Welding gas cylinder, what size? Options

[ipozestu]

I'm about to put a '75 in the air that's been sitting in my garage for a year. This will be my first crack at rust repair. The Hell hole and lower long area is where the most attention is needed.
I'm new to welding, I've picked up so much information here I feel pretty good about starting this.
I picked up a Lincoln 3200HD off craigslist for $200. I've got a regulator, now I need a cylinder. What size should I get? I was looking at a 20lb bottle available on craigslist. It was designated as CO2. Is that the right bottle? Can it be filled with mix gas? Should I get something bigger?
Tips. tricks, comments, suggestions?
Thanks

[dakotaewing]

Buy the biggest bottle you can afford -
The cost difference to refill is minimal, and if you go
with a small bottle, you will run out on a saturday afternoon, and
not be able to exchange until the following Monday. Left with a whole weekend of
welding to complete, and no way to get it done...

just my .02 -

TE

[Wes V]

I believe that the bottle has to be bought from the company (welding supply shop) where you are planning on exchanging it.

It's kind of like those Rhino propane bottles. You "buy" the initial one and then from that point on just exchange it for a full one when it gets low. (you can exchange up to a larger one at a latter date)

I live in L.A. and I don't think there is anywhere that will re-fill a bottle from an "un-known" source.

The fact that the bottle you are talking about is marked as for CO2 would bother me (and I think the welding supply shop). I doubt you could use it when you want to get a different mixture. In other words, once a bottle has been used for CO2, they wouldn't allow you to use it for an Argon/CO2 mix.

Before buying anything more (or totally trust me), go to your local welding supply shop and ask them.

Wes Vann