How do I calculate how many hours an oxy tank will last?

[wendbill]

Got a minor torch for xmas, so now looking at usual issue on whether to run it off an oxy concentrator or tanked oxygen.

I'm in Australia so second hand oxygen concentrators run to around $1200-$1400 usually.

Oxygen tanks run to 88.20 per refill + 10.50 per month hire fee for a 5' tank (8.9m cubed of oxy) or 56.20 per refill + 9.50 per month hire fee for a 3' tank or (4 m cubed of oxy).

So, what formula do I use to calculate how many hours I'd get out of those tanks, based on using (for instance) 8 psi. Feel free anyone to jump in with what range you generally run your minors at.

I'm vaguely figuring by the time you get all the regulators, flash back arrestors etc it will easier just to go straight to the concentrator, but I want to make the calcs based on "typical usage" eg how many hours I'm likely to be torching each week.

Thanks

[squid]

How much would it cost to have an oxycon shipped from the US to Oz? Is the electrical the same or can you use a converter? A used one can usually be had here for less than $300.

I know on the most common size of oxy tank here - about 4 or 5 feet tall - you can get about 10 hours on a minor.

[wendbill]

I think based on weight you'd be looking at about the same again for shipping based on the some of the comments I've seen on the Aussie forums. That would takes it up to about 800 australian I think.

We're on 220-240 volts here so you'd have to use a converter.

10 hours doesn't sound long at all.

[squid]

I know - it adds up REALLY fast if you go with an oxy tank!

[bhhco]

Got a minor torch for xmas, so now looking at usual issue on whether to run it off an oxy concentrator or tanked oxygen.

So, what formula do I use to calculate how many hours I'd get out of those tanks, based on using (for instance) 8 psi. Feel free anyone to jump in with what range you generally run your minors at.

Thanks

I had to convert m3 to cubic foot. The 8.9 m3 tank has 318 cubic foot of oxygen.

The Nortel minor is a strange torch. I'm not sure why they called it a minor other than it was the smallest one in their model line.

Anyway... the odd thing about the minor is it will run on very little fuel, or a lot of fuel. It will produce a very good flame at low fuel use... say 3 cf/hr. But it can also be roared up to about 11 cf/hr. Figure a 4:1 ratio for oxygen to fuel for a neutral flame. Thus, if you run the minor at 3 cf/hr, you would use about 12 cf/hr oxygen. At 11 cf/hr fuel, you would use 44 cf/hr oxygen.

Given a 318 cf tank, it could last 26 hours at 12 cf/hr; but at 44 cf/hr it would last only 7 hours.

I have never met anyone who runs the Minor at full potential... the flame is pretty unruly. I know Minor users (including me) who use it with one oxycon providing 5 lpm (10 CF/hr) oxygen at 5 psig. That would make the fuel usage about 2.5 cf/hr... and it produces a excellent soft glass bead making flame. So, if you are into smaller soft glass lampwork, I'd assume you could get as much as 30+ hours out of the 8.9 m3 oxygen tank.

Still... you can't beat a oxycon for convenience.

Me

[wendbill]

thanks

[kbinkster]

Jean at Nortel told me that 7 LPM (~15 cf/hr) is ideal for the Minor. Many people use less than that for soft glass bead making, like Bill just said.

BTW, Shipping from the US to Australia for an oxygen concentrator can range anywhere from just under $200US to close to $500US.

[wendbill]

I'm only using soft glass at the moment. Sticking to 104 Moretti and Ventrofond. Plan to keep it that way until I miraculously improve (ha ha).

[nklt0]

Hi Wendy,

I heard if you know some one in trades you can get a better refill price. I didn't know any so can't say for sure.

But I worked it out that 1 year of tank oxygen would pay for two oxy cons. So I saved for 1 year and went straight to oxy cons.

