to C25 (Argon/CO2 mix).
I have questions about equipment that I need to buy:
1) I am debating whether to get 40 cu ft or 55 cu ft cylinder
These two cylinders differ in design, not just in size. 40 cu ft has
a flat bottom, while 55 is spherical. Also, 55 cu ft cylinder is
taller, but has smaller diameter than 40 cu ft.
Does the fact that 55 cu ft cylinder has a spherical bottom make it
less prone to leak? (since there is no seam around the bottom)
Or the chance of leaking around the bottom is negligent compared to
chance of leaking at the valve or around the valve?
On the other hand, a 40 cu ft cylinder can stand upright on its flat
So, what are the pros and cons of each?
2) What is the shelf life of C25 mix?
I would rather go for a bigger bottle that would serve me for years,
but if it leaks out, than bigger bottle is a waste of money for me.
How long can I expect 40 cu ft or 55 cu ft cylinders to hold gas? If
they leak relatively fast, I might need to downgrade to a 20 cu ft
Thank you.
Reply to
Alex .
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If you do much welding at all, you will want two cylinders so you don't run out. It takes a while to run get some gas, and it may be a weekend, and you're hosed.
The gas lasts a very very very long time, enough to say it's not a factor.
Two HUGE factors are leaking tanks, and left open valves. Take some Windex with you, and test a tank before you take it. Test it often while using it. The tank might be fine, but your regulator, hose, or welding machine may have a slow leak. No matter how you lose it, if you leave it on, it will run dry. And if you have a leak, you will be losing some while welding, any time you have the valve open. I have lost a lot of gas by simply forgetting to shut it off, and it had to be leaking somewhere because it was gone when I next checked it. Sometimes the packing doesn't leak with the valve closed all the way, but leaks a lot with the valve open. Packing on valves wears out, and you can get a tank with a very small leak, and never know it. If you do get a leaky tank, and you'll know with your Windex bottle, take it back, and they will give you a full tank.
One caveat: Investigate whether you want a mix, or straight CO2. CO2 will have slightly more spatter, and a different final weld appearance than mix, but MIX IS ABOUT THREE TIMES THE COST. Weld properties are slightly different, but if you are using it for noncritical applications, the differences are minimal.
Get the bigger bottles, too.
Just my observations from MIG welding a LOT.
Reply to
Steve B
--Didn't know about the Windex trick; very neat. Is there a reason to avoid soapy water, other than it being messy?
Reply to
If there is I haven't heard it, but Windex is the cheap and common spray soap. I've used diluted Simple Green for years without a problem.
Avoid cleaners with strong ammonia, which attacks brass.
Reply to
Jim Wilkins
Alex . wrote in sci.engr.joining.welding on Mon, 20 Dec 2010 21:39:50 -0800 (PST):
I went from fluxcore to hard wire too, and had to get a bottle of gas as well. I went for a 80cf size since it has a safety cap.
I got C25 because I was working with thin stock (.040). CO2 would last a very long time, as it is in liquid form in the tank, and becomes gas as used. C25 is just a high pressure gas so you only get 80 cubic feet(cf).
Whatever you get it will not go bad in the tank. Just watch out for leaks, both on the tank and your equipment.
Reply to
I just have Windex handy, and it takes a trip to the house to find a spray bottle that works, fill it with water, add a couple of drops of Dawn, etc. A bottle of Windex in the shop is useful for many things, and a no name brand is 99 cents at the Dollar store, as Yogi would say.
Reply to
Steve B

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