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Oxygen.
bigandy - 21/8/10 at 07:34 AM

Morning all.

Does anyone know a good source of those little Oxygen tanks that you used to be able to buy in places like B&Q. They were the ones that were to be used with a propane tank of a similar size, in conjunction with a brazing torch. I think they had cylinders of Mapp gass too?

I'm after one for use in another project

Andy


NigeEss - 21/8/10 at 08:25 AM

There's a few on ebay, search for oxygen cylinder or bottle.


britishtrident - 21/8/10 at 08:45 AM

As far as I known it is no longer available, I tried to get a cylinder from Halfords a few years back but the cylinders all had the wrong handed thread for the oxygen adaptor.

For awhile a web shop called "The House of Hasting" were selling replacement kits of a new adaptor/regulator and a disposable bottle but they don't seem to be around anymore.


Daddylonglegs - 21/8/10 at 09:58 AM

I have one of those mini brazing kits from Halfords, and as you say, you cannot get the oxygen anymore even though they still sell the acetylene

I did manage to get an adaptor to take another oxygen bottle which I sourced elsewhere though and it works fine.

I'll try and find the details as it's a while since I bought it.

JB


Peteff - 21/8/10 at 02:34 PM

Welduk does a small oxygen cylinder here for £20.


Daddylonglegs - 24/8/10 at 08:57 AM

Nice one Pete

That's the one I was looking for, been so long since I ordered mine.

I got the adaptor too as the bottle will not fit directly onto the Bernzomatic head.

Works a treat


Peteff - 24/8/10 at 12:53 PM

I like to give him a mention, he's only 10 miles from me and I've nipped up for bits in the past but not been for ages.


bigandy - 24/8/10 at 01:12 PM

Ah, brilliant, thanks for that link Pete.

The regulator they sell will suit me too, as it has a hose tail aoutput. In case you were wondering, all this is for igniting a small Hybrid rocket engine (40N.s total impulse).

Cheers
Andy


paulf - 26/8/10 at 11:20 AM

If its a hybrid then you must be using nitrous oxide for the oxidizer and if I remember correctly the gas contained in the small oxygen bottles is nitrous oxide rather than pure oxygen .
Isn't the normal method of lighting these to use a small solid fuel Estes type rocket motor pushed into the tail pipe?
Paul

quote:
Originally posted by bigandy
Ah, brilliant, thanks for that link Pete.

The regulator they sell will suit me too, as it has a hose tail aoutput. In case you were wondering, all this is for igniting a small Hybrid rocket engine (40N.s total impulse).

Cheers
Andy


bigandy - 26/8/10 at 12:22 PM

That;s right, the Oxidiser for the main engine is Nitrous Oxide (and the fuel grain is currently a blend of wax/hotglue and iron filings to give it a bit of sparkle, because I am a bit of atart like that ). Igniting the motors with chunks of Estes black powder motors is bloomin expensive though, three Estes motors are not far off a tenner now.

So, I want to use gaseous oxygen to create an oxygen rich environment in the motor combusiton chamber, then use a high voltage spark to ignite the fuel grain. Start the nitrous going, and away the motor goes My calculations show that a disposable oxygen cylinder (400ml size) will contain about 120 litres of oxygen, so I reckon that will give me at least 100 ignitions, far cheaper than Estes motors

The idea is that once the little motor is proven, I can scale it up a little too

Andy


paulf - 27/8/10 at 07:55 AM

Yes thats how i understood it to be working, what I was trying to say was I think the Oxygen in the disposable bottles is actually nitrous oxide or at least it was in some of the smaller kits you could once buy.If that is the case then maybe you could just bleed of some nitrous at low pressure and use that although it may not work if theres no heat to decompose it .
It sounds like an interesting project and is something ive meant to experiment with myself but never got around to.
Paul

quote:
Originally posted by bigandy
That;s right, the Oxidiser for the main engine is Nitrous Oxide (and the fuel grain is currently a blend of wax/hotglue and iron filings to give it a bit of sparkle, because I am a bit of atart like that ). Igniting the motors with chunks of Estes black powder motors is bloomin expensive though, three Estes motors are not far off a tenner now.

So, I want to use gaseous oxygen to create an oxygen rich environment in the motor combusiton chamber, then use a high voltage spark to ignite the fuel grain. Start the nitrous going, and away the motor goes My calculations show that a disposable oxygen cylinder (400ml size) will contain about 120 litres of oxygen, so I reckon that will give me at least 100 ignitions, far cheaper than Estes motors

The idea is that once the little motor is proven, I can scale it up a little too

Andy