HTH

Cheers
Nancy

[jesgen]

Greetings
I am using a Minor Torch. I went with an oxygen tank (300) about the size of the big one you mentioned. I can get refiles for $9.50 each. I bought the tank ($280. I believe) so there is no monthly tank charge and I go to the welding gas place to exchange tanks.
During the summer I would work 2 maybe 3 hours 4 or 5 times a week. A tank of Oxygen lasted me just about 1 month. I am new at lampworking so I am not sure I have a correct flame or not.
I was told the gages I got had flash back arrestors in them. I got gages at $50. each and 20Ft or so hose for $25.
The welding place where I went gives glass blowers a discount because they know that glass blowers do not have much money. They have not been the most friendly to deal with though.
It is a hassel to exchange the oxygen tank. It is a 35 mile drive round trip, and the tanks are heavy.
If I had it to do over again, I think I would get an oxy concentrator. However, if I had gotten an oxy concentrator I might be thinking the oxygen tank might have been the way to go.
This has been my experience and thoughts. I hope you are happy with what ever you decide to do.
Jerry

[wendbill]

Ack, prices are so much cheaper over there.

When I spoke to Supagas, they said that everyone rents bottles over here. Which makes sense. The good part of it is, they pick up and deliver everything which is just as well since I can barely lift a full 9 kg bbq bottle.

They did say depending on useage the oxy cost could go down, though I'd expect my usuage to be similar to Jerry's.

I think I'm leaning towards the oxycon, though I have to get DH over the sticker shock first.

[Kym]

It is a hell of a shock when you look at prices in the US compared to what we pay for oxycons. If we import, that shipping cost converted to AU$, then you have to convert the power system to 220/240v, I don't know what you end up with but it starts to look expensive. Especially if you buy a brand on oxycon not represented in Aust. where do you go for warranty issues or servicing?
Having said that, I paid $3,200 for my oxycon and I am really happy with it. The service has been great. When I had a problem with a cracked pipe, the agent rang me Xmas morning and talked me through the problem finding and rushed a new part to me.
It was such a drag to be on tanks because I couldn't get it delivered and the tank only just fitted in my car. And it was heavy!
If I had been on delivered tanks, I may not have gone to the oxycon but in 2 1/2 years, my oxy will be free. Just to be free of lugging tanks around, makes it worthwhile for me as it was a 40min drive just to get to the gas retailer. Still it would have been nice to have got a less expensive experience.

[wendbill]

I ended up buying a three month old oxy concentrator off ebay Australia. I go pick it up on Sunday. It's still within warranty. It was 1500 which hurts, but when I tried some local suppliers they were quoting 1400 for a second hand one 12-15 years old with no warranty.

I was wondering if I'd be getting into more issues than it was worth by trying to import one.

[misfit]

Can you buy a oxycon from a medical supply house? Mine is a former medical one and I love it.

[wendbill]

Ex-medical supply is where I tried pricing second hand concentrators from initially.

They certainly seem to hold their value over here. I don't think there's any restrictions in Australia about old concentrators have to be. Someone on one of the Aussie forums suggested that there are regulations in the US that mean concentrators have to be retired from medical use after they have run a certain number of hours.

We live in a suburb where we have major hospitals and lots of medical reps in the area. I had beeen hoping that one of the medical reps we know could use his contacts to get me a cheap one (the kids go to school together), but unfortunately while that initially looked promising it came to naught.

[Kym]

That's great. I must say I looked and looked and couldn't find one second hand when I was in the market. You'll be cookin' now!

Kym

[wendbill]

I've spent a long time for looking for one. They don't come up that often. I only bought the minor torch at xmas though, so it would become less of a theoretical problem that needed solving to more of an immediate one.

Of course that brings with it additional issues. I was setting up the hothead at the kitchen table every time I torched but there's no way I'd contemplate using a dual fuel torch inside the house. DH has now cleared some space for me in his shed now so I can have a semi-permanent spot.

[nklt0]

Wendy,

Sounds like you got a bargain!

If its only 3 months old, it's would only have about 2300 hours on it. I was told that oxycon need to be re-build after 15000 hours or some thing like that.

Good luck!

Cheers
Nancy