Thermal Lance

[Lentamentalisk]

Alright, I know its not exactly a hybrid, but where else would I post this?

I was just reading an article in PopSci about a thermal lance (sorry its not online, just in the magazine at the moment).
Now just what is a thermal lance, you might ask.
Well to quote wikipedia (http://en.wikipedia.org/wiki/Thermal_lance) for those of you too lazy to click the link:

A thermal lance or thermic lance or burning bar is a tool which burns iron in an oxygen rich environment (n.b., not thermite) to create very high temperatures for cutting. It consists of a long iron tube packed with iron rods, which are sometimes mixed with aluminum or magnesium rods which increase the heat output. One end of the tube is placed in a holder and oxygen is fed through the tube.

I was wondering if any of you had any experience with thermal lances, or have any clue what quantity of oxygen they would use up.
It seems like possibly the most awesome thing ever, what with the rock-melting capabilities and all... Its like a thermite torch, minus the hard to get chemicals.



edit: youtube video of melting a concrete block with a thermal lance
[youtube][/youtube]

[chartreusesnot]

... did you chopshop a fire hydrant...?
edit, oops, thought you had already made it.

[Lentamentalisk]

more amazing footage, this time of cutting through some huge barrel/pipe thing
[youtube][/youtube]

The other question would be where the combustion is actually taking place. From the videos, it looks like it is all happening at the end of the pipe, so that you can hold on to the rest of it, and that it will just slowly shorten itself. Then there is the question of how do you keep all of the iron rods inside the pipe, and keep them from just falling out.

[john bunsenburner]

Well the iron rod is packed so tigly with the rods that they do nto fallout but that there is gaps for the O2. And yes the pipe its self is burning so that it will need to be replaced after a certain time.
The mythbusters used this to try to hack into a safe.(i think so)

[Ragnarok]

Its like a thermite torch, minus the hard to get chemicals.

What? Iron (III) oxide - a.k.a. "rust" - and aluminium, hard to get?

Okay, you might want something a bit fancier for actually lighting the mix, but for thermite itself, you could hardly ask for the ingredients to be easier to get your hands on.

[rp181]

dont get the thread locked =)

This is very similar to a hybrid rocket engine, but uses a metal fuel.

[Technician1002]

more amazing footage, this time of cutting through some huge barrel/pipe thing
[youtube][/youtube]

The other question would be where the combustion is actually taking place. From the videos, it looks like it is all happening at the end of the pipe, so that you can hold on to the rest of it, and that it will just slowly shorten itself. Then there is the question of how do you keep all of the iron rods inside the pipe, and keep them from just falling out.

The combustion is taking place at the end of the rod. View the video in the original post where they light it with a cutting torch. It uses oxygen from a tank. It creates a very hot gas jet at the tip like a plasma cutter except the heat comes from combustion instead of an electric arc. They work very much like a plasma cutter.

[Lentamentalisk]

well Rag, yes, large quantities of rust, and large quantities of aluminum (not aluminum oxide) are hard to get. Well, rust can be bought at a paint store I heard, but getting real aluminum powder is quite hard. Much harder than packing a pipe with iron rods, and hooking it up to the oxygen tanks that my neighbor offered me.
I will see about getting those tanks and borrowing a regulator...

[rp181]

again with the thread locking...
This is really not a good idea unless you have a real use and a nice concrete place to use it at.

[Lentamentalisk]

My back yard has a ~15'x15' concrete slab patio... Plus, I live just a mile from the ocean, and there is an ex-dump right by the bay, where I do all of my launching and dangerous stuff.
I know how to be safe with fire... Full welding gear and all that, of course.

[Ragnarok]

but getting real aluminum powder is quite hard.

It depends on how much you want, but it's not impossible to get in moderate quantities. For example when I made thermite, I just shoved a large roll of aluminium foil in a old blender. It wasn't quite a powder, but it was certainly close enough for the reaction to work.

Is there any reason you can't do the same?

[Lentamentalisk]

Valid point. I had heard about that method, but never had it confirmed.
Still, this is like a thermite reaction, but in a much more controllable manner. You can throttle it, turn it on and off as you please, and direct it wherever. I know that each has its ups and downs for different aplications, (thermite doesn't require a whole oxy tank and long pipe) but still, you have to admit this is pretty awesome.

[starman]

These are used a lot in ship salvage yards for instance, where lots of very thick steel must be cut to dismantle a typical ship. BTW, I'm sure you are aware but most of the steel in a ship is commonly melted down a reused.

[jimmy101]

The oxy torch really can't be compared with the energy in Thermite type explosives. Thermite is actually a fairly mild explosive, especially compared to most modern gun powders. A pound of Thermite contains much less energy than a pound of even a very crude black powder mixture.

The thing that is unique about Thermite, and the reason it is used at all given how intrinsically wimpy it is, is that it doesn't generate any gaseous byproducts. The "combustion" products are all solids (or liquids if it is still hot enough). The absence of any gaseous products means the energy released stays concentrated in one spot. For most explosives, the expanding gases tend to quickly dissipate a large amount of the explosive's energy. With Thermite you release relatively little energy but the energy that is released stays in one small area. That is why Thermite is sometimes used to melt metal. It isn't that Thermite is all that energetic, indeed it isn't, it just concentrates the energy released into a much smaller volume than most explosives.

The energy released by Iron + Oxygen also tends to stay concentrated in a relatively small area. The combustion product (FeO and Fe2O3) are liquids (if hot enough) or solids. Only at the very hottest part of the flame would the iron oxide be anywhere near the gaseous state. Since little gas is generated the heat tends to concentrate much better than it would with propane + Oxy or even Acetylene + Oxy, both of which produce gaseous combustion products.

[john bunsenburner]

Hey as this is getting a bit of topic;

You do know that for home use thermite can be made of not only Fe2O3 and aluminium, but of many other metal oxides, these include titanium oxide. The result of using titanium oxide in thermite(titanium oxide, along with very fine aluminium can be purchased in paint stores) are nice little blobs of titanium, which look cool and might have some sort of use for you guys.

Question at the mods: As thermite is NOT an explosive according to spudfile rules disscussing it should be ok, am I right about this(especially because thermite is LEGAL in the US)