Used gas cylinders
 

Buying a tank local around here is ridiculous price wise. So I've found tanks cheaper elsewhere but have no real assurance that they've only been filled with 100% argon. If it were filled 75 25 before, and bleed empty, traces of the other gas would remain. How worried would I have to be about contamination while welding if it was then refilled with 100% argon?

Re: Used gas cylinders
 

You're paranoid.

And you registered on this site to ask this?

Re: Used gas cylinders
 

Nah, I've been on the site for awhile just reading and the likes. I was just curious because the welding supply shop guy was talking how once a tank was filled with another gas it is contamintated, which makes sense. So the small amount of trace gas shouldn't have an adverse effect contaminating the weld?

Re: Used gas cylinders
 

I was wondering the same thing. This is HMT, safety isn't an issue.

Re: Used gas cylinders
 

Its a trade in type of deal, not a refill. just trade it in for what you wan.t

Re: Used gas cylinders
 

Yeah you bring yours in and they just hand you another full tank.

Re: Used gas cylinders
 

they dont change what goes in the bottles. if the bottle originally came with 100% argon it will always be filled with 100% argon. and if you can find a "tractor supply co." (thats the store name) their refils are super cheap compared to welding shops.

Re: Used gas cylinders
 

ive had bottles converted, but only from c02 to compressed air. Also, i dont know about your place but i think most places wont exchange your cylinder if it isnt one of theirs

Re: Used gas cylinders
 

the place i go doesnt care. they will swap any bottle. the only problem is you have to take a regulator with you and check the bottle cause the last one i got was half empty

Re: Used gas cylinders
 

I can't really trade in the bottle for a new one since I was planning on getting a 55cu tank for around $80 empty. The place where I'd be going to fill it only has 100% argon tanks of 20cu (for around $100 filled) and an 90cu or 110cu (i forget which one) for around $220'ish. Therefor I can't sign up for there exchange program for $7 dollars a year, meaning if I wasn the tank filled all the way up there is a 1 week turn around as they ship it out. Yet, I'd just figure I could have it transfilled there which would take only a couple minutes, and I'm only paying for the gas so if it isn't filled all the way up I don't really care since they are only 4 miles away and the tank would be fairly easy to lug around. I do have a tractor supply company a hundred yards away from the welding supply place. ;D I thought they only sold a 40 cu tank, and Ihad no idea they filled or exhanged tanks.?