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Author: Subject: LOX/ your favorite combustible
EBAYID_cheap_stuph
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[*] posted on 7-4-2005 at 13:30
LOX/ your favorite combustible


Has anybody here heard of liquid oxygen and CARBON?
what about Mg/LOX or Si/LOX, LOX?charcoal. Al/LOX
what is the enthalpy per mole?
liquid oxygen is available from liquid nitrogen plants. you let the N2 boil off until there is a blue liquid left.
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Joeychemist
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[*] posted on 7-4-2005 at 13:57


What you are referring to is a Sprengle class of liquid oxygen explosives where a porous bag or cartridge of fuel material is dipped in or filled with liquid oxygen. They are sensitive explosives and are made just before use because the explosives do not keep well and loose considerable power within an hour of mixing.

An air tight cartridge would allow these explosives to keep for longer ;)
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EBAYID_cheap_stuph
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[*] posted on 7-4-2005 at 14:37


So is this a possibility for the backyard pyro?
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chemoleo
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[*] posted on 7-4-2005 at 15:21


Comon then, you tell me.

You want to handle liquid oxygen? You need a pressurised O2 cylinder with a proper cryogenic hose. Neither are cheap, nor easily obtainable.
I'd like to find one single person here who's done that at home...




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EBAYID_cheap_stuph
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[*] posted on 7-4-2005 at 16:53


This is very easy for the pyro to do.
Liquid Oxygen comes from liquid air.

You see when you buy liquid nitrogen from a crygenics plant what they are selling you is liquid air.

it just happens to be that nitrogen has a lower boiling point than oxygen. so when you have a dewar or liquid air boiling off the n2 goes off first and then the oxygen. and the argon is last.

I worked with liquid nitrogen at school and i can tell you that it contains LOX.

What you would want to do is get a 20 liter dewar go to the nearest liquid nitrogen plant(LN2 cost about 1 dollar a literand they won't sell to you unless you have a dewar flask)
pour this LN2 in one of those big styrofoam tail gating coolers let it fizz and boil until the liquid is blue in color. You then dunk a bag of kingsford charcoal in the LOX and throw it in the camp fire.
You can also fill a pillow bag with aluminum powder or elemental silicon powder. more energy in the latter.
i might remind that the binding energy released in this reaction is probably greater than tnt.
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chemoleo
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[*] posted on 7-4-2005 at 17:16


Quote:
You see when you buy liquid nitrogen from a crygenics plant what they are selling you is liquid air.

No, nitrogen comes as nitrogen, that's it.
Liquid air is liquid air, with oxygen, nitrogen and noble gasses (those that liquify at that temp). Liquid air is an oxygen source and thus considered a fire hazard, liquid N2 isn't. Liquid nitrogen is made by fractional distillation, air isn't.
What do you think, experiments all over the world are done with liquid air rather than N2? That wouldn't be too good for gazillions of O2-sensitive reactions :o

We have dewars full of nitrogen. In a lab. No O2.

I don't know about the ease of obtaining liquid air though, how available it is. Diving supplies I guess, if they use liquid air rather than just the pressurised version.
I don't think extracting the O2 from it is easy, either. Check this.
Quote:
Oxygen may be obtained from the atmosphere by the liquefaction and fractional distillation of air. Liquid air is a mixture of liquid nitrogen, boiling point -196 degC, and liquid oxygen, boiling point -183 degC. The nitrogen is more volatile (i.e. it has a lower boiling point) and boils off first during evaporation. Because some oxygen evaporates with the nitrogen, separation of the two gases is brought about by fractionation (i.e. by letting the evolved gas mixture bubble through liquid air rich in oxygen in a tall rectifying column). The oxygen in the gas mixture condenses and almost pure nitrogen gas leaves the top of the column, leaving almost pure liquid oxygen which is then evaporated to give oxygen gas. The oxygen gas is distributed as a compressed gas in high pressure cylinders.

Good luck with your OTC explosive!




