Another oxycon question for those with one.
 

So after just starting lampworking and finding out first hand how expensive re-filling oxy is going to turn out I am now looking at oxycons. I have found portable oxycons that are considerably cheaper than standard ones and I want to know if these are suitable? an example is this one "1-7L/min Intelligent Portable Home Oxygen Concentrator Generator Machine 220V AU". I also have the option to purchase a 5L devilbliss concentrator for a bit more so same question again, would this be suitable if the above portable ones are not?

What specs am I looking for to run a nortel mega minor?

I'm sure the portable isn't enough and I doubt the 5 will be enough to run your torch really well. Oxygen is important for a hot flame and clean bright colors. It also depends if you're using boro or soft glass. You need much more oxygen for boro. Basically the more oxygen available to you the better.

Are you in the UK/Europe? I assume you are since you mention 220V.

I don't think the small oxys you see on eBay are up to the job.

The Devilbiss ones, of the type that Tuffnells sell (reconditioned medical units) https://tuffnellglass.com/contents/e...centrator.html are fine for a standard Nortel Minor (I started that way), and would be enough to get you started on a Mega Minor, in soft glass.

You might want a second one to link to it, or to replace it with a 10lpm one, as you get used to the torch and want to do more with it. And if you are starting with boro you might consider 10lpm right away.

Hi Moria, I'm in Australia =) thank you two for the helpful advice, really helps me make an informative decision and for that I am forever greatful!

Oh and also that 4% to 7% drop in purity from tanked to oxygen concentrator will be noticeable on a bigger flame so hunt for a 10L unit if you can find one or a couple of 5L together {which equals just about 8.5L usually}.

That is if you are going to be doing the bigger flame.

I have GTT Cricket on household natural gas ( a lot less burning umph than propane ) and a 10L I got lucky to find cheap here in 'Merica.

But I only do hobby stuff and nothing of any size so a big flame isn't needed to satisfy my molten glass addiction.

The amount of oxygen needed for correct flame chemistry is dependent on your torch selection plus a number of other factors. What torch are you using?

Portable units IMO are not suitable for lampworking. They are not built for 24 x 7 use. Only consider a unit that is like the one suggested by Moira. Again, depending on your torch and settings more than one 5 LPM at 5 PSI unit may be required. When combining units it is important that all units have the same static output pressure. i.e. two or more 5 PSI units work well together. While one 5 PSI plus one 9 PSI not so well.

Prices for used 5 LPM at 5 PSI floor units in the USA are in the range of $225 USD. Sometimes less costly depending on source. Also keep in mind the number of hours in use. A low number is much better than high a number. i.e. 5000 vs 25,000

Have you compared using the Cricket with propane at 5 PSI and natural gas also at 5 PSI?

Have also used both on a Scorpion which has the Cricket as the center fire. In my findings the torch was suffering from lack of fuel. Once the natural gas pressure was increased to 5 PSI the torch performed as expected.

Let me know your findings.

Sorry, LRJ, I forgot that you use higher voltage in the Antipodes too! :-)

Is there much of a market for used or reconditioned oxycons in Aus? That will save you quite a bit of cash.
Also - consider looking at veterinary suppliers. The spec is less fussy than for human medicine, so there are bargains to be had, perfectly good enough for torching!

About the Natural Gas versus Propane thing; I read it in a post or a link to a chemical study.

It said that the btu content of propane (this was some 10 years ago I think, they have changed some of the chemistry in commercial propane a little since then) was something on the order of 5 times more than the btu content of house hold natural gas.

These numbers come from the chemicals themselves and the pressures and volumes of fuel wont change the btu value becasue it is measured at some lab standard for each.

Increasing volume and or pressures will change the heat flame on your torch but the oxygen to fuel chemistry btu values will hold for given quantities.

I agree that my little Cricket would kick a lot more butt if I had it on NG at some 10 or 20 times the flow rate.

I do have the hook ups to put propane on my cricket and it will suck all the oxygen my 10L Devilbiss can put out.

But I am a tinkerer at best and since I don't want to haul a propane tank in and out in a Minnesota winter I hooked it up to the back of my kitchen stove.

My Navy safety training won't allow me to comfortably leave a propane tank inside the house if I am not actively using it so I found a way to play with molten glass without a lot of hassle.

Now, if my next house ( we are moving in the next few years) is plumbed for propane as the heat source, like a lot of the rural houses here in farm country are, then me and my cricket have plans for some light boro work and maybe even some paper weights.

would a 5l concentrator work for my bethleham alpha?

Skars, 5lpm will work with Alpha. Most probably you'll need to run it at 4.5 lpm because purity of oxygen goes down at max flow, but it will work. Gas pressure is to be adjusted respectively. I have a 6lpm bitmos (from construction point of view it is a 5 lpm kroeber but with slightly bigger zeolite sieve beds) and it works really well at 5 lpm. It seems to me Alpha is able to use "modest" resources very efficiently. 5lpm works for minor/mega minor as well but Alpha is a bit hotter and faster.