Welding Tips and Tricks

I got a gas rig months ago, but I haven't used it because I have not found a good deal on bottles (that I didn't let get away from me). I was hoping to get an O2 bottle in the 125 cu. ft. range, figuring that was the biggest bottle I could sling into the car by myself. I wanted an acetylene bottle in the area of 75 cu. ft.

Now I see some guy selling what looks like two 80 cu. ft. O2 tanks and two acetylene tanks which are probably smaller than 75 cu. ft.

I'm wondering if I should jump on this deal. It occurred to me that two smaller tanks might be better than one big one, because when a tank poops out, I'll be able to switch over to a new one and use it immediately instead of waiting until I can get a swap. Good idea, or is there some hitch I have not foreseen?

This is what I do with my barbecue tanks.

Chips O'Toole wrote:I got a gas rig months ago, but I haven't used it because I have not found a good deal on bottles (that I didn't let get away from me). I was hoping to get an O2 bottle in the 125 cu. ft. range, figuring that was the biggest bottle I could sling into the car by myself. I wanted an acetylene bottle in the area of 75 cu. ft.

Now I see some guy selling what looks like two 80 cu. ft. O2 tanks and two acetylene tanks which are probably smaller than 75 cu. ft.

I'm wondering if I should jump on this deal. It occurred to me that two smaller tanks might be better than one big one, because when a tank poops out, I'll be able to switch over to a new one and use it immediately instead of waiting until I can get a swap. Good idea, or is there some hitch I have not foreseen?

This is what I do with my barbecue tanks.

It all depends on the anticipated usage and the actual size. If both smaller acetylene tanks add up to more than 75 ft³, then you might be ahead, depending on price. I can usually score used acetylene tanks on craigslist for around $100 for a 75 ft³'er, so you may want to look around. The huge disadvantage of smaller tanks is the limited withdrawal rate. That's why I have three 75 ft³ tanks manifold'ed together. Don't use it much, but if I need it, it's there.

I forgot all about the withdrawal rate issue.

Truthfully, I expect to end up using propane nearly all the time, but I do want to find out what acetylene is like.

If I'm not mistaken, the size smaller than 75 ft³ is 40 ft³. So with two of those connected together, you can only safely draw about 8-11 CFH, give or take, depending on the old or the new rule. That's plenty for cutting up to ≈ 1", and welding up to about ≈ ¼". For heating, max rosebud is the smallest one, #2 MFA-1 (for small Victory style), or #4 MFA at it's lowest settings (6psi acetylene for 6 CFH withdrawal rate).

Then, you have to manifold the two tanks together, lol. I purchased a kit from OA Doctor to tie my three tanks together, and it's quite involved to scour for all those parts separately. It was like $200 just for the manifold kit.

The guy who has the tanks does not know much about welding, so it's hard to get info from him. It sounds like the O2 tanks are 125 cf. He thinks the acetylene tanks are 4 feet high, so I am guessing 75 cf.

The manifold idea sounds like a good solution. I could have the convenience of four tanks with the option of more flow if I need it.

Where I live I can't buy big tanks. For terrorist reasons (they claim) big tanks can only be rented. 50 years now I have rented big tanks. For gasses I use only a bit of I own small tanks.

It costs a metric $hit ton more to refill small tanks, than big. If you use much gas rent, if you use a little bit, buy.

Withdrawal rate is not a problem for most home users. You don't use a big rosebud for hours at a time.

Chips O'Toole wrote:The guy who has the tanks does not know much about welding, so it's hard to get info from him. It sounds like the O2 tanks are 125 cf. He thinks the acetylene tanks are 4 feet high, so I am guessing 75 cf.

The manifold idea sounds like a good solution. I could have the convenience of four tanks with the option of more flow if I need it.

Get info from him, or better yet pictures. The 75 ft³'ers are more like 30" tall with the cap. 4-footers are 100-140 ft³, so if you can snag them for a good price, get them! So long as your LWS will accept them.




This is where I got my manifold: https://regulatortorchrepair.com/ . Just use the contact form and Jim will respond right away. Or call of course.

It's basically two heavy duty SS-braided hoses, and two T's, with check-valves at the appropriate locations. $237 was my total back in 2016. For two tanks, you only need one T, and two hoses, so that should run around $180 if the pricing has not changed much.

Bill Beauregard wrote:Where I live I can't buy big tanks. For terrorist reasons (they claim) big tanks can only be rented. 50 years now I have rented big tanks. For gasses I use only a bit of I own small tanks.

It costs a metric $hit ton more to refill small tanks, than big. If you use much gas rent, if you use a little bit, buy.

Withdrawal rate is not a problem for most home users. You don't use a big rosebud for hours at a time.

Same here. My lws only rents big tanks. The biggest i can buy is the 60f^3
Not sure but the acetylene might be 40f^3.
I think my argon are 60


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Simclardy wrote:

Bill Beauregard wrote:Where I live I can't buy big tanks. For terrorist reasons (they claim) big tanks can only be rented. 50 years now I have rented big tanks. For gasses I use only a bit of I own small tanks.

It costs a metric $hit ton more to refill small tanks, than big. If you use much gas rent, if you use a little bit, buy.

Withdrawal rate is not a problem for most home users. You don't use a big rosebud for hours at a time.

Same here. My lws only rents big tanks. The biggest i can buy is the 60f^3
Not sure but the acetylene might be 40f^3.
I think my argon are 60


Sent from my SM-G930V using Tapatalk

To me, it sounds like the "terrorists" are the LWS that are holding you up with an extortion scheme...
I'm in the same country, but can easily get larger acetylene tanks filled, and have (waddled) out with a 250cf argon owner bottle fill as well.

That probably doesn't help much, but...

As to the tanks, I will say that moving smaller tanks is a LOT easier than lugging around one of the big ones.
I definitely prefer moving an 80cf or even a 125cf, as opposed to moving my big 250cf bottle. That thing is HEAVY!

Simclardy wrote:

Bill Beauregard wrote:Where I live I can't buy big tanks. For terrorist reasons (they claim) big tanks can only be rented. 50 years now I have rented big tanks. For gasses I use only a bit of I own small tanks.

It costs a metric $hit ton more to refill small tanks, than big. If you use much gas rent, if you use a little bit, buy.

Withdrawal rate is not a problem for most home users. You don't use a big rosebud for hours at a time.

Same here. My lws only rents big tanks. The biggest i can buy is the 60f^3
Not sure but the acetylene might be 40f^3.
I think my argon are 60


Sent from my SM-G930V using Tapatalk

To me, it sounds like the "terrorists" are the LWS that are holding you up with an extortion scheme...
I'm in the same country, but can easily get larger acetylene tanks filled, and have (waddled) out with a 250cf argon owner bottle fill as well.

That probably doesn't help much, but...

As to the tanks, I will say that moving smaller tanks is a LOT easier than lugging around one of the big ones.
I definitely prefer moving an 80cf or even a 125cf, as opposed to moving my big 250cf bottle. That thing is HEAVY!
The smaller bottles I often toss up on my shoulder and walk out of the LWS. The 250 though? Carefully roll that one along, and then plot how to get it into the vehicle with the least amount of pulled muscles!