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BromicAcid
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[*] posted on 7-4-2005 at 20:34


I've read in a few pages that the vacuum trap in a delwar containing liquid nitrogen should not be open to the atmosphere because the oxygen from the atmosphere will condense into it and rise to the level with the top of the liquid nitrogen if left for a few hours. Less oxygen will condense directly into liquid nitrogen because as it evaporates the N2 rises up and prevents the air from circulating down to condense out the oxygen, Might prove to be a feasible way for the preparation of small quantities of liquid oxygen.



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EBAYID_cheap_stuph
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[*] posted on 7-4-2005 at 20:58


that a great idea. bubble some air throught LN2 does anybody know where you can get some elemental silicon cheap somewhere i read that si/LOX has 7 times the energy of tnt.
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[*] posted on 8-4-2005 at 02:30


This is very possible, but you’re not thinking of your average run-of-the-mill Si. What you want is a specially prepared type with a structure made of small crystals (~7 atoms across, IIRC), which is prepared with HF and other nasty chemicals. There was a thread on RS on this and I think we had a similar one.
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[*] posted on 3-6-2005 at 00:47


Now, I swear I saw a vid of a high school class liquefying O2 from gas cylinders using a worm condenser wrapped around a liq Nit cold finger.



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[*] posted on 3-6-2005 at 04:19


I do believe I recall hearing about this. Firstly the LOX embedded porous silicon. The silicon was lab-made if I recall correctly, and it was rather powerful.

I have also seen experiments in getting the LOX, but its not as simple as EbayID would suppose. The thread is HERE

With the first post explaining it pretty good.

Quote:

The boiling point of oxygen is about -184 degrees, and at -184 it begins to condense into a pale blue liquid.

The materials you will need is an oxygen tank with the approiate valves, 2 metal jars, 2 clamps (one big enough for a jar, and one for a test tube), 4 feet of 1/4 inch copper tubing, a good epoxy, a test tube (size depends on how much you want to make) and enough liquid nitrogen to fill one of your jars three times over. It also helps to have a dowel to wrap your tubing around.

Take your tubing and wrap it around the dowel in a tight coil, leaving 5 inches on the top and bottom. cut to size.

drill a 1/4 inch hole in the bottom of one of your jars. slide the coil in, and secure and seal with epoxy. Attach this jar 8 inches off yiour working surface with a clamp.

beneath it, place the other jar on the work surface, and position the clamped test tube directly under the tubing.

begin to slowly fill the top jar with liquid nitrogen, adding it very slowly, and letting it boil off until the jar and pipe are -194 degrees. when it stops boiling, fill it to the top, and repeat the process in the bottom jar.

attach your oxygen tank to the top of the coil, and turn it on very low. the flow should be extremely low.

the oxygen will condense in the coil, and eventually your test tube will fill with liquid oxygen.

i don't know much of what you would do with it, most things burn in it explosivly, which is a good thing.

little fun note: hold two electromagnets about a quarter inch apart, on, and pour small amounts of the liquid o2 between them, adn notice how the oxygen is paramagnetic, and sticks. i had an idea about a fuel distribution system for a "potato gun" type gun, but it would be to expensive and unruly.



On the offhand, Come on Chemoleo, Don't YOU fractionally distill the liquid oxygen like everyday?? Completely easy and backyard appropriate, so is detonating something with the reported force of 7times the power of tnt. /sarcasm:D:D
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[*] posted on 4-6-2005 at 20:23
LOX


I don't know of any company that sells "liquid air", but one company in my area, PraxAir,
sells LOX to hospitals. I don't know if they will sell to individuals.




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[*] posted on 4-6-2005 at 20:34


I do not remember where I saw this method but it was a very simple method to make small ammounts of liquid oxygen. A balloon is filled with oxygen gas, and the mouth is placed, open, over the lip of a test tube. The test tube is then placed in liquid nitrogen and the balloon will slowly deflate leaving liquid oxygen in the test tube.

[Edited on 5-6-2005 by rogue chemist]




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