Quick And Easy Thermic Lance Is Hot Enough To Melt Rocks

October 12, 2015 by Dan Maloney 42 Comments

Heat can be a hacker’s best friend. A little heat can help release a stubborn nut cleanly, and a lot of heat can melt a rusty bolt clean off. An oxy-acetylene torch is handy for these applications, but if you need a more portable setup, and you want enough heat to melt rocks, you might want to look into this field-expedient thermic lance.

Thermic lances have been around a long time in the demolition industry, where cutting steel quickly is a common chore. Commercial thermic lances are just a bundle of steel fuel rods which are set on fire while oxygen is blown down a consumable outer tube. The resulting flame can reach up to 4500°C with impressive results. In need of a similarly destructive device, [NightHawkInLight] came up with a super-simple lance – a small disposable tank of oxygen and regulator, a length of Tygon tubing, and a piece of 5/8″ steel brake line. No need for fuel rods in this design; the brake line provides both fuel and oxygen containment. As you can see in the video below, lighting the little lance without the usual oxy-acetylene torch is no problem – a “wick” of twisted steel wool is all that’s needed to get the torch going. The results are pretty impressive on both steel and rock.

You say you’re fresh out of brake line and still need some “don’t try this at home” action? No problem at all – just hit up the pantry for the materials needed for this tinfoil and spaghetti thermic lance.

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Milling Curves Into Mirrors And Glass

August 26, 2011 by Mike Szczys 18 Comments

[Ben Krasnow] is working on a project that uses an extremely expensive specialty mirror. He needed to cut curves into it, taking care not to chip or shatter the material. He’s found a reliable way of doing this with a CNC mill and is sharing his methods.

The material he’s working with is a cold mirror; it reflects visible light while allowing infrared light to pass through. He had to custom order it, breakage is not acceptable. [Ben] explains that the biggest risk when milling glass is the clamping method used. He built his own jig and uses shims, rather than clamps, to secure the material along the X and Y axes. It is held down on the Z axis using a bar of acrylic spanning from one side to the other with rubber feet on the bottom.

A diamond burr cutter does the work, spinning at 3000 RPM. [Ben] recommends moving the head at the slowest rate possible in order to give the cutter time to do its work. And of course the material needs to be kept cool by pumping cutting fluid across it. As he shows in the video after the break, what you get is a piece of glass that comes out with clean and smooth edges.

In case we’ve sparked your curiosity, this mirror will be used during an MRI scan. The patient looks at a monitor reflected in the mirror at a 45 degree angle. At the same time, an infrared camera records the patient from the other side of the mirror to monitor where they are looking.

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